Bioavailability of dietary cyanocobalamin (vitamin B12) in growing pigs1
Bibliographic record
Abstract
The present project aimed to estimate bioavailability of dietary vitamin B(12), for which little information is available in growing pigs. Two approaches, each using 2 quantities of dietary cyanocobalamin, were compared; the first was based on whole body retention for 8 d and the second was based on nycthemeral portal net flux of vitamin B(12). In the first trial, 15 blocks of 3 pigs (31.7 ± 0.5 kg of BW) were formed according to their vitamin B(12) status. Within each block, 1 pig (CONT) was killed and tissues were sampled for vitamin B(12) determination. The remaining 2 piglets were fed 25 (B(12)-25) or 250 (B(12)-250) μg daily of cyanocobalamin for 8 d. Urine was sampled twice daily, and the pigs were killed and sampled as CONT pigs. The total content of vitamin B(12) in the carcass, urine, and intestinal tract was affected by the dietary treatments (P < 0.01) but not in the liver (P > 0.019). The whole body retention of vitamin B(12) was greater (P = 0.02) in B(12)-250 than B(12)-25 pigs, but the corresponding bioavailability was estimated to be 5.3 and 38.2%, respectively. In trial 2, 11 pigs (35.1 ± 4.0 kg of BW and 75.4 ± 5.9 d of age) fed a diet unsupplemented with vitamin B(12) from weaning at 28 d of age were surgically equipped with catheters in the portal vein and carotid artery and an ultrasonic flow probe around the portal vein. Each pig received 3 boluses of 0 (B(12)-0), 25, and 250 μg of dietary vitamin B(12) according to a crossover design. Postprandial nycthemeral arterial plasma concentrations of vitamin B(12) reached minimum values (P < 0.01) between 15 and 18 h postmeal that were 29.6, 15.6, and 10.0% less than the premeal values for B(12)-0, B(12)-25, and B(12)-250 pigs, respectively (linear, P < 0.01). The cumulative net flux of vitamin B(12) for 24 h corresponded to 2.4 and 5.1 µg for B(12)-25 and B(12)-250 treatments, respectively, and the corresponding bioavailability was estimated to be 9.7 and 2.0%, respectively. Although bioavailability estimates varied according to approaches, both showed the inverse relationship between dietary vitamin B(12) and bioavailability of the vitamin. The dietary supplement of 25 µg was sufficient to maximize hepatic vitamin B(12) retention and to attenuate the nycthemeral decrease of arterial plasma concentration of the vitamin.
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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 | 0.003 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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".