Abstract: [Objective] This study was conducted to characterize the microbial community diversities in pig house environments, to understand the structural differences of bacterial communities in different types of pig house environments, and to identify the potentially pathogenic bacterial genera. [Method] Environmental microbial samples were collected from pregnant sow houses, nursery pig houses and farrowing houses in a large-scale pig farm using air sedimentation method. Three houses were sampled for each type of pig house, with a total of 9 samples. Using Illumina Miseq technology, the high-throughput sequencing was performed targeting on the V3-V4 variant region of bacterial 16S rDNA. The sequencing data were analyzed by QIIME2 software to compare the composition of microbial communities in different types of pig house environments. [Result] At the similarity threshold of 97%, a total of 29 126 OTUs were obtained from the 9 samples, covering 31 phyla, 66 classes, 160 orders, 320 families, 899 genera and 1 831 species of bacteria. The Chao1 index, Shannon index and phylogenetic diversity index of the farrowing houses and nursery pig houses were generally higher than those of the pregnant sow houses. Proteobacteria, Bacteroidota, Firmicutes and Actinobacteriota were the four dominant bacterial groups at the phylum level in the pig house environments. The relative abundance of Proteobacteria was the highest in all three types of pig houses, while the relative abundance of Firmicutes, Actinobacteria and Bacteroidetes varied greatly among different types of pig houses. Acinetobacter, Corynebacterium and Stenotrophomonas were the genera with the highest relative abundance in farrowing houses, pregnant sow houses and nursery pig houses, respectively. There were multiple genera of bacteria with potential pathogenicity to animals, such as Helcococcus, Streptococcus, Legionella and Serratia, in the air of pig houses. [Conclusion] The pig house environments were rich in microbial community diversities. Farrowing houses and nursery pig houses had higher bacterial diversity, evolutionary diversity and abundance than the pregnant sow houses. The potentially pathogenic bacteria found in this study provided references for the selection of disinfection drugs used in pig house environments.

Key words: 16S rDNA high-throughput sequencing, pig house, environmental microorganism, community analysis, diversity