Whole-body propionate and glucose metabolism of multiparous dairy cows receiving folic acid and vitamin B12 supplements
Bibliographic record
Abstract
This study was undertaken to evaluate the effect of supplementation of folic acid and vitamin B 12 on glucose and propionate metabolism. Twenty-four multiparous cows were assigned according to a complete block design in a 2 2 factorial arrangement to one of the following treatments: (1) saline 0.9% NaCl, (2) 320 mg of folic acid, (3) 10 mg of vitamin B 12 , or (4) 320 mg of folic acid and 10 mg of vitamin B 12 . Intramuscular injections were given weekly from 3 wk before the expected calving date until 9 wk postpartum. At 63 d in milk, d-[6,6-2 H 2 ]-glucose (16.5 mmol/h; jugular vein) and [1-13 C]-sodium propionate (13.9 mmol/h; ruminal vein) were simultaneously infused for 4 h; blood samples were collected from 2 to 4 h of the infusion period. Liver biopsies were carried out the following day. Supplements of folic acid and vitamin B 12 respectively increased folate and vitamin B 12 concentrations, both in milk and liver. Although dry matter intake was unaffected by treatments, milk and milk lactose yields tended to be lower by 5.0 and by 0.25 kg/d, respectively, for cows receiving the folic acid supplement. Plasma -hydroxybutyrate concentration with the folic acid supplement followed the same tendency. Hepatic gene expression of methylmalonyl-CoA mutase and S-adenosylhomocysteine hydrolase was higher for cows receiving the combined folic acid and vitamin B 12 supplement compared with cows receiving only the supplement of folic acid, whereas no treatment effect was noted for cows not receiving the folic acid supplement. Whole-body glucose rate of appearance and the proportion of whole-body glucose rate of appearance secreted in milk lactose decreased by 229 g/d and 5%, respectively, for animals receiving the folic acid supplement, concomitant with the lower milk lactose synthesis in these cows, indicating that supplementary folic acid may alter energy partitioning in cows. The absence of treatment effect on plasma concentrations of methylmalonic acid as well as on the proportion of glucose synthesized from propionate, averaging 60%, supports the fact that vitamin B 12 supply was sufficient in control cows in the current study. Our results suggest that the folic acid supplement reduced glucose-derived lactose synthesis by redirecting glucose for other metabolic activity in the mammary gland or in other tissues.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".