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Deux lots d'alevins du tilapia Oreochromis niloticus (14 ± 6 mg et 1660 ± 8 mg, respectivement) ont été nourris avec3 aliments (A1, A2 et A3) formulés uniquement à base de sous-produits agricoles et un aliment industriel commercial contenant de la farine de poisson servant de témoin (At). Les alevins de 14 ± 6 mg et 1660 ± 8 mg ont été mis dans des bassins, à des densités respectives de 1667 et 500 ind/m 2. Deux essais expérimentaux ont été réalisés. Les résultats de l'élevage post-larvaire (14 ± 6 mg) montrent une variabilité inter-groupes non significative (p > 0,05). En revanche, une différence significative (p < 0,05) a été observée chez les juvéniles (1660 ± 8 mg), entre les lots soumis à l'aliment A1, puis A3 et At. Les poids moyens finaux atteints aux stades post-larvaire et juvénile ont été respectivement de 750 ± 180 et 5980 ± 1325 mg (A1), 730 ± 180 et 5340 ± 1264 mg (A2), 650 ± 50 et 4930 ± 1381 mg (A3), puis 680 ± 40 et 4880 ± 1152 mg (At). Comparés au témoin, l'analyse économique a montré une réduction des coûts des aliments tests et de production du kilogramme de juvéniles, respectivement à des taux de 30 %, et 30 à 49 %.

Influence de la salinité sur la structure des branchies et l'ultrastructure des ionocytes chez le tilapia provenant d'un estuaire hypersalé (Sénégal).

The present experiment was conducted to evaluate the efficacy of dietary protein from maggot meal and earthworm meal to replace fish meal protein in Oreochromis niloticus juvenile feed. The fish used for this experiment come from the experience of the larval phase during which fish were fed with the formulated diets [fish diet (FD), maggot diet (MD) and earthworm diet (ED)] content 40% crude protein and the commercial diet (CD) content 34.5% crude protein. At the end of this larval phase, the average weights were 0.75 ± 1.93, 0.71 ± 3.55, 0.55 ± 2.52 and 0.62 ± 2.52 g for FD, MD, ED and CD respectively. These different weights constitute the initials weights for this experience. In this experimental, the formulated diets (FD, MD and ED) content 30% crude protein and 29.5% crude protein for CD. Fish were fed four times daily to triplicate groups at 10.7% body weight for consecutive 90 days. After these days, fish fed with FD gave significantly higher average daily gain (ADG, 0.3 ± 0.03 g.day -1 ) than MD (0.22 ± 0.18 g.day -1 ). Fish fed with ED had the lowest ADG (0.14 ± 0.12 g.day -1 ). The specific growth rate (SGR) were higher in fish group fed with FD, MD and CD and shows no significant difference (p > 0.05) compared to ED. Feed conversion ratio (FCR), protein efficiency ratio (PER) and survival rate (SR) show no significant difference (p > 0.05) in all the test. The production cost of 1 kg of fish (PC) and the carcass chemicals composition were evaluated. In conclusion, these results of this study indicate the possibility of completely using maggot meal as a source protein in the diet of O. niloticus juvenile to increase the growth of fish and reduce the cost of 1 kg of fish produced.