Airborne bacterial aerosols are a significant yet understudied component of intensive poultry farming, particularly in cold climates. This study characterized the concentration, size distribution, and community composition of airborne bacteria in closed-cage broiler houses during winter in Hebei Province, China. Air sampling was conducted at three growth stages (7, 21, and 35 days) and analyzed using culture-based methods and 16S rRNA sequencing. Culturable bacterial concentrations increased significantly with broiler age, from 1.1 × 10³ to 1.6 × 10⁴ CFU/m³. The particle size distribution shifted from a predominance of large particles (≥4.7 µm) at day 7 to a dominance of small, inhalable particles (<4.7 µm) thereafter. Sequencing revealed increasing bacterial richness and diversity with age, alongside significant community structural shifts. Predominant genera included Stenotrophomonas, Lactobacillus, and Ruminococcus. Notably, potential zoonotic pathogens (Shigella and Acinetobacter) were detected in later stages. This study provides critical insights into winter bioaerosol dynamics, highlighting implications for animal welfare, occupational health, and public health.

Bioaerosols are a major source of airborne microbial contamination in intensive poultry production systems. Their concentration and community structure can profoundly influence animal health, public health, and the overall safety of the farming environment. However, the dynamic characteristics of bacterial aerosols in enclosed poultry houses during winter remain insufficiently studied. Using Taihang chickens as a model, this study investigated three key production stages—brooding (15 days), growing (60 days), and laying (150 days)—under winter cage-rearing conditions. A six-stage Andersen sampler was employed alongside culture-dependent enumeration and 16S rRNA high-throughput sequencing to analyze variations in bacterial aerosol concentration, particle size distribution, and community succession patterns. The results revealed a significant increase in the concentration of culturable airborne bacteria with bird age, rising from 8.98 × 10³ colony-forming unit (CFU)/m³ to 2.89 × 10⁴ CFU/m³ (p < 0.001). The particle size distribution progressively shifted from larger, settleable particles (≥4.7 μm) toward smaller, respirable particles (<4.7 μm). Microbial sequencing indicated a continuous increase in bacterial alpha diversity across the three stages (Chao1 and Shannon indices, p < 0.05), while beta diversity exhibited stage-specific clustering, reflecting clear differences in community assembly. The composition of dominant bacterial genera transitioned from potentially pathogenic taxa such as Acinetobacter and Corynebacterium during the brooding stage to a greater abundance of beneficial genera, including Bacteroides, Lactobacillus, and Ruminococcus, in later stages. This shift suggests a potential ecological link between aerosolized bacterial communities and host development, possibly related to the aerosolization of gut microbiota. Notably, several zoonotic bacterial species were detected in the poultry house air, indicating potential public health and occupational exposure risks under winter confinement conditions. This study is the first to elucidate the ecological succession patterns of airborne bacterial aerosols in Taihang chicken houses across different growth stages during winter. The findings provide a scientific basis for optimizing winter ventilation strategies, implementing stage-specific environmental controls, and reducing pathogen transmission and occupational hazards.

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 (<4.7 μm) were dominant across all stages (54.35–65.50%), with the highest proportion observed at day 21, indicating their potential for deep respiratory deposition and long-distance airborne transmission. The number of Operational Taxonomic Units (OTUs), along with Chao1 and Shannon indices, increased significantly with bird age (p < 0.001), demonstrating a clear community succession from early-stage yeast-dominated forms (e.g., Diutina, Blumeria) to mid- and late-stage assemblages dominated by filamentous fungi (e.g., Aspergillus, Cladosporium, Alternaria). Notably, several zoonotic pathogenic genera were detected throughout all rearing stages, highlighting the potential risks of airborne fungi to animal health, occupational exposure, and environmental safety under winter ventilation restrictions. This study characterizes a stage-dependent pattern of increasing airborne fungal concentrations accompanied by shifts in particle size distribution and community composition under winter confined conditions. The findings provide a crucial scientific basis for optimizing winter ventilation and environmental management strategies, improving environmental control technologies, establishing airborne biosafety standards, and developing targeted fungal monitoring and prevention technologies.

