Abstract
Astragalus and ginseng, esteemed as traditional Chinese herbal medicines, have demonstrated the ability to bolster physical health and enhance the immune function of organisms. In this study, the effects of a dietary astragalus–ginseng mixture on the growth performance, intestinal health, and nonspecific immunity of yellow catfish (Pelteobagrus fulvidraco) were evaluated, by measuring growth performance indices, intestinal villus morphology, enzyme activities, and expression levels of immune-related genes. Yellow catfish (n = 120, initial weight: 5.07 ± 0.18 g) were randomly assigned to four dietary groups: a control group (CT, 0 mg/kg) and three astragalus–ginseng treatment groups (AG1, 500 mg/kg; AG2, 1000 mg/kg; AG3, 2000 mg/kg). Each group had three replicates and was fed for six weeks. The results demonstrate that the treatment significantly enhanced the growth performance, as evidenced by increases in FBW, WG, WGR, SGR, and HSI. These improvements may be related to an increase in intestinal villi length and increased LPS activity, both of which are associated with enhanced digestive function. Meanwhile, the activity of antioxidant enzymes in the liver, including CAT, SOD, and GSH, was increased, whereas the level of MDA was decreased. In the serum, GSH was up-regulated, while SOD activity was decreased. Immune-related enzyme activities, such as ALT and LZM, were up-regulated, while AST showed no significant difference. Moreover, the treatment also promoted the expression of the anti-inflammatory factor IL-10. The pro-inflammatory factors, such as IL-1β, IL-6, and TNF-α, were decreased with the addition of low concentrations but increased with high concentrations. In conclusion, supplementation with an astragalus–ginseng mixture could promote growth performance by increasing digestive enzyme activity and intestinal villi length, and improve disease and stress resistance traits by modulating immune genes and antioxidant enzyme activity. A dosage of 1000 mg/kg was found to be optimal.