16S
Microbial DNA was extracted using the HiPure Stool DNA Kits (Magen, Guangzhou, China) according to manufacturers protocols. The 16S rDNA target region of the ribosomal RNA gene was amplified by PCR. Amplicons were extracted from 2% agarose gels and purified using the AxyPrep DNA Gel Extraction Kit (Axygen Biosciences, Union City, CA, U.S.) according to the manufacturers instructions, and then quantified using the ABI StepOnePlus Real-Time PCR System (Life Technologies, Foster City, USA). Purified amplicons were pooled in equimolar and sequenced on the Illumina HiSeqTM 2500 platform.