Evaluation of the three diets of different biochemical compositions on the zootechnical performances of the rainbow trout (Onchorynchys Mykiss walbaum, 1792) and their impact on the water of the Oum Er-Rbia River (Morocco)

In order to compare the effects of three types of extruded foods (A, B and C) on the growth of rainbow trout, an experimental test was conducted on June 15, 2015 at the Oum Er Rbia Fish, Morocco. The comparison of three foods of different composition and energy is performed in isoenergetic condition. In this study, three extruded foods were tested: food A with 39% protein, 27% fat and 19.2 MJ / kg, food B with41% protein , 24% fat and 20 MJ / Kg and food C with40% protein, 26 fat and 19 MJ / Kg .The initial trout weight was ±40 g bred in six freshwater basins with twice-per-hour renewal. Fish were raised under the same conditions of breeding at a density of 1.58 kg / m3 and a load of 1.04 m3 / h. Each group was fed twice a day after 222 days of experimentation. The final weight of three foods A, B and C was 803.14g, 1043.9g and 942.1g. Results showed that the best performances of growth are obtained by food B with a final weight of 1043.9g. The biochemical composition, the origin of the raw material used in the feed and the formulation of the three extruded feeds had an influence on the growth performance of the rainbow trout. Outlet water from magnification basins does not show any pollution of the aquatic environment.