Effects of carotenoid and vitamin E supplementation on oxidative stress and plumage coloration in house finches (Haemorhous mexicanus)

Butler, Michael W.; Giraudeau, M.; Sweazea, K.; McGraw, K. J.

Effects of carotenoid and vitamin E supplementation on oxidative stress and plumage coloration in house finches (Haemorhous mexicanus)

Abstract

There has been much recent interest from both applied and basic scientists in the broad series of benefits that animals reap from acquiring high concentrations of dietary antioxidants, such as carotenoids and vitamins (e.g., vitamin E, or tocopherol). Most attention has been paid to separate effects of these compounds on, for example, coloration, health state, development, and vision, but because of possible interactions between these lipid-soluble molecules, we are in need of more studies that co-manipulate these substances and examine their possible synergistic impacts on animal physiology and phenotype. We capitalized on a model avian system (the house finch, Haemorhous mexicanus), where extensive information is available on the fitness roles of carotenoids, to test how variation in carotenoid and/or vitamin E concentrations in the diet impacts body accumulation of these compounds, factors related to oxidative damage (e.g., breast muscle and plasma oxidative-stress susceptibility, plasma nitric-oxide levels), and plumage color development. As in a previous study of ours on carotenoids and health in finches, we employed a 2 × 2 factorial experimental design on birds in both molting and non-molting conditions, to understand how seasonal shifts in carotenoid use (i.e., pigment incorporation into plumage) might alter the accumulation and roles of carotenoids and vitamins. As expected, lutein supplementation increased the level of circulating carotenoids in both experiments and the color of newly molted plumage. By contrast, vitamin E provisioning did not significantly affect plasma carotenoid levels or plumage coloration in either experiment. Interestingly, carotenoid provisioning decreased circulating vitamin E levels during molt, which suggests either molecular competition between carotenoids and tocopherol at the absorption/transport stages or that vitamin E serves as an antioxidant to offset harmful actions that carotenoids may have at very high concentrations. Finally, in both experiments, we found a reduction in breast-muscle oxidative damage for tocopherol-supplemented birds, which constitutes the first demonstration of a protective effect of vitamin E against oxidative stress in wild birds. Taken together, these findings provide an interesting contrast with our earlier work on season-specific physiological benefits of carotenoids in finches and point to complex associations between indicators of antioxidant and oxidative state in wild-caught animals.

Title	Effects of carotenoid and vitamin E supplementation on oxidative stress and plumage coloration in house finches (Haemorhous mexicanus)
Creator	Butler, Michael W.
	Giraudeau, M.
	Sweazea, K.
	McGraw, K. J.
Publisher	Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
Academic Department	Biology
Division	Natural Sciences
Organization	Lafayette College
Date Issued	November 2013
Date Available	2013-11-06T19:44:58Z
Type	Article
Language	English
Keyword	oxidative damage
	carotenoids
	coloration
	house finch
	tocopherol
Bibliographic Citation	Giraudeau, M., et al. (2013 Nov.) "Effects of carotenoid and vitamin E supplementation on oxidative stress and plumage coloration in house finches (Haemorhous mexicanus)." Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology 166 (3): 406-413.
Standard Identifier	Handle 10385/1357
Standard Identifier	DOI 10.1016/j.cbpa.2013.07.014
Permalink	http://hdl.handle.net/10385/1357
Rights Statement	In Copyright
Rights Holders	Elsevier Inc.