fecal sample
microbial DNA was isolated using the E.Z.N.A. soil DNA Kit (Omega Bio-Tek). Then, NanoDrop 2000 UV-vis spectrophotometer (Thermo Scientific) was used to detect DNA concentration and purity. Next, microbial DNA was amplified with the primers targeting the V3-V4 regions (338F: 5-ACTCCTACGGGAGGCAGCAG-3 and 806R: 5-GGACTACHVGGGTWTCTAAT-3).