Development of maximum metabolic rate and pulmonary diffusing capacity in the superprecocial Australian Brush Turkey Alectura lathami: An allometric and morphometric study

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dc.contributor.authorSeymour, R.
dc.contributor.authorRunciman, S.
dc.contributor.authorBaudinette, R.
dc.date.issued2008
dc.descriptionCopyright © 2006 Elsevier Inc. All rights reserved.
dc.description.abstractThe Australian Brush Turkey Alectura lathami is a member of the Megapodiidae, the mound-building birds that produce totally independent, "superprecocial" hatchlings. This study examined the post-hatching development of resting and maximal metabolic rates, and the morphometrically determined changes in pulmonary gas exchange anatomy, in chicks during 3.7 months of growth from hatchlings (122 g) to subadults (1.1 kg). Allometric equations of the form y=aM(b) related gas exchange variables (y) to body mass (M, g). Metabolic rates were measured with open-flow respirometry (mL O2 min(-1)) of chicks resting in the dark and running above the aerobic limit on a treadmill. Resting metabolic rate (RMR=0.02 M(0.99)) and maximal metabolic rate (MMR=0.05 M(1.07)) scaled with exponents significantly above those of interspecific allometries of adult birds. However MMR was below that expected for other species of adult birds in flapping flight, consistent with the Brush Turkey's ground-dwelling habits. Total lung volumes (mL) increased faster than isometrically (V(L)=0.0075 M(1.19)), as did the surface area (cm(2)) of the blood-gas barrier (S(t)=7.80 M(1.23)), but the data overlapped those of adult species. Harmonic mean thickness of the blood-gas barrier was independent of body size (mean tau(ht),=0.39 microm) and was about twice that expected for flying birds. Diffusing capacity (mL O2 min(-1) kPa(-1)) of the blood-gas tissue barrier increased faster than isometrically (Dto2=0.049 M(1.23)); in hatchling Brush Turkeys, it was about 30% expected for adult birds, but this difference disappeared when they became subadults. When compared to altricial Australian pelicans that hatch at similar body masses, superprecocial Brush Turkeys had higher MMR and higher Dto2 at the same body size. A parallel allometry between MMR and Dto2 in Brush Turkeys and pelicans is consistent with the concept of symmorphosis during development.
dc.description.statementofresponsibilityRoger S. Seymour, Sue Runciman and Russell V. Baudinette
dc.description.urihttp://www.elsevier.com/wps/find/journaldescription.cws_home/525464/description#description
dc.identifier.citationComparative Biochemistry and Physiology -Part A : Molecular and Integrative Physiology, 2008; 150(2):169-175
dc.identifier.doi10.1016/j.cbpa.2006.03.018
dc.identifier.issn1095-6433
dc.identifier.issn1531-4332
dc.identifier.orcidSeymour, R. [0000-0002-3395-0059]
dc.identifier.urihttp://hdl.handle.net/2440/51947
dc.language.isoen
dc.publisherElsevier Science Inc
dc.source.urihttps://doi.org/10.1016/j.cbpa.2006.03.018
dc.subjectLung
dc.subjectBlood-Air Barrier
dc.subjectAnimals
dc.subjectTurkeys
dc.subjectBody Weight
dc.subjectOxygen
dc.subjectPulmonary Diffusing Capacity
dc.subjectOrgan Size
dc.subjectDiet
dc.subjectDiffusion
dc.subjectOxygen Consumption
dc.subjectAustralia
dc.titleDevelopment of maximum metabolic rate and pulmonary diffusing capacity in the superprecocial Australian Brush Turkey Alectura lathami: An allometric and morphometric study
dc.typeJournal article
pubs.publication-statusPublished

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