3.3.2 Effect of GP on bacterial community structure
We analyzed the differences in bacterial abundance in rats before and after GP administration at the phylum and genus levels, and the heatmaps are shown in Figures 3B and C. Compared with the blank group, the abundance of Gram-positive Firmicutes bacteria in the model group decreased significantly, while the abundance of Gram-negativeBacteroidetes, Verrucomicrobia, Proteobacteria, Tenericutes, Cyanobacteria, and Deferribacteres increased significantly (Qin et al., 2010). The abundance of Gram-negative bacteria decreased significantly after GP administration. Next, Grapeland was used to construct a hierarchical tree of the composition of the sample population at each classification level to explore the dominant microbial groups (Fig.3D). The results showed that the dominant species at the phylum level were Firmicutes, Bacteroidetes, Verrucomicrobia and Proteobacteria, and the dominant species at the genus level were Akkermansia, Allobaculum, andOscillospira . It is suggested that the above bacteria can be used as a characteristic index for future fecal microbiota transplantation. Community composition analyses at the taxonomic levels of phylum and genus have preliminarily proved that the bacterial community structure before and after GP treatment is significantly different. We further used principal component analysis (PCA) to analyze the overall structure of the flora before and after the occurrence of intestinal inflammation and under the intervention of GP, which also proved that there were significant differences between the three groups (Fig. 3E).