Fig. 5

Shannon diversity index (A) and Chao1 diversity index (B) of faecal bacterial composition in different surgical groups at different time points (A, no statistical significance). An NMDS plot (C) of faecal bacterial composition of RYGB patients from cohort 1. PERMANOVA adjusted p = 0.0015 for pre-op vs. 2–6 months or 1–2 years post-op; p > 0.05 for 2–6 months vs. 1–2 years post-op. The natural log-transformed relative abundances of faecal bacteria from RYGB patients at pre-op (black), 2–6 months (green) and 1–2 years (orange) post-op (panel D). Data are presented in mean ± SEM. Kruskal-Wallis test was used for group comparisons and Dunn’s test was used for adjusting multiple comparisons. ****p < 0.0001, ***p < 0.001, **p < 0.01, *p < 0.05