Measurements of enzyme response with hulless barley-based diets full-fed to Leghorn and broiler chicks or restricted-fed broiler chicks
Bibliographic record
Abstract
Broiler chicks fed diets high in soluble non-starch polysaccharides (NSP; e.g., wheat- and/or barley-based diets) have a higher capacity to ingest, digest and absorb nutrients when diets are supplemented with appropriate NSP enzymes. However, this same enzyme response is typically reduced or non-significant in older birds, Leghorn chicks and turkey poults. We hypothesise that the enzyme response in the latter classes of poultry is reduced because feed intake is lower in comparison to feed intake by broilers. In the present study, the hypothesis that restricted feeding of broilers would reduce the enzyme response typically observed in full-fed broilers was tested. Two experiments were conducted to determine the feeding value of hulless barley supplemented or not supplemented with enzyme (Avizyme 1100, Finnfeeds Int, UK). In Study 1, eight sources of hulless barley were included at 80% in each diet and fed to four groups of six male broilers or Leghorn chicks from 4 to 17 d of age. The response to enzyme in hulless barley-based diets by broilers was approximately twofold that of Leghorns for growth and feed intake. The Leghorns had higher digesta viscosity than broilers, although the relative drop in digesta viscosity with enzyme supplementation was equal. In a second study (Study 2) broiler chicks were fed one of four diets (two hulless barley cultivars with or without enzyme) at three feed allotment levels (ad libitum, R1 and R2) from 4 to 21 d of age. The R1 and R2 feed allotments were pre-determined fixed daily feed amounts. Actual feed restriction in the R1 group was only achieved for diets with, but not without, an enzyme. At the lowest feed allotment (R2) actual feed intake of diets with or without enzyme were lower than that recorded for ad libitum fed birds. Study 2 demonstrated that restricted-fed broilers had a lower growth response to enzyme supplementation compared to birds allowed ad libitum intake, in part due to improved retention of energy, either directly in response to feed restriction or because digesta viscosity in diets without enzyme was lowered. Although digesta viscosity of restricted-fed birds was lower, it is still high enough to be considered problematic. In determining feeding value of cereal grains or supplements such as enzymes, especially those directed for use with broilers, it is imperative that a broiler chick bioassay be used and that they have ad libitum access to the diets. Key words: Enzyme, hulless barley, viscosity, feed intake
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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) | 0.001 | 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 | 0.001 |
| 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".