657 Effects of adding live yeast or yeast derivative on dry matter disappearance of high-forage diet in batch culture
Bibliographic record
Abstract
The objective of this study was to screen for the effects of live yeast (LY) or yeast derivative (YD) on DM disappearance (DMD), fermentation characteristics and microbial profiles in batch culture. The study was a 2 × 7 factorial arrangement including low (5.8) and high media pH (6.5); treatments were: control (no additives), three LY (LY1, LY2, LY3, 8 × 106 cfu/bottle for each LY), two YD (YD4, YD5, 30 mg/bottle for each YD), and monensin (positive control; 0.17 mg monensin/bottle). Substrate was a high-forage diet containing 60% barley silage and 40% concentrate (DM basis). Inoculum was obtained from two ruminally fistulated beef heifers fed the same diets to the substrate. Substrate (0.75 g) ground through a 1-mm sieve was weighed into a filter bag and incubated for 24 h in a gas-tight culture bottle in three replications by each combination of treatments. The culture was repeated at different day. Data were analyzed using mixed procedure of SAS with a model that includes fixed effects of yeast, pH level and their interactions, and the random effect of day. There was no interaction of yeast products with media pH on DMD. Increased media pH from 5.8 to 6.5 improved (P < 0.01) DMD (averaged 47 vs 54%). Supplementation of LY1 (48.2%) or YD5 (47.8%) had greater (P < 0.05) DMD than control (45.6%) or monensin (46.1%) at pH 5.8; and at pH 6.5, the DMD was greater (P < 0.05) with all 5 yeasts (averaged 54.8%) than control (52.8%) or monensin (52.7%). An interaction between pH and treatment was noticed (P < 0.02) for total VFA concentration (mM) which was greater (P < 0.05) with LY1, LY3, YD4 and YD5 (averaged 62.5) than control (57.0) and monensin (57.8) at pH 5.8. Ratio of acetate to propionate was less with monensin at either pH 5.8 (1.89) or pH 6.5 (2.22), whereas no differences were found between yeast and control. Overall, microbial profiles that were measured based on copy number of 16s rRNA gene (log10) were not affected by yeast supplementation except that the copy number of Fibrobacter succinogenes was less (P < 0.01) with monensin (7.16) than yeasts (7.95). These results suggest that in vitro DMD of high-forage diet varied with source of yeast and media pH. The improved DMD at pH 5.8 with LY1 and YD5 and at pH 6.5 with all five yeast products would be beneficial to high-forage fed cattle.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| 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".