Acclimation to warm temperatures has important implications for mitochondrial function in Atlantic salmon (Salmo salar) [RESEARCH ARTICLE]

Lucie Gerber, Kathy A. Clow, and Anthony K. Gamperl In fish, the capacity of thermal acclimation to preserve cardiac mitochondrial function under future warming scenarios is important to understand given the central roles that cardiac energy metabolism and performance play in this taxa's thermal tolerance. We acclimated Atlantic salmon to 12 and 20°C (for >2 months), and investigated the effects of acute and chronic warming on cardiac mitochondrial respiration and reactive oxygen species (ROS) production (release rate) using high-resolution fluorespirometry. Further, we compared the sensitivity of mitochondrial respiration to nitric oxide (i.e. the NO IC50), and assessed the mitochondrial response to anoxia–reoxygenation (AR). Acute exposure to 20°C increased maximal mitochondrial respiration by ~55%; however, the mitochondria's complex I respiratory control ratio was 17% lower and ROS production was increased by ≥60%. Acclimation to 20°C: (1) preserved mitochondrial coupling and aerobic capacity; (2) decreased the mitochondria's ROS production by ~30%; (3) increased the mitochondria's NO IC50 by ~23%; and (4) improved mitochondrial membrane integrity at 20°C. AR did not affect mitochondrial function at 12°C, but acute exposure to 20°C and AR depressed maximal mitochondrial respiration (by ~9%) and coupling (by ~16%) without impacting ROS production. Finally, warm acclimation did not improve the capacity of mitochondria to recover fro...
Source: Journal of Experimental Biology - Category: Biology Authors: Tags: RESEARCH ARTICLE Source Type: research