Objective: Vegetative protein sources have an important role on reducing cost of diet. Use of these sources has also different metabolic effects. In this study, a 56 days feeding trial was conducted with rainbow trout to examine the effects of substitution of canola meal (containing 12.5 μmol Glucosinolate/g DM) with fishmeal in diets. Method & Materials: Canola meal was substituted by fishmeal at 5 levels 10, 20, 30, 40 and 50 percentage. Each diet was assigned to triplicate groups in a completely randomized design with a control diet. Two hundred and sixteen fishes with average weight 100±15 g were used in this trail. Twelve fishes were randomly assigned to each of 18 plastic tanks and were acclimated in these plastic tanks to the experimental conditions. Results & Conclusion: This substitution caused significant differences in all criteria measured with control diet (p<0.05). With increase of substituted level, quantity of total cholesterol, triglyceride, low and very low density of lipoproteins decreased significantly (p<0.05) and quantity of high density of lipoproteins, specific growth rate (with exception of diets of 30, 40 and 50 percent), body weight index (with exception of diets of 10 and 20 percent) and final body weight (with exception of diets of 10 and 20 percent) increased significantly (p<0.05) with control diet. These results showed that replacement of fishmeal to level of 50 percent by canola meal, based on studies of fish blood serum and growth, is feasible.

Keywords