Non-therapeutic administration of antimicrobial growth promoters to interrogate suppression mechanisms of innate and adaptive immune responses using an ovine model of stress
Bibliographic record
Abstract
Abstract Antimicrobial growth promoters (AGPs) have been administered in non-therapeutic concentrations in livestock feed to increase weight gain per unit of feed consumed. Daily low-dose antibiotic administration is capable of modulating immunity by suppressing inflammation, potentially increasing metabolic resources that can be allocated to muscle development. It is unknown how the AGPs tylosin (TYL) and chlortetracycline (CTC) influence acquired immunity. The objective of this study was to measure acquired immune responses, assess impacts on innate immunity and to elucidate mechanisms of immunosuppression by immunizing 10-week old lambs (male Suffolk cross) with keyhole limpet hemocyanin (KLH) during AGP administration (TYL, CTC or Control diets) while enduring intermittent physical stress. Over a 4-week period, 18 lambs (n=3 per diet/stress group) were monitored. Between the third-fourth experimental week, stressed lambs gained less weight (1.50 ± 0.49 kg) than non-stressed lambs (3.06 ± 0.37 kg, P < 0.03). The weight of lambs fed AGPs did not surpass those on the control diet. Diet and stress did not impact serum concentrations of total IgG and IgM, or anti-KLH IgG and IgM specific titres. Endpoint hematological analysis revealed that stressed lambs had decreased red cell distribution width (RDW%, 29% vs. 31%, P<0.01) and peripheral lymphocyte populations (5.72 × 103/μL vs. 4.69 × 103/μL, P<0.02). A diet × stress interaction was observed for peripheral granulocyte population (P=0.02). The impending restriction of AGP usage in North America has generated interest in identifying AGP alternatives, and elucidation of the mechanisms of AGP function is needed to develop effective non-antibiotic alternatives that mimic their action.
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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) | 0.000 | 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 | 0.001 |
| 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".