Meeting Abstract

P1.84  Saturday, Jan. 4 15:30  DNA methylation in brook trout (Salvelinus fontinalis) following acclimation to thermally stressful environments DUFFY, TD*; MCCORMICK, SD; Conte Anadromous Fish Research Center, Turners Falls, MA and LUMCON, Chauvin, LA; Conte Anadromous Fish Research Center, Turners Falls, MA tduffy@lumcon.edu

Brook trout (Salvelinus fontinalis) is a cold water salmonid that is threatened in the southern portion of its range by increasing summer temperatures. Brook trout may routinely experience temperatures near their thermal limit (~26 °C) and survival under these conditions may be driven in part by thermal acclimation. We wished to examine whether DNA methylation plays a role in thermal acclimation and performance of brook trout. We measured markers of cellular and physiological stress and assessed DNA methylation of gill, liver and muscle tissue in juvenile trout. Fish were acclimated to 12 °C, 20 °C and 22 °C for two weeks then moved to 12 °C for one month. Tissues were collected for physiological measures of stress and DNA methylation at multiple timepoints. After acclimation to 12 °C for one month, fish were exposed to a stair-step increase in temperature over 24 hours and periodically sampled for differential responses in heat shock protein-70 (HSP70) mRNA and protein, plasma lactate, and hemoglobin. Gill total DNA methylation increased significantly following initial acclimation to the high temperatures, but no differences in methylation were observed in liver or muscle. Acclimation temperature predicted survival time when fish were exposed to their thermal maximum. Physiological measures of thermal stress did not differ among fish that were acclimated to different temperatures, but did display predicted changes with increasing temperature. Our results suggest that DNA methylation may be involved in temperature acclimation in brook trout, but the genes involved in differential responses to temperature are still unknown.