UTILISATION OF CASSAVA PEELS FERMENTED WITH OIL PALM SLURRY AS FEED IN THE DIET OF WEST AFRICAN DWARF SHEEP BY Oluwanike ABIOLA-OLAGUNJU B Sc. Honours (Animal Science), University of Ibadan M Sc (Animal Science), University of Ibadan A Thesis in the Department of Animal Science Submitted to the Faculty of Agriculture and Forestry, in partial fulfillment of the requirements for the Degree of DOCTOR OF PHILOSOPHY of the UNIVERSITY OF IBADAN 1 ABSTRACT Shortage of pasture during dry season militates against production of grazing animals in Nigeria. Cassava Peels (CaP) and Oil Palm Slurry (OPS) are agro-industrial by- products obtainable throughout the year. Utilization of CaP as feed can be enhanced through fermentation with OPS. However, there is dearth of information on the use of fermented CaP as feedstuff for West African Dwarf (WAD) sheep. The use of CaP fermented with OPS as feed for WAD sheep was therefore investigated. Samples of OPS randomly obtained from Ikoyi, Badeku, Mamu and Benin in South Western Nigeria and CaP were analysed for their dry matter (DM), and proximate (Crude Protein (CP), Crude Fibre (CF), Ether Extract (EE) and fibre (Neutral Detergent Fibre (NDF), Acid Detergent Fibre (ADF), Acid Detergent Lignin (ADL), cellulose and hemicelluloses) compositions. One litre of OPS was mixed with 1Kg, 2Kg, 3Kg, 4Kg, 5Kg (Diets A – E) of CaP, respectively while 6Kg (Diet F) of CaP only served as the control. The diets were fermented for five days in air-tight cellophane bags, sun-cured and analysed for proximate and fibre contents. Eighteen WAD sheep were allocated to the six treatments in triplicate using completely randomised design and each group was fed ad libitum for 14days. Samples of rumen liquor were collected for in vitro Gas Production (IVGP) to predict the Potential Degradability (PD), Insoluble Degradable Fraction (IDF), Rate of Gas Production (RGP), Organic Matter Digestibility (OMD), Metabolisable Energy (ME), Short Chain Fatty Acids (SCFA), pH and ammonia-N (NH3-N) for 96 hours at 3 hours interval. The pre prandia and 3, 6 and 9 hours post prandia samples of rumen liquor were collected for microbial count in a 4x6 factorial arrangement. Data were analysed using ANOVA (p=0.05) The OPS from Mamu had the highest DM (43.2%), CP (8.2%), EE (6.5%) and CF (8.0%). The CF and EE obtained for the fermented diets decreased with CaP inclusion (4.7 to 3.7% and 10.0 to 7.5%) in diets A and E respectively. Similar decreasing values for ADF (40.2-30.2), NDF (59.0-48.0), ADL (20.2-18.0), Cellulose (20.7-12.3) and hemicellulose (22.0-18.0) contents were obtained due to fermentation. The IDF value was significant for diets A (39.3) and F (47.0) at 24hours and for other treatments at 60 hours. The PD estimates varied significantly from 73.5 in diet E to 98.5 in diet B at 60 hours. The RGP increased with time at all observed hours. The pH value (6.21) was significant at 60 hours. Estimated ME, OMD and SCFA were highest for diet B with values of 11.4, 83.0 and 1.6 respectively. The LogCFU of all treatments pre-prandial was between 5.0 and 5.3. Apparent interaction between 0-9 hours for pH and NH3-N were not significant. The combination of three parts of cassava peels fermented with one part of oil palm slurry from Mamu for five days and sun-cured was best as supplement for grazing West African dwarf sheep. KEY WORDS: West African dwarf sheep, Oil palm slurry, Cassava peels, In vitro fermentation. Word count: 490 2 ACKNOWLEDGEMENT To God is the glory for He said „though it may tarry but it shall surely come to pass‟. These were one of such scriptures which kept me moving at troubled times. I am grateful because GOD is ever faithful. My deep and sincere appreciation goes to my caring and ever listening daddy and supervisor Professor A.O Akinsoyinu who was always willing to assist and give hope to almost every hopeless situation. I also thank my Co-supervisor, Dr O.J Babayemi who contributed this final destination. Money, they say, is the oil of evangelism. I appreciate my caring husband, the one before my heart, who gave me breath when I could not breath. A man who contributed immensely to my new status. My better half, Mr. Isiaka Abiola Olagunju who gave a selfless financial backing throughout the course of this work. He also at a time held the home front when I had to be unavoidably away for days in the laboratory. I appreciate my lovely damsels, Oluwadamilola, Oluwafunmibi, Omotawurayo, Oluwapamilerin (pampam) and my son Tanitoluwa (ten boys). I delivered the last two during this programme. All the kids were always looking through my books and would ever ask „Mummie when will you finish this school‟? Children thank you for your patience and perseverance. My unreserved gratitude goes to the immediate past Head of Department (HOD) of Animal Science, Professor E.A. Iyayi, whose constructive criticisms at my second seminar added colour to my field works. My profound appreciation is also due to the incubent HOD Professor A.D Ologhobo and former HOD Professor O.G. Longe, for their invaluable contributions. I appreciate Dr. A.E. Salako who always gave subtle but encouraging spiritual words that kept me moving at cross roads. I say may the Lord fill you with more wisdom. Dr Femi Adebiyi (femo) was everywhere for me, in the laboratory, during seminars, field work and so on. May God be with you in every area of your life. My sincere gratitude goes to the following academic staff of the Department of Animal Science, Drs. Tolu Ososanya, Bisi Agboola , Lara Akinyemi, A. B. Omojola (granpa) O. A. Abu, O.A. Sokunbi and our P.G coordinator, Gbenga Ogunwole. A very big thank you goes to the following people who gave effortless support during the laboratory work that lasted days and nights; Alfa Taofeek, Ayo Odufoye (AY butter field BREAD), Bose (sherpard girl), Wole (invitro baba), Muhammed Yinusa, Mrs Tope Binuomote, Mrs Toyin Ajayi, Mrs E. O. Joel, Helen Ariri, Mr O. M. Omotosho, Mr A. A. Fabowale, Mr Ebadan Williams (Sir Willy) of the Department of Agronomy university of Ibadan. Those who took my work as a family project and were there spiritually, emotionally and contributed immensely to the success of this write up. They are Mr and Dr Joke 3 Mako, Dr V. A. Akinwande ( Dr Baba), Pastor Mike Adeniran (P mike), Messers Yomi Akinfemi, Soji Adeyosoye (soja man), Femi Alaba (wiper), Mr and Mrs Akinloye. GOD bless you all. The people at the administrative desk were always supportive when keys for overnight work were to be obtained and for prompt attention to official matters, I appreciate the efforts of Mr Bisi and Alhaja Ishola When the dear devil came with its antics, and my laptop crashed during the making of this write-up, my dear friend Deji Degun willingly handed his laptop over to me, not minding the inconveniences. May the Lord honor you. I cannot end this long list without appreciating the members of my family, who gave me moral, support love and care. They also believed in me. Dr and Dr Sola Ogunsuyi, Miss Tolu Makinde, Alhaji Bayo Olagunju, Mr and Mrs Soji Ogunjobi, Mr and Mrs Sola Olasode, Mr Dotun Oyenekan, Dr Adejuwon. I am forever indepted in thanks to my parents, (HRM) Oba Festus Oluwole Makinde the Olu of Igbehin Land and Olori Florence Makinde for leading me in the right direction. Oluwanike Abiola-Olagunju 4 DEDICATION This thesis is dedicated to the glory of GOD the Almighty, who made all things possible and my mother OLORI FLORENCE MAKINDE. 5 CERTIFICATION I certify that this study was carried out under my supervision by Oluwanike ABIOLA-OLAGUNJU, in the Department of Animal Science, University of Ibadan, Ibadan, Nigeria. Professor A.O. Akinsoyinu B Sc Hons M Sc Ph D (Ibadan) Agricultural Biochemistry & Ruminant Nutrition Department of Animal Science, University of Ibadan, Ibadan, Nigeria 6 TABLE OF CONTENTS Title Page 1 Abstract 2 Acknowledgement 3 Dedication 5 Certification 6 Table of Contents 7 List of Tables 15 List of Figures 17 List of Plates 18 CHAPTER ONE 1.0 Introduction 19 CHAPTER TWO 2.0 Literature review 23 2.1 Agro industrial by-products (AIBS) 23 2.1.1 Characteristics of Agricultural by-products 23 2.2 Upgrading agricultural wastes 24 2.2.1 Physical treatment. 25 2.2.2 Chemical treatment. 25 2.2.3 Biological treatment 25 2.3 Fermentation 26 2.3.1 Solid state fermentation 27 2.4 The palm tree and its origin 29 2.5 Characteristics of the palm tree 29 2.6 Production of the palm tree 30 7 2.6.1 Types of oil palm 30 2.7 Technological process of the palm oil. 31 2.7.1 The extraction and technical processes of oil palm 31 2.8 Peculiarities of palm oil in animal nutrition 33 2.8.1 Oil palm slurry utilisation as feed stuff for animals. 34 2.9 Origin of cassava (Manihot esculenta) 36 2.9.1 Characteristics of Cassava (Manihot esculenta) 36 2.9.2. The use of Cassava peel 37 2.9.3 Monogastrics 37 2.9.4 Sheep and Goat 38 2.9.5 Cattle 38 2.10 Limitations to the use of cassava as feedstuff 38 2.11 Cyanogenic glucosides 39 2.12 Voluntary intake 39 2.12.1 Feed intake on fat based diets and organic matter digestibility 40 2.12.2 Dietary fat on crude protein digestibility 41 2.13 The rumen environment 41 2.14 Rumen microbial ecosystem 42 2.15 Microbial interactions in the rumen 42 2.15.1 Methods of classification of rumen microorganisms 43 2.16 Volatile fatty acids 44 2.17. Production of methane through feeds 44 2.18 Role of ammonia in rumen fermentation 45 2.19 Fate of fat in the rumen 46 2.19.1 Effects of added fat on feed degradation 47 2.20 Monitoring Rumen Microbial Change 48 2.21 Animal factors affecting microbial fiber digestion 48 8 2.21.1 Intake 49 2.21.2 Composition of dietary fiber 49 2.22.3 Assessment and techniques of nutritional quality of feeds through in vitro techniques 49 2.23 Origin of invitro gas 51 CHAPTER THREE 3.0 Chemical composition and nutritive potential of oil palm slurry fermented with cassava peel 53 3.1 Introduction 53 3.2 Materials and Method 55 3.2.1 Collection and processing of samples 55 3.2.2 Chemical Analysis 55 3.2.3 Fermentation of the mixtures of Oil palm slurry (OPS) and Cassava peels (CaP) 56 3.2.4 Statistical Analysis 56 3.4 RESULTS 59 3.4.1 Composition of oil palm slurry collected from different locations in South Western Nigeria. 59 3.42 Cell wall fractions of oil palm slurry collected from four different locations in South-Western Nigeria. 61 3.4.3 Proximate composition and cell wall constituents of cassava peel fermented and unfermented 63 3.4.4 Dry matter and proximate composition of fermented graded mixtures of OPS and CaP 66 3.4.5 Cell wall components of fermented graded mixture of OPS and CaP 66 3.5 DISCUSSION 68 9 CHAPTER FOUR 4.0 In vitro fermentation parameters and characteristics of fermented graded mixtures of oil palm slurry and cassava peel by WAD sheep 70 4.1 Introduction 70 4.2 Material and method 71 4.2.1 Experimental diets 71 4.2.2 Analytical procedure 72 4..2.3 Chemical Composition 72 4.3 In vitro gas production of fermented graded mixtures of Oil palm slurry and Cassava peel. 72 4.3.1 Statistical analysis 73 4.4 RESULTS 74 4.4.1 In vitro gas parameters of fermented graded mixtures of OPS and CaP at 24, 60 and 96 hrs incubation period 74 4.4.2 In vitro fermentation parameters of fermented graded mixtures of oil palm slurry and cassava peel at 24 hours incubation period 76 4.4.3 In vitro fermentation parameters of fermented graded mixtures of oil palm slurry and cassava peel at 60 hours incubation period 78 4.4.4 In vitro fermentation parameters of fermented graded mixtures of Oil palm slurry and Cassava peel at 96 hours incubation period 80 4.5. Effect of pH on in vitro characteristics of fermented graded mixtures of Oil palm slurry and Cassava peel at 24, 60 and 96 hrs incubation period 82 4.6 In vitro gas characteristics of fermented graded mixtures of Oil palm slurry and Cassava peel at 24, 60 and 96 hrs of incubation 84 4.7 Ammonia nitrogen concentration of fermented graded mixtures of OPS and CaP at 24, 60 and 96 hours incubation period 86 10 4.8 DISCUSSION 88 4.8.1 In vitro gas production parameters of fermented graded mixtures of ops and cap at 24, 60 and 96 hours 88 4.9 In vitro gas characteristics of fermented graded mixtures of ops and cap at 24, 60 and 96 hours incubation period 90 4.9.1 Short Chain Fatty Acids of fermented graded mixtures of Oil palm slurry and Cassava peel 90 4.9.2 Organic Matter Digestibility of fermented graded mixtures of Oil palm slurry and Cassava peel 90 4.9.3 Metabolisable Energy (ME) of fermented graded mixtures of Oil palm slurry and Cassava peel 91 4.10. The pH of fermented graded mixtures of Oil palm slurry and Cassava peel 91 - 4.11 Ammonia Nitrogen Concentration (NH3 N) of fermented graded mixtures of Oil palm slurry and Cassava peel 92 CHAPTER FIVE 5.1 Performance characteristics and total rumen microbial count of West African Dwarf sheep fed graded mixtures of oil palm slurry and cassava peels 93 5.2 Introduction 93 5.3 Acceptability study 95 5.3.1 Free choice intake of OPS and CaP mixtures 95 5.3.2 Material and method 95 5.3.3 Experimental site 95 5.3.4 Experimental sheep 96 5.3.5 Feeding of animals 96 5.4 RESULTS 99 11 5.4 .1 Acceptability of fermented graded mixtures of OPS and CaP by WAD sheep. 99 5.5 DISCUSSION 101 5.6 Digestibility of fermented graded mixtures of oil palm slurry and cassava peel by wad sheep 103 5.6.1 Material and methods 103 5.6.2 Experimental site 103 5.6.3 Experimental animals 103 5.6.4 Collection of oil palm slurry (OPS) and cassava peels (CaP) 103 5.6.5 Experimental design 104 5. 6.6 Sheep feeding 104 5.7 RESULTS 106 5.7.1 The proximate composition (g/kgdm) of experimental diet fed to WAD sheep. 106 5.7.2 Apparent nutrient digestibility and nitrogen utilisation by WAD sheep fed fermented graded mixtures of OPS and CaP. 108 5.7.3 Nitrogen utilization by WAD sheep fed fermented graded mixtures of Oil palm slurry and Cassava peel 110 5.8 DISCUSSION 113 5.9 Total ruminal microbial count, pH and ammonia nitrogen concentration of WAD sheep fed graded mixtures of OPS and CaP 118 5.9.1 RESULTS 118 5.9.2 Effect of time on ruminal pH and NH3-N concentration of WAD sheep fed fermented graded mixtures of OPS and CaP 120 12 5.9.3 Treatment effect on ruminal pH and NH3-H concentration of West African Dwarf Sheep fed fermented graded mixtures of OPS and CaP 122 - 5.9.4 Interaction of time and treatment on ruminal pH and NH3 N concentration of WAD sheep fed fermented graded mixtures of OPS and CaP 124 5.10 DISSCUSION 126 5.10.1 DIET A 127 5.10.2 DIET B 128 5.10.3 DIET C 128 5.10.4 DIET D 128 5.10.5 DIET E 129 5.10.6 DIET F 129 - 5.11 Effect of treatment on ruminal ammonia nitrogen (NH3 N) and pH of West African Dwarf sheep fed fermented graded mixtures of OPS and CaP 129 - 5.12 Effect of time on ruminal pH and ammonia nitrogen (NH3 N) concentration of WAD sheep fed fermented graded mixtures of ops and cap 130 5.13 Effect of interaction between time and treatment on ruminal pH - and ammonia nitrogen (NH3 N) concentration of wad sheep fed fermented graded mixtures of ops and cap 130 13 CHAPTER SIX 6.1 Summary, Conclusion and Recommendation 132 6.2 Summary 132 6.3 Conclusions 132 6.4 Recommendation 133 References 134 14 LIST OF TABLES Tables 1. Proximate composition (g/100gDM of Oil palm slurry from different locations in the South-West Zone of Nigeria. 60 2. The Fibre Fractions of Oil Palm Slurry collected from four locations in South-Western Nigeria 62 3. Proximate composition of unfermented and fermented Cassava peel 64 4. In vitro gas production parameters of fermented graded mixtures of oil palm slurry and Cassava peel at 24hrs incubation period 77 5. In vitro gas production parameters of fermented graded mixtures of Oil palm slurry and Cassava peel at 60hrs incubation period 79 6. In vitro gas production parameters of fermented graded mixtures of Oil palm slurry and Cassava peel at 96hrs incubation period 81 7. The pH of fermented graded mixtures of Oil palm slurry and Cassava peel fermented at 24, 60 and 96hrs 83 8. In vitro gas characteristics of fermented graded mixtures of Oil palm slurry and Cassava peel at 24 hours incubation period 85 9. Ammonia nitrogen concentration of fermented graded mixtures of Oil palm slurry and Cassava peel at 24, 60 and 96hrs 87 10. Coefficient of Preference of fermented graded mixtures of Oil Palm Slurry and Cassava Peel fed to WAD Sheep 100 11. Dry matter and Proximate composition (g/kgDM) of experimental diet fed to WA D sheep 107 12. Apparent nutrient digestibility (%) by WAD sheep fed fermented graded mixtures of Oil palm slurry and Cassava peel 109 13. Nitrogen utilization by West African Dwarf sheep fed fermented graded mixtures (%) of Oil palm slurry and Cassava peels 111 15 14. Nutrient digestibilities (%) by West African Dwarf sheep fed fermented graded mixtures of Oil palm slurry and Cassava peel 112 15. Effect of time on ruminal pH and Ammonia Nitrogen concentration of rumen liquor of West African Dwarf Sheep fed fermented graded mixtures of OPS and CaP 121 - 16. Treatment effect on ruminal pH and ammonia nitrogen (NH3 N) concentration of West African Dwarf Sheep fed fermented graded mixtures of OPS and CaP. 123 17. Effect of interaction between time and treatment on ruminal pH and - ammonia nitrogen (NH3 N) concentration of WAD sheep fed fermented graded mixtures of OPS and CaP 125 16 LIST OF FIGURES Figures 1. Flow chart production technology for 100tons of fresh fruit bunch of African oil palm 32 2. Chemical composition and fibre fraction of fermented graded mixtures of OPS and CaP 67 3. Ruminal microbial growth curve of WAD sheep fed fermented graded mixtures of OPS and CaP 119 17 LIST OF PLATES Plates 1. Clarified oil palm slurry from a palm oil processing site at Mamu 57 2. Relatively drained palm oil slurry in basket 58 3. Heap of cassava peel at a garri processing site at Eleyele. 65 4. Sheep feeding on a diet during acceptability studies 97 5. Fermented mixtures of OPS and CaP being sun cured 98 18 CHAPTER ONE 1.0 INTRODUCTION Livestock rearing plays an important role in the livelihood of small – scale farmers in Nigeria and contributes to the regional and national economic development. In recent years, the human population has increased rapidly and the demand for food, in particular livestock products is expected to increase in all developed and developing countries. (Phengvilaysouk et al., 2008). Mako (2009) described the major constraint to livestock production in developing countries as inadequacy of feed in terms of quality and quantity all year round. Most ruminant livestock, especially cattle, sheep and goats obtain most of their nutrients from herbages growing on poor soils. Another problem is that these herbages often grow fibrous and are of, low digestibility. These animals gain weight slowly in the rainy season and loose it rapidly in the dry season (Babayemi and Bamikole, 2006) due to all-year round feed inadequacies. The major hindrances to the abundance of all year round lush pasture are in two folds. First is the obvious fast rate of infrastructural development and constant change in government policies. Another factor is the constant rise in population in Nigeria. There is an uncontrollable rise in human head count. The net effect is the negative impact on the available space for herbage production and limited green area for grazing animals (Makkar, 1994). Feeding alone, accounts for approximately 60- 80% of the total cost of animal production (Aregheore, 2000). The conventional feed resources are also in limited supply, very scarce and expensive. This stemmed from the perpetual competition between man and his livestock (Longe et al., 1988). Such feedstuff is maize, a source of dietary energy for livestock farmers. It thus becomes cost ineffective for livestock farmers. All these factors prohibit the use of such feed ingredient for ruminants that may require a large quantity to satisfy energy requirements. Smallholders (Stur et al., 2002) own 95% of all livestock and most of the households produce food mainly for subsistence (Chantalakkana, 2001). Unfortunately, in most towns and villages, free-range system of animal rearing has been the order of the day. Animals are left to roam the streets as scavengers. These animals face the hazardous 19 conditions of being beaten or knocked down by vehicles or at times being poisoned by angry farmers whose crops are damaged. Researchers in the last three decades realized the need for a pressing integration with the use of less popular feed alternative such that ruminant production could be sustained all year round. Thus efforts have been geared at improved supplemental feeding with the use of grasses, crop residues and agro- industrial by products (AIBS) in the dry season (Mako, 2009). Various authors (Ayoade, 1993; Ayoola., 1993; Adebiyi, 2004; Mako, 2009) concluded that non conventional feedstuff is better alternatives to the conventional feed resources. They are readily available in their local areas from crop cultivation and industrial processing. They are easily afforded by the farmers at least cost and are important sources of roughages for ruminants. The AIBS and crop residues have been described as low- quality roughages due to high levels of cellulose, hemicelluloses, lignin and fermentable carbohydrates. (Phengvilaysouk and Wanapat et al., 2008) However, ruminant livestock have the advantage of their unique ability to synthesis high quality protein from non-protein nitrogenous compounds (NPN) through the action of micro- organisms present in their digestive tract (Adeleye, 1991). Many authors (Adebiyi, 2006; Mako, 2009) have reported fermentation as an important tool of upgrading AIBS, especially the protein level for adequate utilisation by the microbes in the rumen. It also aids in the breakdown of the fibrous cell wall thereby making the feed more susceptible to microbial attack. Achinewhu et al. (1998) reported fermentation as being responsible for product stability, flavor development, fibre break down and enhanced nutrient content of feed through the biosynthesis of vitamins, microbial proteins and fibre digestibility. Oil palm slurry (OPS) is the waste or effluent remaining after production of palm oil. It is obtained in a ratio of 2:4 liters of finished palm oil (Aderiye, 1996). It is essentially an emulsion containing 4-5% solids, 0.5-1% residual oil, 75% water, 4.5-9% crude protein and crude fibre content of 8.0% depending on the extraction method used. The OPS is usually channeled into rivers, dams or sunk into a dug pit, which could seal the passage of air and reduce the crop yield of the area of production due to its high biological oxygen demand ( B.O.D) (Apori, 1984). 20 In most villages and localities in the South-Western parts of Nigeria, palm oil production is an all year round exercise thereby making its slurry abundantly available throughout the year. Although several works have been done on the use of oil palm slurry in the feeding of non- ruminants, yet works are scanty on its utilization as feed for ruminants. Reports of Hutagalung et al., (1978) suggested that for optimal results in the use of OPS as feed for ruminant animals, it should be fed along with or used as a binder with other AIBS. The residual oil in the OPS is considered an essential component of many fermentation media, since it possesses defoaming properties as well as serve as a supplemental nutrient source for growth and maintenance of the microbial cells (Yang et al., 2000). Oil palm slurry is also a detoxifying agent that helps in reducing toxic effects. Cassava peel has been established over the years to be well relished by all classes of animals including non-ruminants. It is a source of energy. Though highly acidic, it possesses anti-nutritive factors, and fibrous (Babayemi, et al., 2010). It is also a waste that could be found all year round; especially in the South- Western parts of Nigeria where its cultivation is highest. However, its low protein and cyanide content has been the major limitation for its use in the feeding of livestock. (Okpako et al., 2008). This work is undertaken to evaluate the utilisation of cassava peels fermented with oil palm slurry as feed in the diet of West African dwarf sheep. The objectives of this project are: 1. To evaluate the nutrient composition and availability of OPS in South-Western Nigeria. 