摘要Background Intestinal inflammation is the main risk factor causing intestinal barrier dysfunction and lipopolysaccha-ride(LPS)can trigger inflammatory responses in various eukaryotic species.Yeast hydrolysate(YH)possesses multi-biological effects and is received remarkable attention as a functional ingredient for improving growth performance and promoting health in animals.However,there is still inconclusive on the protective effects of dietary YH supple-mentation on intestinal barrier of piglets.This study was conducted to investigate the attenuate effects of YH supple-mentation on inflammatory responses and intestinal barrier injury in piglets challenged with LPS.Methods Twenty-four piglets(with an average body weight of 7.42±0.34 kg)weaned at 21 days of age were randomly assigned to one of two dietary treatments(12 replications with one pig per pen):a basal diet ora basal diet containing YH(5 g/kg).On the 22nd d,6 piglets in each treatment were intraperitoneally injected with LPS at 150 μg/kg BW,and the others were injected with the same amount of sterile normal saline.Four hours later,blood samples of each piglet were collected and then piglets were euthanized.Results Dietary YH supplementation increased average daily feed intake and average daily gain(P＜0.01),decreased the ratio of feed intake to gain of piglets(P=0.048).Lipopolysaccharide(LPS)injection induced systemic inflamma-tory response,evidenced by the increase of serum concentrations of haptoglobin(HP),adrenocorticotropic hormone(ACTH),cortisol,and interleukin-1β(IL-1β).Furthermore,LPS challenge resulted in inflammatory intestinal damage,by up-regulation of the protein or mRNA abundances of tumor necrosis factor-α(TN F-α),IL-1β,toll-like receptors 4(TLR4)and phosphor-nuclear factor-κB-p65(p-NFκB-p65)(P＜0.01),and down-regulation of the jejunal villus height,the pro-tein and mRNA abundances of zonula occludens-1(ZO-1)and occludin(OCC;P＜0.05)in jejunal mucosa.Dietary YH supplementation decreased the impaired effects of ACTH,cortisol,HP,IL-1β and diamine oxidase in serum(P＜0.05).Moreover,YH supplementation also up-regulated the jejunal villus height,protein and mRNA abundances of ZO-1 and OCC(P＜0.05),down-regulated the mRNA expressions of TNF-α and IL-1β and the protein abundances of TNF-α,IL-1β,TLR4 and p-NFKB-p65 in jejunal mucosa in LPS-challenged pigs(P＜0.01).Conclusion Yeast hydrolysate could attenuate inflammatory response and intestinal barrier injury in weaned piglets challenged with LPS,which was associated with the inhibition of TLR4/NF-KB signaling pathway activation.