Dietary arginine requirement of juvenile yellow perch

We conducted an 8-wk feeding experiment to determine the dietary arginine requirement of juvenile yellow perch (Perca flavescens). The basal diet contained 33 g crude protein/100 g diet (23 g crude protein supplied by crystalline L-amino acids and 10 g crude protein supplied by casein and gelatin). Eight dietary treatments contained graded levels of L-arginine-HCl ranging from 0.44 to 1.84 g/100 g dry diet in gradations of 0.2 g/100 g diet. Diets were made isonitrogenous with L-glutamic acid and were fed to triplicate groups of fish with an initial weight of 11 g/fish. Dietary arginine significantly affected weight gain and feed efficiency but not survival. The best weight gain and feed efficiency values were 155.3% increase from initial weight and 0.63, respectively. Quadratic regression analyses of weight gain and feed efficiency data indicated the dietary arginine requirement to be 1.61 and 1.41 g/100 g diet, respectively. We recommend 1.41 g L-arginine-HCl/100 g diet for juvenile yellow perch fed purified diets. The recently developed dietary arginine requirements of fish are surprisingly similar and generally higher than those of the ureotelic mammals and lower than the uricotelic birds.