16s rRNA Seq of broiler: 3-PL22  42 days old cecal contents
The hypervariable V4 regions of the microbial 16S rRNA gene were amplified using the forward primer 515F (5-GTGCCAGCMGCCGCGGTAA-3) and the reverse primer 806R (5-GGACTACHVGGGTWTCTAAT-3). The resulting PCR products were quantified and purified using 2% agarose gel electrophoresis, and quantified using Qiagen Gel Extraction Kit (Qiagen, Germany), respectively. The purified amplicons were pooled in equimolar concentrations and subjected to paired-end high-throughput sequenced (2250 bp) on an Illumina NovaSeq platform (llumina, USA), following the standard protocols of Novogene Co., Ltd (Beijing, China).