Myocardial Oxygen Consumption in Trout Acclimated to 5°C and 15°C

Abstract

Oxygen consumption and maximum pumping performance were measured in situ perfused trout (Salmo gairdneri) hearts at acclimation temperatures of 5° and 15° C. Myocardial oxygen consumption increased linearly as a function of myocardial power output at both acclimation temperatures. The slope of the regression equation was significantly lower at 5° C compared with that at 15° C This difference was attributed to power output related changes in mechanical efficiency at 5° C (but not at 15° C) and a lower mass-specfic oxygen consumption for maximal performance of the larger heart of cold-acclimated fish.