2. To determine the nutrient contents of graded mixtures of OPS and CaP fermented over a period. 3. To evaluate the intake, digestibility and microbial load in the rumen of sheep fed fermented graded mixtures of OPS and CaP 21 JUSTIFICATION Ruminants are naturally fed with grasses that are low in nutrient especially in the dry season, which suggests the need for supplementation with lesser known feed stuffs of no direct dietary value to man. The available conventional feed ingredients such as maize and pulse legumes are excellent supplements for ruminants, but are rather exorbitant, uneconomical and this therefore necessitates the search for other cheaper source of feed supplies. Palm oil is the second largest source of dietary oil consumed daily by man and Nigeria is rated the fifth largest producer of crude palm oil. There is dearth of scientific documentation on the use of its invariably abundant liquid effluent as alternative feed for ruminants in Nigeria. Most of the researches on Oil palm slurry were carried out in Malaysia (Arowora, 2002). The report of Wambeck (1990) suggested that results that are more valuable would be obtained if oil palm slurry could be integrated with other ingredients in formulation of useful animal feeds. The OPS and CaP are unconventional feedstuffs that are abundantly available in the production areas. Depending on the disposal techniques they could constitute environmental menace. This calls for alternative practical uses particularly in the light of the dearth of scientific documentation on the use of the effluent. Ruminants need the supply of vitamins A, D, E and K which are naturally in short supply in grasses during the and dry seasons of the year Cott (2009). Hence a need to supplement their diets with AIBS like oil palm slurry which contains all of these vitamins due to its residual palm oil content (Hutagalung et al., 1977) In view of these, a bond could be formed between oil palm slurry a liquid effluent and cassava peel since both are obtainable all year round. 22 CHAPTER TWO 2.0 LITERATURE REVIEW 2..1 AGRO INDUSTRIAL BY-PRODUCTS (AIBS) Crop residues or agro-industrial by products are the left over at the sites of harvest of some crops on the farm which are usually left to rot in the fields. While some are used to improve soil fertility, or may be set on fire. They can also be defined as the waste or residues from agro-industrial feed processing plants or small scale units. They are usually fibrous, low in nutrient and are not directly edible but could be fed to animal. Babayemi and Bamikole (2006) described crop residues and agro-industrial by products as bulky with high fibre, low protein and poorly degradable, while Dixon and Egan. (1987) further explained that they are derived from the processing of a particular crop or animal products usually in an agricultural firm. They are, readily available in each locality of production. The nutrient composition and nature of agro-industrial by- products depends on the amount and types of crop grown in that area. Although research work has been in top gear to evaluate the use of these byproducts as feed, a large amount of these by products produced on both private and government could be wasted. In such findings (Ayoade et al., 1991) established that in some eastern parts of Nigeria, more than 60% of livestock farmers are not aware of the value of crop residues and agro-industrial by products. Research to date is geared towards the determination of biological value of residues as they occur, rather than on methods of increasing this value. In an attempt to improve the nutritional quality of fibrous residues, it has been confined mainly to physical treatments, such as grinding. There is the need to explore more and where need be, fully apply other methods of treatments if their potential value as animal feed is to be realised. 2.1.1 Characteristics of Agricultural by-products Only a part of agricultural products can be utilized by man himself. The amount of by- products for feeding farm animals can be considerable. There is a considerable variation in quantity and quality of by-products among the crops, influenced by, varieties, climate, season and stage of harvest. The most important parts of roughage are the aerial parts (stems, leaves). These can be utilised fresh, dry, cut or grazed, in the field or in the stable/barn. 23 Human do not consume crop by-products. These by-products contain high amount of fibrous material which are not easily disposable due to treat on environmental pollution. Statistics on production and utilization of fibrous residues in Nigeria is inadequate. However, the production of roughage could be fairly estimated accurately from crop production, if reliable data are available. Low quality roughage is found in poor grazing range lands. It also includes enormous amount of cereal crop residues such as rice straw, wheat straw, bean straw, maize stover, corn cobs and rice hulls. Analysis of roughages by detergent procedures (Goering and Van Soest, 1970) showed that they are high in lignin, cellulose and hemicelluloses. Also most cereal wastes are characterised as low crude protein, low available energy and deficient in certain minerals. These low quality roughages are inefficiently utilized by ruminants. This is due to low digestibility and poor nutritive value associated particularly with cereal straw. Their utilization is also limited because of low voluntary intake of the animals due to their huge bulk, which makes transportation more costly. The chemical composition of roughages varies with the variety of plant (Kharat, 1974; Salem and Jackson, 1975), location (Van Soest, 1969) and agricultural practices employed in the growing of the crop and handling of the residue from which they are obtained. Chahal. (1985) referred those differences between crop residues and wood residues to be due to their chemical composition. He found that crop residues contain 30-40% cellulose, 16-27% hemicelluloses, 3-13% lignin, and 3.6-7.2% crude protein, while the wood residues contain 45-56% cellulose, 10-25% hemicelluloses and 18- 30% lignin. 2.2 UPGRADING AGRICULTURAL WASTES Approximately 2 billion tonnes of cereal grains and 140 million tonnes of legume and oil are produced throughout the world annually. Choct. (1998) estimated 230 million tonnes of fibrous material as part of a variety of global by-products. In legumes, non starch polysaccharides (NSP) also play a role as energy storage material. Longe (1988) and Derick. (1989) advocated the increased utilization of non-conventional feed resources in non-ruminant feed. They suggested processing techniques, which are simple and inexpensive, and do not significantly increase costs but still make it 24 worthwhile in terms of nutrient availability. Processing techniques widely documented in literature could be grouped into physical, chemical and biological treatments. 2.2.1 Physical treatment. In smallholder livestock systems, most physical treatments of crop residues are either too expensive or the equipment is not available and labour intensive. However, there are benefits in reducing particle size (not necessarily grinding), for ensiling and stall- feeding. Reduction of particle size can be achieved by using a power driven chopper. There are other advantages, in that the surface area of non-lignin material exposed to microbial attack increased the rate of digestion, thereby reducing a possible limitation to intake (Van Soest, 1982). 2.2.2 Chemical treatment. The potential for increasing digestibility and intake of fibrous residues through treatment with alkali has been reviewed (Sundstol and Owen, 1984). Urea treatment is of most practical significance in the tropics, acting as both an alkali and a source of supplementary nitrogen (N) to materials inherently low in crude protein. The procedure will vary according to circumstances. Smith et al. (1989) noted that the greatest improvement was observed when 5% urea solution was added at 20% weight for weight to dry stover followed by an incubation period of five weeks. The stover had been rotor slashed before treatment. Urea treatment is relatively easy to apply and is effective However; its adoption at smallholder farm level has been slow and the cost of urea prohibits adequate usage 2.2.3 Biological treatment Biological treatments include the use of microbial proteins, antibiotics, probiotics, enzymes and ensiling. These constitute the most recent methods of enrichment of non- digestible feedstuffs or those imbued with the well known anti-nutrients. Dierick (1989) emphasized that polyphenols such as tannins are not removed by physical or chemical treatments but by fermentation or germination. Even the nutritive value of maize in form of lysine and tryptophan contents leading to improvement in biological value and utilizable protein was achieved through germination (Ram et al., 1979). Besides ensiling, the most recent additive for improving silage quality is the biological aid. This involves microbial inoculants and cellulolytic enzymes with easy, safer 25 handling and application to its credit. It is neither volatile nor corrosive and is usually aimed at breaking down cell walls to provide a wealth of readily available substrates (Dutton, 1987). Addition of enzymes to feed ingredients results in an improved energy availability that reduces the difference between gross and metabolisable energy of raw materials (Cowan et al., 1996). The level of improvement seen is related to energy type and dosage and correlated well with the substrate specificity of the various enzymes present. The microbial enzyme source, accounts for 90% of commercial enzymes and are more advantageous than the commercially prepared enzymes. According to Underkoffler. (1972) the following advantages are found in the microbial enzymes; (a) Microbial enzymes do not compete for glandular tissues of animals with other more expensive products made from a limited supply of the same glandular tissues. (b) There scanty microbial sources (c) There is irregularity and non predictability of supplies from non microbial sources which may be subjected to seasonal, climatic and other agriculturally related uncontrollable variables. (d) Production from non-microbial sources cannot be expended at will in response to increased demand. Microorganisms both aerobic and anaerobic are able to produce extracellular enzymes to degrade macromolecules like starch, cellulose, hemicelluloses, lignin, and pectin of the plant cell (Priest, 1984) as well as protein and other membrane constituents. It has been reported that the solid state fermentation (SSF) is an alternative process to produce fungal microbial enzymes using lignocellulose materials from agricultural wastes due to its low capital investment and lower operating cost (Haltrich et al., 1996; Jecu, 2000). 2.3 FERMENTATION Fermentation can be described as the change in state of the physical and chemical condition and make up of a substance or substrate (feed) to a more stable form. This process changes the total make up of the substrate, by breaking down the complex formation of the feed through natural or artificial introduction of microorganism (fungal or bacteria) which breaks down the complex cell wall into a more simple form. Fermentation could be anaerobic or aerobic. This process of 26 substrate breakdown is advantageous in many ways. It increases the surface area of the feed particle for the hosts‟ microorganisms for adequate utilization. 1. Fermentation brings about a more stable product thereby increasing the shelf-life of the product. 2. It helps to increase the nutritive value of the substrate through protein enhancement. 3. It improves acceptability of the feed. 4. The aroma of the end substrate is enhanced. 2.3.1 Solid state fermentation Aerobic microbial transformation of solid materials or Solid Substrate Fermentation (SSF) can be defined as the application of living organisms and their components to industrial products. The process is not an industrial, but an improvement in technology that will have a large impact on many different sectors (Hamlyn, 1998). Aderolu (2000) considered SSF as a process in which solid-substrate are decomposed by known mono or mixed cultures of micro organisms under controlled environmental conditions, with the aim of producing high quality products. The substrate is characterized by relatively low water content (Zadrazil et al., 1990). Solid state fermentation (SSF) is an attractive alternative process to produce fungal microbial enzymes, using lignocellulosic materials from agricultural wastes due to its lower capital investment and lower operating cost (Chahal et al., 1996; Haltrich et al., 1996; Jecu. 2000). For the reasons stated, the SSF process will be ideal for developing countries. Solid–state fermentation is characterised by the complete or almost complete absence of free liquid. Water which is essential for microbial activities is present in an absorbed or in complex-form within the solid matrix and the substrate (Cannel and Moo-Young, 1980). These conditions are especially suitable for the growth of fungi, known to grow at relatively low water activities. As the microorganisms in SSF grow under conditions closer to their natural habitats, they are more capable of producing enzymes and metabolites, which will not be produced or will be produced only in low yield in submerged conditions (Jecu. 2000).The SSF‟s are practical for complex substrates including agricultural, forestry, food-processing residues and wastes which are used as carbon sources for the production of lignocellulolytic enzymes (Haltrich et el., 1996). Compared with the two-stage hydrolysis-fermentation process during 27 ethanol production from lignocelluloses, SSF has the following advantages: Sun and Cheng (2002). 1. Increase in hydrolysis rate by conversion of sugars that inhibits the enzymes (cellulase) activity; 2. Lower enzyme requirement; 3. Higher product yield 4. Lower requirement for sterile conditions since glucose is removed immediately and ethanol is produced; 5. Shorter process time ; 6. Less reactor volume. Malherbe and Cloete. (2003) reiterated that the primary objective of lignocellulose treatment by the various industries is to access the potential of the cellulose encrusted by lignin within the lignocelluloses matrix. They expressed the opinion that a combination of SSF technology with the ability of an appropriate fungus to selectively degrade lignin will make possible industrial-scale implementation of lignocelluloses based technologies. New application of SSF has been suggested for the production of antibiotics (Barrios et al., (1994), secondary metabolites (Trejo-Hernandez et al., 1992, 1993) or enriched foodstuffs (Senez et al., 1980). The SSF is a batch process using natural heterogeneous materials (Raimbault, 1998), containing complex polymers like lignin (Agosin et al., 1989), pectin (Oriol et al., 1988a) and lignocelluloses (Roussos, 1985). Bacteria, yeasts and fungi can grow on solid substrates, and find application in SSF processes mainly on the production of feed, hydrolytic enzymes, organic acids, gibberellins, flavours and biopesticides. Bacteria are mainly involved in composting, ensiling and some other food processes (Doelle et al., 1992). Yeasts can be used for ethanol and food or feed production (Saucedo-Castaneda et al., 1992a,). Filamentous fungi are the most important group of microorganisms used in SSF processes owing to their physiological, enzymological and biochemical properties. The hyphae of fungal growth are tolerant to low water activity and high osmotic pressure conditions make fungi efficient and competitive in natural micro flora for bioconversion of solid substrates (Raimbault, 1998). 28 Microorganisms are currently the primary sources of industrial enzymes; 50% originates from fungi and yeast, 35% from bacteria, while the remaining 15% is either from plant and animal origin (Boophathy, 1994). Microbial enzymes are either produced through submerged fermentation (SMF), or solid substrate fermentation (SSF) techniques. According to the Central food technological Research Institute (CFTRI) in India, enzyme production by SSF accomplishes high production per unit volume of fermentor space than SMF technique. Processing wastes such as cassava peels (Ofuya and Nwajuba, 1990) has been upgraded through production of enzymes by SSF techniques. Such information (Iyayi and Losel 2001; Belewu and Banjo. 1999; Iyayi and Aderolu 2004; Onilude 1994; Balagopalan. 1996) clearly showed the use of microorganisms for upgrading lignocelluloses into animal feeds. Like all other technologies, SSF has its advantages. These have received some attention (Mudgett, 1986). Problems commonly associated with SSF are heat buildup, bacteria contamination, scale-up, biomass growth estimation and control of substrate content. 2.4 THE PALM TREE AND ITS ORIGIN The palm tree (Elaeis guineesis spp) is a multipurpose tree crop which grows and fruits all year round. Its cultivation started at the beginning of this century (Davendra. 1977).The tree crop is confirmed a native of West Africa and it flourishes in the humid tropics in groves of varying density. The palm tree moved out of Africa through European travelers who used the nuts as ship ballast and latter found it useful as a source of food for human consumption and also animal feed. The primary areas of production now are Southeast Asia, Latin America, and currently Malaysia produces half the world‟s production followed by Indonesia and Nigeria. 2.5 CHARACTERISTICS OF THE PALM TREE The tree crop is characterised by its vertical trunk and the feathery nature of its leaves. Every year, 20 to 25 new leaves “fronds” develop in continuous whorls at the apex of the trunk. The fruit bunches develop between the trunk and the base of the trunk and 29 the base of the new fronds. Although new plantations start to bear at three years, generally the first commercial crop requires between five and six years and continues to produce for 25-30 years or until the palms grow too high to be harvested. Once a plantation reaches full production, a new inflorescence is produced every 15 days. It weighs between 15 and 20kg and can contain up to 1500 individual palm fruits of between 8 and 10 grammes each. The individual fruit consists of the following four parts; A pericarp,a thin outer covering or skin which upon ripening changes from brown to orange. A mesocarp, a layer of fibrous material, which surrounds the nut. An endocarp or a hard inner shell (nut) to protect the seed or kernel. The seed (kernel). 2.6 PRODUCTION OF THE PALM TREE The African oil palm, yields 20tonnes /ha/yr of fresh fruit bunches (Bolarios, 1986; Garza, 1986). It can produce between 3 and 5 t/ha of crude oil from the fruit (mesocarp) and an additional 0.6 to 1.0t/ha from the palm kernels (Ocampo et al., 1990a). The factors that affect productivity are; climate, soil type, genetic factors, maturity, rainfall, fertilization and the period of harvest. The African palm oil requires a minimum of 1600mm of well-distributed precipitation (Mijares, 1985) a relative humidity no less than 75%, a minimum and maximum temperature of between 17 and 28c, and a total of 200hours of light and soil depth of 100 centimetres. 2.6.1 Types of oil palm There are two basic types of oil palm. These are the “Dura” and the “Pisifera” The basic difference between the two is in their nuts. The “dura” type has a thick and hard shell while the „pisifera‟ has a small kernel, with no shell but rather surrounded by a matrix of fibre. A cross between pisifera male and dura female, results in a “Tenera‟ type of fruit. It has an immediate type of thickness. Tenera is now the most widely grown type in most plantations. 30 2.7 TECHNOLOGICAL PROCESS OF THE PALM OIL There are two major commercial products extracted from the African oil palm. They are; raw or crude oil which is approximately 22% of the weight of fresh fruit bunch while the palm nuts represents 4-6%.When the nuts are processed, it yields palm kernel oil and palm kernel meal. The two main industrial residues, the oil- rich fibrous residue and the palm nutshell are usually incinerated and the ash is returned to the plantation as fertilizer. 2.7.1 The extraction and technical processes of oil palm The technological process by which the oil is extracted from the palm fruit consists of the following steps: Fig 1 flow chart. The fresh fruit bunch includes the stem and the adhering individual palm fruits. Reception: where sand dirt and gravel are separated from the fresh fruit bunch. Sterilization: Necessary to rapidly inactivate certain enzymes which tend to reduce the quality of the oil by increasing the amount of free fatty acids. In addition, this process contributes to the mechanical separation of the fruit from the stem and to the rupture of the oil cells within the mesocarp. Oil extraction: An oil press, into which hot water is injected, is used to separate the crude oil from the solid or fibrous-like material containing the nuts. The crude oil is then pumped to the purification section. Fig 1 shows the quantities of the principal components of the oil palm based on 100 tons of the fresh fruit bunch. The nuts are treated and cracked to extract the kernel, which contains approximately 50% oil. The oil-rich fibrous residue, is traditionally used as a source of energy to run the plants, has a caloric value superior to 18.8MJ/Kg. This is largely due to the residual oil, calculated as between 8 and 18 %.( Solano,1986; Wambeck, 1990). . 31 Fig 1; Showing the flow chart production technology for 100tons of fresh fruit bunch of African oil palm Solano 1986 32 2.8 PECULIARITIES OF PALM OIL IN MAN AND ANIMAL NUTRITION. Palm oil has been used traditionally for more than 5000 years in African countries, where small-scale family farms flourish. It is the most heavily consumed dietary oil in the world after soybean oil. In its natural state, palm oil is red in colour in most of the tropical countries while in the temperate region, it is usually an orange colour like carrot due to the naturally cool environment. This red colour is due to a high concentration of the natural nutrients carotenes, a (precursor of vitamin A) which our bodies need to convert to vitamin A which is essential for good eye sight. Vitamin A can be toxic at excessive levels, whereas carotenes are not. Therefore, vitamin A toxic levels are not possible from consuming virgin palm oil. Palm oil is one of the best sources of Vitamin E an important phytonutrient in edible oils which takes care of the skin pigmentation. Vitamin E consists of four tocopherols and four tocotrienols naturally present in most plants, however they are found most abundantly in palm oil extracted from palm fruits. The antioxidative ability of palm oil is due to its high biochemical content of tocotrienols, naturally present in most plants. However, they are found most abundantly in palm oil extracted from palm fruits and are believed to be much more potent antioxidant than tocopherols. Oils and fats generally are susceptible to attack by atmospheric oxygen, resulting in rancidity. The content of tocols in (Vitamin E) makes palm oil very powerful natural antioxidants. Therefore, it has exceptional resistance to rancidity. It is also known for its excellent stability at high temperatures. This gives it an advantage in cooking over any other oil because it will not denature so easily upon long exposure to heat. The essential vitamins A, D, E AND K (responsible for strong bones) which are mostly needed by pregnant women, young children and the aged and in animals, (pregnant, lactating and young animals) are all present in the red palm oil. Another advantage of the crude palm oil is found in its use in a manner similar to molasses. Up to 5% improves palatability, reduce dustiness, to supply vitamins and to improve the texture of rations prior to pelleting (Devendra, 1977; Hutagalung and Mahyudin, 1981).The oil contains approximately 80% of saturated fatty acids, and 10% of linoleic acid, an essential fatty acid required at a dietary level of 0.1% for pigs. (NRC, 1988) Palm oil is also known to be a detoxifying agent. 