Bioavailability of methionine hydroxy analog-calcium salt relative to dl-methionine to support nitrogen retention and growth in starter pigs
Bibliographic record
Abstract
This study assessed the efficacy of a calcium salt of methionine hydroxy analog (MHA-Ca, 84%) relative to dl-methionine (dl-Met, 99%) in starter pigs. In Experiment 1 (Exp. 1, N balance trial), 42 individually housed barrows (Genesus, average initial BW 19 kg) were used in two blocks of 21 pigs each with six replicates per treatment. Within each block, pigs were randomly allotted to seven diets: a methionine (Met)-deficient basal diet or the basal diet with three added levels of dl-Met (0.02%, 0.04% and 0.06%) or MHA-Ca (0.024%, 0.048% and 0.071%) on an equimolar basis. After a 7-day adaptation period, feces and urine were collected quantitatively for 5 days. Urinary and total N outputs decreased linearly (P < 0.05) with dl-Met or MHA-Ca supplementation. Nitrogen retention, expressed as g/day and as % of intake increased linearly (P < 0.01) with dl-Met and MHA-Ca supplementations. The relative efficacy of MHA-Ca to dl-Met was estimated to be 71.2% on a product-to-product basis for N retention expressed as % of intake. In Exp. 2 (performance trial), 280, 21-day-old crossbred (Pietrain × (Landrace × Large White)) pigs (eight pigs per pen, seven pens per treatment), were allocated to five diets in a completely randomized block design after a 10-day adaptation period. The Met-deficient basal diet contained 16.5% CP and 0.21% Met. Other diets were basal diet supplemented with two graded levels of dl-Met (0.04% and 0.08%) or MHA-Ca (0.062% and 0.12%) on a product basis at a dl-Met to MHA-Ca ratio of 65 : 100 at the expense of maize. BW and feed disappearance were monitored weekly for 3 weeks to determine performance. Final BW, average daily gain and average daily feed intake increased (P < 0.05) and feed to gain ratio decreased (P < 0.05) with the addition of Met to the basal diet irrespective of the source. Overall, the N retention results of Exp. 1 showed that the average relative bioavailability of MHA-Ca to dl-Met to support N retention (% of N intake) was 71% on a product- to-product basis (85% on an equimolar basis). In Exp. 2, pig performance was not different when Met was supplemented in the Met-deficient diet at a dl-Met to MHA-Ca ratio of 65 : 100 on a product basis.
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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 | 0.001 | 0.001 |
| 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 | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 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".