title: sequences of bacteria
design: Bacterial universal primers 515F and 806 were used to amplify the V4 region of bacterial 16S rRNA gene, and the amplified products were sequenced PE250 double-ended on the Hiseq 2500 platform (Shenzhen BDA Gene Co., LTD.). The original number obtained by sequencing After splicing and filtering, high-quality target sequences required for subsequent analysis are obtained, and the sequences are OTU clustered in QIIME software. Chao5 index was calculated at the OTU level to evaluate the abundance of flora. The Shannon and Simpson indices were calculated to assess the diversity of the flora. The Greengenes database was used to classify and annotate OTUs.