2.3. Fecal Sample Preparation and Metagenomic Analysis

The extraction and sequencing of DNA is described in the Supplementary Methods. Amplicon sequencing of the V4 variable region of the microbial 16S rRNA gene was performed using a MiSeq sequencer (Illumina, San Diego, CA, USA). The reads were analyzed in QIIME v.1.7.0 [23] using the HITdb v. 1.0 database [24] for taxonomic assignment (see Supplementary Methods). Prediction of metabolic potential profiles was performed using Greengenes v. 13.5 database [25] and PICRUSt [26].