1627 Molecular physiology of rumen papillae following an acidosis challenge
Bibliographic record
Abstract
The objective of this experiment was to evaluate the effect of ruminal acidosis on transcript abundance and localization of proteins regulated by local inflammation in the ruminal epithelium. Seven ruminally cannulated beef cows were used in a crossover design with two periods and two treatments (acidosis or control). Heifers were fed a baseline TMR with 50:50 forage to concentrate ratio and DMI was recorded daily. The acidosis induction consisted of feed restriction (25% of DMI for 1 d) followed by a grain challenge (30% of baseline DMI) and provision of the full TMR. Ruminal pH was monitored using indwelling probes and ruminal papillae biopsies were collected on d 2 and 6 following the induction of acidosis for RNA extraction and immuno-histofluorescence. Prostaglandin-endoperoxide synthase (PTGS1) and PTGS2 facilitate prostaglandin synthesis and were selected as targets because expression is thought to be regulated by inflammation. Gene expression was measured by quantitative real-time PCR, normalized to the geometric mean of three housekeeping genes within period. Immuno-histofluorescence of toll-like receptor (TLR)-9 and TLR-4 were used to evaluate localization in a subset of samples. Statistical analysis was performed using the MIXED procedure of SAS 9.4, with treatment and period as fixed effects. A pH threshold of 5.8 was used to define the occurrence of ruminal acidosis. During the day of the grain challenge, ruminal pH for acidosis cows was below pH 5.8 for 543 min, whereas pH of controls did not fall below the threshold at any time (P = 0.02). Minimum and mean pH were less on the challenge day (min: 5.4 vs. 6.2 ± 0.17 and mean: 5.9 vs. 6.6 ± 0.14, respectively; P < 0.01) for acidosis than control cows. Two days after acidosis induction, transcriptional abundance of PTGS1 and PTGS2 in ruminal papillae were decreased by 1.37 (P = 0.02) and 2.08 (P < 0.01) fold, respectively, relative to controls. When evaluated at d 6, no differences were observed. TLR-9 was not ubiquitously expressed, but rather was concentrated in small areas within regions of the ruminal epithelium. TLR4 was intracellularly expressed in the stratum basale, stratum spinosum, and stratum granulosum regardless of treatment. The results of this study suggest a potential acute anti-inflammatory response following acidosis, which was also tightly regulated. However, the downregulation of PTGS2 was unexpected; related transcripts are being studied to elucidate these effects.
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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 | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".