Effects of acute versus chronic heat stress on broiler response to dietary protein
Bibliographic record
Abstract
Two experiments were conducted to determine broiler response to dietary protein during short (1 wk) or prolonged (>3 wk) heat stress (HS). In experiment 1, 21-d-old birds were kept at 20.3 degrees C (thermoneutral; TN), 27.3 degrees C (medium temperature; MT), or 31.4 degrees C (high temperature; HT) and fed diets with 18, 20, 23, or 26% CP for 21 d. Each treatment consisted of 2 blocks of 3 replicates of 15 birds. In experiment 2, broilers were fed diets with 18 or 26% CP or fed ad libitum 2 diets with 10 or 30% CP. Birds were kept at TN (23.5 degrees C) or slowly introduced to HS from 7 to 14 d of age and kept at HT thereafter (chronic; CHS; 29.4 degrees C), and a third group was moved to HT at 21 d (acute HS; AHS; 29.4 degrees C). There were 16 replicates of 4 chickens per treatment distributed in 2 blocks. Performance, body composition, and protein deposition were ascertained from 21 to 28 d and from 28 to 42 d (short and prolonged exposures, respectively). Feeding high protein diets in experiment 1 resulted in linear improvements in body weight gain and feed:gain (P < 0.001) for MT and HT birds, whereas TN birds exhibited a linear (P < 0.001) response to protein. Feed intake declined as CP increased for HT birds during the third week of the study (P < 0.05). In trial 2, better performance was always observed in TN birds. HS depressed performance, although feeding high CP partially ameliorated this effect under AHS and CHS. Regardless of temperature, choice-fed birds selected high protein diets (mean 25.6% CP) and performed similarly to those fed 26% CP. CHS birds showed similar performance to those under AHS. Efficiency of protein deposition was unaffected (P > 0.05). Level of HS and duration of hyperthermia may determine the response of birds to dietary protein. Discrepancies between the 2 studies in response of birds to protein found after prolonged exposure to HS are discussed in view of the differences in levels of certain amino acids used within each experiment.
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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 | 0.001 |
| 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) | 0.000 | 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".