Effect of low molecular weight soybean peptide on intestinal immunity in weanling piglets

This experiment was conducted to study the effects of soybean peptide on immunity in weaning piglets.Thirty neonatal piglets were randomly divided into two groups,and were fed basal diet with supplementation of 0(Control group) and 2% soybean peptide(Treatment group) respectively at 7 day-old.All piglets were weaned at 21 day-old.At 21 and 35 day-old,six piglets from each group were slaughtered,and contents from jejunum collected for estimating the levels of Escherichia coli,Enterococcus and Lactobacilli by in vitro culturing methods.The digestive enzyme and Na+-K+-ATPase activities were detected by biochemical analysis method.The immune index and the level of Toll-like receptors 4(TLR4) mRNA expressions in jejunum were determined by radioimmunoassay and real-time PCR respectively.The result showed as follows: compared with control group,at 21 day-old,dietary supplementation with 2% soybean peptide could significantly reduce E.coli quantity(P0.05),increase Lactobacilli quantity(P0.05),significantly increase the lipase(P0.05),lactase(P0.05),trypsin(P0.01) and Na+-K+-ATPase activities(P0.05),elevate IL-2 and sIgA level(P 0.05),and significantly reduce TNF-α level at 21 and 35 day-old(P0.05).TLR4 gene expression levels were lower in treatment group than those in the control group at 21 and 35 day-old,especially at 35 day-old(P0.05).The result indicated that soybean peptide could improve intestinal tract microbial population structure and enhance the intestinal immunity function of weanling piglets.