Christen Felix, Dufresne France, Leduc Gabriel, Dupont-Cyr Bernard A, Vandenberg Grant W, Le François Nathalie R, Tardif Jean-Claude, Lamarre Simon G, Blier Pierre U
Département de Biologie, Université du Québec à Rimouski, Rimouski, Québec, G5L3A1, Canada.
Département de Sciences Animales, Université Laval, Québec, Québec, G1V 0A6, Canada.
Conserv Physiol. 2020 Dec 26;8(1):coaa108. doi: 10.1093/conphys/coaa108. eCollection 2020.
The cardiovascular system is a major limiting system in thermal adaptation, but the exact physiological mechanisms underlying responses to thermal stress are still not completely understood. Recent studies have uncovered the possible role of reactive oxygen species production rates of heart mitochondria in determining species' upper thermal limits. The present study examines the relationship between individual response to a thermal challenge test (CT), susceptibility to peroxidation of membrane lipids, heart fatty acid profiles and cardiac antioxidant enzyme activities in two salmonid species from different thermal habitats (, ) and their hybrids. The susceptibility to peroxidation of membranes in the heart was negatively correlated with individual thermal tolerance. The same relationship was found for arachidonic and eicosapentaenoic acid. Total HO buffering activity of the heart muscle was higher for the group with high thermal resistance. These findings underline a potential general causative relationship between sensitivity to oxidative stress, specific fatty acids, antioxidant activity in the cardiac muscle and thermal tolerance in fish and likely other ectotherms. Heart fatty acid profile could be indicative of species resilience to global change, and more importantly the plasticity of this trait could predict the adaptability of fish species or populations to changes in environmental temperature.
心血管系统是热适应中的一个主要限制系统，但热应激反应背后的确切生理机制仍未完全明了。最近的研究揭示了心脏线粒体活性氧生成速率在决定物种热上限方面可能发挥的作用。本研究考察了来自不同热栖息地的两种鲑科鱼类及其杂种对热挑战试验（CT）的个体反应、膜脂过氧化敏感性、心脏脂肪酸谱和心脏抗氧化酶活性之间的关系。心脏中膜脂过氧化敏感性与个体热耐受性呈负相关。花生四烯酸和二十碳五烯酸也存在同样的关系。热抗性高的组心肌总的HO缓冲活性更高。这些发现强调了鱼类及可能其他变温动物对氧化应激的敏感性、特定脂肪酸、心肌抗氧化活性和热耐受性之间潜在的普遍因果关系。心脏脂肪酸谱可能表明物种对全球变化的恢复力，更重要的是，这一性状的可塑性可以预测鱼类物种或种群对环境温度变化的适应性。
