242 Methionine and Guanidinoacetic Acid Supplementation During the Periconceptual Period of Gestation Shifts Methionine Metabolism of Fetal Bull Calves at D 63 of Gestation
Bibliographic record
Abstract
Abstract Recent research has demonstrated that feeding rumen protected methionine (MET) products increases circulating methionine while feeding guanidinoacetic acid (GAA) may result in a methyl deficiency. Therefore, we hypothesized that maternal MET or GAA supplementation from 63 days before breeding until d 63 of gestation would increase fetal hepatic methyl donors or result in a fetal hepatic methyl donor deficiency, respectively. Eighty MARC II heifers (n = 20 per treatment; initial BW = 344 ± 8 kg; day -63) were weighed and assigned to one of four breeding groups and four treatments stratified by age and starting weight. Heifers were fed a total mixed ration to gain 0.68 kg/d and received 100 g of one of four treatments top dressed: control supplement of ground corn (CON), MET (10 g/d) in a ground corn carrier, GAA (40 g/d) in a ground corn carrier, or MET + GAA (10 g/d MET + 40 g/d GAA) in a ground corn carrier. At breeding (d 0), all heifers were bred to a single sire using male sexed semen. At d 63 of gestation, 35 heifers (CON n = 10, MET n = 8, GAA n = 7, MET + GAA, n = 10) confirmed pregnant with bull calves were humanely slaughtered and fetal liver tissues were collected and sent to Metabolon Inc. for global metabolomics analysis. Data were analyzed as a 2 x 2 factorial with 2 levels of GAA and 2 levels of MET with breeding group included in the model. For this abstract, only metabolites from the methionine cycle and adjacent pathways will be reported and only metabolites with significant P-values will be discussed (P ≤ 0.05). There were no main effects or interactions for the abundance of methionine, GAA, creatine, SAM, SAH or homocysteine. Glycine was decreased and sarcosine increased in fetuses from MET supplemented dams. Serine was affected by a MET x GAA interaction being decreased in livers of CON, MET, and MET + GAA fetuses compared with GAA. Cystathione, S-methylcysteine, s-methylcysteine sulfoxide, and hypotaurine were greater in fetuses of MET supplemented heifers and pyridoxal phosphate was reduced in fetal liver of MET supplemented heifers. The abundance of urea was greater in GAA supplemented fetuses. These results indicate that fetuses from dams fed methionine may be able to maintain balance in methionine supply by shunting methionine through adjacent pathways including the transsulfuration pathway. We also interpret these data to imply that excess methionine is not utilized by the fetus and is metabolized to products that can be excreted. Lastly, GAA did not alter the fetal methyl supply. USDA is an equal opportunity provider and employer. Funded by (USDA-NIFA-AFRI # 2022-67015-36196).
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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".