Evaluation of juvenile silver perch Bidyanus bidyanus (Mitchell) nutritional needs using high- and low-protein diets at two feeding levels

Juvenile silver perch Bidyanus bidyanus (Mitchell) of 3.2 g average weight were reared under controlled conditions on diets containing 23.4% and 40.6% protein. Diets were administered at 3% or 6% of the fish biomass per day, Both the protein concentrations and the feeding level of the diet influence d growth and proximate composition of the fish at the end of the 100-day gr owth trial. The energy requirement for these fish for maintenance was found to be 81.9 kcal x BW-0.8 and, for each unit of energy retained per metabol ic body weight, 7.05 needed to be supplied, whereas for each gram of protei n retained per metabolic body weight, 5.79 g were required. The results ind icate that it is possible to obtain the same weight increment when feeding a 23.4% protein diet at a level of 6% body mass day(-1) compared with only 3% body mass day(-1) of a 40.6% protein diet. This study provides the first estimation of nutrient requirements for juvenile silver perch, and these e stimations require further refinement.