33 2.8 OIL PALM SLURRY (OPS). After the extraction of palm oil from the palm fruit bunch, the final discharge effluent which is in a semi solid form is called the slurry. The process of extraction of palm oil from the fresh fruit bunch (FFB) according to Jamal et al. (2010) requires large amount of water mainly for sterilizing the fruits and oil clarification, resulting in the discharge of organic, non-toxic waste water known as palm oil mill effluent (POME).The quantity of (POME) produced is about 60% for every tone of (FFB) processed. Thus, about 18 to19.5 tones effluent (POME) is generated from the milling process of an average of 30 tonnes FFB (Rashid et al., 2009).Oil palm slurry was described as the liquid effluent produced during the extraction of oil at the rate of 2 to 3 tons per ton of finished oil (Olie and Tjeng. 1972). It contains soil particles, residual oils and suspended solids. Results from Rashid et al. (2009) estimated that OPS contains water 95-96%, oil 0.6-0.7%, total solids 4-5%, pH 4.7, biological oxygen demand (BOD) - 25000mg and total nitrogen of 750mg. After palm oil extraction in Nigeria and due to poor disposal systems, the liquid effluent is channeled into streams and rivers around and the high biological oxygen demand of the slurry causes a tousle with aquatic animal. This could lead to aquatic loss of lives and also render soils around areas of production useless for cultivation since it seals off oxygen penetration to the roots of crops. Davis and Briggs. (1998) described the effluent as a potent environmental pollutant. This effluent represents 0.5 ton per ton of fresh fruit and can cause serious problems to the entire ecosystem (Wambeck. 1990). Oil palm slurry could be put to use either by filter-pressing before drying and grounding to produce dehydrated palm oil mill effluent or centrifuged in the wet state, after undergoing anaerobic, thermophilic and acidophilic fermentation. In the latter case, the product is known as fresh centrifuged slurry solids of between 15 and 20% dry matter. It may be dehydrated to form dry centrifuged slurry solids of between 94 and 97% dry matter. Oil palm slurry has a crude protein value of 4.6% which could be increased by the addition of poultry litter. The enriched slurry could be used to substitute other sources of protein such as soybean and groundnut cake in the diet of broilers (Abu et al., 1984). 34 2.8.1 OIL PALM SLURRY UTILISATION AS FEED STUFF FOR ANIMALS There have been numerous attempts to convert OPS into a viable animal feed resource. In poultry, Yeoung (1980, 1981) evaluated the nutritive value of oil palm by-products with poultry. He reported that the metabolisable energy (ME) value of oil palm slurry in broiler chickens was 1814kcalME/kg at 20% inclusion in diets. He recommended an optimum level to be 15%, beyond which adverse effects on feed intake; body weight gain and feed efficiency, were observed. Swatson (1979) replaced the maize component of a reference diet with raw oil palm slurry at 0, 5, 10, 15% on weight basis. The effect of inclusion was significant (p<0.05) on feed intake compared to birds on control diet (0% oil palm slurry).The oil palm slurry containing diets also recorded a comparatively better feed conversion efficiency. In pigs, Vroom (1978) replaced the maize component of an 18% crude protein diet for weaner pigs with 0, 10, 15, 20% oil palm slurry. He observed that the crude protein level of 18% in oil palm slurry supplemental diets with fish meal had significantly better carcass characteristics for pigs on oil palm slurry based diets. He also reported that increasing the level of oil palm slurry led to a corresponding increase in the rate of gain. However, there was a decrease in feed conversion efficiency compared to pigs on control diet. In ruminants, limited work has been done on the utilization of palm oil slurry. Dvendra (1977) studied the digestibility of diets containing 10-60% oil palm slurry and reported high dry matter digestibility with an average of 87.0%. However, with increasing levels of OPS from (10-60%) significantly lower decreased differences (p<0.05) were observed. The 10% inclusion gave the best results with respect to digestibility values. Devendra (1977) in feeding adult sheep with or without fat supplemented diets at 8% level, recorded digestibility of 85.4% which was equivalent to digestible energy value of 33.6MJ/kg of palm oil. In cattle, Pillai and Tan (1976) fed oil palm slurry to cattle and reported improved live weight gains. Dazel (1978) used OPS with 75% moisture to formulate diets containing palm kernel cake, palm press fibre and mineral supplements for buffaloes, local Indian cattle (L.I.C) and kedan kelantin Cattle in 3year feedlot trial. He observed that fresh or untreated slurry can be effectively utilized and when the dry matter content of the diet 35 was 85% OPS, LIC heifers produced average daily gain (ADG) OF 0.47Kg/day. Feed cost per unit body weight gain was lowered in cattle and buffaloes by OPS inclusion. 2.9 ORIGIN OF CASSAVA (Manihot esculenta) Cassava (manihot esculenta) is an annual staple crop with great economic importance worldwide. Although, the evolutionary and geographical origins has remained unresolved and controversial (Kenneth et al., 1999). It has been established as an important root crop in West Africa, Asia and South America (Okpako et al., 2008).World production of cassava roots was estimated to be 184 million tons in 2002. The majority of production is in Africa where 99.1 million tons were grown, 51.5 million tons were grown in Asia and 32.2 million tons in Latin America and the Caribbean. Nigeria is the world‟s largest producer of cassava. However, based on the FAO statistics, Thailand is the largest exporting country of dried cassava with a total of 77% of worlds export in 2005. Cassava provides energy for about 500 million people and also it is known as one of the leading crops with respect to the energy produced per hectare per year. It has also been discovered to be the third largest source of carbohydrate for humans in the world (Okpako et al., 2008). 2.9.1 Characteristics of Cassava (Manihot esculenta) Cassava plays a particularly important role in the developing sub-Saharan Africa countries, because it performs well on poor soils and requires low rainfall. It is a perennial root crop that can be harvested as needed. Cassava (Manihot esculenta) is characterized by its short-lived perennial, 1 to 5metres tall. From stem cuttings, the plant produces 5 to 10 tubers of very fleshy adventitious roots up to 150centimetres in diameter. Young roots may have 30- 35% stands by weight but very little protein or fat. As many as 300 million people in the tropics consume cassava daily. After planting a stem cutting, the crop does not have to be tended, and the roots are harvested 6-8 months latter before they become woody. Cassava has the greatest yield of starch per acre of any crop in the world often exceeding 20tonnes of roots per acre (Okpako et al., 2008). Cassava roots are bitter and poisonous if eaten raw (bitter cassava, kii). The bitter principal is a glycoside of hydro cyanic acid (HCN), which occurs in the white, yellow and red flesh. Very poisonous forms have greater than 100 ppm of cyanide. If ingested, 36 inhibits a respiratory enzyme and in a series of actions ultimately causes asphyxiation. The lethal concentration of HCN is 150milligrams for a 50killogram adult. Various methods have been used to remove the toxic agent (HCN). In native America, the deadly bitter principal could be removed by boiling or squeezing. Another method of its removal is by adequate fermentation (Adebowale, 1983). Although some cultivars lack HCN (sweet cassava, makasera; less than 50ppm of cyanide), this is highly variable and unreliable. Certain cassava cultivators have very strong preference for the most bitter, i.e. lethal, forms and even intentionally used the most toxic tissues. However, the most poisonous forms often detoxify more completely than the milder forms, because they contain more hydrolytic enzymes linamarase which causes the release of hydrogen cyanide gas. 2.9.2 The use of Cassava peel Cassava has been found to be the third largest source of carbohydrate for human food in the world (Okpako et al., 2008). In Nigeria today; it is an important staple food in almost every household, thereby making its peel, which is non edible by human useful for feeding almost all classes of animals. Handful of researches (Osakwe and Nwose. 2008; Okpako et al., 2008; Pham and Preston, 2009) has been conducted with meaningful results on the incorporation of cassava wastes in animal feeding. 2.9.3 Monogastrics Osakwe and Nwose, (2008) fed twenty eight week old crosses of New Zealand White x Chinchila weaner rabbits in an experiment in which maize was replaced with graded cassava peels at 0, 25, 50 and 100%. It was concluded that maize supplementation in the diets of weaner rabbits could be replaced with cassava peel up to 100% without any adverse effects. However, 75% cassava peels replacement was observed to be the optimum. Using a ration in which cassava peels contained up to 27.3% of the ration, Tewe et al. (1981) observed no significant difference (p>0.05) in the performance of pigs on the control and the test diets. Longe and Adetola. (1983) incorporated cassava peels up to 20% levels in the ration of layers and observed no significant (p>0.05) variations in the feed intake between the birds on the control and test diets. 37 2.9.4 Sheep and Goat Twelve female and twelve castrated male sheep were allocated to rations containing dried fermented cassava peels at 0, 20, 40 and 60% and fed over a period of 6months to determine the optimum level that maize could be replaced without any effect on the performance. Increased fermented cassava peels in the test rations produced greater economic benefits. Fermented cassava peels had a fattening effect on sheep (Adebowale, 1981). 2.9.5 Cattle In the works of Pham and Preston. (2009), four Lai Sind bull aged 26-28months, weighing 290 kg live weight with permanent rumen cannula were fed diets of natural grass and graded dried cassava root peels (RP) at 0, 0.25, 0.50, and 0.75kg DM per 100kg live weight. An apparent negative effect in the balance of rumen bacteria and products was observed. The overall impact of the RP supplementation appeared to be a better balance of nutrients for the animal as reflected in the linear increase in total DM intake. 2.10 LIMITATIONS TO THE USE OF CASSAVA AS FEEDSTUF Anti nutritional factors are substances generated in natural feedstuff as secondary metabolites by the normal metabolism of the plant species. They are usually referred to as “Toxic Factors” due to their deleterious effects when consumed by animals (Radostits et al., 1997; Bruneton, 1999). Many plant components have the potential to elicit adverse effect on the productivity of ruminants. Anti nutritional factors could be classified on the basis of the type of nutrients affected and the biological response elicited in the animals like; (1) Substances depressing digestion or metabolic utilization of proteins. This group is known as protease inhibitors, haemaglutimins (basically, lectin and ricins), saponins, tannins and cyanogenic substances. (2) Substances inactivating certain vitamins and hormones. These consists of lipoxygenase (antivitamin A), racitogens (antvitamin D), dicoumarol (antivitamin k), mimosine (antihormone) and cyanogenic glucoside (anti- thyroid). 38 These factors are widely distributed naturally throughout the plant kingdom and in all the parts of plant (Bruneton, 1999). They occur essentially as defense mechanisms against predators and microbial infections. (Feeny, 1970; Deshpande et al., 1986). It was also described as a means of defense and storage of their nutrients, structure and reproductive elements (Harborn,. 1989). The effects of both secondary metabolites and mycotoxins vary with animal species. Non- ruminants such as pigs and poultry are usually more susceptible to toxicity than animals, which have the capacity to denature potential toxins in the rumen (Norton, 2004). 2.11 CYANOGENIC GLUCOSIDES The cyanogenic glucosides have been implicated in the incidence of goiter and cretinism in humans. The effects of cyanide on livestock performance have been investigated (Okpako et al., 2008). Cassava has a definite anti- thyroid action in man and animals, resulting in the development of endemic goiter and cretinism (Ermanus et al., 1980; Delange et al., 1973). This action is attributed to the endogenous release of thiocyanide from linamarin which is a cyanogenic glucoside contained in cassava. The high moisture content and ratio of carbohydrate to nitrogen, makes cassava tubers an excellent substrate for microbial growth and production of high levels of toxic metabolities. It has been demonstrated (Nartey, 1966) that on cassava meal substrate where Aspergillus flavus thrives, high levels of aflatoxins was produced. This heat- stable carcinogenic metabolite inhibits protein synthesis and causes liver damage in animals (Butler and Barnes, 1963). Like other root crops; cassava roots are richer in protein, ether extract and edible ash than the edible protein (Arowora, 2002). This valuable waste product has been used extensively to feed cattle, sheep, goat, pig and poultry in areas of high cassava production. Diverse ways have been applied to reduce anti nutritional effect of cassava roots to the barest minimum; by soaking, sun drying (Tweyong and Katunga. 2002), par boiling and through fermentation (breaking down of the complex feed constituent to simpler forms and restructuring of the chemistry of the substrate to a more stable form). 2.12 VOLUNTARY INTAKE The digestibility of a feed is most accurately defined as the proportion which is not excreted in the feaces and perhaps assumed to be absorbed by an animal (Mc Donald et 39 al., 1988).Digestibility is affected by the chemical composition and stage of maturity of the forage or feed substance (Mako, 2009) and also by processing and chemical treatments. Voluntary feed intake and digestibility of energy decrease as crude protein content of forages decrease (Van Soest, 1995). In a digestibility trial, the feed under investigation is given to the animal in known amount and the output of faeces measured. The feed would be thoroughly mixed to obtain uniform composition. It is then offered to the animal for at least a week prior to collection of faeces. This would be done to get the animals adjusted to the diet and to clear the tract of the residues from previous feeding. This preliminary period is followed by a period when feed intake and faecal output are recorded. It is highly desirable that diet should be given at the same time daily and the amount of feed offered should not vary from day to day (Mc Donald et al., 1988). 2.12.1 Feed intake on fat based diets and organic matter digestibility (Clapperton (1974). obtained significant variations in apparent dry matter and organic matter digestibility when isocaloric diets supplemented with linseed oil were fed to four groups of sheep. Similar reports (Putnam et al., 1969; 1978; Kane et al., 1979; Palmquist and Conrad. 1980) had been published. Kowalczyk et al. (1977) obtained lowered digestibility of dry grass, after infusing 0, 40, 80 and 120g tallow per day into rumen of lambs. Similar observations for dry matter digestibility were reported (Dyer et al., 1957; Wayne et al., 1971). Phengvilaysouk and Wanapat. (2008) focused on the effect of cassava hay (CH) and coconut oil (CO) supplementation on feed intake and digestibility in a 4 by 4 latin square design. Supplementation improved diet digestibility and feed intake with swamp buffaloes when supplemented with CH or CH and CO compared to supplementation with only CO, which decreased roughage intake. Bohman et al. (1957) incorporated animal fat into fattening steer ration at 5 and 10% levels and found no significant effect on feed intake. 40 2.12.2 Dietary fat on crude protein digestibility Dietary fat decrease protein digestibility significantly (Grainger et al., 1957; Perry and Stewart, 1979). Conversely, for heifer, protein digestibility tended to increase with dietary fat inclusion (Kromfeld and Donoghue, 1980) which accords with similar documented observations (Putman et al., 1969; Wayne, 1971; Palmquist, 1977). Protected tallow at 0, 25 and 37.5% in the diets of beef cattle did not influence protein digestibility (Haaland et al., 1981). Similar findings were observed with linseed oil (Clapperton. 1974; Sharma et al., 1978) and the feeding of 0-15% level of protected tallow (Palmquist and Conrad, 1980). 2.13 THE RUMEN ENVIRONMENT The rumen is a function of the quantity and type of feed eaten by the animal at a particular time. The periodic mixing through contraction of the rumen, salivation rumination, diffusion secretion into the rumen, absorption of nutrients from the rumen and passage of materials down the digestive tract (Preston and Leng, 1987) are imment factors. The rumen environment can be disorganized under abnormal circumstances; A sudden introduction of feed substance into the diet such as grains could result in lacticacidaemia. This is due to a drop in ruminal pH, growth of streptococcus bovis and the accumulation of lactic acid. The saliva helps in maintaining the pH of rumen as a buffer. The quality of saliva secreted by ruminants depends on the diet. The presence of protozoa population affects the salivary flow and may be reduced by its prescence.The protozoa rapidly assimilate starch and sugar and removes the need for copious salivation to maintain rumen pH (Preston and Leng. 1987).Saliva, a buffered bicarbonate solution of about pH 8, contains high concentration of sodium and phosphate ions. Both the saliva and bicarbonate movement across the rumen epithelium maintains the pH within narrow limits. The buffered rumen liquor favours the growth of the anaerobic bacteria, fungi and protozoa with accumulation of VFAs in the fluid (up to 0.2 molar).Perhaps, for continuous fermentation however, the ruminal pH must be constantly maintained at neutral level and to ensure VFAs absorption. The biomass of microbes in the digestive tract and by the death and lyses of the micro- organisms in the rumen, methane and carbon dioxide are produced as products of 41 fermentation. At low rumen pH, carbon dioxide comes out of solution and accumulates in a pocket of the dorsal sac. Methane and carbon dioxide are largely eliminated by eructation, (Dougherty et al., 1964). At high pH most of the carbon dioxide produced by fermentation or entering the saliva, is absorbed and excreted via the lungs. 2.14 RUMEN MICROBIAL ECOSYSTEM The rumen microbial ecosystem is complex and highly dependent on the diet (Mako, 2009). The vast majority of ruminants consume a mixture of carbohydrates of which cellulose and hemicelluloses are the highest components. The diet can contain large amounts of soluble carbohydrates or starch (e.g. molasses or grains). Plants have developed molecular structure in their cell wall specially to stop invasion by micro- organisms. In the rumen, the main agents that break down carbohydrates are anaerobic bacteria, protozoa and fungi. The anaerobic bacteria are the principal agents for fermenting plant cell-wall carbohydrates but the anaerobic phycomycetous fungi, may at times be extremely important (Bauchop, 1981). There is a close relationship between fungi and other microbes in the rumen since the fungi appear to be the first organisms to invade plant cell wall, which allows bacterial fermentation to start and to continue. Some bacteria in the rumen assumed a symphonic association, where one organism uses the products of fermentation of another and the removal of the end- product allows further fermentation of the primary feeds source by the first organism (Preston and Leng, 1987). 2.15 MICROBIAL INTERACTIONS IN THE RUMEN A myriad of micro-organisms are found throughout the digestive tract of the ruminant, but it is only the microbiota in the rumen that have a true symbiotic relationship with the host (Idahor, 2006). The rumen contains varied and dense microbial population predominantly anaerobic bacteria protozoa and fungi. They depend on the ruminant to provide the physiological conditions necessary for their existence. They in turn are essential for digestion and fermentation of the large amounts of fibrous feeds which the host cannot efficiently utilise (Czekawsk,. 1986; Yokoyama and Johnson, 1993). Since the rumen naturally utilises the end products of microbial fermentation and 42 biosynthetic activities to meet its own nutritional requirements. Interestingly, there is no indication of host specificity of these micro-organisms in ruminants. While many species are unique in the rumen, others closely resemble those found in the digestive tracts of other ruminants. The microbial population varies within animals, with time after feeding, between days in the same animal and apparently, in animal in different countries on similar feed (Hungate, 1975). However, the end- products of fermentation are virtually the same. Bacteria associate with related organisms and function as a couple, one organism growing on the end-products of metabolisms of another. The sequential fermentation process involving different species of organism converting cellulose to VFAs is well recognized. The interrelationships between levels are high above a certain optimum, in which ammonia is incorporated into ammonia acids without using ATP. It has been suggested (Satter and Slyter, 1974) that maximum microbial synthesis rate occurs at ammonia concentrations between 5 and 8 mg N/100 ml. Different options have been found, suggesting that diet influences the optimum ammonia level. A study (Schaefer et al., 1980) suggests that value may be as high as 14 mg N/100 ml depending on the diet. The high ammonia concentration needed for maximum microbial cell growth suggested that the rumen micro-organisms probably have similar mechanisms for incorporation of ammonia via glutamate dehydrogenase. 2.15.1 METHODS OF CLASSIFICATION OF RUMEN MICROORGANISMS The types of micro-organisms that develop and are sustained in the rumen are those that have adapted best to the specific conditions of the ecosystem (Idahor. 2006). Hence, saccharolytic microbes predominate due to the readily available carbohydrates (cellulose) and other polysaccharides that constitute the major substrates for fermentation. More so, the low oxygen tension in the rumen encourages the growth of more obligate anaerobes. However, a few facultative anaerobes are present under aerobic conditions (Yokoyama and Johnson. 1993). In a more detailed investigation (Bryant. 1993), twenty-one genera and sixty-three species of rumen bacteria have been classified (Orpin. 