Astragalus membranaceus alters rumen bacteria to enhance fiber digestion, improves antioxidant capacity and immunity indices of small intestinal mucosa, and enhances liver metabolites for energy synthesis in tibetan sheep

Natural, non-toxic feed additives can potentially replace chemical medications and atibiotics that are offered sheep to improve performance. In the present study, Tibetan sheep wesupplemented with the root of Astragalus membranaceus (AMT), a traditional herb used widely China. Twenty-four male Tibetan sheep (31 ± 1.4 kg; 9-month-old) were assigned randomly to oof four levels of supplementary AMT: 0 g/kg (A₀ ), 20 g/kg (A₂₀ ), 50 g/kg (A₅₀ ) and 80 g/kg (A₈dry matter intake (DMI). The A₅₀ and A₈₀ groups increased the diversity of rumen bacteria on d and the relative abundances of fiber decomposing bacteria. Supplementary AMT upregulated thmetabolism of vitamins, nucleotides, amino acids and glycan, and downregulated the metabolisof lipids and carbohydrates. In addition, supplementary AMT enriched rumen bacteria for druresistance, and reduced bacteria incurring cell motility. In general, AMT supplementation increasethe concentrations of catalase (CAT), superoxide dismutase (SOD) total antioxidant capacity (T-AOand secretory immunoglobulin A (sIgA) in the small intestinal mucosa and CAT and SOD in metissue. The liver tissue metabolome response showed that AMT in the A₈₀ lambs compared to thA₀ lambs upregulated the metabolites for energy synthesis. It was concluded that supplementaA. membranaceus increased the relative abundances of fiber decomposing bacteria and improvethe antioxidant capacities and immunity indices of small intestinal mucosa and meat tissue Tibetan sheep.