Preliminary structure and bioactivities of polysaccharide SMWP-U&E isolated from Salvia miltiorrhiza Bunge Residue

The fractional polysaccharide SMWP-U&E was isolated from Salvia miltiorrhiza residue. SMWP-U&E consists of 91.40% carbohydrates and has an average molecular weight of 5.07 × 105 Da. The polysaccharides are mainly composed of arabinose (Ara), fructose (Fru), mannose (Man), glucose (Glc), and galactose (Gal), and their mole percentages are 3.72%, 4.11%, 6.18%, 32.08% and 53.91%, respectively. When effected on weaned piglets, 1.5 g/kg SMWP-U&E supplementation significantly increased the villus height to crypt depth ratio in ileum. PCR-denaturing gradient gel electrophoresis and qRT-PCR results indicated that SMWP-U&E supplementation could change the density of intestinal microbiota and the populations of Lactobacillus and Escherichia coli in jejunum, ileum, caecum, and colon. The supplementation also increased contents of IgA, IgG, IgM, IL-2, IFN-γ, and IL-10; promoted T-AOC and SOD activities; and reduced MDA level in the serum. These findings suggest that SMWP-U&E improves digestion and nutrient absorption in weaned piglets, exerts beneficial effects on intestinal morphology and microflora, and enhances the immune and antioxidant capabilities in mode of weaned piglets. Thus, SMWP-U&E exhibits potential as a new type of plant-derived additive and novel prebiotics.