Characterization, prevalence, and risk factors of breast myopathies (spaghetti meat, woody breast, white striping) in broiler chickens from Ontario, Canada
Bibliographic record
Abstract
Spaghetti meat (SM), woody breast (WB), and white striping (WS) are myopathies that affect the pectoral muscle of fast-growing broiler chickens. Although reported in numerous countries with intensive poultry production, no studies have characterized these myopathies in Canada. By obtaining samples from two large processing plants in Ontario, the objectives of this thesis were to 1) determine the prevalence of and identify the risk factors associated with SM, WB, and WS in Ontario broilers; 2) characterize the morphological changes associated with breast myopathies by evaluating the macroscopic and histological features of affected fillets; and 3) evaluate the transcriptomic profiles of normal and SM- or WB-affected fillets using RNA sequencing and droplet digital PCR. \nThe prevalence of SM, severe WB, and mild or moderate WS was 36.3%, 11.8%, and 96.0%, respectively (n = 9,250). Most (85.1%) of the fillets presented with multiple myopathies. Regression analyses showed that the odds of SM increased with live weight and higher environmental temperature during the grow-out period. The odds of WB increased with live weight and flock mortality rate during grow-out. Macroscopically, the odds of SM and severe WB were significantly associated with increased fillet thickness and weight. Histologically, myopathies had overlapping lesions consisting of polyphasic myodegeneration, perivascular inflammatory cuffing, and endomysial accumulation of fibrous tissue and fat. Transcriptomic analysis showed that there were no differences between normal and SM fillets, while the transcriptomic profile of WB fillets significantly differed from both normal and SM. Most of the differentially expressed genes in WB fillets were involved with the extracellular environment and immune response. \nTaken together, our results show that the macroscopic and microscopic features of SM, WB and WS in our cohort were similar to those has been reported from other countries. These myopathies were highly prevalent in Ontario broilers, suggesting a significant economic impact on the Canadian poultry industry. While WS was present in most fillets, risk factor analysis showed that heavier broilers had an increased risk of both SM and severe WB. Lastly, lack of significant differences in expressed genes between normal and SM fillets suggests that SM may not be caused by factors intrinsic to the broiler breast muscle, but rather could be caused by mechanical disruption after slaughter.
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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 | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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".