The effects of Chinese herbal feed additives on physiological health and detoxification ability in the red claw crayfish, Cherax quadricarinatus, and evaluation of their safety

The side effects of Chinese herbal medicine on metabolism in aquatic animals have not been fully studied. This study focused on evaluating the effects of Astragalus polysaccharide, chlorogenic acid, and berberine on the physiological health and detoxification ability of Cherax quadricarinatus. A basic diet served as a control, and diets containing differing concentrations of Astragalus polysaccharide (1, 2, 4, 8 g/kg), chlorogenic acid (1, 2, 4, 8 g/kg), or berberine (0.1, 0.5, 2.5 g/kg) were prepared. One thousand and eight crayfish (28.83 +/- 0.29 g) were randomly allocated to 12 groups of net cages for 14 days. Samples were taken 7 days after feeding with Chinese herb bioactive ingredients and 7 days after ceasing this feeding. The results showed that compared with the control group, the addition of Astragalus polysaccharide, chlorogenic acid, or berberine did not have a significant effect on the growth performance of each experimental group. Cellular immunity, humoral immunity and antioxidant enzyme activities were increased significantly, while the concentrations of three herbal bioactive ingredients in plasma and metabolic enzymes improved significantly. Moreover, the bioactive ingredients did not cause biological macromolecular damage or histological damage in the hepatopancreas and significantly reduced the content of malondialdehyde. However, high concentrations of berberine (2.5 g/kg) significantly increased alanine aminotransferase and aspartate aminotransferase activities in the hepatopancreas, which could have a potential risk of damage to the hepatopancreas. Our results indicated that Astragalus polysaccharide, chlorogenic acid, and 0.1 g/kg berberine can be used as safe feed additives to stimulate the immune response, antioxidant capacity and detoxification ability and protect the organism from damage under oxidative stress.