With the growing demand for antibiotic-free and sustainable poultry production, plant-derived antimicrobials have emerged as promising alternatives. However, a systematic understanding of the combined effects of oregano essential oil (OEO) and Macleaya cordata extract (MCE) on the broiler gut microbiome remains lacking. This study employed an integrated “structure–function–phenotype” framework to investigate the individual and combined (OMS) effects of OEO and MCE on gut microecological remodeling and its coupling with host growth, metabolic, and immune phenotypes. A total of 960 one-day-old broiler chicks were individually weighed and then randomly allocated to four treatments using body-weight-stratified randomization, with 6 replicate pens per treatment and 40 birds per pen, to ensure similar initial body weight across groups. Over a 42-day trial, we evaluated growth performance, serum biochemistry, antioxidant status, and immune parameters. Compared to the control, the OMS treatment significantly enhanced average daily feed intake (ADFI) and average daily gain (ADG), increased serum total protein (TP), and decreased blood urea nitrogen (BUN), triglycerides (TG), total cholesterol (TC), and alkaline phosphatase (ALP). However, the feed-to-gain ratio (F/G) was also higher in the OMS group, indicating that the improvement in growth rate did not translate into enhanced feed efficiency but was primarily driven by increased feed consumption. OMS also improved overall antioxidant capacity and key enzyme activities, elevated immunoglobulin levels, and reduced pro-inflammatory cytokines. Notably, OMS maintained Lactobacillus dominance, enriched Bacteroides, Enterococcus, and Butyricicoccus, and reduced Escherichia–Shigella. Functional predictions via PICRUSt2 suggested enhanced metabolic pathways related to antioxidant and immune functions; however, these results represent inference-based predictions and should be interpreted cautiously. Overall, the combination of OEO and MCE exerted synergistic benefits on growth, physiological health, and gut microbiota, supporting its potential as a phytogenic strategy for antibiotic-free broiler production.

Fungal aerosols are critical yet understudied bioaerosol components in enclosed poultry environments, particularly during winter when ventilation is restricted. This study investigated stage-specific variations in fungal aerosol concentration, size distribution, and community composition in Taihang chicken houses across three growth stages (15, 60, and 150 days). Culturable fungal concentrations significantly increased from 3.16 × 10³ CFU/m³ to 1.24 × 10⁴ CFU/m³ with bird age (p < 0.001, ANOVA). Respirable particles (<4.7 μm) consistently dominated the fungal size distribution. ITS sequencing revealed progressive increases in fungal richness and distinct community shifts among stages. Several fungi with zoonotic potential, including Aspergillus, Cladosporium, Cryptococcus, and Fusarium, were detected across all stages. These findings demonstrate that wintertime enclosed ventilation, while thermally beneficial, promotes the accumulation of respirable fungal aerosols and elevates occupational and environmental health risks. From a One Health perspective, stage-specific mitigation strategies—such as ventilation optimization, reduction in organic dust sources, and routine monitoring of respirable fungal fractions—are essential for reducing exposure risks in cold-season poultry production.

Ebola virus (EBOV) infection constitutes a significant global public health threat, and no curative treatment is currently available for it. Rapid and accurate detection of EBOV nucleic acid is crucial for controlling the spread of Ebola virus disease (EVD). The gold standard for EBOV diagnosis is real-time reverse transcription polymerase chain reaction (RT-qPCR), which requires costly equipment and skilled personnel, potentially hindering its application for rapid detection, especially in resource-limited settings. Consequently, there is an urgent need to develop a simple, accurate, and rapid diagnostic method for EVD. In this study, a real-time reverse transcription recombinase-aided amplification (RT-RAA) assay was developed for the specific visual detection of the conserved region of the EBOV nucleoprotein (NP) gene. The RT-RAA assay can be completed within 30 min at 42 °C, and results can be visualized using a portable blue light imager. The assay exhibited strong analytical specificity toward EBOV. No cross-reactivity was observed with any of the other public-health-relevant viruses tested. The visual RT-RAA assay demonstrated sensitivity comparable to RT-qPCR, detecting 52 copies per reaction at a 95% probability level, whereas RT-qPCR required 74 copies per reaction. The RAA method demonstrated excellent repeatability and stability, with intra-assay and inter-assay CVs less than 5% and 7%, respectively. These results clearly indicate that the visual RT-RAA method is specific, accurate, simple, rapid, and reliable for EBOV detection.