FACULTY OF VETERINARY MEDICINE

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Subject: search.filters.subject.Aquaculture

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    Comparative evaluation of productivity and cost effectiveness of catfish fingerling production in earthen pond and recirculation system in Ibadan, Nigeria
    (2011) Adeyemo, O. K.; Ganiyu, O. I.; Olugasa, B. O.
    Despite the popularity of the African catfish and its great market potentials, the production is still basically at subsistence level due majorly to inadequate supply of seed for stocking. This has been linked to the absence of reliable production techniques for the mass production and rearing of the species under practical farming conditions. The purpose of this study therefore, was to find a suitable culture system for the mass production of catfish (Clarias gariepinus) fingerlings. Protected earthen pond and a unit of recirculation system were used. Fertilized eggs from female were divided into two equal halves and incubated under the same conditions. Forty-nine thousand frys each were stocked into the protected earthen pond and a unit recirculation system respectively. The frys in the two systems were raised for twenty one days and fed the same quantity and quality of feed throughout the period. The survival rate of the frys in the recirculation system was 79% as against 17% in the earthen pond. However, bigger sized (2.2 ± 0.23g) fingerlings were obtained from the earthen pond relative to those cultured in the recirculation system (0.9 ± 0.07g). The cost of raising frys in a recirculation system (N34,000) was twice that needed for earthen pond (N17,000), but this was more than made up for in the profit from sales, which was N311,360 and N99,156 respectively. The main reason for fish farming is the expected return to be, therefore, the choice of income-generating activities, amongst several options available, should be made on the grounds of their expected returns.
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    Comparative evaluation of productivity and cost effectiveness of catfish fingerling production in earthen pond and recirculation system in Ibadan, Nigeria
    (2011) Adeyemo, O. K.; Ganiyu, O. I.; Olugasa, B. O.
    Despite the popularity of the African catfish and its great market potentials, the production is still basically at subsistence level due majorly to inadequate supply of seed for stocking. This has been linked to the absence of reliable production techniques for the mass production and rearing of the species under practical farming conditions. The purpose of this study therefore, was to find a suitable culture system for the mass production of catfish (Clarias gariepinus) fingerlings. Protected earthen pond and a unit of recirculation system were used. Fertilized eggs from female were divided into two equal halves and incubated under the same conditions. Forty-nine thousand frys each were stocked into the protected earthen pond and a unit recirculation system respectively. The frys in the two systems were raised for twenty one days and fed the same quantity and quality of feed throughout the period. The survival rate of the frys in the recirculation system was 79% as against 17% in the earthen pond. However, bigger sized (2.2 ± 0.23g) fingerlings were obtained from the earthen pond relative to those cultured in the recirculation system (0.9 ± 0.07g). The cost of raising frys in a recirculation system (N34,000) was twice that needed for earthen pond (N17,000), but this was more than made up for in the profit from sales, which was N311,360 and N99,156 respectively. The main reason for fish farming is the expected return to be, therefore, the choice of income-generating activities, amongst several options available, should be made on the grounds of their expected returns.
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    Diazinon-induced clastogenity and pathological changes in ovaries and testes of clarias gariepinus
    (Scientific Research Publishing, 2014) Ola-Davies, O. E; Fagbohun, A. F.; Emikpe, B. O.; Adeyemo, O. K.
    In most tropical developing countries, one of the problems facing aquaculture industry is the pollution of ponds and rivers with pesticides. Chemicals such as diazinon, an organophosphate pesticide, originating from agricultural activity enter the aquatic environment through atmospheric deposition, surface run-off or leaching. Pollutants enter the food chain through accumulation in soft bottom sediment and aquatic organisms. However, information on how these pesticides affect inhabiting organisms is often not available. In a triplicate experimental set-up, seventy-two (72) apparently healthy catfish comprising adult and juvenile of both sexes were therefore exposed to a previously determined no effect concentration (0.405 ppm) of diazinon. Another set of fish was exposed to 0.0625 μg sodium arsenite, a known clastogen, which was used as the positive control, while another set of catfish exposed to the culture water alone was the negative control. Adults and juveniles were exposed separately to avoid cannibalism. After 48 hours of exposure, micronuclei induction was determined in subsets of experimental groups, while exposure continued for 28days. Catfish organs were harvested on days 21 and 28 to determine the effect of long-term exposure to diazinon on histology. Water quality was also monitored before and during exposure in the experimental groups. The result established a significantly high mean micronucleated polychromatic erythrocytes (15.00) in catfish exposed to diazinon suggesting genetic damage (normal is ≤4). The MPE in sodium arsenite exposed fish was 28, while that of the control group was below 4. Effect of sex and age on micronuclei induction was not significant. Histological alteration observed in the ovary and testis was distorted matured cells and extensive testicular degeneration, respectively. The results show that diazinon has clastogenic effect, and may have endocrine disrupting properties because of the histological changes induced in the ovaries and testis.