EFFETS D’UN ALIMENT EXTRUDE SUR LES PERFORMANCES DE CROISSANCE DE LA TRUITE ARC-EN-CIEL (ONCORHYNCHUS MYKISS WALBAUM, 1792) ET SUR LA QUALITE DE L’EAU DE L’OUED OUM ER-RBIA (STATION AIN AGHBAL, AZROU-MAROC)

The objective of our study is to test the efficacy of an extruded food on the growth performance of rainbow trout (Oncorhynchus mykiss Walbaum, 1792) at the fish farm Ain Aghbal in Azrou (Morocco). Generally, only the biochemical composition (percentages of moisture, proteins, lipids and carbohydrates) and the (digestible and crude) energies of the food are previously known, which is insufficient for the choice of the food in terms of growth performance and quality/environment. The rainbow trout breeding tanks used for this test are 222 days (15 June 2015 - 28 February 2016) are fed with water directly taken from the water of the Oum Er-Rbia sources according to an open circuit with a Renewal of water every half hour. The flow rate is 11.04m3/h. The initial breeding conditions, the density (Kg per volume) 1.58kg/m3 and the initial charge with respect to the flow rate is 1.05 m3 / h. Fish are fed by ratios two to three times per day depending on the rearing stage. The frequency of sampling is biweekly where we measured the zootechnical performances of the fish and taken water samples for physicochemical analyzes in order to assess the quality of the waters of exit of the basins before their rejection in the Oum-Er-Rbia river. The results show that the test food shows a better growth of the rainbow trout and a conversion index not exceeding 0.9 for a size of 1043 g of trout.