Fecal DNA bioinformatic analysis
Metaphlan (version 4) (For biomarker identification, the feature table using calcNormFactors function was normalized, the TMMwsp option. The limma R package (version 3.42.2) function voom (Data was normalized using rarefaction technique from Phyloseq R package (Bray–Curtis dissimilarity matrix and Permutational analysis of variance (PERMANOVA) analysis for beta-diversity were performed using vegan R package, after normalization by relative frequency for each sample.Spearman’s rank correlation was used to associate differentially abundant taxa with the hydrogen and methane levels at the phylum, family, genus, and species levels. Correlation coefficients and p-values were calculated using the Psych R package version 2.2.9. (