Che Sunoh, Susta Leonardo, Sanpinit Pornnicha, Malila Yuwares, Barbut Shai
Department of Animal and Avian Sciences, University of Maryland, College Park, Maryland, USA.
Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada.
Poult Sci. 2025 Apr;104(4):104976. doi: 10.1016/j.psj.2025.104976. Epub 2025 Mar 4.
Gaping is a recently described condition that affects the Pectoralis minor (tender) muscle of broiler chickens, characterized by post-mortem separation of myofiber that leads to meat depreciation and economic losses. In this study, we aimed at understanding prevalence, morphological features, and transcriptomics signatures of this poorly understood myopathy. Between July 2022 and January 2023, a total of 5,180 chicken tenders were collected from 32 flocks across two plants in the USA, handling light (2.7 kg) and heavy (4.1 kg) birds. The prevalence of moderate and severe gaping was 24.8 % and 53.7 %, respectively. The light bird plant had a lower prevalence of moderate gaping (P < 0.001), while the heavy bird plant had a lower prevalence of severe gaping (P < 0.001). Spaghetti meat prevalence from 8,000 fillets was 46.9 % for moderate and 8.3 % for severe cases, with no significant inter-plant differences. Use of peracetic acid treatment at the poultry plants significantly increased the prevalence of severe gaping. Physical and histological features, along with gene expression, were evaluated in 120 samples representative of three gaping severity tiers. Severely gaped tenders showed greater width compared to normal and moderately gaped tenders in both light and heavy birds (P < 0.05). An increase of 1 cm in tender width was associated with a 1.99-fold increase in the odds of classification into a more severe gaping category (95 % CI: 1.15 - 3.46). Affected muscles revealed histological evidence of myodegeneration, inflammation, and lipidosis with fibrosis. For one-unit increase in the myodegeneration score, samples had a 1.75-fold increase in the odds of being classified into a more severe gaping category (95 % CI: 1.37 - 2.23). Gene expression analysis using droplet digital PCR showed differential expression of 19 genes involved in oxidative stress response, cellular signaling, muscle development, and collagen formation between weight groups and myopathy categories. Notably, 21 out of 22 differentially expressed genes showed higher expression in light birds. This study provides the comprehensive description of gaping in broiler chickens and lays a crucial benchmark for assessment of future mitigating strategies.
豁裂是一种最近才被描述的病症，它影响肉鸡的胸小肌（ tender ），其特征是死后肌纤维分离，导致肉质下降和经济损失。在本研究中，我们旨在了解这种鲜为人知的肌病的患病率、形态特征和转录组学特征。在2022年7月至2023年1月期间，从美国两家工厂的32个鸡群中总共收集了5180份鸡胸肉，处理轻体重（2.7千克）和重体重（4.1千克）的鸡。中度和重度豁裂的患病率分别为24.8%和53.7%。轻体重鸡所在工厂的中度豁裂患病率较低（P < 0.001），而重体重鸡所在工厂的重度豁裂患病率较低（P < 0.001）。8000片鱼片的“意大利面条肉”患病率，中度为46.9%，重度为8.3%，工厂间无显著差异。家禽工厂使用过氧乙酸处理显著增加了重度豁裂的患病率。在代表三种豁裂严重程度等级的120个样本中评估了物理和组织学特征以及基因表达。在轻体重和重体重鸡中，重度豁裂的鸡胸肉与正常和中度豁裂的鸡胸肉相比，宽度更大（P < 0.05）。鸡胸肉宽度每增加1厘米，分类为更严重豁裂等级的几率增加1.99倍（95%可信区间：1.15 - 3.46）。受影响的肌肉显示出肌变性、炎症和伴有纤维化的脂肪变性的组织学证据。肌变性评分每增加一个单位，样本被分类为更严重豁裂等级的几率增加1.75倍（95%可信区间：1.37 - 2.23）。使用液滴数字PCR进行的基因表达分析显示，在体重组和肌病类别之间，19个参与氧化应激反应、细胞信号传导、肌肉发育和胶原蛋白形成的基因存在差异表达。值得注意的是，22个差异表达基因中有21个在轻体重鸡中表达更高。本研究提供了对肉鸡豁裂的全面描述，并为评估未来的缓解策略奠定了关键基准。
