Function of the gut microbiota. (A) Gene numbers of KEGG classification in gut microbiota. (B) PCoA of gut microbiota function between the CON, T2DM, and DN groups. (C) ANOSIM analysis of gut microbiota function between the CON, T2DM, and DN groups. (D) LEfSe analysis of gut microbiota functions between the CON and DN groups. (E) LEfSe analysis of the gut microbiota functions between the T2DM and DN groups. (F to I) Gut microbiota function with a decreasing trend between the CON, T2DM, and DN groups.