an investigation on the effects of different diets on the growth performance of nile tilapia, oreochromis niloticus (linné, 1758)

The objective of this study is to investigate the possibility of substituting a diet based on fish meal, for nile tilapia fish fry (oreochromis niloticus), by another food based agro-industrial by-products. four plants and animal by-products were selected for the formulation of this diet, namely feathers poultry flour (fpf), date stones flour (dsf), peas flour (pf) and tomato waste flour (tf). the four above-mentioned by-products were combined to obtain four experimental diets (d1-d4) containing isoproteic (29- 39% crude protein) and iso-energetic (15-21 kj gross energy by g feed), so as to replace completely, fish meal. the fifth diet, based on fish meal was used as control died (cd). the results of livestock and biochemical analyses, such as the specific growth rate (sgr), feed conversion efficiency (fce), the protein efficiency ratio (per) and the apparent protein retention (apr) show that d3 and d4 give better results compared to the control diet (cd). the least interesting results were obtained with experimental d1 diet. finally, for all analytical results obtained, it was highlighted that the diet d4 is relatively more efficient nutritionally, compared to the other diets formulated, which gives a better weight gain.