The nasopharyngeal, ruminal, and vaginal microbiota and the core taxa shared across these microbiomes in virgin yearling heifers exposed to divergent in utero nutrition during their first trimester of gestation and in pregnant beef heifers in response to mineral supplementation
Bibliographic record
Abstract
ABSTRACT Emerging evidence has indicated that microbial transmission from the bovine dam to her fetus may take place before birth, and that the maternal microbiota during pregnancy modulates programming of fetal metabolic and nervous system development, highlighting the potential and extended role of the maternal microbiome in calf health and development. In the present study, we characterized the nasopharyngeal, ruminal and vaginal microbiota from two cohorts of beef heifers managed at the same location: 1) virgin yearling heifers (9 months old) born from dams received gestational diets which resulted in low (LG, n = 22) or medium (MG, n = 23) weight gain during the first 84 days of gestation; and 2) pregnant replacement heifers that received a vitamin and mineral supplement (VTM, n = 17) or not (Control, n = 15) during the first 6 months of gestation. Nasopharyngeal and vaginal swabs as well as ruminal fluid were collected from both cohorts and the microbiota of each sample was assessed using 16S rRNA gene sequencing. In addition to the comparison between treatment groups within each cohort, the similarity of the microbiota of the three sample types were evaluated, and shared taxa amongst these communities were identified. The bacterial genera present in the rumen and vagina that can influence methanogenic archaeal genera were predicted using a stepwise-selected generalized linear mixed model. No significant difference was observed in the alpha and beta diversity in any of the nasopharyngeal, ruminal and vaginal microbiota between LG and MG offspring virgin heifers, or between the control and VTM pregnant heifers ( p > 0.05). Subtle compositional changes in the vaginal microbiota in yearling heifers, and in the nasopharyngeal and ruminal microbiota of pregnant heifers were detected in response to treatments. Forty-one archaeal and bacterial OTUs were shared by over 60% of all samples from both virgin and pregnant heifers. Two taxa within the Methanobrevibacter genus were identified as core taxa and this genus was more relatively abundant in pregnant heifers compared to virgin heifers. Among the 25 top genera, Prevotella and Prevotella UCG-003 (negative) and Christensenellaceae R-7 group (positive) were predicted to have a significant effect on ruminal Methanobrevibacter spp. The results of this study indicate that there is little impact of divergent gestational nutrition during the first trimester on the calf microbiome at 9 months postnatal, and that VTM supplementation during pregnancy may not alter the maternal microbiome. This study provides evidence that there are several microbial taxa, including methanogenic archaea, that are shared across the respiratory, gastrointestinal, and reproductive tracts, suggesting the need for a holistic evaluation of the bovine microbiota when considering potential maternal sources for seeding calves with pioneer microbiota.
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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 | 0.000 |
| 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".