Shotgun sequencing for metagenomics
Approximately 2 μg DNA per sample was prepared. Sequence libraries were generated using the NEBNext Ultra DNA Library Prep Kit for Illumina (NEB, USA). The libraries were sequenced on the Illumina NovaSeq 6000 platform (insert size 350 bp, read length 150 bp) at Novogene Bioinformatics Technology Co., Ltd. (Tianjin, China).Metagenomics raw data is about 6 G each sample. Raw sequence reads were trimmed using Trimmomatic v0.39 to remove adapters and low-quality regions and then removed from contaminating human reads using Bowtie2 v2.4.2 (Reference database: GRCh38).