Late-born intermittently fasted juvenile garden dormice use torpor to grow and fatten prior to hibernation: consequences for ageing processes.
Torpor is thought to slow age-related processes and to sustain growth and fattening of young individuals. Energy allocation into these processes represents a challenge for juveniles, especially for those born late in the season. We tested the hypothesis that late-born juvenile garden dormice (Eliomys quercinus) fed ad libitum ('AL', n = 9) or intermittently fasted ('IF', n = 9) use short torpor bouts to enhance growth and fat accumulation to survive winter. IF juveniles displayed more frequent and longer torpor bouts, compared with AL individuals before hibernation. Torpor frequency correlated negatively with energy expenditure and water turnover. Hence, IF juveniles gained mass at the same rate, reached similar pre-hibernation fattening and displayed identical hibernating patterns and mass losses as AL animals. We found no group differences in relative telomere length (RTL), an indicator of ageing, during the period of highest summer mass gain, despite greater torpor use by IF juveniles. Percentage change in RTL was negatively associated with mean and total euthermic durations among all individuals during hibernation. We conclude that torpor use promotes fattening in late-born juvenile dormice prior to hibernation. Furthermore, we provided the first evidence for a functional link between time spent in euthermy and ageing processes over winter.
Department of Integrative Biology and Evolution, Research Institute of Wildlife Ecology, University of Veterinary Medicine Vienna, Savoyenstraße 1, 1160 Vienna, Austria sylvain.giroud@vetmeduni.ac.at.
Sylvain
S
Giroud
Université de Strasbourg, IPHC, 23 rue Becquerel 67087 Strasbourg, France CNRS, UMR7178, 67087 Strasbourg, France.
Sandrine
S
Zahn
Université de Strasbourg, IPHC, 23 rue Becquerel 67087 Strasbourg, France CNRS, UMR7178, 67087 Strasbourg, France.
François
F
Criscuolo
Université de Strasbourg, IPHC, 23 rue Becquerel 67087 Strasbourg, France CNRS, UMR7178, 67087 Strasbourg, France.
Isabelle
I
Chery
Université de Strasbourg, IPHC, 23 rue Becquerel 67087 Strasbourg, France CNRS, UMR7178, 67087 Strasbourg, France.
Stéphane
S
Blanc
Hawkesbury Institute for the Environment, Hawkesbury Campus, University of Western Sydney, Bourke Street, Richmond, 2753 NSW, Australia.
Christopher
C
Turbill
Department of Integrative Biology and Evolution, Research Institute of Wildlife Ecology, University of Veterinary Medicine Vienna, Savoyenstraße 1, 1160 Vienna, Austria.
Thomas
T
Ruf
D000375:Aging / Q000235:genetics*; D000818:Animals; D001823:Body Composition; D004435:Eating; D005260:Female; D005508:Food Deprivation; D006605:Hibernation; D008297:Male; D008969:Molecular Sequence Data; D046330:Myoxidae / Q000254:growth & development / Q000502:physiology*; D012621:Seasons; D059505:Telomere Homeostasis; D013997:Time Factors; D064348:Torpor
Eliomys quercinus; doubly labelled water; intermittent fasting; pre-hibernation fattening; telomere length; winter survival