Ocean warming combined with lower omega-3 nutritional availability impairs the cardio-respiratory function of a marine fish [RESEARCH ARTICLE]

Marie Vagner, Eric Pante, Amelia Viricel, Thomas Lacoue-Labarthe, Jose-Luis Zambonino-Infante, Patrick Quazuguel, Emmanuel Dubillot, Valerie Huet, Herve Le Delliou, Christel Lefrancois, and Nathalie Imbert-Auvray Highly unsaturated fatty acids of the omega-3 series (HUFA) are major constituents of cell membranes, yet are poorly synthesised de novo by consumers. Their production, mainly supported by aquatic microalgae, has been decreasing with global change. The consequences of such reductions may be profound for ectotherm consumers, as temperature tightly regulates the HUFA content in cell membranes, maintaining their functionality. Integrating individual, tissue and molecular approaches, we examined the consequences of the combined effects of temperature and HUFA depletion on the key cardio-respiratory functions of the golden grey mullet, an ectotherm grazer of high ecological importance. For 4 months, fish were exposed to two contrasting HUFA diets [4.8% eicosapentaenoic acid (EPA)+docosahexaenoic acid (DHA) on dry matter (DM) versus 0.2% EPA+DHA on DM] at 12 and 20°C. Ventricular force development coupled with gene expression profiles measured on cardiac muscle suggest that combining HUFA depletion with warmer temperatures leads to: (1) a proliferation of sarcolemmal and sarcoplasmic reticulum Ca2+ channels and (2) a higher force-generating ability by increasing extracellular Ca2+ influx via sarcolemmal channels when the heart has to sustain excessive effort due ...
Source: Journal of Experimental Biology - Category: Biology Authors: Tags: Ecophysiology: responses to environmental stressors and change RESEARCH ARTICLE Source Type: research