Metabolic responses to cold acclimation in the swimming musculature of lake whitefish, <i>Coregonus clupeaformis</i>

Abstract

Abstract To evaluate the acclimatory capacity of juvenile lake whitefish ( Coregonus clupeaformis ), a species which is extensively distributed in northern latitudes and which experiences a fairly wide range of temperatures, we assessed the effect of acclimation at 5 and 18°C on the glycolytic and aerobic capacity of swimming muscle. Cold acclimation during six months does not increase the proportion of red muscle in the swimming musculature or the levels of cytochrome oxidase and citrate synthase, indicating a lack of thermal compensation of the aerobic capacity of the swimming muscles. By contrast, the glycolytic potential of the swimming musculature, as assessed by the activities of hexokinase and phosphofructokinase, displayed positive thermal compensation. This may facilitate the conservation of locomotory capacity at low temperatures.