Lipid-induced thermogenesis is up-regulated by the first cold-water immersions in juvenile penguins

• Published in: Journal of Comparative Physiology B
• Main Authors: Teulier, Loïc, Rey, Benjamin, Tornos, Jérémy, Le Coadic, Marion, Monternier, Pierre-Axel, Bourguignon, Aurore, Dolmazon, Virginie, Romestaing, Caroline, Rouanet, Jean-Louis, Duchamp, Claude, H. B., Roussel, Damien
• Other Authors: Laboratoire d'Ecologie des Hydrosystèmes Naturels et Anthropisés (LEHNA), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École Nationale des Travaux Publics de l'État (ENTPE)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Biométrie et Biologie Evolutive - UMR 5558 (LBBE), Université de Lyon-Université de Lyon-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2016
• Subjects: Metabolism · Mitochondria · Skeletal muscle · Energy substrates · Oxidative phosphorylation efficiency; [SDE.BE]Environmental Sciences/Biodiversity and Ecology; King Penguins
• Online Access: https://sde.hal.science/hal-01332835; https://doi.org/10.1007/s00360-016-0975-3

International audience The passage from shore to marine life is a critical step in the development of juvenile penguins and is characterized by a fuel selection towards lipid oxida- tion concomitant to an enhancement of lipid-induced ther- mogenesis. However, mechanisms of such thermogenic improvement at fledging remain undefined. We used two different groups of pre-fledging king penguins (Apteno- dytes patagonicus) to investigate the specific contribution of cold exposure during water immersion to lipid metabo- lism. Terrestrial penguins that had never been immersed in cold water were compared with experimentally cold-water immersed juveniles. Experimentally immersed penguins underwent ten successive immersions at approximately 9–10 °C for 5 h over 3 weeks. We evaluated adaptive ther- mogenesis by measuring body temperature, metabolic rate and shivering activity in fully immersed penguins exposed to water temperatures ranging from 12 to 29 °C. Both never-immersed and experimentally immersed penguins were able to maintain their homeothermy in cold water, exhibiting similar thermogenic activity. In vivo, perfusion of lipid emulsion at thermoneutrality induced a twofold larger calorigenic response in experimentally immersed than in never-immersed birds. In vitro, the respiratory rates and the oxidative phosphorylation efficiency of isolated muscle mitochondria were not improved with cold-water immersions. The present study shows that acclimation to cold water only partially reproduced the fuel selection towards lipid oxidation that characterizes penguin acclima- tization to marine life.