Growth performance and feed utilization of Tilapia zillii (Gervais, 1848) fed partial or total replacement of fish meal with poultry by-product meal

The aim of this study was to investigate the growth performance, feed utilization and body composition of Tilapia zillii fed diets where poultry by-product meal replaced fish meal protein at 0, 50 and 100% levels in high energy diets. This is the first research study conducted to evaluate poultry by-product as an alternative feed source for T. zillii. Experimental diets were prepared isonitrogenously and isocalorically (55% CP; 20.5 kJ GE g(-1)). Ninety fish (mean weight 2.45 +/- 0.04 g) were cultured in glass aquariums containing brackish water (25 C average temperature and 11 parts per thousand salinity) for a period of 45 days. At the end of the trial, relative growth rate, specific growth ratio and daily dry protein intake in fish fed diet 1 (control) and 2 (50% poultry by-product meal inclusion) were similar and appeared significantly (p < 0.05) better than the fish fed diet 3 (100% poultry by-product meal inclusion). Feed conversion ratio was significant different among diet 2 and diet 3 (p < 0.05). No differences were found among diets, in terms of fish whole body proximate composition. The results of this study show that T. zilli can be cultured in brackish water with feeding a diet containing 50% poultry by-product meal without any adverse effect on growth performance of fish.