Browsing by Author "Anifowose O. R."

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Causal Factors of Mass Mortality of Hatchery Reared Clarias gariepinus fry during Exogenous Feeding
(AkiNik Publications, 2021) Anifowose O. R.; Oladosu G. A.; O. O. Oladele
The study investigated the causal factors associated with mass mortality of hatchery-reared Clarias gariepinus Burchell 1822 fry during exogenous feeding. A feeding trial and fry re-infection trial were conducted using four different starter diets. The food samples were fed to 480 post-yolk-absorbed fries for 21 days in two replicates. Samples of dead fry were cultured for bacteria using standard methods. The total aerobic and coliform were significantly higher in all food samples, meanwhile, alkaline pH (9.25±0.34) and low dissolved oxygen (4.5±1.08) were not significantly different (P>0.05) in all water tanks. The bacterial pathogens isolated from dead fries were Aeromonas hydrophila Stainer, 1943 and Pseudomonas aeruginosa Migula, 1990, whereas significantly higher mortality in experimentally infected fry was observed (α < 0.05). Mass mortality of C.gariepinus fry observed in this study was associated with bacterial pathogens, bacterial contamination of food, alkaline pH, and low dissolved oxygen
Comparative growth performance and survival of hatchery reared African catfish fry (Clarias gariepinus Burchell 1822) fed on live and artificial diets
(Akinik Publications, 2022) Anifowose O. R.; Oladosu G. A.; Oladele, O. O.
Background: Feed determines to a large extent the sustainability in aquaculture since the survival and growth of the fish fry depends on the quality of feeds. The comparative growth performance and survival in Clarias gariepinus fry fed with live and artificial feeds were carried out. Methods: Four hundred and eighty healthy fries collected from a commercial hatchery were randomly divided into four experimental groups of 40 fry with three replicates for each group, and fed with four different feeds (three live feeds and one artificial feed) to differentiate each group; Artemia Lush® (AL), Artemia Inve® (AI), Dried-ground Shrimp (S), and artificial feed Durante® (D) for three weeks. The proximate composition of feed samples was analyzed, Physico-chemical parameters and microbiological analysis of water in experimental tanks were analyzed on weekly basis. The fish were assessed for growth performance and survival on weekly basis. Results: There was a significant difference of P< 0.05 in all proximate compositions of the feeds analyzed, there was no significant difference (P> 0.05) in the Physico-chemical parameters of water in the experimental tanks within twenty-one days. The final weight, final length, specific growth rate, and survival of fry fed with live feeds Artemia were similar to artificial feed Durante® but the economic analysis was reduced in artificial feed compared to live feeds while fry fed with Dried-ground Shrimp had poor growth and survival rate. Conclusion: The feeding of live and artificial feeds to Clarias gariepinus fry within the first twenty-one days produced a similar growth response and survival rate but artificial diet required reduced cost than live diets while dried-ground shrimp should not be recommended for feeding Clarias gariepinus fry.
Pathogenicity of Aspergillus fumigatus in experimental infection of different developmental stages of Clarias gariepinus
(Science domain International, 2023) Owolabi M. O.; Anifowose O. R.; Oladosu G. A.; Wolabi O. O.
Aims: This study aimed to investigating the pathogenicity of Aspergillus fumigatus in the experimental infection of Clarias gariepinus fingerlings and juvenile catfish. Experimental Procedure: Aspergillus fumigatus used for this study was isolated from the gills and liver of infected juveniles presented for microbial diagnostic examination, cultured on Sabouraud dextrose agar for 3 – 4 days, and identified at the Aquatic Animal and Wildlife Laboratory (AAWL), Department of Veterinary Medicine, University of Ibadan. Methodology: One hundred and forty healthy eight-week old Clarias gariepinus fingerlings (average weight of 4g) and 140 healthy sixteen-week old juvenile (average weight of 10g) were purchased from a commercial fish farm in Ibadan. The fingerlings and juveniles were randomly divided into seven groups, each with 20 fish in five litters of water. The fungal suspension containing 3.2 X 106 spores/ml of Aspergillus fumigatus was used for the pathogenicity test. Six groups were infected by immersion in water containing fungal spores at the rates of 2ml/L and 5ml/L for fingerlings and juveniles respectively. The clinical signs, skin lesions and mortality were observed daily for 14 days. Results: Aspergillus fumigatus isolated in this study has green spiked conidia; and the size of the conidia is 2.5µm. The conidia have a smooth surface and small spikes covering their surface. Moreover, the mortality rate was significantly (p = 0.40) higher in infected fingerlings (80%) than juveniles (62%) at fourteen days post-infection. The gross lesions observed during experimental infection of fingerlings and juveniles included exophthalmia, atrophied barbel, congested trunk kidney, hyperemia of gill filaments, and skin depigmentation. The histopathological organ changes caused by Aspergillus fumigatus were obvious in the liver and gills. Vacuolar degeneration of hepatocytes and necrosis of some melanomacrophage cells, in addition, severe erosion of the primary and secondary lamellae, were observed in infected juveniles. Conclusion: Aspergillus fumigatus causes high mortality in fingerlings and juvenile of African Catfish (Clarias gariepinus).