Meeting Abstract
The effects of temperature on post-exercise recovery in fishes are widely studied, but questions remain about which metabolic processes are most important in driving temperature-dependent recovery. For example, is it more advantageous to recover oxygen debt faster at cooler temperatures or remove lactate quickly at warmer temperatures? We examined the influence of temperature on recovery processes and thermoregulation following exhaustive exercise in juvenile brook charr (Salvelinus fontinalis). Fish were acclimated to and exercised at 15°C, then allowed to recover at either 15°C or 10°C while their excess post-exercise oxygen consumption (EPOC) was measured. Additionally, post-exercise metabolite levels were measured in fish assigned to one of three thermal recovery regimes (i) 6 hr recovery at 15°C, (ii) 6 hr recovery at 10°C, as well as (iii) 3 hr recovery at 10°C followed by a 3 hr recovery at 15°C (to simulate behavioral thermoregulation). We found that EPOC was completed more rapidly at 10°C compared with 15°C, but the lower temperature had the trade-off of hindering the recovery of plasma lactate and osmolarity levels. Specifically, post-exercise plasma lactate and osmolarity remained elevated for the entire recovery period in fish recovering at 10°C, whereas these variables recovered fully by 6 hr in fish from the other two recovery regimes. Currently, we are completing behavioral preference experiments to determine if brook charr will utilize behavioral thermoregulation and which physiological advantage they choose to optimize: EPOC recovery or lactate clearance.
