Environmental health enhancement by recycling poultry processing waste into protein ingredient in common carp Cyprinus carpio L. diets

This study was designed to investigate recycling poultry processing waste into protein concentrate as a step for supporting environmental health and resource sustainability, using it as a partial replacement of fish meal in diets prepared for common carp Cyprinus carpio L. fingerlings and explore its effect on fish growth, feeding efficiency and feed digestibility. Poultry waste was recycled into protein concentrate by a physical method, the chemical composition of this concentrate was analyzed, amino acid profile was determined, as well as the chemical composition of the prepared diets was analyzed. Four diets were prepared with substitution ratios of 0, 25 ,50 and 75% of fish meal with poultry waste protein concentrate. The results showed significant differences (P< 0.05) between the four experimental diets in terms of weight gain, specific growth rate (SGR), feed conversion ratio (FCR), protein efficiency ratio (PER) and protein productive value (PPV).  The treatment T3 (substitution rate of 75%) outperformed all other three treatments. No significant differences were observed between the studied treatments in the total apparent digestibility coefficients and the digestibility coefficients of different nutrients (protein, fat, carbohydrates and ash).&nbsp