1975; 1977; Ogimoto and Imai, 1981) describe a system of differentiating these rumen microorganisms according to morphological divisions. These are according to shapes (cocci, rods and spirilla), sizes 43 (ranging from 0.3 to 50 um and according to their different structures (including the presence of a cell envelope, cytoplasmic and surface adherents or appendages). Generally, preliminary classification of the rumen microorganisms has largely followed a system based on the type of substrate they will attack and on the different end products of fermentation. However, there is a considerable ambiguity because most species are capable of fermenting more than a few substrates (Yokoyama and Johnson. 1993). 2.16 VOLATILE FATTY ACIDS The end product of fermentation of organic matter by micro-organisms in the rumen are the volatile fatty acids (VFAs).The major (VFAs) acetic, propionic and butyric while the isobutyric, isovaleric, valeric and some other acids are produced in small amount. The rate and volume of the end products produced is directly proportional to the microbial activity in the rumen (Mako, 2009). Also, (Bergman, 1990) stated that concentrations and relative proportions of VFAs are related to the nature of the feed. In a similar report (Firkins et al., 1986; Robinson et al., 1986) the VFAs produced depend on the extent (effective degradability) of the feed ingested by the animals which subsequently determines the amount of substrate available for fermentation. 2.17 PRODUCTION OF METHANE THROUGH FEEDS Ruminants depend on micro- organisms to ferment plant cell wall and polysaccharides into volatile fatty acids and (VFAs) and other amino acids. They also produce wastes such as carbon dioxide (CO2) and methane (CH4).Methane production in the rumen is a loss of energy, since the proportion of animal feed which is converted to CH4. is eructed as gas. Approximately, 6% of dietary gross energy intake is lost to the atmosphere as CH4 (Holter and Young. 1992; De Ramus et al., 2003). Recently, emission of CH4 and other volatile organic compounds has attracted the attention of air regulatory agencies in many parts of the world. Methane contributes to climatic change and global warming (Johnson and Johnson. 1995) by trapping outgoing terrestrial infrared radiation 20 times more effectively than CO2. This leads to increased surface temperature and directly affects an atmospheric oxidation reaction that produces CO2 in animal agriculture. 44 There may be potential to reduce the extent of CH4 production by manipulating diet and management practices that influence ruminal microbial fermentation (Johnson and Johnson. 1995).Environmental pollution and menace could be caused by over feeding and / or poor synchronization of release of nutrients in the rumen. Attempts have been made to manipulate rumen fermentation using ration manipulation strategies, including the addition of ionophores, fats and yeast cultures. For example, addition of monensin to dairy cattle rations decreased CH4 production, decreased feed intake and increased milk yield (Sauer et al., 1998). This suggests that reduction in CH4 production per unit of ingested feed is associated with improvement of feed utilization efficiency. A suppressing influence of ration fat content on CH4 production has been reported (Sauer et al., 1998; Dohme et al., 2001; Lee et al., 2003).It is not only the total amount of fat, but also its composition that excerts biological important influences on rumen fermentation (Gatechew et al ., 2001 ; Fievez et al., 2003). Gatechew et al., (2005) observed differences in methane produced from incubation of commercial total mixed rations (TMR) for lactating dairy cows. The proportion of CH4 in total gas did not differ among TMR at 6 and 24 hrs of incubation, but differences did occur at 48 and 72 hrs giving an average of 33.8 ml CH4/g DM produced at 24 hrs of incubation. Approximately 0.80 of total CH4 was produced during the first 24 hrs of incubation 2.18 ROLE OF AMMONIA IN RUMEN FERMENTATION The 40-60% of the dry matter of the microbial cells in protein and therefore the synthesis of amino acid and proteins are the reactions that require ATP. The pathways of synthesis of amino acids in rumen microbes are not clearly defined. It is however; abundantly clear that ammonia is highly important for the efficient synthesis of amino acids and therefore microbial protein (Satter and Slyter, 1974). At low ammonia level in rumen fluid, reactions that fix ammonia into acids require ATP whereas, when ammonia level is high above a certain optimum, the ammonia is incorporated into amino acids without using ATP. It has been suggested (Satter and Slyter, 1974) that maximum microbial synthesis rate occur at ammonia concentrations between 5 and 8 mg N/100 ml. Different options have been reported, suggesting that diet influences optimum level of ammonia. Another study (Schaefar et al., 1980) suggests the value may be as high as 14 mg N/100 ml depending on diet. The high ammonia concentration needed for maximum 45 cell growth suggests that the rumen micro-organisms probably have similar mechanism for incorporation of ammonia via glutamate dehydrogenase. 2.19 FATE OF FAT IN THE RUMEN Fat supplementation of animal ration could be done using animal fat (e.g. lard, tallow, cod liver oil, salmon oil and whale oil) or vegetable oil (e.g. soya bean oil, palm oil, linseed oil and cotton seed oil). The incorporation of plant oil into rations is done through the addition of the pure oil or crop residues/plant oil by-products. Examples of oil crop residues which have been used in ruminant nutrition are groundnut cake, cotton seed cake, palm kernel cake, coconut cake and babassu cake (Apori, 1984). Reports of supplementation (Kirchgessne et al., 1967) showed that 100-350g per animal per day as the minimum, depending on the basic foodstuff and nature of dietary fat Sundstol. (1974) recommended 25-30g digestible ether extract per kilogram 4% fat corrected milk as the minimum level and an upper limit of 700g ether extract per day per animal.Fat added to the diet of ruminants varies from negligible amounts to levels in excess of 10% of the dry matter in leafy forages or where animals are able to select leafy-tip materials (Hawke, 1973). Fats added to the diet are mainly in the form of triglycerides with smaller amounts of phospholipids and sterol esters. Dawson and Kemp. (1970) reported that triglycerides are rapidly hydrolysed by the rumen microbes into free fatty acids and glycerol. The unsaturated fatty acids then undergo extensive hydrogenation and isomerisation before being used by the animal. The long chain fatty acids (largely stearic, palmitic and oleic acids) are absorbed only from the intestines.Rumen bacteria incorporated some of the long chain fatty acids into their cellular components. Nutritional limitation to fat use is attributed to its effect on fermentation of the fibrous cell wall components in the rumen and to a lesser extent, on protein degradation. (Apori, 1984). Storry. (1972) stated that the effect of fat on fibre digestion depended on quality, quantity and physical form of fat being used. Andrews and Lewis. (1970) reported that fatty acid mixtures found in most common fats are associated with relatively high digestibility. Macleod and Buachanan. (1972) however reported that highly saturated fatty acids (as found in hydrogenated tallow) are poorly digested, 46 probably due to poor dispersion and hydrolysis in the rumen and solubilisation in the small intestine. Devendra and Lewis. (1974) summarized various effects of fat on fibre digestion as absorption of fat on fibrous particles, by preventing attack of rumen microorganisms. Others are adverse effect on integrity of microbial cell walls, modification of rumen microbial population, especially reduction in cellulytic bacterial population it also reduced availability of calcium and magnesium iron as are result of formation of soaps. Macleod et al. (1972) reported that saturated fatty acids and blended tallow tend to depress fibre digestion to a greater extent than flaked tallow. There was no benefit from extending the preliminary period beyond 10days, provided that fat supplemented diets are acceptable from the start of the experiment. They attributed the reduction in the digestibility of fibre to the coating of feed particles with fat. The degree of saturation of dietary lipid was identified as a factor which could critically affect digestibility in ruminants (Devendra. 1977). 2.19.1 Effects of added fat on feed degradation Fallow and Yellow grease (YG), both by-products, are typical fats used in the diets of lactating dairy cows. The gas technique was used to examine the effect of source and levels of added fat on gas production and rumen fermentation of a total mixed ration (Getachew et al., 2000). Fatty acids in the form of triglyceride has no effect (when comprising up to 25% of the diet) on gas production, but fatty acids in the form of potassium salts (YG soap) significantly depressed gas production. In the animal, however, there is a limit to the amount of fatty acids that can be successfully fed, and this is lower than in vitro. The fatty acids in potassium salts are quickly available to microbes as free fatty acids in ruminal fluid. They have detrimental effects on microbial growth. In contrast, the fatty acids in the triglyceride form must be released through hydrolysis of the ester bond and therefore are available at a slower rate. Hydrolysis refers to breaking the chemical bond between the individual fatty acid and the glycerol backbone of the triglyceride. The effects of fatty acids on rumen fermentation are important because feeds with high levels of residual fat, for example rice bran produced in the production of white rice are commonly fed to ruminants. 47 2.20 MONITORING RUMEN MICROBIAL CHANGE In addition to rate and extent of digestion, the gas production method can be used to study substrate related factors that influence microbial population in the rumen. This enables manipulation of microflora to increase the utilization of feeds through degradation of fiber and lignin, increasing the efficiency of nitrogen utilization or allowing the degradation of antinutritional and toxic components of feeds. Such controlled fermentation system could potentially be used with genetic engineering of plants to solve animal productivity problems. The technique is suitable for application of molecular based assays, such as polymerise chain reaction (PCR) and ribonucleic acid (RNA) – targeted oligonucleotide probes. It facilitates study and measure of rumen microbial growth, with the goal of increasing the efficient utilization of feeds and reducing environmental impacts. Gas technique, (Muetzel and Becker, 2003) was used in combination with ribosomel RNA targeted probes to measure the efficiency of microbial growth, when barley straw was supplemented with legume leaves. Nutrient synchronization carbohydrate and nitrogen sources must be available simultaneously in order to maximize microbial growth. Ruminal ammonia concentrations can be influenced by the degradation rates of carbohydrates and nitrogen-containing compounds. For a given level of dietary protein, an increased rate of protein degradation enhances the runimal ammonia concentration while an increased rate of carbohydrate degradation decreases. Increased carbohydrate availability for fermentation promotes microbial growth and as a result less nitrogen is lost from the rumen in the form of ammonia-nitrogen (Getachew et al., 2000a). The gas method offers an opportunity to study microbial requirement for nitrogen and carbohydrate to enable efficient fermentation activity and accumulation in the rumen. Using this technique, studies have been conducted to assess rumen microbial requirements for nitrogen when different types of carbohydrate sources are incubated. 2.21 ANIMAL FACTORS AFFECTING MICROBIAL FIBER DIGESTION Animal and feeding systems can have a significant effect on the digestion of fibre. Notably, intake, dietary interactions, feeding strategies and feed additives will, to some degree, influence microbial growth and subsequent fiber digestion. 48 2.21.1 Intake The extent of fibre digestion is the result of competition between the rates of digestion and passage and, as such, is not a static value. Rumen liquid and particulate turnover rates are positively correlated with intake. Thus, as intake increases, the digest flowing from the rumen will contain feed particles at earlier stages of digestion, and this will result in a lower dry matter digestibility (Russell et al., 1992). Because the rate of degradation of structural carbohydrate is of the same order as passage rate, at high levels of intake the depression in digestibility of structural carbohydrate can be two to three times greater than that of the faster degrading, nonstructural carbohydrate. Although a high level of intake may depress ruminal fibre digestion, compensation occurs through increases in gross energy intake and hindgut digestion (Bourquin et al., 1990). 2.21.2 Composition of dietary fiber Rumen available energy normally limits growth of bacteria, and any additional organic matter fermented in the rumen. Hence changing the forage: concentrate ratio will probably increase microbial protein synthesis by providing more energy. Sniffen and Robinson (1987) suggested that the yield of bacteria was maximized with a forage content of 70% in the diet dry matter. Because structural carbohydrate-fermenting microbes are usually limited by a ruminal pH less than 6 (Hoover, 1986), the depression in fiber digestibility at higher inclusion rates of concentrate can most likely be explained by the rapid degradation of nonstructural carbohydrate. It is likely that fiber digestion will not be maximized at single forage: concentrate ratio; rather, it will depend on the various rates of digestion of structural and nonstructural carbohydrate supplied by the forage and the concentrate. This may be shown indirectly by the studies of Tamminga. (1981), who reported no relationship between forage: concentrate ratio and bacterial yield. 2.22 ASSESSMENT AND TECHNIQUES OF NUTRITIONAL QUALITY OF FEEDS THROUGH IN VITRO TECHNIQUES The quality of forage is a limiting factor in the growth and yield of ruminants (Minson, 1990).The in vitro determination in quantifying intake and digestibility of feedstuff has 49 been found to be time consuming (Coelho et al; 1988; Carro et al; 1994) laborious, expensive and also require a large quantity of feed. This makes it better suitable for large scale evaluation. In recent times, major attempts were made in predicting intake and digestibility using laboratory procedures. However three major biological techniques to determine the nutritive value of feeds are available. These are; 1. Digestion with rumen microorganisms (Tilley and Terry. 1963) 2. Cell from fungal cellulose 3. In situ incubation of samples in nylon bags in the rumen. (Mehrez and Orskov. 1977). Biological methods are more effective in this study since microorganisms and enzymes are more sensitive to factors influencing the rate and extent of digestion than are chemical methods. (Van Soest. 1994) The ability to correlate well with actually measured in vivo parameters and also a replicable efficient laboratory method determines a viable invitro technique. Method (Tilley and Terry. 1963) was found convenient and widely used when large scale testing of feedstuffs is required. This method is usually adopted in most forage evaluation laboratories and involves two stages. Forages are subjected to 48hours fermentation in a buffer solution containing rumen fluid. Thus followed by 48hours of digestion with pepsin in an acid solution and the residue are treated with neutral detergent solution after 48 hours to deduce the true dry matter digestibility. Although this method has been extensively justified with in vivo values (Van Soest. 1994), it has several shortcomings. The method gives only one observation and unless lengthy and labour intensive, time course studies are made. The technique does not provide information on the kinetics of forage digestion. The residue determined destroys the sample and therefore a large number of replicates are needed. The method is therefore cumbersome to apply materials such as tissue culture samples or cell-wall fractions. Both the rate and extent of disappearance of feed constituents have appraised the use of in-situ and in-sacco technique for many years (Mehrez and Orskov. 1977).The method provides a meaningful means of measuring rate of disappearance and potential degradability of feedstuff and feed constituents. In this technique however, only a small amount of forage samples can be assessed at any time and also requires at least 50 three fistulated animals to account for variations due to animals. Hence it is of limited value in laboratories undertaking routine screening of a large number of data samples, very laborious, time consuming and provides a limited number of data points (Cone, 1991). Therefore it requires a large number of samples; large error could result in values obtained at early stages of digestion due to a reduced weight loss and adherence of microbes to poor quality roughages at early stages. This can lead to higher weights and distortion of results Orskor and Ryle. (1990) showed the possibility of underestimation of dry matter loss from the nylon bag technique at an early stage of incubation, which could be due to adherence of microbes. Tilley and Terry. (1963) established that the nylon bag technique overestimated fermentation. This extent was due to the carbohydrate composition of feeds, especially at short incubation times and this infers that it could be caused by a rapidly fermentable fraction which was lost from bags before it was fermented. The relationship between rumen fermentation and gas production has long been established (Gatechew et al., 1998) The genesis however of rumen gas fermentation, technique began in the early 1940s (Quin, 1943).The idea of this method became a routine method of feed evaluation after the works of Menke et al., (1979) where a high correlation between gas production and in vitro apparent digestibility was reported. 2.23 ORIGIN OF INVITRO GAS The incubation of feedstuff with buffered rumen fluid during in vitro results in carbohydrate fermentation to short chain volatile fatty acids (SCFA), gasses (mainly Co2 and CH4) and microbial cells. The fermentation of carbohydrate to acetate, butyrate and propionate, results in gas production (Wolin, 1960;, 1992; Blummel and Orskor, 1993). Fermentation of protein produced relatively small gas (Wolin, 1960) as compared to carbohydrates, (Wolin, 1960 cited by Gatechew et al., (1998). Gas production from fat fermentation is negligible (Menke and Steingas, 1988;; Gatechew et al., 1997). Incubation of 200mg of coconut oil, palm kernel oil and /or soybean oil, 2.0 and 2.8ml of gas were produced, while 200mg of ceasin and cellulose produced about 23.4ml and 80ml gas respectively (Menke and Steingass. 1988; Gatechew et al., 1997). In the gas technique, gas produced is the indirect gas produced as a result of fermentation (CO2 and CH4) while the indirect gas produced is from the buffering of 51 the of SCFA (CO2 released from the bicarbonate buffer) Such works (Blumel and Orskor; 1993) it was established that incubation of roughages with bicarbonate buffers produced about 50% of the total gas from buffering of the SCFA and the rest was generated from fermentation. When a substrate is fermented to acetate and butyrate, gas is produced. A conclusion was drawn from Van Soest. (1994) that substrate fermentation to propionate yields gas only from buffering of the acid. This suggested that relatively lower production is associated with propionate production. It is also important to note that the type of substrate fermented influences the major proportions of different SCFA (acetate, propionate and butyrate) Blumel and Orskor. 1993s. Hence, the molar ratio of acetate to propionate was used to substantiate substrate related differences. Rapidly degradeable carbohydrates yield higher propionate as compared to acetae while slowly fermentable carbohydrates yield higher acetate when incubated (Gatechew et al., 1998). The intrinsic characteristics of the carbohydrate fraction such as the proportion of starch or cellulose and the extent of lignifications of the cell wall also the intrinsic factor which is the supply of fermentable nitrogen required by micro-organisms to help them synthesis cellular constituents such as protein and nucleic acids required for growth, are one of the factor affecting the rate of fermentation of feed by rumen microbes, hence the production of gas. Information (Hume et al., 1970) had concluded that microbial protein was maximal with an ammonia concentration of 88mgN/1 but microbial protein flow was highest with an ammonia concentration of 133mg N/1.Allen and Miller. (1976) also informed that greatest flow of non-ammonia nitrogen through the abomasum was achieved when the ammonia concentration in the rumen was between 160 and 200mgN/1. Menke et al. (1979) using an in sacco method, observed that an ammonia concentration of 200mg N/1 were necessary to acquire the maximum rate of disappearance of barley DM in sheep. Similarly, Wallace. (1979) perceived an increase in in situ DM and CP degradation rates of barley grain accompanied by increased bacterial growth when rumen NH3 concentration was increased from 97 to 214mg. 52 CHAPTER THREE 3.0 CHEMICAL COMPOSITION AND NUTRITIVE POTENTIAL OF OIL PALM SLURRY FERMENTED WITH CASSAVA PEEL 3.1 INTRODUCTION Meeting the nutritional needs of ruminants throughout the year is a major challenge facing livestock farmers in the tropics due to the seasonality of forages. Grazing animals have adequate amount of lush pasture to feed on in the wet season, which is usually low in nutritive value. The latter (dry) six months of the year are characterised by scarcity and lignifications of available forage with low protein content (Babayemi et al., 2010). The rapid increase in population, the attendant infrastructural development and land acquisition by the government for other uses other than agricultural purposes that has gradually decreased the green area available for animal grazing during the rainy and dry seasons is another plaguing problem. Farmers are faced with the problem of escalating prices of conventional feedstuff, which consequentially increase the feeding cost of the animals. This various preponderances in livestock production, have made researchers sort out other alternative ways that could solve the problem of feed all year round like the browse plants, crop residues and agro industrial wastes and by products. Agro industrial by products are derived from the processing of a particular crop or animal product usually by an agricultural firm (Dixon and Egan, 1987). They have been found to be cheaper and available in each locality of their production. The use of agro industrial by products allows us to convert materials that have limited application for use as human food. Jakanda (1975) stated that the utilisation of non-conventional feed stuffs by farmers and feed manufactures reduce cost of animal feed. Although they contain high levels of cellulose (Phengvilaysouk and Wanapat, 2008) hemicellulose, lignin as well as low levels of fermentable carbohydrates and poor quality protein (Adeleye, 1991), ruminant animals are unique in their ability to 53 synthesis high quality protein from non-protein nitrogenous (NPN) compounds through the action of micro-organisms present in their digestive tract. Agro-industrial by products and crop-residues account for 70% of the total feed intake during the dry season (Adeoye, 1994). Diverse techniques like physical, biological and chemical means have been employed in upgrading or improving on their inadequacies, such as increasing the protein content, reduction of the cellulose, hemicelluloses and most of all the lignin content of feed for the animals to gain better access to available nutrients. Oil palm slurry is an agro-industrial by product of oil palm industry obtained after the processing of the palm fruits (Elaeis guineensis). This by-product is a potential environmental pollutant (Davis and Briggs, 1998) and its utilisation as animal feed will minimise the environmental problem as well as provide energy for the animals (Webb et al., 1977). Oil palm slurry contains 4.6% crude protein (Abu et al., 1984). This value could be higher or lower depending on the extraction method used (mechanical or manual). However, due to its high moisture content, Webb et al., (1978) suggested that oil palm slurry should be processed before its incorporation into feed. Cassava peel is a waste generated after the tuber (root crop) has been peeled. Various varieties of cassava exist but the one peculiar to Africa is Manihot esculenta. The limitation to the use of cassava for feeding livestock is in its low protein content. The flour for example contains about 3.0% protein and the peels about 1.66% protein (Okpako et al., 2008). Farmers usually feed cassava peels as a whole diet to their animals especially in South- Western Nigeria. This diet alone could lead to low performance and productivity due to its low content of protein and vitamins. Cassava peels and oil palm slurry are both obtainable all year round in most villages in South-West of Nigeria. Though oil palm slurry contains high moisture content, like palm oil, it also has the ability to increase acceptability, and reduce dustiness, supply vitamins and improve the texture of rations (Devendra, 1977). In addition, it is a strong detoxifier, which gives it the ability to reduce toxicity in a feed thereby making the feed more acceptable. This study is aimed at determining the chemical composition of oil palm slurry (OPS) collected from four different locations. In addition, to access the suitability of 54 combining mixtures of oil palm slurry and cassava peels (CaP) fermented as feed resource for farmers in the South-Western Nigeria. 