Resilience and phenotypic plasticity of Arctic char (Salvelinus alpinus) facing cyclic hypoxia: insights into growth, energy stores and hepatic metabolism.
Loïck Ducros, Mohamed Touaibia, Nicolas Pichaud, Simon G Lamarre
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引用次数: 0
Abstract
Arctic char (Salvelinus alpinus) is facing the decline of its southernmost populations due to several factors including rising temperatures and eutrophication. These conditions are also conducive to episodes of cyclic hypoxia, another possible threat to this species. In fact, lack of oxygen and reoxygenation can both have serious consequences on fish as a result of altered ATP balance and an elevated risk of oxidative burst. Thus, fish must adjust their phenotype to survive and equilibrate their energetic budget. However, their energy allocation strategy could imply a reduction in growth which could be deleterious for their fitness. Although the impact of cyclic hypoxia is a major issue for ecosystems and fisheries worldwide, our knowledge on how salmonid deal with high oxygen fluctuations remains limited. Our objective was to characterize the effects of cyclic hypoxia on growth and metabolism in Arctic char. We monitored growth parameters (specific growth rate, condition factor), hepatosomatic and visceral indexes, relative heart mass and hematocrit of Arctic char exposed to 30 days of cyclic hypoxia. We also measured the hepatic protein synthesis rate, hepatic triglycerides as well as muscle glucose, glycogen and lactate and quantified hepatic metabolites during this treatment. The first days of cyclic hypoxia slightly reduce growth performance with a downward trend in specific growth rate in mass and condition factor variation compared to the control group. This acute exposure also induced a profound metabolome reorganization in the liver with an alteration of amino acid, carbohydrate and lipid metabolisms. However, fish rebalanced their metabolic activities and successfully maintained their growth and energetic reserves after 1 month of cyclic hypoxia. These results demonstrate the impressive ability of Arctic char to cope with its changing environment but also highlight a certain vulnerability of this species during the first days of a cyclic hypoxia event.
期刊介绍:
Conservation Physiology is an online only, fully open access journal published on behalf of the Society for Experimental Biology.
Biodiversity across the globe faces a growing number of threats associated with human activities. Conservation Physiology will publish research on all taxa (microbes, plants and animals) focused on understanding and predicting how organisms, populations, ecosystems and natural resources respond to environmental change and stressors. Physiology is considered in the broadest possible terms to include functional and mechanistic responses at all scales. We also welcome research towards developing and refining strategies to rebuild populations, restore ecosystems, inform conservation policy, and manage living resources. We define conservation physiology broadly and encourage potential authors to contact the editorial team if they have any questions regarding the remit of the journal.