16S RNA sequencing of zebrafish intestine
Bacterial DNA was extracted from the samples and the V3-V4 hypervariable regions of the bacterial 16S rRNA gene were amplified by thermocycler PCR system (GeneAmp 9700, ABI, USA). The PCR products were purified and pooled in equimolar and paired-end sequenced (2  300) on an Illumina MiSeq platform (Illumina, San Diego, USA). Optimized sequences obtained by data quality control splicing were further processed by the Deblur method to obtain the amplicon sequence variant (ASV) in the samples, and switch to SILVA database for classification