Metagenomic stool
For comprehensive community and functional profiling, 100 ng of high-quality DNA was fragmented enzymatically (NEBNext Ultra II kit). Fragmented DNA was end-repaired, A-tailed, and ligated to sequencing adapters. Libraries were purified and size-selected (AMPure XP beads), and quality was assessed using TapeStation. For sequencing, libraries were pooled and sequenced on an Illumina NovaSeq 6000 platform. For quality control, library concentration and fragment size distribution were verified prior to sequencing using iQuant dsDNA HS Assay Kit.