3.2 MATERIALS AND METHOD 3.2.1 Collection and processing of samples Oil palm slurry was collected from four different oil palm processing locations in South-Western Nigeria. Oyo state ------- Badeku jako Osun state ------ Ikoyi Ogun state ------ Mamu Edo state ------- Nifor Cassava peels (Cap) was collected from a cassava processing unit at Eleyele Ibadan, Oyo state and it served as control for this experiment. Samples of oil palm slurry and O cassava peels collected were then oven dried at 105 C until constant weight was recorded for dry matter determination. Each of the samples was thoroughly mixed and sub sampled. The dried samples were milled in a Thomas Willey laboratory mill fitted with 0.5mm mesh. The milled samples were kept in airtight bottles until required for chemical analysis. 3.2.3 Chemical Analysis Crude protein, crude fibre, ether extract and ash content of the samples were determined using standard procedure of A.O.A.C (1995). Cell wall components consisting of Acid detergent fibre (ADF), Neutral detergent fiber (NDF) and Neutral detergent lignin (NDL) were determined using Van Soest (1994) method. Hemicellulose contents were estimated as the difference between NDF and ADF while cellulose was estimated as the difference between ADL and Hemicellulose. 55 3.2.3 Fermentation of the mixtures of Oil palm slurry (OPS) and Cassava peels (CaP) Different ratios of fresh samples of Cassava peel (CaP) were fermented with a constant amount of oil palm slurry (OPS) as follows: Diet A -1 kg of cassava peel + 1 liter of OPS Diet B -2 kg of cassava peel + 1 liter of OPS Diet C - 3 kg of cassava peel + 1 liter of OPS Diet D - 4 kg of cassava peel +1 liter of OPS Diet E -5 kg of cassava peel + 1 litre of OPS Diet F -6 Kg of Cassava peel only (control) Fermentation was carried out at these ratios in airtight cellophane bags for microbial action. Samples were fermented for five days and after which each diets were separately sun–cured. The proximate composition and the fibre fractions of the fermented mixtures were determined. 3.2.4 Statistical Analysis Data were analysed using analysis of variance (SAS, 1999). Significant means were separated using the Duncan‟s Multiple range test. Experimental model of the design was: Yij = u + ai + Eij Where Yij = Individual observation U = General mean of population ai = treatment effect Eij = Composite error effect 56 Plate 1: Clarified Oil palm slurry from a palm oil processing site at Mamu (Arrow is indicating slurry) 57 Plate 2: Relatively drained palm oil slurry in basket. 58 3.4 RESULTS 3.4.1 Proximate composition of oil palm slurry collected from four different locations in South –Western zones of Nigeria. The results of the dry matter and proximate composition of Oil palm slurry and Cassava peel are presented on Table 1. Results revealed significant differences in proximate composition of oil palm slurry collected from different locations in South- Western Nigeria. A significant p<0.05 value of 43.20 Dry matter (DM) was obtained from Mamu while collection from Nifor had the least significant value of 6.03. The Crude protein (CP) values ranged from the highest value of 8.15 for Mamu to 6.19 for Nifor. Significant (p<0.05) observation was obtained within locations for Crude fibre (CF) with values of 10.21, 9.15 and 8.50 recorded for Badeku, Nifor and Ikoyi respectively. Significantly low value (p<0.05) of 8.00 was obtained for Mamu. The least values obtained for ash (p<0.05) 7.00 was recorded for Badeku and highest (10.00) for Mamu. All the locations were significantly different (p<0.05) for Ether extract (EE) recording values of 35.00, 39.20, 32.27 and 32.01. 59 TABLE 1: Proximate composition (g/100gDM) of Oil palm slurry from different locations in the South-West Zone of Nigeria. Mamu Ikoyi Badeku Edo SEM Dry matter 43.20a 16.61b 8.20c 6.03bc 0.06 Crude protein 8.15a 7.00b 7.31b 5.15c 0.08 Crude fibre 8.00c 8.50cc 10.21a 9.15b 0.06 Ash 10.00a 8.11b 7.00c 7.10c 0.01 Ether extract 35.00b 39.20a 32.27c 32.01c 0.01 . a, b and c means on the same row with different superscripts are significant (p<0.05) 60 3.42 CELL WALL FRACTIONS OF OIL PALM SLURRY COLLECTED FROM FOUR DIFFERENT LOCATIONS IN SOUTH-WESTERN NIGERIA The cell wall fraction results of oil palm slurry collected from four different locations in South- Western Nigeria are represented on Table 2. There were significant variations among all the parameters observed for cell wall fractions. Value for Mamu was least 25.80 for Acid detergent fibre (ADF) followed by Ikoyi 28.21 and the highest value of 31.00 was recorded for Badeku. Samples collected from Edo state recorded highest values of 50.41 for Acid Detergent Lignin (ADL) while Mamu recorded least value of 43.25. Significantly varied values of 45.28, 49.22, 53.54 and 47.08 respectively, were obtained for Mamu, Ikoyi, Badeku and Edo states for Neutral Detergent Fibre (NDF). OPS collection from Mamu revealed significantly p<0.05 varied values of 23.77 and 19.48 for cellulose and hemicellulose contents while Badeku recorded significant p<0.05 values of 22.54 and 27.87 for both cellulose and hemicellulose contents. 61 TABLE 2: The Fibre Fractions of Oil Palm Slurry collected from four locations in South-Western Nigeria Parameters Mamu Ikoyi Badeku Edo SEM d b a c Acid detergent fibre 25.80 28.21 31.00 26.45 0.02 d b a c Acid detergent 43.25 46.26 50.41 45.00 0.01 lignin c b a b Neutraldetergent 45.28 49.22 53.54 47.08 0.01 fibre d b a c Cellulose 23.77 25.22 27.87 24.37 0.02 d b a c Hemicellulose 19.48 21.01 22.54 20.63 0.03 . a, b, c and d means on the same row with different superscripts are significant (p<0.05) 62 3.4.3 PROXIMATE COMPOSITION AND CELL WALL CONSTITUENTS OF CASSAVA PEEL FERMENTED AND UNFERMENTED The proximate composition and cell wall constituents of cassava peel unfermented and fermented is shown on Table 3. The analysis was done in triplicates and values obtained were not significantly different hence average values were recorded. Cassava peel unfermented values were; 73.63 Dry matter (DM), Crude protein (CP) 5.50, Crude fibre (CF) 21.02, Ash 8.50, Ether extract (EE) 23.20, Acid detergent fibre (ADF) of 43.21, Neutral detergent fibre (NDF) of 59.00, Acid detergent lignin (ADL) of 33.46 hemicellulose of 15.79 and cellulose content of 17.67. Fermented Cassava peel results revealed Dry matter (DM) of 68.42, Crude protein (CP) of 6.50, Crude fibre (CF) of 20.36, Ash content of 6.90, Ether extract (EE) of 28.00, Acid detergent fibre (ADF) of 58.52, Acid detergent lignin (ADL) of 31.00, and Neutral detergent fibre (NDF) of 40.45, Cellulose 12.95 and Hemicellulose content 18.05. 63 TABLE 3: Proximate composition of unfermented and fermented Cassava peel Parameter Unfermented Cassava peel Fermented Cassava peel Dry matter 73.63 68.42 Crude protein 5.50 6.50 Crude fibre 21.02 20.36 Ash 8.50 6.90 Ether extract 23.20 28.00 Acid detergent fibre 43.21 40.45 Neutral detergent fibre 59.00 58.52 Acid detergent lignin 35.46 31.00 Cellulose 17.67 12.95 Hemicellulose 15.79 18.05 64 Plate 3: Heap of cassava peel at a garri processing site at Eleyele. 65 3.4.4 DRY MATTER AND PROXIMATE COMPOSITION OF FERMENTED GRADED MIXTURES OF OPS AND CaP The dry matter, proximate composition and cell wall fractions of graded fermented mixtures of Oil palm slurry and Cassava peel are represented in Fig 2. The results of this study showed that Diet C had the least significant p>0.05 value (52.27) for DM while Diet A recorded the highest value of (71.04). Diet B, also observed significant values of 68.47 while diets D and E were not significantly varied. All the graded mixtures significantly varied p<0.05 for (CP). Diet A obtained the least value of 9.10 and Diet C recorded the highest value of 14.15, A drastic reduction in (CF) was recorded from 19.20 for Diet A, 18.96 for Diet B, 14.25 for Diet C. Diets D and E values were 17.00 and 18.04 respectively, while (Diet F) recorded the highest value of 20.36. The results also showed that there was a significant p<0.05 reduction in the Ether Extract (EE) values from 20.21 for Diet A and 20.47 Diet E. Significant p<0.05 increases 30.21, 36.00, 33.40 and 31.75 were recorded for Diets B, C, D and F respectively. Ash values of 3.20 was least for Diet C. 3.4.3 CELL WALL COMPONENTS OF FERMENTED GRADED MIXTURE OF OPS AND CaP. The Acid Detergent Fibre (ADF) showed that the mixture of Diet A recorded a high significant p< 0.05 value of 22.00, least value of 16.50 was observed for diet C, while Diets D and E were not significantly p>0.05 varied. Similar decreasing trend in variation p<0.05 was observed for Neutral Detergent Fibre (NDF) from diets A to E, the highest value of 35.00 was recorded for Diet A, while Diet C revealed a value of 27.00. Diet A observed highest value of 37.35 Acid Detergent Lignin (ADL) while the least value of 31.25 was revealed for Diet C and Diets B, D and E also recorded significant p<0.05 variations of 34.21, 37.05 and 36.42 respectively. Significant p<0.05 observations were obtained for diets A and B with values of 24.35 and 21.66 respectively. Diets C obtained the least value of 20.75 for Cellulose contents. The least observation of 10.50 was recorded for Diet C while the highest value of 13.75 was obtained for Diet E in their Hemicellulose contents. 66 40 35 30 25 Diet A 20 Diet B 15 Diet C 10 Diet D Diet E 5 0 Fig 2: Chemical composition and fibre fraction of graded fermented mixture of OPS and CaP 67 3.5 DISCUSSION Analyses of samples of Oil palm slurry from four different locations in the South- Western Nigeria revealed that samples from Mamu had the highest Crude protein, low crude fibre. Protein is required for normal body growth, repairs and maintenance (Okpako et al., 2008). The CaP and OPS fermented mixtures had CP values higher than OPS collected from Mamu. This increase could be due to the oil content which acted as a substrate for the possible secretion of some extracellular enzymes such as amylase and cellulase into the CaP by the OPS in an attempt to make use of the cassava starch as carbon source. Another reason could be the increased growth and proliferation of microorganisms in form of single cell protein, which accounted for the increase in the protein content of the CaP with OPS. This result is in accordance with the established results by other authors (Adebiyi 2006; Okpako et al., 2008; Babayemi 2010) that fermentation reduces the CF and increases the CP of a feed. Although there were variations (P<0.05), that could be attributed to the different levels of CaP inclusion ratios in each diet at a constant OPS. Jones and Porter. (1998) observed that the inclusion rate of oil to a diet could affect microbial activity and the release of protein. This could be responsible for the least CP value of (9.10) in diets compared to Diet C, which recorded the highest CP of (14.15). Diet A had the highest concentration of oil, which might have suppressed microbial activity. Diet C might have had adequate proportion of oil to CaP, which probably favoured microbial activity. These changes may also be attributed to fermentation that occurred in the mixtures of OPS and CaP. Fermentation encourages the growth of anaerobic microorganisms and aid the conversion of nitrogen and carbon to true protein (Ward et al., 1975). Campbell and Laherrere (1998) also stated that fermentation gives desirable biochemical changes and significant modification of food quality. Benefits of fermentation according to Steinkraus (1995) include fortification of diet and the removal of toxins. The residual oil contained in the slurry is also an added advantage to the rate of fermentation, since oils and lipids have been found essential components of many fermentation media (Adebiyi, 2006). This can best explain why protein production was highest (at 3%) after fermentation as the level of cassava peels 68 increased. This result was close to the findings of Wanapat et al., (2005) that CP was significantly improved by supplementation at 4% oil inclusion only. There was also a reduced crude fibre content across the treatments due to multiplication of microorganisms resulting in the breakdown of the polysaccharides to monosaccarides. Although the extent of break down varied significantly. The result conformed with the findings of Mccaskey and Anthony. (1979) that fermentation brings about improvement in nutrient composition, acceptability and convenience in the use of silage feeding equipment. The ash content of a feed sample is an indication of mineral composition. In this study, reduced ash contents were recorded for diets (B-E) as shown in Fig 2. This suggests that oil in the mixtures aided microbial fermentation thereby reducing the ash contents. A reduced ash content recorded for diet A was statistically similar to that obtained for diet F which might have been an indication of a reduced microbial activity in both diets. This result disagreed with the conclusions of Oboh and Akindahunsi 2003; Okpako et al., 2008 and Babayemi 2010 that fermentation increased the ash content of cassava products. High NDF could result in low intake while high ADF may engender low digestibility (Babayemi et al., 2010). Judging by the results in Tables 1, 2, 3 and that obtained, in Fig 2, it could be concluded that the features of fermentation and break down of the fibrous cell wall components of the Diets, reduced the ADF and NDF values. However, this effect of fermentation was least observed for Diet A which had recorded the highest values due to the highest concentration of oil (Jones and Porter, 1998). Diet C had the least values of NDF and ADF suggesting its high potential digestibility among other diets. 69 CHAPTER FOUR 4.0 CHEMICAL COMPOSITION AND IN VITRO FERMENTATION PARAMETERS AND CHARACTERISTICS OF FERMENTED GRADED MIXTURES OF OIL PALM SLURRY AND CASSAVA PEEL BY WAD SHEEP 4.1 INTRODUCTION The rain forest zones of Nigeria are characterised by the first six months of lush, green and fresh grass for grazing ruminants, while low quality dry grass is usually a complementary problem of the last six months of the year. Makkar et al. (1994) described the shortage of forage in Nigeria as a major constraint to ruminant production. Earlier remarks of Babayemi et al., (2003) considered the other six months of the year as a time when forage is scarce. More so, the dry period, is characterised by standing hay and low quality feed that eventually culminates in growth retardation of the animals. There is therefore, the need to source for more avenues to make feed available to the animals during the dry season. Although tree crops and many browse plants such as Leuceanea leucocephala and Moringa olifera, provide a better alternative yet it is highly important to source for more, to make choices readily available to both the animals and the farmer. Agro-industrial by-products are other possible alternatives. These industrial wastes are cheap, readily available in their locality of production. At times, they constitute social menace and environmental hazards if not utilized. Agro-industrial by-products include palm kernel meal, cassava seivate, bean seed hull and oil palm slurry. Oil palm slurry is the effluent of palm oil extraction. Its production rate is at a ratio of 2:3 litres of finished oil (Olie and Teng, 1972). Essentially, oil palm slurry is an emulsion containing 4-5% solids, 0.5-1% residual oil and 95% water (Apori, 1986). Webb et al. (1977) suggested that Oil palm slurry should be combined with other feedstuffs for meaningful results to be obtained. Cassava peel is also an agro-industrial by product obtained from cassava processing plant. It constitutes a major source of livestock feed ingredient especially in the South 70 Western geopolitical zone of Nigeria where it is intensively cultivated. Okpako et al., (2008) asserted that the major limitation to the use of cassava peel for feeding livestock is in its low protein content. Feed consumption by animal particularly, the ruminant is largely dependent on the acceptability, rate of feed degradation in the rumen and the amount of energy that could be supplied by the feed (Van Soest, 1995). In vitro method of feed evaluation has been validated over time and adjudged as one of the means of evaluating feed degradation by animals. Reports (Menke and Steingass., 1988, Coelho et al., 1988; Carro et al., 1994) have rated the process as one of the most accurate methods of estimating the quality of feedstuffs. The process is less expensive, simple and replicable. The incubation of feedstuff with buffered rumen fluid during in vitro studies in fermentation results in short chain volatile fatty acids (SCFA), gasses (mainly CO2 and CH4) and microbial cells. The objective of this study was to determine the chemical composition and in vitro fermentation characteristics of graded mixtures of Oil palm slurry (OPS) and Cassava peel (CaP) by WAD sheep. 4.2 MATERIAL AND METHOD 4.2.1 Experimental diets : Diet A -1 kg of cassava peel + 1 litre of OPS Diet B -2 kg of cassava peel + 1 litre of OPS Diet C - 3 kg of cassava peel +1 litre of OPS Diet D - 4 kg of cassava peel +1 litre of OPS Diet E -5 kg of cassava peel + 1 litre of OPS Diet F -6 Kg of Cassava peel only (control) 71 4.2.2 Analytical procedure 4.2.3 Chemical Composition Proximate composition of the graded mixtures of OPS and CaP was analysed in triplicates by the standard procedure of (A.O.A.C 1995). The fibre fractions were determined by Van Soest method (1995). 4.3 In vitro gas production of fermented mixtures of Oil palm slurry and Cassava peel. The graded levels of each mixture (from Diet A, Diet B, Diet C, Diet D, Diet E and o Diet F control) were oven dried at 105 C until constant temperature was attained. Two hundred milligram (200mg) of each milled sample was weighed into 120ml calibrated syringes with pistons lubricated with Vaseline. A buffered mineral solution was . prepared consisting of (NaHCO3 + NaHPO4 + KCl + NaCl + MgSO4 7H2O + CaCl2 + 0 2H2O (1:2, v/v) and stirred at 39 C under continuous gassing with carbon dioxide (CO2). Rumen fluid was collected from three female WAD sheep that were previously fed concentrate consisting 20% corn bran, 25% wheat offal, 20% palm kernel cake, 10% groundnut cake, 4% oyster shell, 0.5% common salt, 0.25% fish meal and 0.25% grower” premix. The liquor was collected into a pre-warmed thermos flask and was later filtered through a four layer cheese cloth, gassing with CO2. Thirty (30ml) of buffered rumen liquor fluid ( inoculum) was pumped into a syringe containing sample. The syringes 0 were placed in an incubator at 39 C. Gas production rate was recorded at 3, 6, 9, 12, 15, 18, 21 up to 96 hours and each syringe was gently swirled after reading. At the end of the 96 hour incubation the average volume of gas produced from the blanks was deducted from the volume of gas produced per sample. The volume of the gas produced was plotted against the time, and the gas production (1- e-ct) characteristics were estimated using the equation Y= a + b as described by Orskor and Mc Donald (1979) where: Y= volume of gas produced at “t” a= intercept (gas produced from insoluble fraction) 72 c = gas production rate constant for the insoluble fraction (b) t = incubation time Metabolisable energy ME, (MJ/Kg DM) and Organic Matter Digestibility (OMD %) were estimated.(Menke and Steingass, 1988) and short chain fatty acids (SCFA) were calculated (Getachew et al, 1999) ME= 2.20 + 0.136*GV + 0.057*CP + 0.0029*CF OMD = 14.88 + 0.889*GV + 0.057*CP + 0.0029*CF SCFA = 0.0239*GV – 0.0601 Where GV, CP, CF and XA are net gas production (ml/200 mg DM), crude protein, crude fibre and ash of the incubated samples respectively. 4.3.1 Statistical analysis Parameters obtained were subjected to analysis of variance procedure (ANOVA) using SAS package of (1999). Significant means were separated using Duncan multiple range test of same package. Experimental model: Yij = u + i + Eij Yij = individual observation U = general mean of the population i = treatment effect Eij = composite error effect 73 4.4 RESULTS 4.4.1 In vitro gas parameters of fermented graded mixtures of OPS and CaP at 24, 60 and 96 hrs incubation period In vitro gas production over a period of 96 hrs is represented in Fig: 3. Gas production was consistently high in Diet C, followed by Diet F compared with other diets. Gas production in diet A was higher than diet D until equilibrium was attained at 60 hr, after which diet C attained the highest at 96 hr.Gas production as reported by other authors is an indication of diet fermentation by the microbial population (Van Soest, 1982 ). 74 120 100 80 Diet A 60 Diet B 40 Diet C 20 Diet D Diet E 0 Diet F Incubation period Fig 3: In vitro gas parameters of fermented graded mixtures of OPS and CaP at 24, 60 and 96 hrs incubation period 75 Volume of gas produced ml/200mg DM 3hrs 6hrs 9hrs 12hrs 15hrs 18hrs 21hrs 24hrs 30hrs 36hrs 42hrs 48hrs 54hrs 60hrs 72hrs 84hrs 96hrs 4.4.2. In vitro fermentation parameters of fermented graded mixtures of oil palm slurry and cassava peel at 24 hours incubation period The results of in vitro fermentation characteristics at 24 hours are presented in Table 4. The values obtained for the insoluble but degradable fraction (b), significantly varied (p<0.05) for all diets, with the highest value (48.00 ml) for Diet C and the least value (39.33 ml) for diet A. The value obtained for the potential degradability (a+b) was not significant (p>0.05) for all diets. Rate of degradation (c) increased with increasing -1 level of Cassava peel (CaP); from Diets A-C, the least value of (0.0553 h ) recorded -1 for diet A while the highest value (0.0796 h ) was record for diet C. However, variations in diets E and F was not significant (p>0.05). Time of degradation (t) and effective degradability (y) showed no significant variations (p>0.05) in all the diets. 