Aba Mustapha *,Belghyti Driss ,Benabid Mohamed
We evaluated the influence of level energy of ratio protein digestible and energy digestible on the body composition of fillet in rainbow trout .Two extruted diets A and B with different energy levels were used: The comparison of the two foods with different formulation is performed in isoenergetic conditions. Following this study, two diets were formulated : the extruded diet A with 41% crude protein, 27% fat and 20% carbohydrate while the extruted food B with 39.7% CP, 24 % fat and 15,7 carbohydrates with digestible energy respectively of 21.32 Mj and 19.32 Mj. The initial average weight of the trouts was 100 g from the same batch of eggs were divided randomly into six fiberglass conical tanks at open circuit. The diet was assigned to 6 tanks for 50 fish each with three replicates for each diet and the experiment was conducted for 127 days. The ratio DP/DE of diet influenced body composition and their distribution in the fillet of fish. The fat composition of the fish muscle varied we obtained the high level fat for the low ratio Digestible Protein/ Digestible Energy (DP/DE). The study showed that the fat content decrease in the part ventral of the fillet to dorsal and anterior to the posterior. The lipid content increased with dietary lipid levels and depends on the protein content in feeds and the ratio DP/DE. Fat composition of the muscle reflected fat levels of diets.