title: gut microbiomes
design: The total genomic DNA from gut microbiota in fecal samples was extracted, then verified by 1.2% agarose gel electrophoresis, and DNA concentrations were determined using NanoDrop spectrophotometry. All samples were quantified on a Microplate reader (BioTek, FLx800, USA). The V3-V4 hypervariable region of the 16S rRNA gene was amplified using barcoded primers and sequenced via the Illumina platform. The amplicons from different samples were pooled, purified and sequenced. The microbial sequence data were analyzed using QIIME 2 (version 2019.4) and R package.