| The intestinal epithelial barrier can maintain the integrity of the intestinal epithelial mucosa,preventing harmful pathogens from invading the intestinal tissue,and is also the basis for maintaining the intestinal homeostasis of animals.Previous studies have shown that intestinal microbes play a key role in the intestinal epithelial barrier function of animals.The mining of intestinal microbes that regulate the intestinal epithelial barrier function is of great significance.Compared to commercial pigs,Guizhou Congjiang miniature pigs have several advantages including lower diarrhea incidence during the early-weaning period.The relative abundances of Eubacterium hallii,Butyricicoccus pullicaecorum and Blautia hansenii in the intestine of Guizhou Congjiang miniature pigs is higher than those in commercial pigs.Therefore,this study investigated the roles of three microbes(E.hallii,B.Pullicaecorum,and B.hansenii)in intestinal epithelial barrier function of mice and dissected the underlying mechanism.These findings will provide theoretical basis and important re ference for the manipulation of intestinal microbes used to improve the intestinal health of pigs.Experime nt 1 Study on the regulation of intestinal epithelial barrier function in mice by strain E.hallii and B.pullicaecorum.SPF mice of 3 weeks old(n = 15)were gavaged with E.hallii and B.pullicaecorum respectively,and the C trl group was gavaged with sterile PBS solution,mice in E.hallii and B.pullicaecorum groups were given 150 μL PBS suspension containing the E.hallii(108 CFU/ml)and B.pullicaecorum(108 CFU/ml)by gavage every other day for 4 wk,and those in Ctrl were given 150 μL sterile PBS by gavage.The body weight was measured and recorded at the age of 8 weeks and slaughtered for sampling.The indexes were determined to screen the serum differential metabolites that may affect the intestinal epithelial barrier function.SPF mice of 3 weeks old(n = 8)were gavaged with the selected metabolites,and the Ctrl group was gavaged with sterile PBS solution,mice in the selected metabolites groups were given 150 μL PBS suspension containing the corresponding metabolite by gavage every other day for 4 wk,and those in Ctrl were given 150 μL sterile PBS by gavage.Body weight was measured and recorded at the age of 8 weeks,and slaughtered and sampled for verification.(1)E.hallii and B.pullicaecorum can significantly reduce the serum D-lactate and endotoxin levels in mice,and the expression of E-cadherin in the intestinal tissue of mice was significantly increased.E.hallii can significantly increase the ratio of villus height/crypt depth in the duodenum and jejunum of mice,which indicating intestinal epithelial barrier function in mice was enhanced.(2)E.hallii and B.pullicaecorum can significantly affect the composition and content of serum metabolites in mice,and affect amino acid metabolism,lipid metabolism and metabolism in mice.(3)The differential metabolites in mice serum affected by E.hallii and B.pullicaecorum was screened out and tested.The results showed t hat Tebuconazole and N-Acetyl-L-Tyrosine could significantly reduce the serum D-lactate and endotoxin levels in mice,and significantly increase the villus height/crypt depth ratio in the duodenum,jejunum and ileum of mice,indicating that E.hallii and B.pullicaecorum can affect the intestinal epithelial barrier function of mice by up-regulating the content of serum metabolites Tebuconazole and N-Acetyl-L-Tyrosine.Experime nt 2 Study on the regulation of intestinal epithelial barrier function in mice by strain B.hansenii.SPF mice of 3 weeks old(n = 15)were gavaged with B.hansenii,and the Ctrl group was gavaged with sterile PBS solution,mice in B.hansenii was given 150 μL PBS suspension containing the B.hansenii(108 CFU/ml)by gavage every other day for 4 wk,and those in Ctrl were given 150 μL sterile PBS by gavage.The body weight was measured and recorded at the age of 8 weeks and slaughtered for sampling.The indexes were determined to screen the serum diffe rential metabolites that may affect the intestinal epithelial barrier function.SPF mice of 3 weeks old(n = 8)were gavaged with the selected metabolites,and the Ctrl group was gavaged with sterile PBS solution,mice in the selected metabolites groups were given 150 μL PBS suspension containing the corresponding metabolite by gavage every other day for 4 wk,and those in Ctrl were given 150 μL sterile PBS by gavage.Body weight was measured and recorded at the age of 8 weeks,and slaughtered and sampled for verification.(1)B.hansenii can significantly reduce the serum D-lactate and endotoxin levels in mice,significantly increase the expression of E-cadherin in mice intestinal tissue,and significantly increase the ratio of villus height/crypt depth in the duodenum,indicating enhanced intestinal epithelial barrier function in mice.(2)B.hansenii can significantly affect the composition and content of serum metabolites in mice,and affect amino acid metabolism,lipid metabolism and metabolism in mice.(3)To further screen out the differential metabolites in mouse serum affected by B.hansenii,and carry out experiments.The results showed that Phenylacetyl-L-Glutamine,Curdione,Pentamidine and Fluconazole could significantly reduce serum D-lactate and endotoxin levels in mice,and 2-Phthalimidoglutaric acid significantly reduced fractional serum endotoxin levels,indicating that B.hansenii can increase serum endotoxin levels by the contents of differential metabolites Phenylacetyl-L-Glutamine,C urdione,Pentamidine,Fluconazole and 2-Phthalimidoglutaric acid affect the intestinal epithelial barrier function in mice.In conclusion,E.hallii,B.pullicaecorum and B.hansenii can affect the serum D-lactate and endotoxin levels,the integrity of intestinal epithelial mucosa and the expression of intestinal epithelial barrier function proteins in mice.The mechanism may up-regulate the composition and content of serum metabolites,which is related to amino acid metabolism,lipid metabolism and metabolism in mice.Therefore,the results of this study suggest that E.hallii,B.pullicaecorum and B.hansenii may be important microbial targets for improving and regulating the intestina l epithelial barrier function of animals and maintaining the intestinal health of animals. |
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