Vandermeeren 2019 MiP2019
Oxidative stress susceptibility and management appear to be important factors in fish physiological impairment during a rapid increase in temperature. Because of their rich poly-unsaturated fatty acid (PUFA) diet, and their membrane composition, salmonids are susceptible to oxidative damages such as peroxidation. In a recent study in our laboratory, ROS efflux have been shown to increase in artic char’s heart mitochondria when they get close to their critical thermal maximum . Our present study aimed to determine if oxidative stress impact and management can partly explain tolerance to high temperature stress in fish.
Four salmonids groups, brook char, arctic char, and their reciprocal hybrids, were submitted to a temperature challenge test (TCT) to determine their critical thermal maximum. We compared fatty acid content and catalase activity from the heart to the TCT response for each individual. Fatty acid profiles were determined by Gas Chromatography with FID detection, while catalase activity was assayed by spectrophotometry.
Our study revealed that catalase activity, peroxidation index, omega-3, EPA and ARA content of the fish heart are all negatively correlated with tolerance to an acute temperature increase. Our results establish for the first time a functional link between heart lipid composition and individual tolerance to an acute thermal stress, pointing out to mitochondria as a likely mechanistic cause of general homeostasis collapse when reaching the upper thermal limit of an ectotherm.
Stress:Oxidative stress;RONS, Temperature Organism: Fishes Tissue;cell: Heart
- Dept biology, Univ Québec à Rimouski, Rimouski, QC, Canada. - [email protected]
Figure 1: Relationships between Peroxidation Index (a), total omega-3 content (b), EPA (c), ARA (d) and temperature challenge test (TCT) duration in min. All values are expressed as residuals calculated from least linear regressions on body mass. Arctic char (AC, full circles), Brook char (BC, full squares), Hybrid arctic (HA, empty circles) and Hybrid brook (HB, empty squares). Equation a) Peroxidation index = -0.69x+8.74*10-15, b) Total n-3 content= -0.087x+3.32*10-16, 7 c) EPA = -0.017x+8,6*10-17 and d) ARA = -0.009x+3,93*10-17.
Figure 2: Relationship between catalase activity and temperature challenge test (TCT) duration in min. All values are expressed as residuals calculated from least linear regressions on body mass.
- Christen F, Desrosiers V, Dupont-Cyr BA, Vandenberg GW, Le François NR, Tardif JC, Dufresne F, Lammare SG, Blier PU (2018) Thermal tolerance and thermal sensitivity of heart mitochondria: Mitochondrial integrity and ROS production. Free Radic Biol Med 116:11-18.