| Dietary fibers have been suggested to maintain intestinal health,but the dietary fiber contains various components including cellulose,xylan and beta-glucan,which components has played a key role is unclear as well as its related mechanismr.Here,we explored the effects of different fiber fractions on growth and intestinal health in a porcine model.Thirty-two weaned pigs were allotted to four groups and fed with fiber-free diet(FFD)or diet containing 5% cellulose(CEL),xylan(XYL)or beta-glucan(GLU).The digestive trail was carried out from d 18 to 21.After 21 d,pigs were slaughtered and blood,tissue samples,ileal and cecal digesta were collected.We observed an elevated 16 S rRNA gene copies in ileum and cecum digesta after NSP ingestion.Experimental results suggested:1)NSP supplementation had no significant effect on the growth performance of pig(P>0.05).2)The digestibility of dry matter,Calcium,phosphorus,ash,energy and crude fiber were lower in CEL and GLU group than that in FFD group(P<0.05).The digestibility of Calcium and ether extract were lower in XYL group than that in FFD group(P<0.05).Amongst the NSPs-treat groups,the digestibility of dry matter,phosphorus,ash,energy and crude fiber in CEL group than that in GLU group(P<0.05).The digestibility of ether extract in XYL group than that in CEL group(P<0.05).3)CEL supplementation can improve the intestinal weight of pig compared with the FFD group(P<0.05).Amongst the NSPs-treat groups,the intestinal length showed a tendency of increasing in CELand GLU group.XYL decreased the intestinal weight and intestinal length of piglets compared with cellulose(P<0.05).4)NSPs supplementation decreased serum glucose concentration compared with the FFD group(P<0.05).However,the serum superoxide dismutase concentrations was elevated in CEL group and glutataione concentrations was elevated in GLU group(P<0.05).5)GLU supplementation not only increased the ratio of villus height/crypt depth in small intestine(P<0.05),but also elevated the activity of sucrasein the jejunum and ileum compared to FFD group(P<0.05).Amongst the NSPs-treat groups,pigs on GLU-containing diet showed significantly higher villus height(P<0.05)and villus height/crypt depth(P<0.05)in the duodenum,and elevated the activity of sucrase in the jejunum compared to XYL and CEL group(P<0.05).6)Compared with the FFD group,NSP supplementation increased piglet the mRNA expression of CLDN-1 in duodenum and jejunum,that of SGLT1 and GLUT2 in jejunum and ileum(P<0.05).Amongst the NSPs-treat groups,GLU supplementation increased piglet the mRNA expression of SGLT1 in duodenum(P<0.05).7)Compared with the FFD group,NSP significantly increased the content of acetic acid in the ileum(P<0.05),and there was a tendency to increase the pH value of ileum in piglets.GLU could increase the content of short chain fatty acids,especially butyric acid,and reduce the pH value of cecum(P<0.05).8)We observed an elevated 16 S rRNA gene copies in ileum and cecum digesta after NSP ingestion.Interestingly,we found that cecum digesta contained higher bacterial diversity than ileum digesta(P<0.05).9)NSP had no significant influence on overall diversity,but acutely altered the abundance of specific bacteria.Importantly,NSPs decreased the abundance of phylum Firmicutes,but increased the phylum Proteobacteria in ileal samples.Among the NSP-treated groups,pigs on CEL-containing diet had exclusively higher abundance of Lactobacillus spp.In the ileum.Whereas,the GLU-treated samples had more Clostridium spp.Taken together,NSP had no significant effcet on the production performance of weaned piglets,but the components of NSP can significantly lower the digestibility of some nutrients.Specifically,GLU and CEL can promote barrier function in weaned piglet intestine,while the promoting role of Xylan was weaker than GLU and CEL.The mechanism underlying these effects may attribute to the improvement of the intestinal microbial composition,and promotion of the short fatty acids(SCFAs)production.This study revealed the comparative nutritional effects of different dietary NSP components on pigs,which provides essential information for further exploring the mechanism of dietary fiber regulating the intestinal health of livestock,and contribute to the rational application of dietary fiber in the future. |
