Lague Sabine L, Chua Beverly, Farrell Anthony P, Wang Yuxiang, Milsom William K
Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4
Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4.
J Exp Biol. 2016 Jul 1;219(Pt 13):1974-84. doi: 10.1242/jeb.132431.
Bar-headed geese (Anser indicus) fly at high altitudes during their migration across the Himalayas and Tibetan plateau. However, we know relatively little about whether rearing at high altitude (i.e. phenotypic plasticity) facilitates this impressive feat because most of what is known about their physiology comes from studies performed at sea level. To provide this information, a comprehensive analysis of metabolic, cardiovascular and ventilatory responses to progressive decreases in the equivalent fractional composition of inspired oxygen (FiO2 : 0.21, 0.12, 0.09, 0.07 and 0.05) was made on bar-headed geese reared at either high altitude (3200 m) or low altitude (0 m) and on barnacle geese (Branta leucopsis), a low-altitude migrating species, reared at low altitude (0 m). Bar-headed geese reared at high altitude exhibited lower metabolic rates and a modestly increased hypoxic ventilatory response compared with low-altitude-reared bar-headed geese. Although the in vivo oxygen equilibrium curves and blood-oxygen carrying capacity did not differ between the two bar-headed goose study groups, the blood-oxygen carrying capacity was higher than that of barnacle geese. Resting cardiac output also did not differ between groups and increased at least twofold during progressive hypoxia, initially as a result of increases in stroke volume. However, cardiac output increased at a higher FiO2 threshold in bar-headed geese raised at high altitude. Thus, bar-headed geese reared at high altitude exhibited a reduced oxygen demand at rest and a modest but significant increase in oxygen uptake and delivery during progressive hypoxia compared with bar-headed geese reared at low altitude.
斑头雁（Anser indicus）在飞越喜马拉雅山脉和青藏高原的迁徙过程中会在高海拔地区飞行。然而，我们对在高海拔地区饲养（即表型可塑性）是否有助于这一惊人壮举了解相对较少，因为目前已知的关于它们生理学的大部分信息来自于在海平面进行的研究。为了提供这一信息，我们对在高海拔（3200米）或低海拔（0米）饲养的斑头雁以及在低海拔（0米）饲养的黑雁（Branta leucopsis，一种低海拔迁徙物种）进行了全面分析，研究它们在吸入氧气等效分数（FiO2：0.21、0.12、0.09、0.07和0.05）逐渐降低时的代谢、心血管和通气反应。与低海拔饲养的斑头雁相比，高海拔饲养的斑头雁代谢率较低，低氧通气反应略有增加。尽管两个斑头雁研究组的体内氧平衡曲线和血液携氧能力没有差异，但血液携氧能力高于黑雁。静息心输出量在各组之间也没有差异，并且在逐渐缺氧过程中至少增加了两倍，最初是由于每搏输出量增加。然而，高海拔饲养的斑头雁心输出量在更高的FiO2阈值时增加。因此，与低海拔饲养的斑头雁相比，高海拔饲养的斑头雁在静息时表现出较低的氧气需求，并且在逐渐缺氧过程中氧气摄取和输送有适度但显著的增加。
