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First published online February 29, 2008
Journal of Experimental Biology 211, 883-889 (2008)
Published by The Company of Biologists 2008
doi: 10.1242/jeb.014068
`Blood-doping' effects on hematocrit regulation and oxygen consumption in late-stage chicken embryos (Gallus gallus)
Department of Biological Sciences, University of North Texas, PO Box 305189, Denton, TX 76203, USA
* Author for correspondence (e-mail: burggren{at}unt.edu)
Accepted 21 January 2008
The extent to which hematocrit (Hct) is regulated and the impact of altered
Hct on blood oxygen transport in avian embryos are largely unknown.
Consequently, we investigated how acute blood removal or Ringer solution
injection modified Hct in day 15 embryos, and how `blood doping' with
erythrocyte-enriched whole blood influenced O2 consumption in day
15–17 chicken embryos. Mean Hct (±s.e.m.) at day 15, 16 and 17
was 26.7±0.6%, 28.0±0.4% and 30.7±0.5%, respectively.
Blood withdrawal (19 increments of 125 µl each, separated by 30 min) caused
a progressive fall in Hct to
12% at day 15. Hct decline was strictly
proportional to the extent of blood withdrawal. Incremental Ringer solution
injection over an 8 h period, transiently increasing blood volume up to 85%
over initial values, did not decrease Hct, indicating that injected Ringer
solution rapidly left the circulating blood compartment. Blood doping with
erythrocyte-enriched whole blood artificially elevated Hct from 27% to 38%,
but caused no significant change in routine O2 consumption
(0.35–0.39 ml O2 min–1
egg–1) at any point over the subsequent 6 h period in day
15–17 embryos. We conclude that Hct is not protected acutely in day 15
chicken embryos, with no evidence of erythrocyte sequestration or release.
Additionally, at day 15–17, Hct increases of
10% do not enhance
embryonic oxygen consumption, suggesting that blood oxygen carrying capacity
per se is not limiting to oxygen consumption.
Key words: hematocrit, oxygen consumption, blood volume, development, embryo
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