22S rRNA gene of intestinal tract
Sequencing libraries were generated using TruSeq DNA PCR-Free Sample Preparation Kits (Illumina, USA). Sample index codes were added during library preparation. DNA library quality was assessed on a Qubit 2.0 Fluorometer (Thermo Scientific) and an Agilent Bioanalyzer 2100 system. Libraries were sequenced on an Illumina HiSeq 2500 platform using 256 bp paired-end reads.