Impact of a defined bacterial community including and excluding <i>Megamonas hypermegale</i> on broiler cecal microbiota and resistance to <i>Salmonella</i> infection
Bibliographic record
Abstract
ABSTRACT Intensive broiler production practices impair the transmission of commensal microbes from hens to offspring, resulting in a lower abundance of non-spore-forming strict anaerobic bacteria. We evaluated the effects of introducing a defined community (DC) of bacteria including and excluding Megamonas hypermegale to chicks prior to a Salmonella challenge. Inoculation with DC resulted in higher phylogenetic diversity (PD) and the dominance of Bacteroidetes species in the cecal microbiota, with a decrease in the relative abundance of Salmonella and Escherichia/Shigella , as well as a lower Enterobacteriaceae load. Substantial shifts in microbiota composition were coupled with subtle changes in metabolites and host responses, including changes in interferon-γ, macrophage colony-stimulating factor, propionate, valerate, and isovalerate concentrations in the ceca. We identified bacterial isolates included in the DC that were able to establish and persist after a single exposure, many of which were members of Bacteroidetes phyla. Although co-culture with M. hypermegale was observed to reduce Salmonella counts in vitro , in vivo inoculation of M. hypermegale without an accompanying DC was shown to increase splenic Salmonella counts. Inoculation with DC containing M. hypermegale increased cecal concentration of valerate and propionate. Our findings provide further insight into how DC might be selected to impact infection resistance. The comparison of DC differing by one single isolate is useful to aid our understanding on the role of individual strains in the broiler cecal community, guiding the formulation of DCs that can potentially favor poultry health and production. IMPORTANCE Intensive production practices can reduce beneficial gut bacteria in broiler chickens, potentially leading to higher disease risk. We investigated whether introducing a defined community (DC) of commensal bacteria, with or without M. hypermegale , could improve gut health and resistance to Salmonella in broiler chicks. Our findings show that DC increases microbial diversity and reduces the relative abundance of potential pathogens, like Salmonella and Escherichia/Shigella in the ceca, which was coupled with subtle changes in the immune responses of the birds and higher concentration of volatile fatty acids in the ceca. This study suggests that inoculation with DC in early-life can alter microbiota composition, providing a potential strategy to be employed in broiler production. However, further research is needed to understand the role of individual bacteria and refine these bacterial communities for practical use in farming, thus enabling the development of natural methods to enhance poultry health and safety.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 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 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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 source (direct Gemma or distilled Codex), 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".