390 Effects of dietary-induced pH changes on feed digestion, nitrogen metabolism, fermentation, and biohydrogenation of polyunsaturated fatty acids in dual-flow continuous culture fermenters
Bibliographic record
Abstract
Abstract Ruminal pH decreases as greater concentrations of grain are consumed, and as a result, reduces biohydrogenation of polyunsaturated fatty-acids. Our objective was to investigate effects of diet on pH and biohydrogenation activity in vitro. Eight dual-flow, continuous culture fermenters were blocked by side of the room and randomly assigned, within block, to 1 of 4 treatments. Treatments consisted of 100:0 roughage-to-concentrate (Grass), 50:50 roughage-to-concentrate plus flax oil supplement (Mix+F), 10:90 roughage-to-concentrate plus corn oil supplement (Con+C), or 10:90 roughage-to-concentrate plus flax oil supplement (Con+F). Fermenter pH, area under the curve, and maximum pH were lowest for Con+C and Con+F (P < 0.05). Apparent and true DM, OM, and NDF digestibility were greater with grain inclusion (P < 0.05) while ADF digestibility was not affected by treatment (P > 0.10). Protein degradation was lowered as grain inclusion increased (P < 0.05). Total VFA concentrations were lowest for Grass, highest for Con+C and Con+F, and intermediate for Mix+F (P < 0.05). Acetate-to-propionate was lowest for Con treatments (P < 0.05). Biohydrogenation of 18:2n-6 and 18:3n-3 fatty-acids were reduced (P < 0.01) with inclusion of concentrate regardless of roughage-to-concentrate ratio. Concentrations of stearic acid recovered from effluent were greatest for Grass, intermediate for Mix+F, and lowest for both Con+C and Con+F (P < 0.05). Linoleic acid proportions in effluent were greatest for Con+C and Con+F and intermediate for Mix+F (P < 0.05), and inclusion of concentrate, regardless of amount, increased the amount linoleic acid recovered from fermenter overflow (P < 0.01). Between Con+C and Con+F concentrations of alpha-linolenic acid (ALA) was greater when flax oil was supplemented (P < 0.01). Proportions of ALA in effluent was similar (P > 0.10) between Grass and Con+C; however, between Mix+F and Con+F ALA concentrations tended (P = 0.06) to be greater for Con+F. Omega6-to-omega3 ratios were similar across Grass, Mix+F, and Con+F (P > 0.10) and greatest for Con+C (P < 0.05).
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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) | 0.001 | 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".