Growth performance of Clarias gariepinus hatchlings fed on enzyme pre-digested dry diets from first feeding

Abstract

Lack of affordable larval diets is largely held responsible for the low survival (10-30%) and slow growth of catfish (Clarias gariepinus) fry, required for production of farmed human food fish and as bait for the Nile Perch fishery within the L.Victoria basin. Unlike the role of enzymes from live feed organisms that has been well documented, the role of microbial enzyme- incorporated dry diets is poorly understood in fish larval nutrition. Survival and growth of catfish larvae fed on phytase and protease pre-digested dry diets was evaluated as an alternative to expensive imported live feeds. Seven iso-nitrogenous (55% crude protein) dry diets were formulated and incorporated with phytase and protease enzymes at 750, 1000 and 1250 Units/Kg of feed. They were fed to C. gariepinus hatchlings after two days of hatching (after york absorption) as weaning diets along with hatchlings weaned onto Artemia for the first 24 hours and then onto an imported diet (Ranaan CS-starter feed/799 for catfish) in triplicates under hatchery conditions. There was significant differences in larval with the lowest in the control; zero enzyme (10.98%), highest in diet with 1250 units of protease followed by 1000 units of protease 94.23% and the imported diet with 41.66% survival). There was no significant difference in weight gain among diets (P= 0.40) but slight difference was observed in specific growth with the highest in larvae fed on the imported diet (0.21g) and least (0.06) in the control. These results indicated that enzyme pre-digested dry diets can nourish catfish larval as weaning diets.