76 TABLE: 4 In vitro gas production parameters of fermented graded mixtures of oil palm slurry and Cassava peel at 24hrs incubation period. Fermentation Diet A Diet B Diet C Diet D Diet E Diet F SEM Characteristics ab c a d e b B 39.33 46.00 48.00 43.50 41.00 47.21 1.17 a+b 60.33 57.50 62.50 62.00 56.00 64.24 1.50 e d a ab c b C 0.0553 0.0633 0.0796 0.0683 0.0671 0.0770 0.03 T 6.00 6.00 6.00 6.00 6.00 6.00 0.01 Y 37.33 35.00 37.60 35.00 36.00 36.12 1.16 a, b, c, d, e Means along the same row with different superscripts are significant (p<0.05). Insoluble degradable fraction (b), potential degradability (a+b), rate of degradation (c), time (t) and effective degradability (y) Diet A- 1 litre Oil palm slurry + 1kg cassava peel Diet B - 1 litre Oil palm slurry + 2kg Cassava peel Diet C - 1 litre Oil palm slurry + 3kg Cassava peel Diet D - 1 litre Oil palm slurry + 4kg Cassava peel Diet E -1 litre Oil palm slurry + 5kg Cassava peel Diet F - 6kg Cassava peel SEM=Standard Error of Mean 77 4.4.3 In vitro fermentation parameters of fermented graded mixtures of oil palm slurry and cassava peel at 60 hours incubation period The in vitro fermentation parameters of fermented graded mixtures of Oil palm slurry and Cassava peel at 60 hours of incubation is presented in Table 5. In this study, the value of (b) was significant (p<0.05) in all the diets, from 64.50 ml (diet A) to the highest 78.50 ml (diet C) although no particular trend was observed. The (a+b) also followed the same pattern within diets and the highest (98.50 ml) value was record for diet C, while the least value (73.50 ml) was obtained for diet A. The observed value of -1 (c) was significantly higher (p<0.05) for Diet C (0.049h ). There were no significant -1 differences (p<0.05) in values within diets, A, E and F. The values were (0.039 h , -1 -1 0.039 h and 0.041 h ) respectively 78 TABLE : 5 In vitro gas production parameters of fermented graded mixtures of Oil palm slurry and Cassava peel at 60hrs incubation period. Fermentation Diet A Diet B Diet C Diet D Diet E Diet F SEM Characteristics e c a b d bc B 64.50 70.41 78.50 74.00 67.00 69.21 0.650 e b a c d bc a+b 73.50 96.27 98.50 93.50 86.00 90.42 1.840 d c a b d d C 0.039 0.043 0.049 0.045 0.039 0.041 0.001 T 6.00 6.00 6.00 6.00 6.00 6.00 0.000 Y 32.00 34.00 33.00 32.00 34.50 34.00 0.006 a,b,c,d,e Means along the same row with different superscripts are significant (p<0.05) Insoluble degradable fraction (b), potential degradability (a+b), rate of degradation (c), time (t) and effective degradability (y) Diet A - 1 litre Oil palm slurry + 1kg cassava peel Diet B - 1 litre Oil palm slurry + 2kg Cassava peel Diet C - 1 litre Oil palm slurry + 3kg Cassava peel Diet D - 1 litre Oil palm slurry + 4kg Cassava peel Diet E - 1 litre Oil palm slurry + 5kg Cassava peel Diet F - 6kg Cassava peel SEM=Standard Error of Means 79 4.4.4 In vitro fermentation parameters of fermented graded mixtures of Oil palm slurry and Cassava peel at 96 hours incubation period The in vitro fermentation parameters of fermented graded mixtures of Oil palm slurry and Cassava peel at 96 hours incubation period is shown in Table 6. At 96 hrs, values obtained for (b) were not significant in all diets. The values of (a+b) were significantly lower (p<0.05) in diet E with the value of 83.60 ml compared to higher value of 94.67 ml for diet C. No significant differences were observed for (c) among diets A, B, E -1 and F, but diets C and D varied significantly (p<0.05) with the values of 0.036 h and -1 0.026 h respectively. The variation in the value for time (t) was not significant in all diets. The value of (y) of the diets varied significantly (p<0.05) with highest value of 57.00 recorded for diet C, while the lowest value of 26.34 was obtained in diet F. 80 TABLE 6 : In vitro gas production parameters of graded fermented mixtures of Oil palm slurry and Cassava peel at 96hrs incubation period. Fermentation Diet A Diet B Diet C Diet D Diet E Diet F SEM Characteristics B 71.00 69.50 72.67 74.00 74.63 74.01 2.38 e b a ab c d a+b 85.50 92.26 94.67 90.00 83.60 89.24 3.56 a a b c a a C 0.038 0.043 0.036 0.026 0.042 0.041 0.002 T 6.00 18.00 9.00 6.00 14.00 12.00 2.36 c ab a d b e Y 35.00 38.15 57.00 30.00 48.33 26.34 2.26 a ,b ,c ,d ,e Means on the same row with different superscripts are significant (p<0.05) Insoluble degradable fraction (b), potential degradability (a+b), rate of degradation (c) time (t), effective degradability (y) Diet A - 1 litre Oil palm slurry + 1kg cassava peel Diet B - 1 litre Oil palm slurry + 2kg Cassava peel Diet C - 1 litre Oil palm slurry + 3kg Cassava peel Diet D - 1 litre Oil palm slurry + 4kg Cassava peel Diet E - 1 litre Oil palm slurry + 5kg Cassava peel Diet F - 6kg Cassava peel SEM=Standard Error of Means 81 4.5. Graded mixtures of Oil palm slurry and Cassava peel at 24, 60 and 96 hrs incubation period on pH using in vitro technique The pH of the fermented graded mixtures of Oil palm slurry and Cassava peel at 24, 60 and 96 hours of incubation represented in Table 7. The pH values varied significantly (P<0.05) only at 60 hours and increased with increasing level of CaP. The highest value of 6.66 was recorded for diet E, while diet C recorded the least value of 6.21. There were no significant variations in values obtained in all the diets at both 24 and 96 hours of incubation. 82 TABLE 7: The pH of fermented graded mixtures of Oil palm slurry and Cassava peel fermented at 24, 60 and 96hrs. Incubation Diet A Diet B Diet C Diet D Diet E Diet F SEM Periods 24 6.45 6.37 6.37 6.34 6.37 6.34 0.03 c c d b a ab 60 6.50 6.50 6.21 6.81 6.91 6.60 0.07 96 6.70 6.62 6.61 6.59 6.75 6.50 0.04 a,b,c,d Means along the same row with different superscripts are significant p< 0.05 Diet A -1 litre Oil palm slurry + 1kg Cassava peel Diet B -1 litre Oil palm slurry + 2kg Cassava peel Diet C -1 litre Oil palm slurry + 3kg Cassava peel Diet D -1 litre Oil palm slurry + 4kg Cassava peel Diet E - 1 litre Oil palm slurry + 5kg Cassava peel Diet F - 6kg Cassava peel SEM=Standard Error of Means 83 4.6. In vitro gas characteristics of fermented graded mixtures of Oil palm slurry and Cassava peel at 24, 60 and 96 hrs of incubation The in vitro characteristics of fermented graded mixtures of Oil palm slurry and Cassava peel at 24, 60 and 96 hours are represented in Table 8. In this study, significant differences (p<0.05) were observed in the gas volume (GV) at 24 hours and the highest value was in diet C (67.67), least value (52.14) was recorded for diet D. A similar trend was observed for Metabolisable Energy (ME), Organic Matter Digestibility (OMD %) and Short Chain Fatty Acids (SCFA,µmol) with highest values of 11.42, 82.98 and 1.56 respectively in diet C, while least values of 8.83, 72.17 and 1.27 respectively were obtained for diet A. 84 TABLE 8: In vitro gas characteristics of fermented graded mixtures of Oil palm slurry and Cassava peel at 24 hours incubation period Parameter Diet A Diet B Diet C Diet D Diet E Diet F SEM e ab a d c b GVmol/200mgDM 52.14 55.71 67.67 53.18 54.38 63.71 0.09 e d a c b b ME MJ/kg DM 8.83 9.04 11.42 9.47 9.76a 10.94 0.08 d c a e bc b OMD % 72.17 73.85 82.98 69.82 71.57 79.85 0.03 e d a c ab b SCFA mmol 1.27 1.30 1.56 1.33 1.37 1.46 0.01 a,b,c,d,e Means along the same row with different superscripts are significant (p<0.05) GV= Gas Volume (ml/200mgDM) ME=Metabolisable energy(MJ/Kg DM) OMD=Organic Matter Digestibility (%) SCFA=Short Chain Fatty Acids SCFA(mmol) Diet A -1 litre Oil palm slurry + 1kg Cassava peel Diet B -1 litre Oil palm slurry + 2kg Cassava peel Diet C -1 litre Oil palm slurry + 3kg Cassava peel Diet D -1 litre Oil palm slurry + 4kg Cassava peel Diet E -1 litre Oil palm slurry + 5kg Cassava peel Diet F - 6kg Cassava peel SEM=Standard Error of Means 85 4.7. Ammonia nitrogen concentration of fermented graded mixtures of OPS and CaP at 24, 60 and 96 hours incubation period The ammonia nitrogen concentration of graded fermented mixtures of Oil palm slurry and Cassava peel at 24, 60 and 96 hours of incubation are shown in Table 9. The results revealed that at 24 60 and 96 hours, significant differences (p<0.05) were obtained for all the diets at all observed hours with diet C recording the highest values of 10.50, 12.10 and 13.60 respectively while the least recorded values were 4.0, 6.5 and 6.9 at 24, 60 and 96 hours. 86 TABLE 9: In vitro Ammonia nitrogen concentration of fermented graded mixtures of Oil palm slurry and Cassava peel at 24, 60 and 96hrs incubation period. Incubation Diet A Diet B Diet C Diet D Diet E Diet F SEM Periods e d a c c 24 4.0 6.2 10.5 7.8 7.1b 8.4b 0.02 e d a c b 60 6.5 7.2 12.1 8.5 9.0 9.2b 0.01 e d a c c 96 6.9 8.1 13.6 9.7 9.9 10.0b 0.03 a, b, c, d, e Means along the same row with different superscripts are significantly different p<0.05 Diet A -1 litre Oil palm slurry + 1kg Cassava peel Diet B -1 litre Oil palm slurry + 2kg Cassava peel Diet C -1litre Oil palm slurry + 3kg Cassava peel Diet D -1litre Oil palm slurry + 4kg Cassava peel Diet E -1litre Oil palm slurry + 5kg Cassava peel Diet F- 6kg Cassava peel OPS - Oil palm slurry CaP - Cassava peel SEM=Standard Error of Means 87 4.8 DISCUSSION 4.8.1 In vitro gas production parameters of fermented graded mixtures of OPS and CaP at 24, 60 and 96 hours Proximate composition is usually the basic and the most common form of feed evaluation by animal nutritionists. A more reliable technique of estimating livestock feed is in vitro gas fermentation (Menke and Steingas, 1988). Although the two methods are independent of each other, however, they are interrelated. Gas production is an indication of microbial degradability of samples (Babayemi et al., 2004b, Fievez et al., 2005) At 24 hours, the insoluble but degradable fraction (b), in diet C with OPS and CaP in the ratio 1:3, could be attributed to the high amount of Crude Protein in the mixture. This facilitated high rate of microbial activity by supplying the required nitrogen for their cellular protein synthesis as established by Roger et al., (1977). The highest value of 48.00 ml obtained for this diet, could also be connected with the adequate ratio of oil to cassava peel in the diet compared to other diets. This is in agreement with the findings of Jones and Porter (1998) who reported that adequate combination of oil and carbohydrate would improve fermentation. The high concentration of oil to cassava peel in diet A inhibited the activities of microorganisms, hence the slow rate of gas production. This assertion was corroborated by the work of Palizdar et al., (2011) in which it was reported that saturated fatty acids had more inhibitory effect on rumen microbial ecosystem. Since gas production is dependent on the relative proportion of soluble, insoluble but degradable and undegradable particles of diets, mathematical description of gas production profiles allows evaluation of substrate and fermentability of soluble and slowly fermentable components of feeds (Getachew et al., 1998). The values of a+b, c, and y in the diet C were similar to diet F, but significantly higher (p<0.05) than other diets. The implication of this is that, diet C, which had ratio 1:3 (OPS: CaP) would enhance optimal degradability in vivo. The values of „b‟ obtained in this study (68.67 – 75.25) were higher than those reported for dry matter (DM) degradation of some tropical legumes and grasses (Ajayi et al., 2007) and the values of 9.5-32.0 ml/200 mg DM reported for some crop residues (Babayemi et al., 2009). 88 The potential degradability (a+b) of a diet depicts the level at which the diet could be degraded if it were in the actual rumen of the animal (in vivo). This largely depends on how much of the fibre fractions (ADF and NDF) have been broken down for easy access of the microbes to the nutrients available in the diet. At 24 hrs, there were no significant variations among the diets, which suggest that early hours of incubation and oil inclusion could not be effective for the different diets including the control (diet F). A corroborative result was obtained elsewhere (Jones and Porter. 1988) which established that the time of oil inclusion was a determinant in facilitating degradability in the rumen. The potential degradability (c) increased down the treatments except diets D&E, which could be attributed to the different levels of oil inclusion. At 60 hrs, the fermentable fractions of the substrate in each of the diets increased along with the cellular activity of the rumen microbes due to prolonged period of incubation. This could have suppressed the binding capacity of the oil to the diet. It agrees with the earlier report of Devendra and Lewis, (1974). The values obtained for potential degradability were significantly (76.50-86.00 ml/200mg DM) higher than those reported for dry matter of some legumes and grasses (kimambo et al., 1994; Ajayi et al., 2009; Babayemi et al., 2009).This result buttressed other findings (Yang et al., 2000; Peacock et al., Park et al., 2003 and 1994) that oil serves as a supplemental nutrient source for growth and maintenance of microbial cells. The higher values of CaP have also been reported to have high degradability during fermentation (Ofuya and Nwajiuba, 1990; Arowora, 2002). Therefore, the combination of these two might be responsible for the high degradability recorded. . At 96 hrs, the significant variations in the values of a+b, c and y across the diets were due to different levels of oil inclusion. Diet C, however had the highest values for a+b and y (94.67 and 57.0) which gave it an outstanding performance. 89 4.9. IN VITRO GAS CHARACTERISTICS OF FERMENTED GRADED MIXTURES OF OPS AND CAP AT 24, 60 AND 96 HOURS INCUBATION PERIOD 4.9.1 Short Chain Fatty Acids of fermented graded mixtures of Oil palm slurry and Cassava peel When feedstuffs are incubated with buffered rumen fluid (inoculum) in vitro, gas production is basically the result of microbial degradation of carbohydrates under anaerobic condition to acetic, propionic and butyric acids (Wolin, 1960; Steingass and Menke, 1986). Gas production from protein fermentation is relatively small compared to carbohydrate fermentation. The contribution of fat to gas production is negligible (Wolin, 1960). The result obtained for diet C (1.56 µmol) was highest in all the diets and it conformed with other finding (Yang et al., 2000) that oil has the ability to increase microbial growth in fermentation, This was as a result of the unique trend observed in the earlier discussion. It could be attributed to higher preference of the microbes for this diet due to the favorable ratio of oil to cassava peel (1:3). Futhermore, oil is considered a component of many fermentation media because of its supplemental nutrient source for microbial activity depending on its level of inclusion in the substrate. (Peacock et al., 1994). Oil also acts as an adjunct to fermentation (Jones and Porter, 1998). 4.9.2. Organic Matter Digestibility of fermented graded mixtures of Oil palm slurry and Cassava peel The OMD value is a good measure of the amount of feed which was accessible to the microbes in the rumen. Diet C recorded highest value of OMD (82.98 %) indicating that nutrient uptake was best at this ratio. Higher levels of oil inclusion (diets A and B) might have reduced the capacity of the microbes in breaking down the lignin content due to its inhibitory effect. The findings of Phengvilaysouk and Wanapat, (2008) also supported the supplementation of cassava hay with oil. At higher levels than Diet C, the oil ratio to the cassava peel might not have been sufficient for microbial attack on the lignocellulose cell components of the mixture. This statement however is at variance with the findings of Wanapat et al., (2007) that OMD fermentation was best at oil supplementation level of 4% for cassava hay. Again, the detoxifying effect of the oil may be hindered due to uneven mixture that reduces microbial activity. 90 4.9.3. Metabolisable Energy (ME) of fermented graded mixtures of Oil palm slurry and Cassava peel A correlation between ME values measured in vivo and predicted from 24hr in vitro gas production and chemical composition of feed was reported (Menke and Steingass. 1988). The in vitro gas production method has been widely used to evaluate the energy value of several classes of feed (Getachew et al., 1998;2002). A direct correlation between metabolisable energy was recorded from in vitro gas production together with CP and fat content. This compared with metabolisable energy value of conventional feeds measured in vivo (Menke and Steingass, 1988). The results obtained in this study is in order with that reported elsewhere (Mako et al., 2009). This could be due to the varying levels of oil present in each diet. This however, was not in line with other reports (Babayemi, 2007; Hriston et al., 2009). 4.10. The pH of graded fermented mixtures of Oil palm slurry and Cassava peel The pH is a strong determinant of the microbial activity in the rumen. Documented pH level for optimum rumen microbial performance is between 6.5-6.9 (Grants and Mentes, 1992). All the pH values obtained in this experiment were within the recommended range for normal rumen performance. Hriston et al., (2009) noticed that oil inclusion to diets increased pH of the rumen slightly. The trend is at variance with the finding at 60 hrs. The pH increased as CaP inclusion rate increased as reported by Phengvilaysouk and Wanapat (2008). At 24 and 96 hrs for buffallow when fed cassava hay supplemented with different levels of coconut oil. Kamel et al.,( 2009) described pH as dependent on administrated dosage of the substrate composition and microbial population in the inoculum. This explains the variations in the response observed at different levels of oil supplementation. At 60 hrs of fermentation, a peculiar drop in pH was observed for diet C. This observation connotes the tendency of microbes in using carbon from oil as carbon source for cellular protein synthesis (Roger et al., 1977). This produced VFAs (propionate, acetate and butyrate ) which are acidic, hence, a drop in the pH (6.21).The protein fermentation produced branched chain fatty acids (valeric, iso-valeric and iso-butyric acids) which increased the pH (6.61) at 96 hrs. This suggests that the oil to cassava peel ratio was favourable for microbial actions and nutrient release as in line with the report of Yang et al., (2000). 91 - 4.11. Ammonia Nitrogen Concentration (NH3 N) of fermented graded mixtures of Oil palm slurry and Cassava peel The pH and ammonia nitrogen concentration has a direct relationship. The pH is directly proportional to the ammonia nitrogen concentration. The concentration of ammonia in Diet A (4.0) was the least obtained at 24 hrs, among all the diets. At 60 and 96hrs, slight increase in the concentration was observed. This suggested that ratio of oil to cassava was not too favourable and could have inhibited activities of the microbes. Another important factor might be the low crude protein content (8.10 %) observed compared with other diets, since the ammonia concentration is a function of the crude protein content in the feed. The value observed was lower than the values stated by other authors (Preston and Leng. (1987); Wanapat and Pimpa, (1999 ). The trend of ammonia nitrogen produced as Diet C was steady from 24 to 96 hrs, and was within the range of value cited elsewhere (Boniface et al., 1986; Preston and Leng. 1989) as the optimal level for microbial activities. All the other diets including the control, also recorded values within the reported range for optimal microbial performance. This might probably be due to the favourable range in pH values, for optimal performance (Grants and Mentes. 1992). 92 CHAPTER FIVE 5.1 PERFORMANCE CHARACTERISTICS AND TOTAL RUMEN MICROBIAL COUNT OF WEST AFRICAN DWARF SHEEP FED FERMENTED GRADED MIXTURES OF OIL PALM SLURRY AND CASSAVA PEELS 5.2. INTRODUCTION The ultimate focus of livestock industry is the conversion of feeds into prime animal products, which are either edible to man or surplus for his basic requirement (Payne and Wilson, 1999). The frequent increase in price of conventional feedstuff such as maize, millet, sorghum and soybean and also the competition between human and livestock for feed ingredients as a source of feed, has made most ingredients unaffordable for livestock feeding especially ruminants. Another limiting factor to the use of conventional feedstuff is the unavailability at the time they are required for feeding. The search for such alternative feedstuff has brought agro industrial by products in focus. These unconventional feedstuffs are readily available, economical and are abundant at various processing sites thereby, making them very acceptable particularly, to ruminant husbandmen. A very important reason for the wide acceptability of these agro-industrial by products by ruminants, is their innate ability to synthesise high quality protein from non-protein nitrogenous (NPN) compounds, through the action of microorganisms present in their digestive tract (Cott, 2009). Protein available for digestion in the small intestine thus consists of microbial protein and feed protein that has escaped microbial breakdown in the rumen (Preston, 1995). Cassava peels (CaP) and Oil palm slurry (OPS) are agro-industrial by-products that possess same attributes earlier ascribed to these wastes. A unique characteristic, which they both bear, is that both are by products of cash cropping, and are harvest both frequently within a year, thereby making their wastes abundantly available throughout the year. However, while research have been conducted on the use of cassava peels as feed for ruminants, there is dearth of information on the use of oil palm slurry as feed 93 for ruminants. In addition, the use of a combination of Oil palm slurry and Cassava peel as fed for ruminants requires investigation. The quality of a feed is considerably determined by its physical characteristics, which may be relatively independent of its chemical composition. Feeds and foods are not equal in their capacity to support the rational functions of animals such as maintenance, growth, reproduction and lactation. Feeds supply energy and the essential nutrients in the form of proteins, vitamins and minerals. Energy and protein are limiting nutrients in ruminant ration and have so far received the most attention in evaluation systems (Preston, 1995; Arowora, 2002). Acceptability or free choice intake attributes of a feed connotes the actual response of an animal to a particular feed and the possible visual effects of the feed to the animal. This conversely depicts the efficiency of the feed in the rumen (Van Soest, 1995). Digestibility trial shows a fast mimic of the extent of nutrient breakdown of the proximate constituents and the fibre fractions of a feed in the rumen of an animal. It is a valid measure of how nutritious the feed is. It could also be defined as the proportion of a feed that is available to the animal for absorption from the gastro-intestinal tract. (Awah, 1981) Rumen microorganisms are responsible for the degradability of feedstuff prior to its digestibility by the host animal (Idahor, 2006). Therefore, it is important to examine the effect of the collective microorganisms in the rumen of an animal. This will complement the in vitro determination in the laboratory thereby categorically estimating how much the feed would meet the requirements of the animal for growth and other metabolic activities. This study was undertaken to evaluate the accceptability, digestibility and estimation of the total ruminal microbial count of WAD sheep fed fermented graded mixtures of Oil Palm slurry (OPS) and Cassava peel (CaP). 