Ventilation-driven microbial and antimicrobial resistance divergence in intensive poultry houses and the associated...

Ventilation strategies in intensive poultry production systems play a critical role in shaping airborne microbial communities and the dissemination of antibiotic resistance, with potential implications for environmental and public health. In this study, bioaerosols from closed (mechanically ventilated) and open (naturally ventilated) chicken houses were systematically characterized using high-throughput metagenomic sequencing to compare microbial community composition and antibiotic resistance gene (ARG) profiles under contrasting ventilation regimes. Open chicken houses exhibited significantly higher microbial diversity (P < 0.05), reflecting increased environmental microbial inputs, while the relative abundance of the potentially antibiotic-resistant pathogen Staphylococcus aureus was also elevated. In contrast, closed chicken houses facilitated the accumulation of a core microbial community, including potential pathogens such as Helicobacter pullorum and Clostridium perfringens. Closed chicken houses showed a greater enrichment of macrolide resistance genes. In addition, the overall abundance of ARGs, expressed as ARG copies per 16S rRNA gene, was significantly higher in closed houses than in open houses (P < 0.05). Although total ARG abundance was lower in open chicken houses, the proportion of contigs harboring both ARGs and mobile genetic elements (MGEs) was significantly higher (P < 0.05), indicating increased potential for horizontal gene transfer. These findings reveal differences in microbial diversity and associated health risks between different poultry production systems and underscore the importance of optimizing ventilation strategies to control pathogen transmission and the spread of antibiotic resistance.