Fig. 1

Relative bacterial abundance at the phylum level and beta diversity. a Relative bacterial abundance of the control and the oxygen groups (n = 9) at the phylum level at day 0. b PCA plot of the control and the oxygen groups (n = 9) at day 0 based on unweighted UniFrac distances (R² = 0.086, p = 0.055). c Relative bacterial abundance of the control and the oxygen groups (n = 9) at the phylum level at day 7. d PCA plot of the control and the oxygen groups (n = 9) at day 7 based on unweighted UniFrac distances (R² = 0.185, p = 0.001**). PCA, principal coordinates analysis. **p < 0.01. The corresponding phyla of the pathogenic bacteria in this study: Proteobacteria (Gammaproteobacteria and Proteus) and Firmicutes (Streptococcus)