94 5.3 ACCEPTABILITY STUDY 5.3.1 Free choice intake of fermented graded mixtures of OPS and CaP 5.3.2 Material and method Sample of OPS were collected from four different oil palm processing locations in the South Western Nigeria namely: Oyo state-Badeku, Osun state-Ikoyi, Ogun state- Mamu, Edo state- Nifor Cassava peels was also collected from a cassava-processing unit at Eleyele in Ibadan. Both (OPS) and (CaP) were combined as follows: Diet A - 1litre OPS +1kg CaP Diet B - 1litre OPS +2kg CaP Diet C - 1litre OPS +3kg CaP Diet D- 1litre OPS +4kg CaP Diet E - 1litre OPS +5kg CaP Diet F - (Control)-CaP 6kg only The diets were tied and fermented for five days in airtight cellophane bags and then sun dried. 5.3.3 Experimental site The experiment was conducted at the sheep and goat unit of the Teaching and Research Farm, University of Ibadan, Ibadan, Nigeria, situated in the derived savannah O 1 O 1 vegetation belt. The location is 70 27 N and 30 45 E at an altitude of between 200 O and 300m above sea level. Mean temperature of 15-29 C with an average annual rainfall of about 1250mm. The soils are much drained and belong to the altisol (Babayemi et al., 2003).The surrounding of the house was sprayed with herbicides while the inside of the house was fumigated at 3 days interval with germicide and insecticide simultaneously for 18 days and left to rest for 3 days before the animals were brought in. The feed and water troughs were washed and disinfected to get rid of 95 any pathogens present in the vicinity. Analyses were carried out at the ruminant nutrition laboratory of the Department of Animal Science, University of Ibadan, Ibadan. 5.3.4 Experimental sheep Six WAD sheep weighing between 20.00-25.00kg aged between 5-6 months previously certified free of endo and ectoparasites by the University Veterinary department, were subjected to free choice feeding to evaluate acceptability of the combination of graded OPS and CaP levels (Diets A, B, C, D, E and F) in a cafeteria feed preference study (Babayemi et al., 2006). They were housed together in the sheep pens, which were constructed to achieve good ventilation. The floor of the house was made of concrete and covered with wood shavings for easy cleaning. 5.3.5 Feeding of animals The previously fermented diets were placed strategically in six different troughs and then offered to the sheep as outlined (Babayemi et al., 2006). The wooden feeder (150cm x 60cm) was used to, enable the six sheep feed simultaneously in a convenient situation. Each animal had access to each of the diets. The position of the feeders was changed every day before serving the diets to prevent adaptation of the animals to a particular diet. The feeding was allowed from 0800 to 1600 hours daily. Feed consumed was determined by deducting the feed refusal from the quantity offered. The experiment lasted fourteen (14) days in which the first (7days was for adjustment of the animal micro flora to the diets and the latter days was for data collection).The treatment preferred was accessed from the coefficient of preference (COP) value as follows using the formula. Co-efficient of preference (COP) = Average Intake / Individual daily Intake If COP is <1, the material will be rejected and when >1, the material will be accepted. (Bamikole et al., 2004) 96 Plate 4: Fermented graded mixtures of OPS and CaP during sun curing 97 Plate 5: Some sheep feeding on a diet during acceptability study 98 5.4 RESULTS 5.4.1 ACCEPTABILITY OF FERMENTED GRADED MIXTURES OF OPS AND CaP BY WAD SHEEP The coefficient of preference of graded mixtures of OPS and CaP fed to WAD sheep is shown in table 10. In this study, Diet C, recorded the highest COP value of (1.41) compared to other diets followed by Diet B, with a value of (1.11) while diets D and E recorded the lowest COP values of 1.00 and 1.07 respectively. Diets A and F recorded values of 0.82 and 0.75, which were, less than unity. 99 Table 10: Coefficient of Preference of fermented graded mixtures of Oil Palm Slurry and Cassava Peel fed to WAD Sheep Parameters Mean daily intake (kg DM) Coefficient of preference (COP) Diet A 2.46 0.82 Diet B 3.45 1.11 Diet C 4.51 1.41 Diet D 3.02 1.00 Diet E 3.23 1.07 Diet F 2.28 0.75 Diet A-1 litre Oil palm slurry + 1kg cassava peel Diet B -1 litre Oil palm slurry + 2kg Cassava peel Diet C- 1litre Oil palm slurry + 3kg Cassava peel Diet D- 1litre Oil palm slurry + 4kg Cassava peel Diet E-1litre Oil palm slurry + 5kg Cassava peel Diet F- 6kg Cassava peel 100 5.5 DISCUSSION Free choice intake or acceptability study of a feed is a quick accessement of the physical quality of the feed by the animal. It is one of the in vivo trials that reveals the actual reaction of animals to a feed. Coefficient of Preference (COP) is a direct measure of acceptability and nutritional capabilities of a feedstuff. In this study, some physical changes were observed after fermentation. Diet A had coffee brown colour and very oily, Diet B also had a coffee brown colour but contained lesser oil than A although they both had sweet aroma, diet C was slightly brown, crispy with a sweet aroma while diets D and E were of creamy white colour as the control diet F but without any particular odour. Diet C was the most relished with COP of 1.41. This might be attributed to its favourable physical attributes compared to other diets. The too oily appearance of diet A probably slowed down microbial activities in the rumen, which consequentially perhaps led to low digestibility therefore resulting in low intake. This might be the reason for its low acceptability by the sheep. Diet F was the least relished of all the diets.This might be due to the repulsive physical attributes. This conformed with the observations of Campel and Laherrere (1998) that fermentation of food in animal or plant tissue subjected to the action of microorganisms gives desirable biochemical changes and significant modification of food quality. The inclusion rate and time of supply of oil to a diet, could also affect microbial activity (Adebiyi, 2004). However, report (Krueger et al., 1974) that small ruminants prefer sweet and generally reject bitter plants, might be the reason why sheep accepted more of diet C due to the favourable OPS to CaP ratio which aided in reducing the antinutritional factor in the diet. This probably gave the microbes added advantages of breaking down the fibrous content resulting in the attributes exhibited over diet F (Adebowale, 1981). Oldham and Alderman (1980) also reported that ad libitum intake by animals was increased by higher crude protein content of diets. These findings also buttressed the reason for the highest value of COP for Diet C compared to other diets. This diet had the highest crude protein content of 14.15% while diets B, C, D and E were all consumed beyond the recommended body weight of 3-5% dry matter DM requirement 101 for ruminants (ARC, 1980; Devendra, 1978). Diets A and F were eaten below the recommended average body value. 102 5.6 DIGESTIBILITY OF FERMENTED GRADED MIXTURES OF OIL PALM SLURRY AND CASSAVA PEEL BY WAD SHEEP 5.6.1 Material and methods 5.6.2 Experimental site The experiment was carried out at the sheep and goat unit of the Teaching and Research Farm of the University of Ibadan, Ibadan Nigeria, between the months of December 2009 to March 2010. The animal pen was made of low walls of 1m by 1.5m in size and each pen was about 0.22 m long 0.12 m wide. The floor of the pen was made of concrete and the roof was made of the sheep unit which housed the pens was made of corrugated iron sheets. The pens were dusted and washed thoroughly with detergent and were further disinfected with broad-spectrum insecticide, acaricides and larvicides (diasuntol). The feeding and drinking troughs were washed and disinfected and the whole house was left to rest for two weeks before usage. Wood shavings were spread on the floor of the pen as bedding materials and there after replaced fortnightly. 5.6.3 Experimental animals Eighteen (18) post weaned female West African dwarf sheep aged 5-6 months weighing 20.0-25.0kg were used for the experiment. They were purchased from Oyo town in Oyo state. On arrival, the sheep were given prophylactic intramuscular treatment of oxytetracycline and vitamin B complex, at the dosage of 1m/10kg body weight of the animal. They were also drenched with albendazole to control endoparasites and treated for mange and other ectoparasites using Livermectin. 5.6.4 Collection of oil palm slurry (OPS) and cassava peels (CaP) Oil Palm slurry (OPS) was collected fresh from Mamu in Ogun State of Nigeria while fresh Cassava peel (CaP) was collected from a garri processing plant at Eleyele in Ibadan Oyo state. The samples were then mixed in various grades as follows: 103 (Diet A):1 litre OPS + 1kg CaP (Diet B): 1 litre OPS + 2kg CaP (DietC): 1 litre OPS + 3kg CaP (Diet D): 1 litre OPS + 4kg CaP (Diet E): 1 litre OPS + 5kg CaP (Diet F): 6kg CaP only Each of these mixture was tied in cellophane bags in an airtight condition to encourage microbial activities. Fermentation was carried out for five days and afterwards sun- cured. O Each sun-cured sample was then oven dried at 105 C (AOAC. 1990) and kept for dry matter determination 5.6.5 Experimental design The animals were allowed 2 weeks of adjustment to their new environment (acclimatisation) and the effect of the administered drugs to wear out. Three sheep of similar average body weight were randomly allotted into separate metabolic cages with fitted facilities for separate collection of feaces and urine (Akinsoyinu, 1974). The design of the experiment was a completely randomized design (CRD). Rumen fluid was also collected through suction tubes and analysis was carried out in 4 by 6 latin square arrangement. 5.6.6 Sheep feeding The experiment lasted 14 days, in which the first seven days was to adjust the sheep and their ruminal micro-flora to the new test diets and the latter was for data collection. The animals were fed at 0900 hours in the morning and at 0300 hours in the afternoon daily. Feed was served at 3% of the body weight of the animals. Water and salt lick were accessible to the animals throughout the metabolic period. Feed refused was weighed at 0800 hours every morning and deducted from the total offered for intake determination prior to serving new feed daily. Fresh water was also served ad libtum. During seven days of collection, total faeces and urine were collected, weighed and 104 O 10% aliquot was taken and stored in the freezer at -4 C. After 7-day collection period, the total faeces from daily collection were bulked, mixed and dried in the oven and kept till required for chemical analysis. Urine samples was collected and measured daily for each animal in the morning using measuring cylinder and kept into separately labeled containers. Two drops of concentrated sulpuric acid was added to each container daily after collection of each sample to prevent microbial growth and loss of nitrogen measured. Approximately 10% of total urine was sampled daily and stored at O -4 C till required for nitrogen analysis. Three days to the end of data collection, rumen fluid was collected from each animal prepandia (before feeding), and at three hours interval after feeding over a period of twelve hours. Samples were immediately squeezed out through a four layer cheese cloth after each collection into labeled 5ml plastic specimen bottles. The pH of each sample was immediately taken with the aid of a portable digital pH meter. The samples were then taken to the laboratory in a thermos -1 -6 flask for total microbial count. Each sample was diluted at the rate of 10 -10 with O sterile distilled water using pour plate technique for 48 hours at a temperature of 39 C. The plates were taken out and total microbial count was done with the aid of a colony counter. The remaining samples were then used to determine the ammonia nitrogen concentration by distillation with 0.01N HCL as described (Preston, 1995).The design of the experiment was a 4x6 factorial arrangement. 105 5.7 RESULTS 5.7.1 The proximate composition of experimental diet fed to WAD sheep. The proximate composition of experimental diet fed to West African Dwarf Sheep is represented in Table 11. The dry matter composition of all the diets revealed significant differences only among diets A (52.27) and C (71.04) while statistical similar variations in values were obtained for diets B (68.47) and F (68.42). Diets D and E obtained similar variation in values. The highest CP value (1.15) was obtained for diet C while the least value (5.50) was recorded for diet F. Ash values of 3.20 and 5.01 were significant for diets C and D only while diets A and B were statistically similar. Diets E and F were also not statistically varied. Significant (p<0.05) values were observed for the CF and EE. The least CF value (14.25) was obtained for diet C and the highest (20.36) was recorded for diet F. EE values 36.00 were highest for diet C while diet A obtained the least value of 21.20. 106 Table 11: Dry matter and Proximate composition (g/kgDM) of experimental diet fed to WAD Sheep Parameter Diet A Diet B Diet C Diet D Diet E Diet F SEM d b a c c b Dry matter% 52.27 68.47 71.04 63.29 63.00 68.42 0.05 d c a b b e Crude protein 8.10 9.05 14.15 11.25 11.21 6.50 0.08 c b e d ab a Crude fibre 18.96 19.20 14.25 17.00 18.04 20.36 0.03 d b e b c d Ash 6.58 4.29 3.20 4.98 5.01 6.90 0.01 e c a b ab d Ether extract 21.20 30.21 36.00 33.40 31.75 28.00 0.05 a ,b, c, d, e means on the same row with different superscripts are significant (p<0.05) Diet A-1 litre Oil palm slurry + 1kg cassava peel Diet B -1 litre Oil palm slurry + 2kg Cassava peel Diet C- 1litre Oil palm slurry + 3kg Cassava peel Diet D- 1litre Oil palm slurry + 4kg Cassava peel Diet E-1litre Oil palm slurry + 5kg Cassava peel Diet F- 6kg Cassava peel WAD – West African Dwarf SEM-Standard Error of Means 107 5.7.2. Apparent nutrient digestibility and nitrogen utilisation by WAD sheep fed fermented graded mixtures of OPS and CaP The apparent nutrient digestibility and nitrogen utilization by West African dwarf sheep fed graded mixtures of OPS and CaP is shown in Table 12. The results revealed that the variations in DM digestibility were significant (p<0.05) only on animals placed on diets A and C recording 58.41 and 89.43. Animals on diet C had the highest CP digestibility value of 92.70 and the least 80.I6 for sheep on diet A. The CF digestibility was significantly p<0.05 high for Diet C with a value of (87.39) followed by Diet B (86.88) while the least value p< 0.05 (56.02) was observed for Diet A. The values obtained for EE, ADF, NDF and hemicellulose contents were statistically similar p>0.05 108 TABLE 12: Apparent nutrient digestibility (%) by WAD sheep fed fermented graded mixtures of Oil palm slurry and Cassava peel. Parameters Diet A Diet B Diet C Diet D Diet E Diet F SEM e b a d c ab Dry matter 58.41 76.08 89.43 70.21 70.64 74.52 2.05 d c a b e b Crude protein 88.16 89.48 92.70 90.00 80.26 90.32 1.02 e c a b ab d Crude fibre 56.02 78.48 87.39 85.88 80.00 64.05 2.23 Ether extract 90.90 95.00 91.35 83.17 93.24 92.04 3.12 Neutral detergent 83.42 88.45 90.05 84.96 88.55 85.66 1.07 Fibre Acid detergent fibre 54.29 72.86 76.84 64.25 73.51 66.76 2.88 Cellulose 17.59 28.74 36.63 23.29 17.08 15.60 2.05 Hemicellulose 13.82 15.59 17.93 20.71 15.04 18.90 1.45 Diet A-1 litre Oil palm slurry + 1kg cassava peel Diet B -1 litre Oil palm slurry + 2kg Cassava peel Diet C- 1litre Oil palm slurry + 3kg Cassava peel Diet D- 1litre Oil palm slurry + 4kg Cassava peel Diet E-1litre Oil palm slurry + 5kg Cassava peel Diet F- 6kg Cassava peel WAD – West African Dwarf SEM-Standard Error of Means 109 5.7.3 Nitrogen utilization by WAD sheep fed fermented graded mixtures of Oil palm slurry and Cassava peel The nitrogen utilization of sheep fed graded mixtures of Oil palm slurry and Cassava peel is shown in table: 13. The N-utilisation of sheep, N-intake, fecal-N, Urinary-N, N- balance and N-retention, ranged from 10.00-16.01g/d, 1.45-4.24, 0.60-1.20, 2.01-5.45, 45.60-75.05 % respectively. Significant variations (p<0.05) were observed in the fecal-N and N- retention of the sheep fed graded mixtures, with sheep on Diet C (4.24,75.05) recording the highest values for both parameters while least values (1.45,45.60) were obtained for sheep on Diet A. N-Intake varied significantly (p<0.05) for sheep fed Diets, A, B, C and F. The highest values was obtained for sheep on Diet C (16.01g/dm) and lowest for sheep on Diet A (10.00g/dm). Statistical similar variations in values were obtained for sheep on diet D and E. Same trend was observed for the Urinary-N and N-balance for animals on Diets A,B,C and F. The value of (1.20g/d) was least for animals on Diet C for Urinary- N, while the highest value of (1.20g/d) was recorded for animals on Diet A. Treatment effect was not significant (p>0.05) for animals on diets D and E. The value of 5.45 was significantly (p<0.05) higher for animals on Diet C followed by 4.89 for animals on Diet F while those on diet A was least with the value of 2.01. Treatment effect was also not significant (p>0.05) for sheep on diets D and E. In the total digestible nutrients, the CP, CF, EE, NFE and TDN were all significantly (p<0.05) highest for sheep on diet C with the values of 11.51, 20.22, 15.09, 34.18, 73.04% respectively. Sheep on diet F followed with variations of 13.05, 18.79, 13.10, 32.06 and 69.24% values respectively. The least significant variations for all the parameters were recorded for sheep on diet A. 110 Table 13: Nitrogen utilization by West African dwarf sheep fed fermented graded mixtures (%) of Oil palm slurry and Cassava peels Parameters Diet A B C D E F SEM e c a d d b N-Intake (g/d) 10.00 14.21 16.01 13.45 13.89 15.00 0.02 a b e c ab d Feacal-N (g/d) 4.24 2.51 1.45 1.70 1.82 1.63 0.04 a b e c c d Urinary-N (g/d) 1.20 1.00 0.60 0.84 0.80 0.75 0.04 Total-N excreted (g/d) 5.40 3.51 2.01 2.54 2.62 2.38 0.02 d a c c b N-Balance (g/d) 4.56e 10.7 14.0 10.91 b 11.27 12.62 0.02 e d a c ab b N-Retention(%) 45.60 56.00 75.05 60.01 65.35 70.25 0.01 111 Table 14: Digestible Nutrients intake (%) by West African Dwarf sheep fed fermented graded mixtures of Oil palm slurry and Cassava peel Diet composition Parameters A B C D E F SEM d c a b ab e Crude Protein 5.27 7.75 11.51 9.45 8.90 4.05 1.21 e d a c c b Crude Fibre 9.03 13.45 20.22 17.67 17.32 18.79 0.89 e c a c d b Ether Extract 12.00 13.78 15.09 13.23 12.40 13.10 0.21 e d a b dc c Nitrogen Free Extract 23.70 30.11 34.18 32.65 31.88 32.06 1.10 e d a c ab b Total Digestible Nutrients 53.90 58.06 73.04 60.57 62.00 69.24 0.09 a, b, c, d, e means on the same row with different superscripts are significantly different(p<0.05) Diet A - 1 litre Oil palm slurry+ 1kg cassava peel Diet B - 1 litre Oil palm slurry+ 2kg cassava peel Diet C - 1 litre Oil palm slurry+ 3kg cassava peel Diet D - 1 litre Oil palm slurry+ 4kg cassava peel Diet E - 1 litre Oil palm slurry+ 5kg cassava peel Diet F (control) 6kg cassava peel only SEM=Standard Error of Means 112 5.8 DISCUSSION High protein, feeds have been found usually acceptable, stimulate appetite and digestive activity (Cott, 2009). In this experiment, animals on diet C had the highest DM (Dry matter) and CP (Crude Protein), compared to animals on other Diets and the control. This indicated that maximum microbial activity at this ratio of OPS to CaP was probably attained. This may be linked to its high CP of 14.15% obtained from the proximate composition. Sheep on control (Diet F) recorded lower values of DM and CP compared to those on Diet C. This may be attributed to the residual anti nutritional factor (glucocyanide) present even after fermentation. Adebowale (1981) observed that about 80% of the anti nutritional factors only could be removed in cassava peel after fermentation. Treatment effect of OPS to CaP ratio was least observed on the DM and CP digestibility parameters in sheep placed on Diet A, which might be due to a higher concentration of oil to cassava ratio that could have hindered the effect of rumen microbes (Jones and Porter, 1998). However, there is the dearth of information on any particular level of oil palm slurry to cassava peel inclusion in the DM and CP digestibility of nutrients in sheep or small ruminants. The residual oil present in the slurry represents a percentage of palm oil in feed. Conversely, Gonzalez et al. (1999) reported no treatment effect on DMI digestibility in the use of 0.5 and 10% palm oil with diets based on cassava foliage meal for growing pigs. The DMI values of animals on diets B, D, E and F, in this study, compared with the range of values obtained by Mako (2009), when Water hyacinth, Guinea grass and concentrates were fed to goats. The lower values observed for animals on diet A could be adduced be attributed to low activity of the micro flora in the rumen, hence low by- pass protein from the rumen, subsequent low digestion as well as absorption in the omasun abomasum (Mako, 2009) due to high concentration of oil in the diet. However, reduced feed intake has been established to have a direct relationship with feed retention time in the rumen. (Van Soest, 1995). Nguyen et al. (2005) where a linear increase in DM was observed as the level of oil ingestion increased. As the strength of OPS decreased due to increased inclusion of cassava peels, DM digestibility in this study increased Nguyen and Thom. (2004) reported similar results that groundnut oil at 5mI/kg live-weight could improve feed 113 intake, growth rate and profitability. The highest DM value(89.43) recorded, for sheep on diet C in this work was higher than 71.2; 83.3% reported by Chhay et al. (2003) for diets in which levels of palm oil were added to basal diet of ensiled cassava leaves. These values were similar to 76.08 and 74.52g/DM obtained for Diets B and F (control).The reported (Oldham and Alderman, 1980) high DM digestibility value for animals on diet C compared to those on diets B and F might be traced to the higher CP value recorded. The high CP digestibility in animals fed diet C compared with other diets in this study might be related to the high CP as earlier stated and the favourable mixture of the diet which aided microbial breakdown. However, this CP value of the diet is higher than the 8-12% (ARC) recommended ammonia levels required for optimal rumen functioning of small ruminants. The excess ammonia produced could be a useful source of protein build up by the rumen micro flora for microbial activities. An inference drawn from the reports of Shahid et al., (2000) was that excess ammonia not utilised by the microbes was absorbed in the blood circulation and converted to urea in the liver, with a consequence of metabolic burden on liver of the animal. The CP digestibility (90.26g/DM) obtained for animals on diet F (control), was higher than those of animals on other diets except diet C. This could be connected to the residual anti nutritional factor present after fermentation that aided in protecting the protein from fermentation in the rumen. F Foulkes and Preston (1978); Wanapat et al. (1997), indicated that cassava hay was a good source of rumen by-pass protein due to the condensed tannins acting to protect the protein from fermentation in the rumen, which may increase the supply of amino acids to the small intestine. Animals on diet D recorded the least CP digestibility value; this was not expected because the animals on diet A recorded the least values in other parameters, hence the lowest microbial activity than animals on diet D and other diets. Therefore, reason for the low CP digestibility in animals on diet D could not be ascertained. The CP digestibility values of 88.16-92.70% obtained in this study were higher than those reported for Water hyacinth 80.13-67.89% (Mako. 2009) probably due to fermentation which influenced high microbial activity in the rumen of the animals. It has been reported (0kpako et al., 2008) that fermentation brings about high microbial activity hence high protein synthesis. 