Article
Metabolism of Avian Embryos: Patterns in Altricial and Precocial Birds
Physiological Zoology
(1979)
Abstract
We measured rate of oxygen consumption (Vo,) of individual eggs in five species of
birds. The pattern of oxygen consumption during development differs markedly
between altricial and precocial species. The Vo, increased throughout incubation in
eggs of the altricial species (Poephila guttata, Ploceus cucullatus, and Columba Iivia).
In eggs of the precocial species (Coturnix coturnix and Anser anser) Vo, increased
during the first 75% of incubation but then remained relatively constant until shortly
before hatching. Growth patterns of embryos of Poephila and Coturnix differ in the
same way as their patterns of oxygen consumption differ. We suggest that a decline
in growth rate late in incubation results in the stabilization of V0 , in the precocial
species. In growing embryos, V0 , increases with (body mass) 0 · 92 . The exponent is
higher than that characterizing metabolism-mass relations of adult birds because of
the energy demands of rapid embryonic growth. In both altricial and precocial species,
eggshell conductance to gases is adapted primarily to regulate water loss and does not
obviously limit Vo, of the embryo. The V0 , prior to pipping is more closely correlated
with egg mass (and thus embryo mass) than with eggshell conductance. As a result,
oxygen tensions in the air cells of Poephila and Ploceus eggs just prior to pipping are
surprisingly low, only 72 and 85 torr, respectively.
Disciplines
Publication Date
June, 1979
Publisher Statement
Physiological Zoology © 1979 The University of Chicago Press
Citation Information
Carol M. Vleck, Donald F. Hoyt and David Vleck. "Metabolism of Avian Embryos: Patterns in Altricial and Precocial Birds" Physiological Zoology Vol. 52 Iss. 3 (1979) p. 363 - 377 Available at: http://works.bepress.com/carol-vleck/23/