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Cardiovascular responses to progressive hypoxia in ducks native to high altitude in the Andes

Citation

Lague, SL and Ivy, CM and York, JM and Chua, BA and Alza, L and Cheek, R and Dawson, NJ and Frappell, PB and Farrell, AP and McCracken, KG and Scott, GR and Milsom, WK, Cardiovascular responses to progressive hypoxia in ducks native to high altitude in the Andes, Journal of Experimental Biology, 223, (4) pp. 1-10. ISSN 0022-0949 (2020) [Refereed Article]


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Copyright Statement

© 2020. Published by The Company of Biologists Ltd

DOI: doi:10.1242/jeb.211250

Abstract

The cardiovascular system is critical for delivering O2 to tissues. Here, we examined the cardiovascular responses to progressive hypoxia in four high-altitude Andean duck species compared with four related low-altitude populations in North America, tested at their native altitude. Ducks were exposed to stepwise decreases in inspired partial pressure of O2 while we monitored heart rate, O2 consumption rate, blood O2 saturation, haematocrit (Hct) and blood haemoglobin (Hb) concentration. We calculated O2 pulse (the product of stroke volume and the arterial–venous O2 content difference), blood O2 concentration and heart rate variability. Regardless of altitude, all eight populations maintained O2 consumption rate with minimal change in heart rate or O2 pulse, indicating that O2 consumption was maintained by either a constant arterial–venous O2 content difference (an increase in the relative O2 extracted from arterial blood) or by a combination of changes in stroke volume and the arterial–venous O2 content difference. Three high-altitude taxa (yellow-billed pintails, cinnamon teal and speckled teal) had higher Hct and Hb concentration, increasing the O2 content of arterial blood, and potentially providing a greater reserve for enhancing O2 delivery during hypoxia. Hct and Hb concentration between low- and high-altitude populations of ruddy duck were similar, representing a potential adaptation to diving life. Heart rate variability was generally lower in high-altitude ducks, concurrent with similar or lower heart rates than low-altitude ducks, suggesting a reduction in vagal and sympathetic tone. These unique features of the Andean ducks differ from previous observations in both Andean geese and bar-headed geese, neither of which exhibit significant elevations in Hct or Hb concentration compared with their low-altitude relatives, revealing yet another avian strategy for coping with high altitude.

Item Details

Item Type:Refereed Article
Keywords:heart rate variability, oxygen transport, oxygen consumption, heart rate, haemoglobin, hypoxia
Research Division:Biological Sciences
Research Group:Zoology
Research Field:Animal physiology - systems
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the biological sciences
UTAS Author:Frappell, PB (Professor Peter Frappell)
ID Code:143173
Year Published:2020
Web of Science® Times Cited:5
Deposited By:Ecology and Biodiversity
Deposited On:2021-03-03
Last Modified:2021-11-19
Downloads:0

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