EFFECTS OF DIETARY PROTEIN AND ENERGY LEVELS ON GROWTH AND BODY COMPOSITION OF CASPIAN TROUT LARVA (SALMO TRUTTA CASPIUS)

A 3 * 2 factorial feeding trial of three dietary protein levels (45, 50 and 55%) and two dietary crude energy levels (4200 and 4600cal/g) with three replications was conducted to investigate the proper dietary protein and energy levels for the growth of fingerling Caspian trout (Salmo trutta caspius). Fingerlings with average weight of 135±0.24 mg were fed the experimental diets for 45 days. Results indicated that weight gain, FCR, SGR and PER were affected significantly by dietary protein and energy levels (P<0.05). At the constant protein levels growth performance of the fishes were improved as dietary energy levels increased (P<0.05). Also, at the constant energy levels, growth indices and survival were increased significantly as dietary protein level increased (P<0.05). Growth performance of the fishes fed with 50 and 55% protein and 4600cal/g energy were significantly better than other treatments (P<0.05). Lipid content of the fishes fed with high-energy level was significantly higher than those of fed with the low dietary energy (P<0.05). Body moisture of the fishes fed with high-energy level was significantly lower than those fed with the low dietary energy (P<0.05). We suggest that for Caspian trout larva, a diet with 50% protein and 4600cal/g energy is appropriate.