Metabolic reduction after long-duration flight is not related to fat-free mass loss or flight duration in a migratory passerine
Metabolic reduction after long-duration flight is not related to fat-free mass loss or flight duration in a migratory passerine
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DOI：
10.1242/jeb.215384
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发表时间：
2020-10-01
影响因子：
2.8
通讯作者：
Groom, Derrick J.
中科院分区：
文献类型：
--
作者：
Gerson, Alexander R.;DeSimone, Joely G.;Groom, Derrick J.
候鸟在长途飞行中分解大量蛋白质，导致器官和肌肉质量急剧减少。解释这一现象的众多假设之一是，瘦质量的减少与静息新陈代谢的减少有关，从而在加油过程中节省飞行后的能量。然而，瘦体重和静息代谢率之间的关系仍然不清楚。此外，在长时间飞行前后，瘦体重与静息代谢率和峰值代谢率之间的耦合还没有被探索过。我们将迁徙的黄腰林莺(Setophaga Coronata)在两种湿度条件下的风洞中飞行，以控制飞行中瘦质量损失的速度，将飞行时间与总瘦质量损失分离。在长时间飞行前后，我们测量了静息和峰值代谢，并用定量磁共振测量了脂肪质量和瘦体重。飞行时间从28分钟到600分钟不等，在脱水条件下飞行的鸟类比在潮湿条件下飞行的鸟类损失更多的脱脂质量。飞行后，静息代谢减少了14%，但峰值代谢没有变化。有趣的是，静息代谢的减少与飞行时间或脱脂体重的变化无关，这表明飞行中的蛋白质代谢不太可能演变为一种帮助中途加油的节能措施，但新陈代谢减少本身可能有利于抵达新栖息地的候鸟。
Migratory birds catabolize large quantities of protein during long flights, resulting in dramatic reductions in organ and muscle mass. One of the many hypotheses to explain this phenomenon is that decrease in lean mass is associated with reduced resting metabolism, saving energy after flight during refueling. However, the relationship between lean body mass and resting metabolic rate remains unclear. Furthermore, the coupling of lean mass with resting metabolic rate and with peak metabolic rate before and after long-duration flight have not previously been explored. We flew migratory yellow-rumped warblers (Setophaga coronata) in a wind tunnel under one of two humidity regimes to manipulate the rate of lean mass loss in flight, decoupling flight duration from total lean mass loss. Before and after long-duration flights, we measured resting and peak metabolism, and also measured fat mass and lean body mass using quantitative magnetic resonance. Flight duration ranged from 28 min to 600 min, and birds flying under dehydrating conditions lost more fat-free mass than those flying under humid conditions. After flight, there was a 14% reduction in resting metabolism but no change in peak metabolism. Interestingly, the reduction in resting metabolism was unrelated to flight duration or to change in fat-free body mass, indicating that protein metabolism in flight is unlikely to have evolved as an energy-saving measure to aid stopover refueling, but metabolic reduction itself is likely to be beneficial to migratory birds arriving in novel habitats.