Effect of low molecular weight soybean peptide on intestinal immunity in weanling piglets | 低分子质量大豆肽对断奶仔猪肠道免疫功能的影响

Chinese. 选择胎次相近的刚出生健康仔猪30头,随机均分为对照组和试验组,在断奶前常规补料,其中试验组饲喂基础日粮+2%大豆肽,试验猪21 d一次性断奶,分别在21日龄与35日龄时每组随机取6头仔猪宰杀,取空肠黏膜及内容物,分析大豆肽对仔猪肠道细菌数量、肠黏膜组织中消化酶及Na+-K+-ATP酶活性、细胞因子分泌、sIgA水平及Toll样受体4(TLR4)mRNA表达量的影响。结果表明:日粮中添加2%大豆肽后,能显著降低21日龄仔猪空肠肠道大肠杆菌数(P0.05),提高乳酸杆菌数(P0.05),提高空肠黏膜脂肪酶(P0.05)、乳糖酶(P0.05)、胰蛋白酶(P0.01)及Na+-K+-ATP酶活性(P0.05),显著提高空肠黏膜IL-2与sIgA水平(P0.05),显著降低21日龄和35日龄空肠黏膜TNF-α水平(P0.05),大豆肽能够下调21日龄和显著下调(P0.05)35日龄仔猪空肠黏膜TLR4 mRNA表达量。结论:大豆肽可改善仔猪肠道微生物菌群结构,调控机体肠道免疫功能,促进断奶仔猪肠道健康。

English. 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(P0.05),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.