Effects of direct-fed microbial supplementation on digestibility and fermentation end-products in horses fed low- and high-starch concentrates1
Bibliographic record
Abstract
A study was conducted to determine whether direct-fed microbials (DFM) could be used to increase digestibility and minimize the risk of acidosis associated with feeding an increase in the amount of starch fed to horses. Fifteen mature Thoroughbred geldings were randomly assigned to 1 of 3 treatments in a 3 x 3 Latin square design balanced for carryover effects. Within each 26-d period, horses were offered grass hay + low-starch concentrate (LS; 1.2 g of starch x kg of BW(-1) x meal(-1)) from d 1 to 13 and then were abruptly changed to hay + high-starch concentrate (HS; 2.4 g of starch.kg of BW(-1)x meal(-1)) on d 14 continuing through d 26. The DFM treatments were offered in concentrate pellets at a target dosage of 10(8) cfu/(50 kg of BW x d) as follows: no DFM (CON; control), Lactobacillus acidophilus (LAC1; single-species DFM), or a mixture of L. acidophilus, Lactobacillus casei, Bifidobacterium bifidum, and Enterococcus faecium (LAC4; multiple-species DFM). Total feces were collected over 72 h from d 11 to 13 (LS; low dietary starch collection), from d 15 to 17 (AC; abrupt change in dietary starch collection), and at the end of each experimental period, from d 24 to 26 (HS; high dietary starch collection). Data collected consisted of total DM intake and fecal output, fecal pH, fecal acetate and propionate concentrations, and viable numbers of DFM in the feed. With the exception of Fe digestibility, there were no starch x DFM interactions. There was an effect of starch level (P <or= 0.02) on most nutrient digestibilities, except for Mg (P = 0.08) and CP, K, and Zn (P > 0.10). Horses supplemented with LAC4 had increased ether extract (P < 0.05) and a tendency for decreased Na (P < 0.10) digestibilities compared with CON horses. All DFM-supplemented horses had increased Cu (P < 0.05) and Fe and numerically increased Zn digestibilities compared with CON horses. Fecal pH decreased (P < 0.05), and fecal propionate concentration increased (P < 0.05) as dietary starch content changed from LS to HS. There was a tendency for elevated fecal pH (P < 0.10) in LAC1 horses compared with CON horses. These results confirm that increasing starch in the equine diet can enhance nutrient digestibility of the diet. Supplementing equine diets with either a single or mixed strain direct-fed lactic acid bacteria had limited effects on nutrient digestibility or on reducing the risk of acidosis associated with feeding high-starch concentrates to horses. The potential response of DFM supplementation should be evaluated when a more acute acidotic state is induced in horses than in the current study.
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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 | 0.000 | 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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".