Supplemented with Astragalus dregs improves growth performance, immunity, and antioxidant capacity in fattening pigs

This study aimed to investigate the impact of Astragalus dregs - the residue after the extraction of principal active components - on the growth performance, antioxidant capacity, and immune function of fattening pigs. Twenty-four 130 days of age fattening pigs were randomly assigned to the control group and experimental group (supplemented with 10% Astragalus dregs). The production performance was evaluated by average daily gain (ADG), average daily feed intake (ADFI) and diarrhoea rates. Additionally, nutrient digestibility, blood biochemical parameters, antioxidant capacity, and immune function factors were analysed. The group supplemented with Astragalus dregs showed a trend towards improved ADG and ADFI and reduced diarrhoea rates (p > 0.05). Moreover, it significantly enhanced the digestibility of dry matter, crude protein, and ether extract (p < 0.05). Blood analysis revealed that globulin and total protein were increased, and glucose, cholesterol and triglyceride levels were decreased (p < 0.05) in the group supplemented with Astragalus dregs. The antioxidant capacity was significantly promoted by elevated T-AOC, GSH-px, and SOD activities and reduced malondialdehyde levels (p < 0.05). The immune function factors demonstrated that IgA, IgG, IgM, and anti-inflammatory cytokines IL-10 and IL-22 were significantly increased, meanwhile pro-inflammatory cytokines IL-2 and IL-6 were decreased (p < 0.05). These findings indicate that Astragalus dregs, as a dietary supplement, may enhance growth performance, antioxidant capacity and immune function in fattening pigs. It is suggested that future studies should explore the optimal supplementation ratio of Astragalus dregs in pig diets.