Fig. 4

Diversity analyses on all treatment groups reveal no clear alteration of alpha diversity but some differences in beta diversity. A Boxplots of Simpson’s index to estimate α diversity changes, using Phyloseq’s estimate richness function, in each treatment group between the start (Day − 3) and the end of the treatment (Day 42). The higher the alpha diversity, the lower the Simpson index value. None of the comparisons were statistically significant. B PCA plots showing β diversity amongst samples, calculated on relative abundances by Bray-Curtis distance between each sample, using the phyloseq R/Bioconductor package [41]. The combination of bupropion and naltrexone, as well as sibutramine, were statistically significant and explained a consistent proportion of the variance (as explained by the value of R²), bupropion and naltrexone: P.value = 0.001, R² = 0.13, sibutramine: P.value = 0.001, R² = 0.23