A comparative and ontogenetic examination of mitochondrial function in Antarctic notothenioid species

In this study we examined aerobic metabolic capacity in three species,Trematomus bernacchii,T. pennellii andT. newnesi, and between two life stages, juvenile and adult, by assessing mitochondrial function of permeabilized cardiac fibers. Respiratory capacity differed among the adult notothenioids in this study, with greater oxidative phosphorylation (OXPHOS) respiration in the pelagicT. newnesi than the benthicT. bernacchii andT. pennellii. The variation in mitochondrial respiratory capacity was likely driven by differences in the mitochondrial content, as measured by citrate synthase activity, which was the highest inT. newnesi. In addition to high OXPHOS,T. newnesi exhibited lower LEAK respiration, resulting in greater mitochondrial efficiency than eitherT. bernacchii orT. pennellii. Life stage largely had an effect on mitochondrial efficiency and excess complex IV capacity, but there were little differences in OXPHOS respiration and electron transfer capacity, pointing to a lack of significant differences in the metabolic capacity between juveniles and adults. Overall, these results demonstrate species-specific differences in cardiac metabolic capacity, which may influence the acclimation potential of notothenioid fishes to changing environmental conditions.
Source: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology - Category: Physiology Source Type: research