Effects of Varying Protein Levels on Clarias gariepinus (Burchell, 1822) Growth, Protein Utilization and Yield in Hapa System

The study evaluated effects of varying dietary protein levels on growth, protein utilization, survival and yield of the African catfish, Clarias gariepinus using floating net-hapa (1 m x 1 m x 1 m) system. A total of 300 catfish fingerlings (4.50± 0.01 g) were randomly stocked at 20 fish/m3 hapa. Five diets: Diet 1 (40% cp), Diet 2 (42.5% cp), Diet 3 (45% cp), Diet 4 (47.5% cp) and Diet 5 (50% cp) were formulated and fed to triplicate groups for 24 weeks. Growth responses and economic performances of fish harvested under various treatments were evaluated. Results showed that no significant differences (p > 0.05) were observed in metabolic growth rate, percentage survival, total feed intake, cost of feeding and total cost of production in all the treatments. However, significant differences (p < 0.05) existed in specific growth rates, gross profit, profit index and economic conversion ratio. The preferential diet being 42.5% protein, produced the highest mean final weight (946.89 g), specific growth rate (3.21%/day), food conversion ratio (0.27), protein productive value (59.55%) and protein index (5.29 g/day), highest yield (17,850 kg/hapa), gross profit (774/hapa) and economic conversion ratio (58.98). From these results, it was concluded that C. gariepinus would grow best in floating net-hapa when fed diets containing 42.5% protein.