Microbiome-Metabolome Analyze The Immune Microenvironment of Cecal Contents, Soft and Hard Feces of Hyplus Rabbits

Background: Intestinal microbiota and its metabolites play a vital role in host growth, development and immune regulation. Methods: This study analyzed the microbial community distribution, cytokines and short chain fatty acids (SCFAs) content of cecal contents (Con) group, soft feces (SF) group and hard feces (HF) group of 140-day-old Hyplus rabbits, and verified the effect of soft feces on cecal immune microenvironment by fasting soft feces.Results: The results showed that there were significant differences in the levels of phylum and genus composition, cytokines and SCFAs among Con group, SF group and HF group. In addition, metabolic pathway enrichment analysis found that there were two significantly up-regulated differential metabolic pathways in SF group and HF group compared with con group, P125-PWY, namely the super pathway of (R, R) - butanediol biosynthesis and P341-PWY, namely the glycolysis V pathway. At the same time, Christensenellaceae_R-7_Group and Lachnoclostridium are significantly enriched in the above two pathways. The correlation analysis of cytokines and SCFAs with differential microbial communities showed that Muribaculaceae and Ruminococcaceae_UCG-014, Ruminococcaceae_NK4A214_group and Christensenellaceae_R-7_Group are closely related to cytokines and SCFAs. After fasting soft feces (CP), the contents of SCFAs and cytokines (IL-4, IL-10) in cecum decreased significantly, while cytokines (TNF-a, IL-1β) increased significantly. The results of multiple immunofluorescence showed that the expression of claudin-1, occludin and ZO-1 related to intestinal immune barrier increased significantly in CP Group. Conclusions: In conclusion, soft feces are not only rich in probiotics and SCFAs, but also play a very important role in improving the immune microenvironment of cecum. This study may provide a valuable reference for the treatment of inflammatory intestinal diseases.