Effects of astragalus and ginseng polysaccharides on growth performance, immune function and intestinal barrier in weaned piglets challenged with lipopolysaccharide.

Abstract

This experiment was conducted to evaluate the effects of astragalus polysaccharides (Aps) and ginseng polysaccharide (Gps) on growth performance, liver function, immune function, TLR4 signalling pathways and intestinal barrier in weaned piglets challenged with lipopolysaccharide (LPS). In an experiment spanning 28days, 180 weaned piglets were randomly divided into three treatment groups: basal diet (Con), basal diet supplemented with 800mg/kg Gps (Gps) and basal diet supplemented with 800mg/kg Aps (Aps). At the end of the experiment, 12 piglets of each group were selected; half (n=6) were intraperitoneally injected with LPS and half with normal saline. Dietary supplementation with Aps and Gps significantly increased (p<.05) the average daily gain and feed conversion rate. Lipopolysaccharide challenge increased (p<.05) expression of serum urea nitrogen (BUN), alanine aminotransferase (ALT), aspartate aminotransferase (AST), interleukin-1β (IL-1β) and tumour inflammatory factor-α (TNF-α), but decreased (p<.05) serum superoxide dismutase (SOD) level, total antioxidant capacity (T-AOC) and immunoglobulin A (IgA) expression. Lipopolysaccharide-challenged piglets fed with Aps or Gps had lower (p<.05) BUN, ALT, AST, IL-1β and TNF-α levels and greater (p<.05) SOD, T-AOC and IgA levels. Lipopolysaccharide challenge increased (p<.05) the expression of TLR4, MyD88 and NF-κB, and LPS-challenged piglets fed diets supplemented with Aps or Gps increased TLR4 and MyD88 and decreased NF-κB expression. Lipopolysaccharide challenge reduced (p<.05) the jejunal villus height, and piglets fed with Aps or Gps had increased (p<.05) jejunal villus height. Supplementation with Aps or Gps enhanced the expression of occludin and claudin in challenged or unchallenged piglets. In conclusion, dietary supplementation with Aps or Gps enhanced piglet growth performance, alleviated liver dysfunction and reduced immunological stress caused by LPS, as well as increased the intestinal barrier function.