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AJP Regulatory Integrative and Comparative Physiology 297, 4 (2009) R950-R959
Dietary palmitate and linoleate oxidations, oxidative stress, and DNA damage differ according to season in mouse lemurs exposed to a chronic food deprivation.
Sylvain Giroud1, Martine Perret1, Caroline Gilbert2, 3, Alexandre Zahariev2, Joëlle Goudable4, Yvon Le Maho2, Hugues Oudart2, Iman Momken2, Fabienne Aujard1, Stéphane Blanc2
(10/2009)

This study investigated the extent to which the increase in torpor expression in the grey mouse lemur, due to graded food restriction, is modulated by a trade-off between a whole body sparing of polyunsaturated dietary fatty acids and the related oxidative stress generated during daily torpor. We measured changes in torpor frequency, total energy expenditure (TEE), linoleate (polyunsaturated fatty acid) and palmitate (saturated fatty acid) oxidation, hexanoyl-lysine (HEL; the product of linoleate peroxidation), and 8-hydroxydeoxyguanosine (8OHdG; a marker of DNA damage). Animals under summer-acclimated long days (LD) or winter-acclimated short days (SD) were exposed to a 40% (LD40 and SD40) and 80% (LD80 and SD80) 35-day calorie restriction (CR). During CR, all groups reduced their body mass, but LD80 animals reached survival-threatened levels at day 22 and were then excluded from the CR trial. Only SD mouse lemurs increased their torpor frequency with CR and displayed a decrease in their TEE adjusted for fat-free mass. After CR, SD40 mouse lemurs shifted the dietary fatty acid oxidation toward palmitate and spared linoleate. Such a shift was not observed in LD animals and during severe CR, during which oxidation of both dietary fatty acids was increased. Concomitantly, HEL increased in both LD40 and SD80 groups, whereas DNA damage was only seen in SD80 food-restricted animals. HEL correlated positively with linoleate oxidation confirming in vivo the substrate/product relationship demonstrated in vitro, and negatively with TEE adjusted for fat-free mass, suggesting higher oxidative stress associated with increased torpor expression. This suggests a seasonal-dependant, cost-benefit trade-off between maximizing torpor propensity and minimizing oxidative stress that is associated with a shift toward sparing of dietary polyunsaturated fatty acids that is dependent upon the expression of a winter phenotype.
1 :  MAOAC - Mécanismes adaptatifs : des organismes aux communautés
2 :  DEPE-IPHC - Département Ecologie, Physiologie et Ethologie
3 :  UHP - Université Henri Poincaré - Nancy I
4 :  Institut des Sciences Pharmaceutiques et Biologiques
Sciences du Vivant/Biodiversité/Evolution

Sciences de l'environnement/Biodiversité et Ecologie