Approximately 30 ng of high-purity DNA from each sample was used for amplification using 16S rRNA gene fusion primers. The PCR products were purified using Agencourt AMPure XP magnetic beads and subsequently eluted in an appropriate buffer. Following purification, DNA libraries were constructed, and their size and concentration were analyzed using the Agilent 2100 Bioanalyzer. Sequencing was performed on the DNBSEQ platform (BGI, China), selected based on the library insert sizes.