Department of Zoology, Institute of Ecology and Earth Sciences, The Centre of Excellence FIBIR, Tartu University, Vanemuise 46, 51014 Tartu, Estonia.
J Exp Biol. 2010 Jul 1;213(Pt 13):2225-33. doi: 10.1242/jeb.042085.
Carotenoid and melanin pigments in the plumage of birds are hypothesized to be sensitive to oxidative stress. We manipulated oxidative status of captive greenfinches (Carduelis chloris L.) by the administration of buthionine sulfoximine (BSO), a selective inhibitor of the synthesis of glutathione (GSH), an intracellular antioxidant. Half of the birds in the treated group, as well as in the control group, also received dietary carotenoid (lutein) supplementation. BSO treatment reduced erythrocyte GSH levels and caused oxidative damage as indicated by the increased concentration of plasma malondialdehyde (MDA), an end product of lipid peroxidation. BSO treatment also reduced the brightness (i.e. increased blackness) of the tips of tail feathers grown during the experiment. These results show that a low systemic GSH level is required for development of eumelanin plumage coloration and that such a low GSH level is also potentially dangerous for the organism. Carotenoid supplementation increased plasma carotenoid levels and chroma of the yellow parts of the feathers grown during the experiment. However, carotenoid supplementation did not reduce plasma MDA levels. Manipulation of GSH did not affect plasma carotenoids or carotenoid-based plumage coloration. These findings argue against the antioxidant function of lutein in vivo and carotenoid signaling of antioxidant status.
鸟类羽毛中的类胡萝卜素和黑色素色素被假设对氧化应激敏感。我们通过给予丁硫氨酸亚砜胺（BSO）来操纵圈养绿翅金雀（Carduelis chloris L.）的氧化状态，BSO 是谷胱甘肽（GSH）合成的选择性抑制剂，GSH 是一种细胞内抗氧化剂。处理组和对照组的一半鸟类也接受了类胡萝卜素（叶黄素）的饮食补充。BSO 处理降低了红细胞 GSH 水平，并导致氧化损伤，表现为血浆丙二醛（MDA）浓度增加，MDA 是脂质过氧化的终产物。BSO 处理还降低了实验期间生长的尾羽尖端的亮度（即增加了黑色度）。这些结果表明，低系统 GSH 水平是真黑色素羽毛颜色发育所必需的，而这种低 GSH 水平对生物体也是潜在危险的。类胡萝卜素补充增加了实验期间生长的羽毛黄色部分的血浆类胡萝卜素水平和色度。然而，类胡萝卜素补充并没有降低血浆 MDA 水平。GSH 的操纵没有影响血浆类胡萝卜素或基于类胡萝卜素的羽毛颜色。这些发现反对叶黄素在体内的抗氧化功能和抗氧化状态的类胡萝卜素信号传导。