114 Digestibility value of crude fibre (CF) 87.39 obtained for animals on diet C, was the highest. This could be due to the favourable OPS to CaP ratios, which facilitated the high microbial breakdown of the cellulose cell wall in the diet. It could then be traced to the residual CP available to the microbes in the rumen of the animals as discussed earlier, which aided the diet in staying longer in the rumen. This caused a gang up of microbes in the breakdown of the CF contents in this diet for single cell formation (Mako, 2009). Oil has also been discovered an adjunct to fermentation (Jones and Porter, 1998). In the study of (Perry and Stewart, 1979), it was pointed out that the influence of oil at 3% inclusion level, in sheep diet significantly p<0.05 increased fibre digestibility. Sheep on diet A had the least value of CF compared to the animals on other diets and the control. The reduction in the build up of rumen microorganisms responsible for the breakdown of CF (Kane et al., 1965) might be the reason for this observation. This connotes that the ratio 1:1 of OPS to CaP mixture was unfavourable to the ruminal microflora of the animals for this diet thereby suppressing CF digestibility. Palmquist and Conrad (1980) reported no effect of fat on CF digestibility. Prak kea et al, (2003) also noted that, CF digestibility was not significantly different at all the levels of oil to broken rice inclusions, that has been established to have a direct relationship with feed retention time in the rumen (Van Soest, 1995). Observations from the present study, showed that ether extract (EE), nitrogen detergent fibre (NDF), acid detergent fibre (ADF), cellulose and hemicelluloses contents were not significantly influenced (p>0.05) by dietary treatments. However, Gonzalez et al. (1999) indicated for diets based on cassava foliage meal for growing pigs that NDF digestibility decreased while ether extract digestibility was enhanced with increasing levels of dietary palm oil. Further reports Phengvilaysouk and Wanapat (2008) revealed that supplementation of cassava hay with coconut oil significantly (p<0.05) improved digestion of NDF and ADF. Results of the N-balance showed that animals on diet C had the highest N-balance, which might be because of the relatively higher nitrogen intake and the high micro floral gang up towards the feed ingested. It could be deduced that the ratio of the feed mixture, i.e. OPS to CaP was favorable to the microbes in the rumen of the animals on this diet. The reduction in the microbial utilization by the animals fed diet A, may be connected to the low intake of the feed, due high CF and low CP composition of the mixture. Mako (2009) deduced that dry matter intake (DMI) was a limiting factor in 115 feed utilization since it will affect the overall performance of the animal which may result in a low microbial utilization of the feed. Cheng et al. (1984) reported that microbial colonisation of highly lignified particles was limited. Though the crude protein content of animals fed diet F was low compared to other diets, the value of N- retention obtained (70.25) was higher than that of sheep on the other diets except for animals on diet C. This observation could be due to the residual anti nutrient which might be present in the feed that aided in trapping down the bypass protein, hence a high N-retention as reported (Wanapat et al., 1997). The high total digestible nutrients (TDN) and apparent digestibility of dry matter, crude protein, positive N-balance and N-retention of animals on diet C may be indicative of proper utilisation of the feed by the animals placed on this diet as compared to other diets. 116 Plate 6: Culture showing some colonies formed after 48 hours incubation period 117 5.9 TOTAL RUMINAL MICROBIAL COUNT, pH AND AMMONIA NITROGEN CONCENTRATION OF WAD SHEEP FED FERMENTED GRADED MIXTURES OF OPS AND CaP 5.9.1 RESULTS The trend in the total microbial count in the rumen of sheep fed graded mixtures of Oil palm slurry and Cassava peel is presented in Figure 3. The trend in the graph revealed that at 0 hour (pre-prandia), animals on diets C, D and E had the least count of microorganisms in the rumen; with colony forming units (cfu) of 5.0, 5.0 and 5.0 respectively. Values for animals on diet B was (cfu) of 5.1 while Sheep fed diets A and F had cfu 5.2 and 5.3 respectively. At the third hour of collection, animals on diet F recorded a sharp decline in total microbial count with the value of 4.9 cfu. Sheep on diets B and E also had a slight increase in microbial population with values of 5.2 and 5.1 respectively. Animals on diet C, had a steady increase in total count (5.3). Diet A had a stationary microbial growth at this hour while Diet D showed a slight increase in total count (5.1) At the sixth hour, animals on Diets B and C followed yet a steady trend of increase in total cfu of 5.3 and 5.6 respectively. While sheep on Diet F showed a sharp increase to 5.3. The same growth rate was observed for animals on diet E which recorded an increase of 5.2. Sheep on diet D had a slight increase to 5.2 while diet A maintained a constant microbial growth of 5.2 cfu. At the ninth hour, the total ruminal microbial count for all the animals decreased with values of 4.9, 4.6, 4.9, 4.7 and 5.1 respectively for sheep on diets A, B, C, D, E and F. 118 5.8 5.6 Diet A 5.4 Diet B 5.2 Diet C 5 4.8 Diet D 4.6 Diet E 4.4 4.2 Diet F 4 O hr 3hrs 6hrs 9hrs Tme (hrs) Figure 3: Ruminal microbial growth curve of WAD sheep fed fermented graded mixtures of OPS and CaP 119 colony formng unit (Cfu) 5.9.2 Effect of time on ruminal pH and NH3-N concentration of WAD sheep fed fermented graded mixtures of OPS and CaP - The effect of time on ruminal pH and NH3 N concentration of WAD sheep fed fermented graded mixtures of OPS and CaP was shown on Table: 15. The results revealed that values obtained for pH did not vary significantly at all the hours of rumen liquor collection (0 to 9) hour. There were variations in ammonia nitrogen (NH3-N) concentration recorded at all the observed hours of rumen liquor collection with the highest values recorded at the third (17.9), sixth (16.2), ninth (9.5) and least value was recorded at 0 hour (4.3). 120 TABLE 15: Effect of time on ruminal pH and Ammonia Nitrogen concentration of WAD Sheep fed fermented graded mixtures of OPS and CaP Parameters Time (hrs) 0 3 6 9 SEM pH 6.3 6.3 6.28 6.25 1.25 NH3-N conc 4.38 17.94 16.23 9.57 2.45 OPS - Oil palm slurry CaP - Cassava peel Conc -concentration SEM= Standard Error of Means 121 5.9.3 Treatment effect on ruminal pH and NH3-H concentration of West African Dwarf Sheep fed fermented graded mixtures OPS and CaP Treatment effect on ruminal pH and ammonia nitrogen concentration of sheep fed fermented graded mixtures of OPS and CaP mixtures are represented on Table 16. It was revealed from the results that treatments had a varied effect on the pH of the rumen fluid. The least observed value of 6.35 was for animals on diet A while those on diets C, D and E were not significantly (p>0.05) varied. Sheep on diet F recorded the highest value of 7.12. The NH3-N concentration was also significant different in all the sheep on all the diets with the highest value of 13.19 for diet C while the least recorded value of 10.46 was for animals on diet A. 122 TABLE 16: Treatment effect on ruminal pH and ammonia nitrogen (NH3-N) concentration of W A D Sheep fed fermented graded mixtures of OPS and CaP. Diets Parameters A B C D E F SEM pH 7.12 6.52 6.60 6.58 6.20 6.64 0.08 NH3-N 10.46e 10.79d 13.19a 12.89b 12.04b 11.48c 0.01 concentrations a, b, c, d, e Means on the same row with different superscripts are significant (p<0.05) Diet A- 1 litre Oil palm slurry+ 1kg cassava peel Diet B- 1 litre Oil palm slurry+ 2kg cassava peel Diet C - 1 litre Oil palm slurry+ 3kg cassava peel Diet D - 1 litre Oil palm slurry+ 4kg cassava peel Diet E - 1 litre Oil palm slurry+ 5kg cassava peel Diet F (control) 6kg cassava peel only OPS – Oil Palm Slurry CaP – Cassava Peel SEM= Standard Error of Means 123 - 5.9.4 Interaction of time and treatment on ruminal pH and NH3 N concentration of WAD sheep fed fermented graded mixtures of OPS and CaP - The interaction between time and treatment on ruminal pH and NH3 N concentration of WAD sheep fed fermented graded mixtures of OPS and CaP is presented in Table 17. The interaction between time and treatment was not significant on pH at 0 hour. However, it was significant for NH3-N concentration. The least value (3.4) was recorded for sheep on control diet and the highest value of (5.5) for animals on diet A although no significant variation (p<0.05) was obtained for animals on diets C, D and E. At the 3rd hour, a significant variation was recorded for pH values among animals on all diets. The highest values (6.7) recorded was for the control and the least value was obtained for sheep on diet E (6.0). A significant variation was also obtained for the NH3-N concentration with the least value recorded for sheep on diet F (16.7) while the highest value was obtained for animals on diet A (19.5). The 6th hour observation revealed a significant variation (p<0.05) in diets. The least value of pH was obtained for animals on diet D (6.2) and the highest was reported in the control (6.6). There was no significant difference (p>0.05) between the animals on diets B 6.3 and C 6.5 variations also followed the same trend as observed for sheep on the control diet. Animals on control diet recorded the least value of 13.4 while sheep on diet B recorded the highest value of 18.8. Significant variations (p<0.05) were observed on the pH of animals on all the diets at the 9th hour. The highest value was obtained for sheep on the control (5.9). No significant differences were observed for the pH values among sheep on diets A, B and C while significant variations were also observed in the NH3-N concentrations. 124 TABLE 17: Effect of interaction between time and treatment on ruminal - pH and ammonia nitrogen (NH3 N) concentration of WADsheep fed fermented graded mixtures of OPS and CaP PARAMETERS DIETS pH NH3-N TIME a 0 HR (pre pandia) CONTROL 6.45 3.45 a A 6.50 5.50 c B 6.50 4.10 b C 6.20 4.56 b D 6.40 4.35 b E 6.10 4.35 AVERAGE 6.36 4.39 3HRS e CONTROL 6.70 16.67 a A 6.20 19.45 ab B 6.15 18.56 bc C 6.50 17.75 bc D 6.50 17.00 ab E 6.00 18.23 AVERAGE 6.34 17.94 6HRS e CONTROL 6.60 13.40 b A 6.20 17.65 a B 6.25 18.83 d C 6.55 15.49 d D 6.15 16.54 c E 6.20 16.45 AVERAGE 6.34 16.39 9HRS c 6.58 8.30 CONTROL a A 6.24 10.20 a B 6.30 10.05 a C 6.20 10.34 b D 6.00 9.03 b E 6.00 9.48 6.22 9.57 AVERAGE a,b,c,d means on the same row with different superscripts are significantly different (p<0.05) NH -3 N- Ammonia nitrogen SEM- Standard Error of Means 125 5.10 DISSCUSION A progressive increase in the microbial load signified a successful microbial degradation of a large proportion of the diets utilized for the synthesis of cellular protein needed for optimal metabolic activities. In this work, at the 0 hour (pre-pandia), varied ruminal microbial populations were obtained for animals on diets A, B and F while the same microbial counts were recorded for sheep on diets C, D and E. This observation is an indication of normal flora (McSwency et al., 2006), which is a function of the graded levels of diet previously fed to each group of animals prior to overnight starvation, thereby influencing the microbial level of the rumen before feeding. The graded levels of diet also had different carbon concentrations that could be the effect of the feed ingested the previous day on the microbial population before collection of rumen liquor the following morning. Also at this hour (pre-feeding), the reduction in the microbial population might be due to extinction of some microbes that could not survive after a series of microbial synthesis through glycogenetic pathway (utilisation of stored up glycogen). The survivors in a resting stage (no cellular division or multiplication), might be waiting for - the diet of the day to be reactivated for metabolic activities. Hence, a low NH3 N - recorded for all the diets was expected. NH3 N concentration for all the animals were within the standard range in literature pre pandia which is between 4-10 mg/ml (Hemston and Moir, 1979). Values lower than the recommended range recorded for animals on Diet F might be due to a high concentration of anti-nutritional factors such as (glycocyanide) which led to acidity. A high microbial activity is directly proportional to the efficient utilisation of nutrients in the diet. This could explain why there was a spontaneous reaction amongst all the sheep micro floral activity after feeding as observed in the NH3-N concentrations from 0 to 3rd hour. This finding conforms to those of Shahid et al. (2010) in the rumen metabolism of sheep fed poultry litter. A continous increase was obtained in the NH3- N concentration at 3hrs post feeding. In the control et, there was a gradual reduction in the microbial load which probably may have been an indication of the presence of residual anti-nutritional factor (Adebowale 1981) which corroborated the work of Pham Ho Hai et al.( 2009). 126 An increasing trend in the microbial load was obtained at the 3rd and 6th hours for all diets probably because the microbes still had sufficient nutrients available in the feed. This observation was contrary to that of Shahid et al. (2010) who obtained a decreased - NH3 N concentration at 6th hour post-prandia was observed. At the 6th and 9th hours, a decline in microbial load was observed in the rumen and this connotes the exhaustion of the nutrients in the diet by the microbes. Furthermore, there could have been an over crowdedness of microbes over a long period of cell divisions and multiplication, which could have caused a buildup of metabolites that were eventually toxic against them, leading to lag phase. 5.10.1 DIET A At 0 (pre pandia) to 3rd hour, stationary phase assumed by the microbes might have been as a result of the inhibitory effect of the oil concentration in OPS to CaP ratio of 1:1, which probably was capable of inactivating the microbial activities. Although, Wanapat et al, (2005); Phengvilaysouk and Wanapat. (2008) established that coconut oil supplementation reduced protozoa population in the rumen of buffalo. A slight resistance to the oil inhibitory effect by the microbes, was observed at the 3rd to 6th hours but at 6th to 9th hours, a reduced growth in the microbial load was noticed probably because the anaerobic microbes were in a stationary phase while the aerobic microbes were either inactivated or dead. This implied that very little of the nutrients was available to the animal for active microbial activity. This could be noticed in the low dry matter intake (DMI) of sheep placed on this diet. 127 5.10.2 DIET B From 0 to 6th hours, there was a gradual but slow rate of increase in the microbial growth with the sixth hour corresponding to the optimum growth, this trend is an indication of the unfavorable strength of oil to cassava peel ratio (1:2) which had a negative effect on microbial interactions. Though the impact was less observed yet, nutrient was released to the animals but the microbes were not at the best of their performance. 5.10.3 DIET C The consistent increase of the microbial load that continued in a progressive manner from 0 to the 6th hours where optimal growth was recorded could be due to a favourable ratio of OPS to CaP (1:3). In this diet; highest microbial load was observed. It can then be deduced from the animals on this diet that the microbes were at their best active performance and nutrient was released to the sheep steadily. Shahid et al. (2010) explained that increased DMI reduced the cellulose cell wall or structural carbohydrates, with a corresponding increase in cell contents as well as increased rate of digestion due to microbial stimulation with corresponding increases in microbial population and protein synthesis. Therefore, high DMI obtained from sheep on this diet might be an added advantage for its gradual and steady increase in microbial load. Between the 6th and the 9th hour, a remarkable decline in cellular synthesis was observed which might be an indication of the efficient utilisation of nutrients in the diet by the microbes. Although this work did not focus on classification, a decrease in protozoan population will positively affect bacteria population, which favours fibre degradation. 5.10.4 DIET D Between 0 to 3rd hours, a slight increase in microbial population was observed at which optimal microbial growth was attained at the 3rd hour, due to the availability of nutrients. A continuous growth could not be maintained at 3rd to 9th hours because of possible cidal effect of the potentially toxic ingredient in the diet. The slight increase observed in the microbial growth might have resulted from the utilisation of the 128 nutrients to build up their resistance against the toxic level of the diet which the inclusion ratio (oil to cassava ratio; 1:4) could not breakdown totally. 5.10.5 DIET E Though the microbial growth was progressive, yet it was not at an optimal increase from the 0 to the 6th hour due to an unfavourable ratio of oil to cassava peel (1:5). 5.10.6 DIET F The negative growth of the microbes from the 0 to the 3rd hour which was different from all the other diets cannot be defined, but might possibly be as a result of the toxic threshold of the glycocyanic content of the diet which influenced the extinction of some microbes. An exponential increase (from a point of exponential decrease) might have been due to the slow but gradual self-replication of the survivors until a resistance was built against the toxic level up to the 6th hour. In other words, nutrient supplied by diet F might be inadequate for the animal. 5.11 EFFECT OF TREATMENT ON RUMINAL AMMONIA NITROGEN - (NH3 N) AND pH OF WEST AFRICAN DWARF SHEEP FED FERMENTED GRADED MIXTURES OPS AND CaP - The most suitable rumen NH3 N levels for microbial activities were 5 to 20mg/100ml in ruminants fed on low quality roughages (Boniface et al., 1986). Preston and Leng, - (1987) also reported that the optimum level of NH3 N in rumen fluid for microbial growth ranged from 5 to 25mg/ml and a range of 8.5 to over 30mg/ml was considered optimum by (Mc Donald et al., 1996). The results from all the diets in this experiment ranged within all the findings of the above authors irrespective of the level of oil supplementation. This result is also similar to the findings of Wanapat et al. (2005), observed that the NH3-H concentration in the rumen fluid was not significantly affected by increasing level of oil in the diet. 129 The pH of 7.12 that was recorded for Diet A must have been associated with the unfavorable OPS to CaP mixture, which reduced the microbial activity although the effect of the oil and fermentation might be a reason for the alkalinity. Jones and Porter (1998) described oil as an excellent adjunct for improving fermentation productivity and in the reduction of anti-nutritional factors. The pH values of other diets fed, including the control in this study was within the recommended range (6.5-7.0) - indicated for optimal rumen microbial activity. Therefore, the NH3 N might be a better determinant of the best-preferred diet. This might perhaps be Diet C because it recorded the highest stipulated value within stipulated values within the range in literature. 5.12 EFFECT OF TIME ON RUMINAL pH AND AMMONIA NITROGEN - (NH3 N) CONCENTRATION OF WAD SHEEP FED FERMENTED GRADED MIXTURES OF OPS AND CAP - Maximum production of NH3 N at 6 hours of collection indicated that active degradation by the microbes had just commenced. At the 9th hour, there was a drop in - the production of NH3 N which may be an indication of a negative time of collection due to the total utilization of nutrients in the rumen by the microbes. 5.13 EFFECT OF INTERACTION BETWEEN TIME AND TREATMENT ON - RUMINAL pH AND AMMONIA NITROGEN (NH3 N) CONCENTRATION OF WAD SHEEP FED FERMENTED GRADED MIXTURES OF OPS AND CaP - The highest average pH (6.36) value and the least ammonia nitrogen (NH3 N) 4.39 concentration were both observed at 0 hour. This could be due to low nutrient availability, which implies low microbial activity. At 3 hours post prandia, a sudden - increase in NH3 N (17.94) was recorded with no numerical variation obtained for pH (6.34). This increased value might have resulted from the efficient feed utilization which was in accordance with the report of Shahid et al. (2010) that - NH3 N increased significantly at 3 hours post feeding. At 6 hours after feeding, pH - was constant but a slight reduction in NH3 N concentration was observed, probably 130 due to the utilization of the nutrients by the microbes in building up of their cellular protein (Shahid et al., 2010). A drastic decline in value was observed in both pH - (6.22) and NH3 N (9.57) concentration at the 9th hour and this could be due to nutrient deficiency and reduced microbial population. If the degradation were - allowed to continue beyond the 9th hour, a further reduction in pH and NH3 N could have been recorded, this would have probably led to the proliferation of lactic acid bacteria with an eventual production of excess lactic acid resulting in lacticacidaemia. 131 CHAPTER SIX 6.1 SUMMARY, CONCLUSION AND RECOMMENDATION 6.2 Summary The inadequate supply of forage all year round, land acquisition by the government for non- agricultural purposes and the incessant increase in prices of conventional feedstuffs are some of the factors hindering the adequate production of ruminant livestock in Nigeria. Recent efforts are therefore, focused towards the use of alternative sources, which are, less expensive, not in competition with man as feedstuff and are readily available to each locality. In Nigeria, cassava peel has been widely acceptable as a source of feed for ruminants. th Nigeria is the 5 largest palm oil producing country but there is dearth of information on the use of its effluent (Slurry) as alternative feed resource for ruminants. Therefore, this study involved three different experiments meant to evaluate the nutrient potential of fermented combination of both ingredients for ruminant (sheep) feeding. 6.3 Conclusion The chemical composition of oil palm slurry collected from different locations in this study, indicated a higher Crude Protein value than Cassava peel which had a positive influence on the Crude Protein fortification of the fermented combination of Oil palm slurry and Cassava peel. Fermentation also improved the quality of the mixture by breaking down the fibre contents in each graded combination through microbial metabolic activities. The best result was obtained at the ratio 1:3 Oil palm slurry to Cassava peel. However, this dilution ratio of oil palm slurry to cassava peel is an important factor to be considered. The in vitro fermentation results revealed that the effective degradability was most efficient at the ratio of 1:3, Oil palm slurry to Cassava peel. Mixtures at higher or lower ratios were not as effective. Acceptability results revealed that fermentation improved the physical and chemical stability of the diets depending on the dilution ratio. The Total Digestible Nutrients, N- Balance and N-Retention and total microbial count of the rumen microbes indicated 132 that optimum performance in West African Dwarf sheep was best at 3% CaP to 1litre Oil palm slurry. At the ratio of 1:3 (OPS to CaP), minimum cassava peel with little quantity of oil palm slurry will be required thereby controlling the economy of alternative feed resources. Ordinarily, diet F was expected to perform best but oil inclusion has enhanced best performance in diet C. 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