Potential of using unconventional animal protein ingredients to replace fish meal in Nile tilapia diets

ABSTRACT

The study was performed to evaluate the partial replacement of fish meal by unconventional animal protein ingredients; feather meal [FM] and/or rabbit manure [RM] in Nile tilapia diets. Fish were fed for 15 weeks on six isonitrogenous and isocaloric experimental diets. The control group diet contained fish meal, whereas the other five groups received diets in which fish meal was partially replaced by incorporation of [7.5-15%] FM or [7.5-15%] RM or [7.5 and 7.5%] FM and RM respectively. Incorporation of FM at both levels [7.5-15%] in Nile tilapia diets decreased body weight gain, feed intake and reduced the digestibility of DM and CP. RM at levels of [7.5-15]% increased fish body weight gain, feed intake, protein intake and improved digestibility of DM and CP. Feed conversion ratio [FCR], specific growth rate [SGR], protein intake and protein efficiency ratio [PER] were decreased by incorporation of 7.5% FM in fish diet. Meanwhile 7.5% RM resulted in an increase of FCR and improve PCR, while 15% RM increased SGR. A combination of 7.5% FM and 7.5%RM achieved' best DM and CP retention and highest CP content in body composition. The lowest nutrient retention, CP content of fish body and dressing% were recorded in groups fed FM containing diets. Conclusively, the present results suggested that FM and RM could be included safely in Nile tilapia diets to reduce feed cost. Partial replacement of fish meal by incorporation of RM in the diet of Nile tilapia achieved the best growth performance