Regulatory Effect Of Coated Sodium Butyrate On Intestinal Damage Induced By Lipopolysaccharide In Weaned Lambs

This experiment was conducted to investigate the effects of coated sodium butyrate(CSB)on the alleviation of intestinal injury in weaned lambs challenged with lipopolysaccharide(LPS).Twenty-four weaned lambs with an average body weight(11.79 ±0.54 kg)were randomly allocated to 4 groups with 6 replicates per group and 1 lamb per replicate according to similar body weight: Control group(CON),lipopolysaccharide group(LPS),2 g/kg CSB group(CSB2L)and 3 g/kg CSB group(CSB3L).Three lambs in each group were slaughtered on the 28 th day.CON and LPS groups were fed with basal diet,CSB2 L group and CSB3 L group were supplemented with 2 g/kg and 3 g/kg CSB,respectively.LPS,CSB2 L and CSB3 L groups were intraperitoneally injected with 100 μg/kg BW LPS,and CON group was intraperitoneally injected with the same amount of sterile normal saline 3 hours before slaughter on the 28 th day.The results showed as follows:(1)Effects of CSB on the intestinal physical barrier of weaned lambs challenged with LPSThe villi of the jejunum and ileum were arranged disorderly and accompanied by swelling and shedding of villi after injection of LPS.The jejunum and ileum villi in the CSB2 L and CSB3 L groups were more complete and neatly arranged,with reduced swelling and mild epithelial shedding.LPS stimulation significantly reduced jejunum and ileum villi height and villi height/crypt depth(P<0.05).The decrease of jejunum and ileum villus height and the decrease of villus height/crypt depth in CSB2 L and CSB3 L groups were all relieved(P<0.05).LPS challenge significantly increased the concentrations of D-lactate(DLA)and diamine oxidase(DAO)in the serum of weaned lambs(P<0.05).CSB2 L group and CSB3 L group significantly decreased the concentrations of DLA and DAO after LPS challenge(P<0.05).Significantly decreased Claudin-3,ZO-1,and Occludin proteins expression levels of the ileum were observed in the LPS group than in the CON group(P<0.05).The protein expression levels of Claudin-3,Occluding and ZO-1 in the ileum of the CSB2 L and CSB3 L groups were significantly higher than those of the LPS group(P<0.05).Compared with the CON group,the number of goblet cells in the small intestine of the LPS group was significantly decreased(P<0.05).Compared with the LPS group,except for the duodenum and jejunum of the CSB2 L group,the number of goblet cells in the ileum and CSB3 L group of the CSB2 L group was significantly increased(P<0.05).The m RNA expression of MUC2 in the ileum tissue of the LPS group was significantly lower than that of the CON group(P<0.05).Compared with the LPS group,the m RNA expression of MUC2 in the CSB2 L and CSB3 L groups was significantly increased(P<0.05).(2)Regulatory effects of CSB on serum inflammatory factors and intestinal TLR4/My D88/NF-κB signaling pathway in weaned lambs challenged with LPSCompared with the CON group,the serum levels of TNF-α,IL-1β and IL-8 in the weaned lambs in the LPS group were significantly increased(P<0.05).Compared with the LPS group,the levels of TNF-α and IL-1β in the CSB2 L and CSB3 L groups(P<0.05),and the IL-10 levels in the CSB2 L and CSB3 L groups were significantly increased(P<0.05).LPS stimulation significantly increased the m RNA expression of My D88,TLR4 and NF-κB,IL-6 and IL-1β in the ileum(P<0.05).Compared with the LPS group,the expression levels of these genes in the CSB group were reduced(P<0.05).LPS improved the protein expression levels of TLR4,My D88 and the phosphorylation of NF-κB p65 signaling pathways in the ileum(P<0.05).CSB treatment significantly inhibited the expression of TLR4,My D88 and the phosphorylation of NF-κB p65(P<0.05).(3)Effects of CSB on intestinal microbes and VFA concentration of weaned lambs challenged with LPSThe number of OTUs of the cecum and colon was reduced under the stimulation of LPS,the addition of CSB increased the number of OTUs of the colon to a certain extent,and 3 g/kg had a stronger uniqueness.The addition of CSB increased the abundance of microbes in the cecum and colon(P<0.05),but had no significant effect on colonic diversity(P>0.05).Main phylum of the caecum and colon were similar in each group.LPS stimulation significantly reduced the relative abundance of Tenericutes(P<0.05),and the CSB addition group had no significant change compared with the CON group(P>0.05).At the genus level,the addition of CSB mainly alleviated the decrease in the relative abundance of Ruminococcaceae＿UCG-010,Ruminococcaceae＿NK4A214＿group,[Eubacterium]＿coprostanoligenes＿group,norank＿f＿＿norank＿o＿＿Mollicutes＿RF39 and the increase in the relative abundance of Negativibacillus and norank＿f＿＿Barnesiellaceae.After LPS stimulation,the concentration of butyric acid and TVFA in the ileum of weaned lambs decreased significantly(P<0.05).Compared with the LPS group,the ileum TVFA concentration in the CSB2 L group was significantly increased(P<0.05),the butyric acid in the CSB2 L group was not significantly different(P>0.05),and the butyric acid and TVFA concentrations in the CSB3 L group were significantly increased(P<0.05).The bacterial genera Lysinibacillus,Campylobacter,and unclassified＿f＿Lachnospiraceae of the colon were significantly negatively correlated with propionic acid and TVFA,while Ruminococcaceae and Candidatus＿Soleaferrea were positively correlated with the concentration of colonic VFA(P<0.05).Conclusion: Supplementing the two doses of CSB can improve the intestinal damage of weaned lambs caused by LPS stress and maintain intestinal homeostasis,and the effects are basically the same.