Migratory birds engage in 2 periods of endurance flight annually as they travel between summer breeding and overwintering grounds, and such endurance flights likely incur oxidative costs. These costs may differ between fall and spring migration, especially for females who must prepare for breeding and egg laying in spring. The objective of this study of a migratory bird was to test proposed hypotheses about how key components of the female’s antioxidant system differ in response to flight training in the fall and spring and to dietary antioxidant supplementation. We hand raised female European Starlings (Sturnus vulgaris) and fed them either a diet supplemented with dietary anthocyanins or a diet without added anthocyanins. We flew females in a wind tunnel for 15 days during fall and spring migration seasons and measured over time oxidative lipid damage (d-ROMs) and 3 components of the antioxidant system: nonenzymatic antioxidant capacity (OXY), uric acid, and glutathione peroxidase (GPx) activity. Prior to flight training, OXY and oxidative damage were lower in females during spring compared with fall, and females fed a low-antioxidant diet had consistently higher circulating uric acid. GPx activity decreased more in spring immediately after a long-duration flight. Females fed a high-antioxidant diet had a greater decrease in OXY after the 15-day flight training. Flight-trained females had higher circulating uric acid than untrained females immediately after the longest-duration flight and decreased GPx activity after the 15-day flight training. In sum, females upregulated enzymatic and nonenzymatic endogenous antioxidants in spring, and females fed a diet with less antioxidants appear to compensate by increasing circulating uric acid. Our findings emphasize the important role of dietary antioxidants for birds during migration, and similar flights in fall and spring likely represent distinct oxidative challenges in the life history of female birds.

中文翻译：

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季节、花青素补充剂和飞行训练对迁徙欧洲椋鸟的抗氧化系统有不同的影响

候鸟每年在夏季繁殖地和越冬地之间进行两次耐力飞行，这种耐力飞行可能会产生氧化成本。这些成本在秋季和春季迁徙之间可能有所不同，特别是对于必须准备在春季繁殖和产卵的雌性而言。这项对候鸟的研究的目的是检验提出的假设，即雌性抗氧化系统的关键成分在对秋季和春季飞行训练以及膳食抗氧化剂补充剂的反应中有何不同。我们人工饲养雌性欧洲椋鸟 (Sturnus vulgaris)，并给它们喂食添加了膳食花青素的饮食或不添加花青素的饮食。我们在秋季和春季迁徙季节让雌性在风洞中飞行 15 天，并随时间测量氧化脂质损伤 (d-ROM) 和抗氧化系统的 3 个组成部分：非酶抗氧化能力 (OXY)、尿酸和谷胱甘肽过氧化物酶。 GPx) 活动。在飞行训练之前，与秋季相比，春季女性的氧和氧化损伤较低，并且喂食低抗氧化剂饮食的女性的循环尿酸始终较高。在长时间飞行后，春季的 GPx 活动立即下降更多。喂食高抗氧化饮食的女性在 15 天的飞行训练后，OXY 下降幅度更大。受过飞行训练的女性在最长飞行时间后立​​即比未受过训练的女性具有更高的循环尿酸，并且在 15 天的飞行训练后 GPx 活性降低。总共，女性在春季上调了酶促和非酶促内源性抗氧化剂，喂食抗氧化剂较少的女性似乎通过增加循环尿酸来补偿。我们的研究结果强调了膳食抗氧化剂在迁徙过程中对鸟类的重要作用，秋季和春季的类似飞行可能代表雌鸟生活史中不同的氧化挑战。