Effects of polyphenolic compound green tea catechin on growth performance, some biochemical and mucosal indices in crucian carp (Carassius carassius)

The present study was performed to evaluate the effects of diets supplemented with green tea catechin on growth performance, metabolism, and some mucosal immune parameters in crucian carp (Carassius carassius). Seventy-two healthy fish with mean weight 8.03 ± 0.36 g were randomly distributed into three treatment groups with three replicates in each group and 12 fish in each aquarium. Fish in treatment groups were administrated with 100 and 500 mgkg-1 catechin for 45 days. Results showed that growth performance did not change in treatment groups compared to the control group (P>0.05). Serum biochemical parameters including glucose, triglyceride, and total cholesterol levels in both treatment groups decreased with respect to the control group (P<0.05). Mucosal immune parameters, namely lysozyme and alkaline phosphatase showed higher activity in both treatment groups compared to the control group (P<0.05). In contrast, protease activity increased in higher dose group in comparison with the control group (P<0.05). The results indicated that green tea catechin, especially at 500 mg kg-1, could exert beneficial effects on some biochemical parameters and skin mucosal immunity in crucian carp.