16S rRNA of Crassostrea gigas
16S rRNA gene sequencing was conducted to analyze gut microbiome of oysters. Total bacterial community DNA was extracted from gut samples with FastDNA Spin Kit for Soil (MP Biomedicals, USA). The quality and quantity of DNA were assessed by 1% agarose gel electrophoresis. Subsequently, the total DNA was amplified in an ABI GeneAmp 9700 thermocycler (ABI, USA) using primer pair 338F (5-ACTCCTACGGGAGGCAGCAG-3) and 806R (5-GGACTACHVGGGTWTCTAAT-3) to target the V3-V4 regions of the 16S rRNA gene.