Effects of Astragalus membranaceus extract and Eucommia ulmoides leaf extract on growth performance, blood biochemistry, and antioxidant capacity of gibel carp juveniles (Carassius auratus gibelio var. CAS V)

The study aims to investigate the effects of dietary Astragalus membranaceus extract (AME) and Eucommia ulmoides leaf extract (ELE) supplementation on the growth performance, blood biochemistry, and antioxidant capacity of gibel carp (Carassius auratus gibelio var. CAS V, 10.01 g ± 0.24 g). Six experimental diets supplemented were marked as A0E0 (basic diet, 0% AME and 0% ELE), A0E0.1 (0% AME and 0.1% ELE), A0.02E0, A0.02E0.05, A0.02E0.1, A0.02E0.2 (0.02% AME with 0%, 0.05%, 0.1%, and 0.2% ELE). After 8 weeks, A0.02E0 diet significantly increased the final body weight (FBW), weight gain rate (WGR), specific growth rate (SGR), and decreased the glucose (GLU), triglyceride content (TG), and total cholesterol (TC) of the plasma, the malonaldehyde (MDA) content of the liver, the A0E0.1 group significantly increased the total protein (TP) and albumin (ALB) content of the plasma, decreased the alanine aminotransferase (ALT) content of the plasma when compared with A0E0 group (Independent T-test: P < 0.05). A0.02E0.1 group significantly increased the FBW, WGR, SGR, and decreased the moisture of the whole body when compared with A0E0.1 group (Independent T-test: P < 0.05). One-way ANOVA analysis showed that 0.02% AME with different levels of ELE (0.05%, 0.1% and 0.2%) significantly increased FBW, SGR, WGR, the crude protein and crude lipid of whole body, the GLU, TP, ALB, TC, and TG content of the plasma, and the activities of the lysozyme, total superoxide dismutase, and catalase (CAT) of the liver when compared with A0.02E0 diet (Tukey's test: P < 0.05). Two-way ANOVA analysis showed that the AME and ELE showed significantly interaction effect on FBW, WGR, SGR, GLU content, TG content, TC content, ALT content, CAT activity. In conclusion, it could be recommended that AME and ELE interaction can be used for growth promotion and antioxidant capacity improvement in aquaculture animals.