Effects of Odoribacter laneus on gut microbiota dysbiosis in acute pancreatitis mice

Because Odoribacter laneus plays a protective role in the intestinal barrier, we used fecal samples for 16S rRNA sequencing to explore the influence of OL on the intestinal microbiota in AP mice. From 18 fecal samples, we obtained the full length of bacteria. The coverage and Shannon curves showed that most samples tended to be flat, which suggested that the volume of sequencing data was reasonable and sufficient. Subsequently, we used four alpha diversity indices to measure the abundance and diversity of the microbiota, that is, ACE, Chao1, Shannon, and Simpson. There were no differences in the four alpha diversity indices among the three groups, which demonstrated that the alpha diversity of intestinal microbiota is not altered by AP or OL treatment. We evaluated the beta diversity of gut microbiota among groups by the PCoA and NMDS. Although the OL group could not be separated entirely from the AP group, the distribution was slightly different from the AP group. Furthermore, the Anosim analysis revealed an obvious difference in beta diversity among the three groups. These analyses further revealed that the overall gut microbial compositions in the three mice groups were different. Regarding the relative abundance, it was observed that Firmicutes and Bacteroidetes were the predominant phyla in the three groups. In the AP group, the Proteobacteria phylum overgrowed compared with the CON group, while it decreased in the OL group. The abundance of Escherichia-Shigella genus showed a similar trend.To determine the key intestinal microbiota considerably changed by AP or OL treatment, all sequences were analyzed with the LEfSe method. In the CON group, the characteristics of microbiota were concentrated in the genera Allobaculum, Intestinimonas, Coriobacteriaceae, and Oscillospiraceae. The intestinal microbiota of the AP group was characterized by the enrichment of the genera Escherichia-Shigella, Clostridium, and Monoglobus. Meanwhile, the Lactobacillus, Alloprevotella, Butyricicoccus, Lactococcus, and Bifidobacterium genera was enriched in the OL group. Collectively, AP mice showed gut dysbiosis of increased pathogenic bacteria and O. laneus could reverse the dysbiosis by regulating probiotic bacteria.