title: Oxidative damage increases with reproductive energy expenditure and is reduced by food-supplementation.
abstract: A central principle in life-history theory is that reproductive effort negatively affects survival. Costs of reproduction are thought to be physiologically based, but the underlying mechanisms remain poorly understood. Using female North American red squirrels (Tamiasciurus hudsonicus), we test the hypothesis that energetic investment in reproduction overwhelms investment in antioxidant protection, leading to oxidative damage. In support of this hypothesis we found that the highest levels of plasma protein oxidative damage in squirrels occurred during the energetically demanding period of lactation. Moreover, plasma protein oxidative damage was also elevated in squirrels that expended the most energy and had the lowest antioxidant protection. Finally, we found that squirrels that were food-supplemented during lactation and winter had increased antioxidant protection and reduced plasma protein oxidative damage providing the first experimental evidence in the wild that access to abundant resources can reduce this physiological cost.
authors.affiliation: Department of Natural Resource Sciences, Macdonald Campus, McGill University, Ste-Anne-de-Bellevue, Québec H9X 3V9, Canada. q.fletcher@gmail.com
authors.forename: Quinn E
authors.initials: QE
authors.lastname: Fletcher
authors.forename: Colin
authors.initials: C
authors.lastname: Selman
authors.forename: Stan
authors.initials: S
authors.lastname: Boutin
authors.forename: Andrew G
authors.initials: AG
authors.lastname: McAdam
authors.forename: Sarah B
authors.initials: SB
authors.lastname: Woods
authors.forename: Arnold Y
authors.initials: AY
authors.lastname: Seo
authors.forename: Christiaan
authors.initials: C
authors.lastname: Leeuwenburgh
authors.forename: John R
authors.initials: JR
authors.lastname: Speakman
authors.forename: Murray M
authors.initials: MM
authors.lastname: Humphries
mesh_terms: D000818:Animals; D001798:Blood Proteins / Q000378:metabolism; D004734:Energy Metabolism; D005260:Female; D007774:Lactation / Q000097:blood / Q000378:metabolism*; D009752:Nutritional Status; D018384:Oxidative Stress; D012589:Sciuridae / Q000097:blood / Q000378:metabolism* / Q000502:physiology
chemical_list: D001798:Blood Proteins