Growth and biochemistry changes of Caspian Kutum (Rutilus frissi kutum) under different levels of dietary protein and lipid

This study was carried out to evaluate the effects of different dietary protein (30, 35, 40%) and lipid levels (10, 12, 14%) on growth performance and physiological changes of juveniles Caspian Kutum (Rutilus frisii kutum). Six hundred and seventy five fish (1.15 ± 0.01 g) were distributed into 27 aquaria (45 L) and were fed four times daily for 8 weeks. Interaction between protein and lipid did not significantly affect the growth factors (p > 0.05). Results showed that increasing the level of protein to 35% significantly increase some growth indices such as final weight (WF), weight gain (WG). The best growth performance was observed in fish 14% dietary lipid. Protein efficiency ratio (PER) and glucose of fish was not affected by interaction dietary protein and dietary lipid level. Triglyceride and cholesterol levels were significantly affected by protein and lipid and the interaction, High levels of triglycerides in fish fed with 30% protein and 10% and 12% lipid and the maximum amount of cholesterol in fish fed with 40% protein and 12% and 14% lipid were observed. The results of this study show a lower protein content (30%) and older (40%) than Kutum need can be a negative influence on the growth and physiological parameters. Increasing dietary lipid to 14% of Kutum juveniles were no negative effects on growth parameters. In order to improve the performance of Kutum in this weight range fed diets with 35% protein and 14% lipid is suggested.