title: Does reproduction protect against oxidative stress?
abstract: A central principle of life-history theory is that parents trade investment in reproduction against that in body maintenance. One physiological cost thought to be important as a modulator of such trade-off is oxidative stress. Experimental support for this hypothesis has, however, proved to be contradictory. In this study, we manipulated the nestling rearing effort of captive canaries (Serinus canaria) soon after the hatching of their nestlings using a brood-size manipulation to test whether an increase in nestling rearing effort translates into an increase in oxidative damage, an increase in ceruloplasmin (which is upregulated in response to oxidative damage) and a decrease in thiol antioxidants. We also compared the blood oxidative stress level of reproducing birds with that of non-reproducing birds, a crucial aspect that most studies have invariably failed to include in tests of the oxidative cost of reproduction. Compared with non-breeding canaries and pre-manipulation values, plasma oxidative damage (reactive oxygen metabolites and protein carbonyls) decreased in breeding canaries irrespective of sex and brood size. In contrast, oxidative damage did not change in non-breeding birds over the experiment. Ceruloplasmin activity in plasma and both non-protein and protein thiols in red blood cells did not change throughout the experiment in both treatment groups. Our results suggest that reproduction may result in decreased rather than increased blood oxidative stress. Our results may explain some of the inconsistencies that have so far been reported in experimental tests of the oxidative cost of reproduction hypothesis.
authors.affiliation: Department of Biology, Ethology Group, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium Institute for Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow G12 8QQ, UK davidcostantini@libero.it.
authors.forename: David
authors.initials: D
authors.lastname: Costantini
authors.affiliation: Institute of Environmental Sciences, Jagiellonian University, Ulica Gronostajowa 7, 30-387 Kraków, Poland.
authors.forename: Giulia
authors.initials: G
authors.lastname: Casasole
authors.affiliation: Department of Biology, Ethology Group, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium.
authors.forename: Marcel
authors.initials: M
authors.lastname: Eens
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D002171:Canaries / Q000097:blood / Q000378:metabolism / Q000502:physiology*; D002570:Ceruloplasmin / Q000378:metabolism; D005260:Female; D008297:Male; D009425:Nesting Behavior / Q000502:physiology*; D018384:Oxidative Stress / Q000502:physiology*; D012098:Reproduction / Q000502:physiology*; D013438:Sulfhydryl Compounds / Q000097:blood
chemical_list: D000975:Antioxidants; D013438:Sulfhydryl Compounds; D002570:Ceruloplasmin
keywords: Antioxidants; Life history; Oxidative damage; Parental care; Thiols; Vertebrates