Liu Yang, Amevor Felix Kwame, Qi Kunlong, Feng Jing, Xian Lili, Lei Zang, Peng Leilei, Xu Dan, Shu Gang, Wang Yingjie, Wu Liuting, Wang Yan, Zhao Xiaoling
State Key Laboratory of Swine and Poultry Breeding Industry, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, Sichuan, 611130, PR China; Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, Sichuan, 611130, PR China; Key Laboratory of Livestock and Poultry Multi-omics, Ministry of Agriculture and Rural Affairs, Sichuan Agricultural University, Chengdu, Sichuan, 6611130, PR China.
Institute of Animal Husbandry and Veterinary Medicine, College of Agriculture and Animal Husbandry, Tibet Autonomous Region, Lhasa 850004.
Poult Sci. 2025 May 30;104(9):105378. doi: 10.1016/j.psj.2025.105378.
Understanding the physiological and molecular mechanisms underlying altitude adaptation is critical for optimizing poultry health and performance in diverse environments. This study comparatively evaluated the respiratory metabolism, hematological profiles, antioxidant capacity, immune status, and hypoxia-related gene expression in Snowy White chickens raised at contrasting altitudes. A total of 380 chickens from a low-altitude region (Sichuan) and 550 from a high-altitude region (Tibet) were reared under standardized dietary and management conditions. The results should that key indicators of anaerobic metabolism, including serum lactate and lactate dehydrogenase (LDH) levels, were significantly elevated in high-altitude chickens, indicating greater reliance on glycolysis under hypoxic stress (P < 0.05). Hematological analysis revealed significantly increased red blood cell (RBC) count, hemoglobin concentration, hematocrit, and mean corpuscular hemoglobin in high-altitude birds (P < 0.05), while mean corpuscular volume (MCV) was higher in low-altitude chickens (P < 0.05), reflecting divergent strategies in oxygen transport efficiency. Oxidative stress markers showed that high-altitude chickens had elevated malondialdehyde (MDA) levels, indicating increased lipid peroxidation, whereas low-altitude chickens demonstrated superior antioxidant defense, with significantly higher total antioxidant capacity (T-AOC) and total superoxide dismutase (T-SOD) activity (P < 0.05). In addition, immunoglobulin levels (IgM and IgG) were markedly higher in low-altitude chickens, suggesting enhanced immune responsiveness. Furthermore, qRT-PCR revealed elevated expression of hypoxia-related genes including hypoxia-inducible factor 1-alpha (HIF-1A), endothelial PAS domain-containing protein 1 (EPAS1), vascular endothelial growth factor (VEGF), and erythropoietin (EPO) in the heart, lungs, and kidneys of the high-altitude chickens (P < 0.05), while egl-9 family hypoxia-inducible factor 1 (EGLN1) expression was significantly downregulated in these tissues. These physiological and molecular adaptations highlight the mechanisms by which Snowy White chickens maintain homeostasis under chronic hypoxic stress and offer insight into genetic and metabolic pathways supporting high-altitude resilience. Taken together, these findings offer valuable insights into high-altitude resilience in avian species and may inform breeding strategies for improved adaptability to hypoxic environments.
了解海拔适应背后的生理和分子机制对于优化家禽在不同环境中的健康和性能至关重要。本研究比较评估了在不同海拔饲养的雪白鸡的呼吸代谢、血液学指标、抗氧化能力、免疫状态和缺氧相关基因表达。来自低海拔地区（四川）的380只鸡和来自高海拔地区（西藏）的550只鸡在标准化饮食和管理条件下饲养。结果表明，高海拔鸡的无氧代谢关键指标，包括血清乳酸和乳酸脱氢酶（LDH）水平显著升高，表明在缺氧应激下对糖酵解的依赖性更大（P<0.05）。血液学分析显示，高海拔鸡的红细胞（RBC）计数、血红蛋白浓度、血细胞比容和平均红细胞血红蛋白显著增加（P<0.05），而低海拔鸡的平均红细胞体积（MCV）较高（P<0.05），反映了氧运输效率的不同策略。氧化应激标志物显示，高海拔鸡的丙二醛（MDA）水平升高，表明脂质过氧化增加，而低海拔鸡表现出更强的抗氧化防御能力，总抗氧化能力（T-AOC）和总超氧化物歧化酶（T-SOD）活性显著更高（P<0.05）。此外，低海拔鸡的免疫球蛋白水平（IgM和IgG）明显更高，表明免疫反应增强。此外，qRT-PCR显示高海拔鸡心脏、肺和肾脏中缺氧相关基因的表达升高，包括缺氧诱导因子1-α（HIF-1A）、含内皮PAS结构域蛋白1（EPAS1）、血管内皮生长因子（VEGF）和促红细胞生成素（EPO）（P<0.05），而这些组织中egl-9家族缺氧诱导因子1（EGLN1）的表达显著下调。这些生理和分子适应突出了雪白鸡在慢性缺氧应激下维持体内平衡的机制，并为支持高海拔适应能力的遗传和代谢途径提供了见解。综上所述，这些发现为鸟类的高海拔适应能力提供了有价值的见解，并可能为提高对缺氧环境的适应性的育种策略提供参考。
