Monternier Pierre-Axel, Teulier Loïc, Drai Jocelyne, Bourguignon Aurore, Collin-Chavagnac Delphine, Hervant Frédéric, Rouanet Jean-Louis, Roussel Damien
Laboratoire d'Ecologie des Hydrosystèmes Naturels et Anthropisés, UMR 5023 CNRS, Université de Lyon, ENTPE, Lyon, France.
Service de Biochimie, CHU Lyon Sud, CarMeN, UMR 1060 INSERM, Université de Lyon, France.
Comp Biochem Physiol A Mol Integr Physiol. 2017 Oct;212:1-8. doi: 10.1016/j.cbpa.2017.06.018. Epub 2017 Jun 21.
Fasted endothermic vertebrates must develop physiological responses to maximize energy conservation and survival. The aim of this study was to determine the effect of 1-wk. fasting in 5-wk. old ducklings (Cairina moschata) from whole-body resting metabolic rate and body temperature to metabolic phenotype of tissues and mitochondrial coupling efficiency. At the level of whole organism, the mass-specific metabolic rate of ducklings was decreased by 40% after 1-wk. of fasting, which was associated with nocturnal Tb declines and shallow diurnal hypothermia during fasting. At the cellular level, fasting induced a large reduction in liver, gastrocnemius (oxidative) and pectoralis (glycolytic) muscle masses together with a fuel selection towards lipid oxidation and ketone body production in liver and a lower glycolytic phenotype in skeletal muscles. At the level of mitochondria, fasting induced a reduction of oxidative phosphorylation activities and an up-regulation of coupling efficiency (+30% on average) in liver and skeletal muscles. The present integrative study shows that energy conservation in fasted ducklings is mainly achieved by an overall reduction in mitochondrial activity and an increase in mitochondrial coupling efficiency, which would, in association with shallow hypothermia, increase the conservation of endogenous fuel stores during fasting.
禁食的恒温脊椎动物必须产生生理反应以最大限度地保存能量并维持生存。本研究的目的是确定5周龄雏鸭（疣鼻栖鸭）为期1周的禁食对其从全身静息代谢率和体温到组织代谢表型及线粒体偶联效率的影响。在整个生物体水平上，禁食1周后雏鸭的质量特异性代谢率降低了40%，这与禁食期间夜间体温下降和白天轻度体温过低有关。在细胞水平上，禁食导致肝脏、腓肠肌（氧化型）和胸肌（糖酵解型）的肌肉质量大幅减少，同时肝脏中燃料选择倾向于脂质氧化和酮体生成，骨骼肌中的糖酵解表型降低。在线粒体水平上，禁食导致肝脏和骨骼肌中氧化磷酸化活性降低，偶联效率上调（平均提高30%）。本综合研究表明，禁食雏鸭的能量保存主要通过线粒体活性的整体降低和线粒体偶联效率的提高来实现，这与轻度体温过低相结合，会增加禁食期间内源性燃料储备的保存。
