Achour Ahlem, Yehia Moustafa, Alfonso-Avila Angel Rene, Allard Prus Jean-Michel, Ouellet Véronique, Alnahhas Nabeel
Department of Animal Science, Faculty of Agricultural and Food Sciences, Université Laval, Quebec City, QC, G1V 0A6, Canada.
Deschambault Research Center in Animal Science (CRSAD), Deschambault, QC, G0A 1S0, Canada.
J Anim Sci. 2025 Jan 4;103. doi: 10.1093/jas/skaf310.
Heat stress (HS), whether constant or cyclic, poses a significant challenge to the poultry industry, leading to reduced performance, compromised animal welfare, and health issues. Despite its well-known effects, the specific impact of HS on muscle growth and development remains incompletely understood. This study investigated the effects of chronic cyclic mild HS on body weight (BW), breast muscle yield (BMY), meat quality, glycolytic metabolites, and gene expression in the breast muscles of finishing broilers. A total of 900 Ross 308 chicks (450 males and 450 females) were reared under thermoneutral (TN, n = 10 pens, 5 pens/sex, 45 birds/pen, 450 birds in total) or HS (n = 10 pens, 5 pens/sex, 45 birds/pen, 450 birds in total) conditions (30 °C, 45% RH for 10 h/d from days 28 to 34). On day 35, 2 birds per pen were sampled for meat quality and RNA-Seq analysis. HS reduced BW (P = 0.002) and Pectoralis major muscle yield (P = 0.02) and tended to decrease BMY (P = 0.06). Meat quality traits, glycolytic metabolites, and muscle protein functional properties were not affected (P > 0.05), likely due to compensatory feed intake before and after HS exposure. Transcriptomic analysis revealed 301 differentially expressed genes (DEGs), including 138 downregulated and 163 upregulated genes under HS (|Log2FC| > 1.0, P < 0.05). Several downregulated DEGs showed significant positive correlations with BW and muscle mass. Functional enrichment indicated these genes were involved in structural pathways, including extracellular matrix-receptor interaction, cytoskeleton organization in muscle cells, and regulation of the actin cytoskeleton. These pathways are essential for muscle integrity, growth, and repair. Our findings suggest a previously underexplored mechanism by which HS impairs broiler performance through disruption of structural gene networks critical for muscle development.
热应激（HS），无论是持续性的还是周期性的，都给家禽业带来了重大挑战，导致生产性能下降、动物福利受损以及健康问题。尽管其影响广为人知，但HS对肌肉生长和发育的具体影响仍未完全了解。本研究调查了慢性周期性轻度HS对育成肉鸡体重（BW）、胸肌产量（BMY）、肉质、糖酵解代谢产物以及胸肌中基因表达的影响。总共900只罗斯308雏鸡（450只雄性和450只雌性）在热中性（TN，n = 10栏，每性别5栏，每栏45只鸡，共450只鸡）或HS（n = 10栏，每性别5栏，每栏45只鸡，共450只鸡）条件下饲养（从第28天到第34天，温度30°C，相对湿度45%，每天10小时）。在第35天，每栏抽取2只鸡进行肉质和RNA测序分析。HS降低了体重（P = 0.002）和胸大肌产量（P = 0.02），并倾向于降低BMY（P = 0.06）。肉质性状、糖酵解代谢产物和肌肉蛋白质功能特性未受影响（P > 0.05），这可能是由于在HS暴露前后的补偿性采食量所致。转录组分析揭示了301个差异表达基因（DEG），包括HS条件下138个下调基因和163个上调基因（|Log2FC| > 1.0，P < 0.05）。几个下调的DEG与BW和肌肉质量呈显著正相关。功能富集表明这些基因参与了结构途径，包括细胞外基质-受体相互作用、肌肉细胞中的细胞骨架组织以及肌动蛋白细胞骨架的调节。这些途径对于肌肉完整性、生长和修复至关重要。我们的研究结果表明了一种此前未被充分探索的机制，即HS通过破坏对肌肉发育至关重要的结构基因网络来损害肉鸡的生产性能。
