EVALUATION OF COTTONSEED MEAL AS PARTIAL ANI) COMPLETE REPLACEMENT OF FISII MEAL IN PRACTICAL DIETS OF NILE TILAPIA, OREOCHROMIS NILOTICUS (BOULENGER) FINGERLINGS

Abstract

he main objectives of this study was to determine the effect of partial and total replacement of fish meal by cotton seed meal in practical diets of Nile tilapia fingerlings on growth performance, feed utilization, body composition and some biological measurements of Nile tilapia, Oreochromis niloticus (L.). Fish of an average weight 18.1 ± 0.2 g were stocked in 15 glass aquariums (80 l each) at a rate of 15 fish per aquarium. Fish meal (40 % of the diet) was used as the sole source of animal protein in the control diet. Percent replacement of fish meal by cottonseed meal on the basis of crude protein were as follows: 0 % (control diet A), 25 % (diet B), 50 % (diet C), 75 % (diet D) and 100 % (diet E). Diets were fed to fish at a rate of 4 %, then gradually reduced to 3 % of the total fish biomass daily, for a period of 14 weeks. The results of this study revealed that, the fish fed diet B had significantly (P ≤ 0.01) best average body weight, average body length, specific growth rate (SGR), weight gain %, feed conversion ratio (FCR), and protein efficiency ratio (PER) from those of fish fed control diet A and all other diets. The same parameters of fish fed diet C were not significantly different (P > 0.05) from those of fish fed the control diet A. Condition factor (K), hepatosomatic index (HSI) and survival rate % of the fish fed