Dynamics and Health Risks of Fungal Bioaerosols in Confined Broiler Houses During Winter

Fungal bioaerosols play a critical ecological and health role in intensive poultry production systems. However, their dynamic characteristics and community succession patterns in confined cage environments during winter remain poorly understood. This study investigated a typical confined broiler house in Hebei Province, China, during winter. A combined approach of Andersen six-stage sampling, colony counting, and Internal Transcribed Spacer (ITS) high-throughput sequencing was employed to comprehensively analyze the concentration, particle size distribution, diversity, and community composition of fungal bioaerosols across three key growth stages: 7 days (brooding phase), 21 days (growing phase), and 35 days (finishing phase). The results revealed a significant increasing trend in fungal aerosol concentration as the rearing cycle progressed, increasing from 1125 ± 125 CFU/m3 at day 7 to 3872 ± 565 CFU/m3 at day 35 (p < 0.001), reaching high-risk exposure levels in the later stages. Small-sized fungal bioaerosols (