The Effects Of Dietary Pectin Supplementation On Intestinal Glycosylation In Weaned Piglets Challenged By LPS

Damage to the intestinal barrier of piglets caused by weaning stress is an important cause of slow growth,diarrhea and even death of piglets.The current research focused on the effects of dietary pectin supplementation on growth performance,intestinal barrier function and intestinal glycosylation in weaned piglets challenged by LPS,and establish fluorescent lectin-based immunohistochemical method to investigate intestinal glycosylation.In this experiment,a total of 36 healthy crossbred(DLY)weaned piglets(6.77± 0.92 kg)at 21 d randomly assigned to 4 groups(n=9/group)in a 2×2 factorial design experiment.The main factors were diet treatment(CON or PEC)and immunological challenge treatment(LPS or normal saline).LPS challenge(80 g/ kg.bw)was performed on the 14 d and 21 d of the experiment.End of the experiment,8 piglets of each group were selected for slaughter and collect samples.(1)Dietary PEC supplementation can effectively improve the growth performance of piglets challenged by LPS.LPS challenge significantly reduced BW and ADG for 21 d(P < 0.05),and significantly increased FCR in the piglets(P < 0.05).Dietary PEC supplementation significantly increased BW and ADG on day 14(P < 0.05),reduced FCR on day 1-14(P < 0.01).and significantly alleviated LPS challenge resulted in decreased BW,ADG and ADFI at 21 d in the piglets(P < 0.05).(2)Dietary PEC supplementation can effectively improve the intestinal damage caused by LPS and promote intestinal health(n = 8/Group).LPS challenge significantly reduced the ileal villi height and VCR,down-regulated the expression of MUC2,TFF3 in ileal and colon(P < 0.05),significantly upregulated the expression of IL-1?,MCP-1,TLR4 in ileum and MCP-1,TLR4 in colon(P < 0.05),simultaneously increased plasma LPS content and AKP activity(P < 0.05);Dietary PEC supplementation can effectively increase ileal villi height and VCR,significantly improve the ileal villi height and VCR decreased by LPS stress(P < 0.05),up-regulated the expression of MUC2,TFF3 in ileum,and downregulated the expression of TLR4,MCP-1,IL-1?,up-regulated the expression of IL-10 in ileum and colon,significantly alleviate the up-regulation of the expression of IL-1?,MCP-1,TLR4 in ileum and MCP-1 in the colon caused by LPS challenge(P < 0.05),reduce plasma D-lactate and AKP content(P < 0.01),significantly alleviated the increase of plasma D-lactic acid,DAO and AKP content caused by LPS challenge(P < 0.05).(3)Establish fluorescent lectin-based immunohistochemical method to investigate intestinal glycosylation.In this experiment,fluorescent lectin immunohistochemical techniques was used to label lectin with FITC as the probe,the best blocking time,tissue permeability and dosage of 5 lectins(UEA-1,ConA,DBA,PNA,WGA)are screened out.The optimal conditions for immunohistochemistry of fluorescent lectin were as follows: deparaffinized sections were blocked with Carbohydrate blocking solution for 30 min.Sections were then incubatedwith5 ?g/mL FITC-lectin for 1 h at room temperature,and mounted with DAPI Mounting medium.This method was characterized with high sensitivity,good specificity and more diversification regarding quantification.(4)Dietary PEC supplementation can change the intestinal glycosylation pattern.LPS challenge had no significant effect on AOD staining in ileum of piglets by various lectin(P > 0.05),and dietary PEC supplementation had a tendency to reduce WGA(P = 0.08).(5)Dietary PEC supplementation can promote the structural change in the ileal O-glycosylation core structure and inhibits the effects of LPS on the O-glycosylation core structure 1 and 2 glycosyltransferases.LPS challenge significantly down-regulated the expression of CIGALT1,CIGALT1C1,GCNT3,B3GALT5,FUT1,FUT2,ST3GAL1,ST6GALNAC1 in ileum of piglets,and upregulated the expression of GCNT1,B3GNT3,B3GNT6(P < 0.05).Dietary PEC supplementation significantly down-regulated the expression of ileum C1GALT1,C1GALT1C1,GCNT1,B3GNT3,GCNT3,B3GALT5,FUT1,ST3GAL1,ST6GALNAC1,MGEA5,and up-regulated the expression of B3GNT6 and FUT2(P < 0.05).Dietary PEC supplementation significantly alleviated the increased expression of GCNT1 and B3GNT3 in ileum caused by LPS challenge(P < 0.05),and down-regulated the expression of GCNT3,B3GALT5,FUT1 and ST6GALNAC1(P < 0.05).In conclusion,LPS challenge can induce the decline of immune function and intestinal damage of the body,which will eventually lead to the decline of production performance.Dietary PEC supplementation can alleviate the performance degradation caused by LPS challenge at some extent,which may be due to the fact that PEC can improve the utilization rate of nutrients of piglets,and improve the immune function and intestinal mucin barrier function of piglets.In this study,fluorescent lectin-based immunohistochemical method modified by intestinal glycosylation in pigs was successfully established,and found that the glycosylation modification pattern exists in the intestinal region.Dietary PEC supplementation can promote the change of the ileal O-glycosylation modification pattern to the core 3,and affects the expression of FUT2 and OGA,the results show that PEC can alleviate the damage of piglet intestine by inducing glycosylation modification mode and core sugar chain structure type change.