Effects of Dietary Lipid Levels on Growth Performance, Apparent Digestibility Coefficients of Nutrients, and Blood Characteristics of Juvenile Crucian Carp (Carassius auratus gibelio)

In this study, the effects of dietary lipid levels on growth, apparent digestibility, and blood biochemical indices of juveniles crucian carp (Carassius auratus gibelio) were evaluated. Triplicate groups of fish (average weight 2.05±0.02 g) were fed four isonitrogenous experimental diets formulated with increasing levels (13.6, 61.3, 115, and 259.8 g kg) of lipid. The weight gain (WG), specific growth rate (SGR) was highest in fish fed 115 g kg of lipid, the WG and SGR of 259.8 g kg 1 lipid group was significantly lower than these of other groups. Second-order regression analysis of WG on levels of dietary lipid indicated that the optimal dietary lipid level for maximum WG was 99.3 g kg. The apparent digestibility coefficients of crude protein, lipid, and dry matter tended to increase with increasing level of dietary lipid (P<0.05). With the increased level of dietary lipid, blood glucose, triglycerides, cholesterol and alkaline phosphatase showed a increased trend, the same as total protein and albumin, while globulin showed a decreased trend. The results indicated that the best growth performance of crucian carp juveniles would occur in fish fed a 99.3 g kg lipid diet and that high dietary lipid levels could promote digestion of crude protein, lipid, and dry matter in the nutrient, but may result in liver damage to some degree.