16S functional gene prediction analysis of gut microbiota in various groups of mice. A. KEGG functional prediction analysis showed that, compared with that in Group P, the gut microbiota in Group F could increase both carbohydrate and nucleotide metabolism, while decreasing both lipid and amino acid metabolism. B. COG functional prediction analysis showed that compared with that in Group P, the abundance of proteins associated with transcription, translation, ribosomal structure and biogenesis, carbohydrate transport and metabolism, and nucleotide transport and metabolism was significantly increased in Group F.