Effect of partial replacement of fishmeal with african yam bean (Sphenostylis stenocarpa) meal on eggs, sperm quality and spawning performance of African Catfish Clarias gariepinus (Burchell, 1822) broodstock
Twelve months old African catfish Clarias gariepinus broodstock (mean weight 634±0.45 g) were cultured for 96 days in twelve (12) 1 m x 1 m x 0.7 m outdoor concrete tanks. There were four treatments with three replicates each. Four isonitrogenous diets at 37% crude protein were formulated at different inclusion levels of fishmeal to African yam bean meal. Fishmeal concentrations (550, 350, 150 and 000 g/Kg) were decreasing with increasing concentrations of African yam bean meal (000, 200, 400 and 550 g/Kg) for diets D1 (control), D2, D3 and D4. Fish were randomly selected and stocked at 5 fish per tank (3 females: 2 males). Fish were fed allotted experimental diets (000:550, 200:350, 400:150 and 550:000 g/Kg) at 5% of their body weight twice daily to evaluate their responses to feed, and its effects on their eggs, sperm quality and spawning performance. Fish fed formulated feed showed significant difference in reproductive performance over the control diet (000 g/Kg AYBM). Fish fed diet D4 (550 g/Kg) had significantly higher (p<0.05) milt volume (0.6±0.37) % motility (71.2±2.2), motility duration (25.9±0.4). The findings showed that diet D4 was the best diet and it gave a good result on fertility and sperm quality.
Key Words: African yam bean, sperm quality, milt volume, motility duration, fertilization, Clarias gariepinus.