Dietary protein and energy modifications to maximize compensatory growth of channel catfish (Ictalurus punctatus)

A feeding trial was conducted to evaluate influences of dietary protein and energy modifications as well as indispensable amino acid supplementation o n channel catfish growth and body composition during compensatory growth. F our diets were formulated to contain 32% or 37% crude protein and were main tained isocaloric at an estimated digestible energy (DE) level of 3.0 or 3. 6 kcal/g; a fifth diet was formulated to be equal to the diet containing 32 % crude protein and 3.0 kcal DE/g but with the addition of an indispensable amino acid supplement at 5% of diet. Each of the five experimental diets w as fed to channel catfish initially weighing 17 g for 6 weeks using either satiate feeding (control) or not feeding for 3 days then feeding to apparen t satiation for the next 11 days in three cycles. Weight gain of channel catfish was significantly (P < 0.05) affected by die tary treatment with a dietary energy level of 3.6 kcal DE/g enhancing weigh t gain. Cumulative weight gain also was increased in fish fed diets contain ing 37% crude protein compared to those fed diets containing 32% protein or the diet supplemented with amino acids. Compensatory growth was observed i n response to the restricted feeding regime. Feed consumption was affected by dietary protein level and feeding regime. Fish fed diets containing amin o acid supplementation and 37% protein reduced cumulative feed consumption compared to fish fed the diets with 32% protein. Fish on the restricted fee ding regime had reduced feed consumption compared to satiate fed fish. Feed efficiency was improved in fish fed the high-energy diets and those fed th e diet with 37% protein. Fish on the restricted feeding regime also had imp roved cumulative feed efficiency compared to fish fed daily to apparent sat iation. Hepatosomatic index at the end of the experiment was altered by fee ding regime, while intraperitoneal fat ratio was elevated by feeding higher dietary energy. Composition of Liver and muscle was only slightly altered by dietary treatment. Therefore, the restricted feeding regime was capable of inducing elevated growth rates during refeeding but the dietary manipula tions did not augment growth rates. (C) 2001 Elsevier Science B.V. All righ ts reserved.