Effects Of Viral And Bacterial Porcine Epidemic Diarrhea On Intestinal Flora And Tight Junctions In Weaned Piglets

The intestinal development of newborn animals is not perfect and the immune function is low.In the face of the changes of the environment and the infection of the pathogens,the digestive tract dysfunction will be caused,often accompanied by the imbalance of the intestinal microecology and the destruction of the intestinal barrier function,and the most common is diarrhea.Although many measures have made significant progress in controlling diarrhoea,diarrhoea is still a high incidence of disease.Severe cases can lead to death.In this experiment,weanling piglets(2 week old)were selected as models,and10 healthy piglets were randomly selected from the same column.Several diarrhea piglets were detected by polyacrylamide gel electrophoresis.The results of high throughput sequencing were divided into two groups: Control group and Porcine epidemic diarrhea virus-infected groups,PED-V group);Porcine epidemic diarrhea bacteria-infected groups,(PED-B group).The changes in intestinal microflora structure,interaction between microbes and the metabolism of short chain fatty acids in piglets were investigated after weaning,and the changes in intestinal mucosal morphology and the expression of ZO-1,Occludin,Claudin-1 and JAM1 in intestinal mucosa were analyzed.Results: the richness of intestinal bacteria in the PED-V and PED-B groups of the diarrhea piglets was lower than that in the Control group,and the decrease in the PED-B group was significantly lower than that in the Control group(P<0.05).At the level of class classification,the dominant flora of group Control was Clostridia 53%,Bacteroidia 20% and Bacilli 15%.The dominant flora of group PED-V was Clostridia55%,Bacilli 17% and Bacteroidia 14%,and the dominant bacteria group in PED-B group was Clostridia 25%,Epsilonproteobacteria 24%,Bacteroidia 18% and Gammaproteobacteria 17%.At the genus classification level,the abundance of Lachnospiraceae in the PED-V group was significantly lower than that in the Control group,and the abundance of the Megasphaera was significantly increased(P<0.05);The abundance of Campylobacter,Enterobacteriaceae and Prevotella was increased significantly(P<0.05),and the abundance of the Lachnospiraceae,Megasphaera decreased significantly(P<0.05)in the PED-B group compared with the Controlgroup.The results showed that the formation of intestinal bacterial colonies in weanling piglets and the interaction between two microorganism populations with different functions could be affected by or without diarrhoea and infection.The number of connectors and module hubs in the PED-V group and the PED-B group network is much smaller than that in the Control group network.Diarrhea can significantly reduce the levels of short chain fatty acids,acetic acid,propionic acid and butyric acid in group PED-B,and increase the pH of colon contents in PED-V group and PED-B group.Diarrhea also deepened the colonic crypt depth.Compared with the Control group,the expression of tight junction protein ZO-1,Occludin and Claudin-1 in PED-V group and PED-B group were significantly decreased(P<0.05).Conclusion: the composition of microbe bacteria in PED-V group is similar to that in Control group,while the composition of microbe bacteria in PED-B group is different from that of Control group;virus and bacterial apparent diarrhea can cause the disorder of intestinal microflora function;virus and bacterial apparent diarrhea can cause intestinal mucosal barrier injury.