sequences of bacteria
The fecal DNA was extracted using the PowerSoil DNA Isolation kit (MO BIO Laboratories, USA) according to the manufacturers instructions. V1-V9 variable regions of the 16S rRNA genes from bacteria and archaea were amplified by PCR using the primer 27F (5-AGRGTTTGATYNTGGCTCAG-3) and 1492R (5-TASGGHTACCTTGTTASGACTT-3) with adapter sequences and barcode sequences. After PCR amplification, sequencing was performed on an Illumina HiSeq 2500 platform (Illumina, Inc., San Diego, CA, USA) by Biomarker Technologies Co. Ltd. (Beijing, China).