Optimum feeding rate, and energy and protein maintenance requirements of young Clarias batrachus (L.), a cultivable catfish species

Abstract. Protein and energy maintenance and optimum feed requirements are reported in the catfish, Clarias batrachus (L.), fed a purified diet (40% CP; 1487·1kJ/100g) at 0 to 8% (BW/day) ration levels. Linear (r = 0·985) increase was observed in daily average growth increment up to a ration level of 4% (BW/day), corresponding to 6·03g protein/(kg^0·8BW/day) and 224·26 kJ energy/(kg^0·8 BW/day). Maintenance requirements, obtained by regressing daily average growth increment to zero, were 0·942 g/(kg^0·8 BW/day) for protein and 36·02 kJ/(kg^0·8BW/day) for energy. Net gains in muscle protein and energy also depicted linear increase (r = 0·975) with feeding levels up to 6·03g protein/(kg^0·8 BW/day) and 224·26kJ energy/(kg^0·8 BW/day). On fitting the above data to regression equations, giving the amount of dietary protein and energy required to maintain a constant amount of body protein and energy, values of 1·005g/(kg^0·8 BW/day) and 42·11 kJ/(kg^0·8BW/day) were obtained for protein and energy respectively. The optimum feeding rate for this species, as evident from specific growth rate and conversion efficiencies, appears to be 3% (BW/day) at 30 ± 2°C. Moisture and lipid contents in muscle were found to be significantly ( P < 0·05) affected by the ration levels.