GIT biogeography of microbial composition and functional potential. Spatial variation of the relative abundance of taxa of interest in the three GIT regions at phylum (A) and species (B) levels; comparing the abundance of CAZymes of interest in the three GIT regions at class (C) and family (D) levels; Heatmaps showing the spatial distribution of major KOs responsible for phosphotransferase system (E) and SCFA production (F). G, graphical scheme of distinct patterns of MAGs correlate with their function within the GIT. Only regional differential taxonomic and functional terms were presented in the heatmaps. Level of significance in the boxplot: Ns p ≥ 0.05, ^*p < 0.05, ^**p < 0.01.