microbiota amplicons
V1-V3 region of bacterial 16S rRNA gene, protozoan 18S rRNA gene and V6-V8 region of archaeal 16S rRNA gene were performed using BAC9F (5-GAGTTTGATCMTGGCTCAG) and 515R (5-CCGCGGCKGCTGGCAC) primers, RP841F (5-GACTAGGGATTGGARTGG) and REG1302R (5-AATTGCAAAGATCTATCCC) primers, and Arc915aF (5- AGGAATTGGCGGGGGAGCAC) and 1386R (5- GCGGTGTGTGCAAGGAGC) primers, respectively