Environmental variation associated with overwintering elicits marked metabolic plasticity in a temperate salmonid, Salvelinus fontinalis.

Autor:	Middleton EK; Department of Biological Sciences, University of New Brunswick, Saint John, Canada, E2K 5E2., Gilbert MJH; Department of Biological Sciences, University of New Brunswick, Saint John, Canada, E2K 5E2., Landry T; Département de Biologie, Université de Moncton, Moncton, Canada, E1A 3E9., Lamarre SG; Département de Biologie, Université de Moncton, Moncton, Canada, E1A 3E9., Speers-Roesch B; Department of Biological Sciences, University of New Brunswick, Saint John, Canada, E2K 5E2.
Jazyk:	angličtina
Zdroj:	The Journal of experimental biology [J Exp Biol] 2024 Feb 01; Vol. 227 (3). Date of Electronic Publication: 2024 Feb 12.
DOI:	10.1242/jeb.246743
Abstrakt:	Poleward winters commonly expose animals, including fish, to frigid temperatures and low food availability. Fishes that remain active over winter must therefore balance trade-offs between conserving energy and maintaining physiological performance in the cold, yet the extent and underlying mechanisms of these trade-offs are not well understood. We investigated the metabolic plasticity of brook char (Salvelinus fontinalis), a temperate salmonid, from the biochemical to whole-animal level in response to cold and food deprivation. Acute cooling (1°C day-1) from 14°C to 2°C had no effect on food consumption but reduced activity by 77%. We then assessed metabolic performance and demand over 90 days with exposure to warm (8°C) or cold winter (2°C) temperatures while fish were fed or starved. Resting metabolic rate (RMR) decreased substantially during initial cooling from 8°C to 2°C (Q10=4.2-4.5) but brook char exhibited remarkable thermal compensation during acclimation (Q10=1.4-1.6). Conversely, RMR was substantially lower (40-48%) in starved fish, conserving energy. Thus, the absolute magnitude of thermal plasticity may be masked or modified under food restriction. This reduction in RMR was associated with atrophy and decreases in in vivo protein synthesis rates, primarily in non-essential tissues. Remarkably, food deprivation had no effect on maximum oxygen uptake rates and thus aerobic capacity, supporting the notion that metabolic capacity can be decoupled from RMR in certain contexts. Overall, our study highlights the multi-faceted energetic flexibility of Salvelinus spp. that likely contributes to their success in harsh and variable environments and may be emblematic of winter-active fishes more broadly. Competing Interests: Competing interests The authors declare no competing or financial interests. (© 2024. Published by The Company of Biologists Ltd.)
Databáze:	MEDLINE
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