LONG-TERM EVALUATION OF COTTON SEED MEAL AS A PROTEIN-SOURCE FOR NILE TILAPIA, OREOCHROMIS-NILOTICUS (LINN)

Long-term evaluation of different cotton seed meals (CSM) as protein sources for Nile tilapia, Oreochromis niloticus, was conducted. Corticated CSM (CC) and decorticated CSM (DC), with or without crystalline L-lysine supplementation, were incorporated into practical, isocaloric ( 475 kcal GE 100 g) diets containing approximately 30% crude protein. Fish meal (FM)-based diet served as a control. Test diets were fed to triplicate groups of O. niloticus (20 g) at a daily rate of 2-3% of their body weight for 130 days. Fish which received FM diet had significantly better percent gain, specific growth rate (SGR), feed conversion (FC) and protein efficiency ratio (PER) than those fed CSM diets. DC diets produced significantly better growth and FC than CC diets, while PER was not significantly different. The addition of crystalline L-lysine to CSM diets did not significantly affect fish performance. Cost/benefit analyses of the test diets indicated that CC was economically the best, followed by DC, while FM diet showed the least economic potential. © 1990.