Characterization of airborne bacterial diversity in conventional hen houses, enriched colonies and aviaries, and link between possible bioaerosol sources
Bibliographic record
Abstract
BACKGROUND: Canada's transition toward alternative housing systems for laying hens may have an impact on bioaerosol content and concentrations in those environments. This project aimed to characterize the airborne bacterial diversity in six conventional hen houses, six enriched colonies and six aviaries. The bacterial diversity found in bioaerosols was also compared to the diversity found in feces or litter samples from each corresponding housing type to investigate similarities between possible bioaerosol sources and bioaerosols. RESULTS: ) and CHAO1 indexes were higher in air samples from conventional hen houses and enriched colonies, compared to their corresponding fecal or litter samples, which was not the case for aviaries samples. No significant differences were found between the Shannon and inverse Simpson (InvSimpson) indexes of air samples, compared to their corresponding fecal or litter samples. Firmicutes were the dominant phyla in all samples, followed by Actinobacteria. Dominant genera were Lactobacillus, unclassified Lanchnospiraceae, unclassified Actinomycetales, unclassified Clostridales and unclassified Ruminococcaceae. OTUs (Operational Taxonomic Units) were associated with hen microbiota and gut microbiota, and soil. Homogeneity of molecular variance analyses (HOMOVA) revealed significant differences between air samples from aviaries, compared to air samples from conventional and enriched cage houses. Significant differences were found between air and fecal or litter samples from conventional hen houses and enriched colonies, but not among aviary samples. CONCLUSIONS: Findings highlight the effects of housing types on airborne bacterial diversity, and similarities in bacterial diversity between air and fecal or litter samples from three types of husbandry. Most dominant OTUs were shared across all samples, but were different in proportions, which may account for the differences in alpha and beta diversities. The overlap in bacterial diversities between air and litter samples collected in aviaries brings out the contribution of litter to ambient bioaerosols.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".