Measurement of maximum oxygen consumption in guinea fowl Numida meleagris indicates that birds and mammals display a similar diversity of aerobic scopes during running

David J. Ellerby, Northeastern University
MaryEllen Cleary, Northeastern University
Richard L. Marsh, Northeastern University
Cindy I. Buchanan, Northeastern University

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Originally published in Physiological and Biochemical Zoology 76(5):695–703, 2003. DOI: 10.1086/376430

Abstract

Judgement of exercise performance in birds has been hampered by a paucity of data on maximal aerobic capacity. We measured the maximal rate of oxygen consumption (V̇o₂_,max) in running guinea fowl Numida meleagris, a bird that has been used in several previous studies of avian running. Mean V̇o₂_,max during level treadmill running was 97.5±3.7 mL O&8322; kg⁻¹ min⁻¹ (mean ± SEM, N=5). V̇o₂_,max was on average 6% higher when the birds ran uphill compared with the value during level running (paired t-test, P=0.041, N=5). The mean basal rate of oxygen consumption (V̇o₂_,bmr) of the same individuals was 7.9±0.5 mL kg⁻¹ min⁻¹.Mean factorial aerobic scope based on individually measured values of V̇o₂_,max and V̇o₂_,bmr was 13.2 ± 0.6 (mean ± SEM, N=5). This value was considerably lower than the factorial aerobic scope previously measured during running in Rhea americana, a large flightless ratite. The difference in factorial scope between these two running birds likely reflects the effects of body size as well as size-independent differences in the ability to deliver and use oxygen. These data confirm a previous prediction that birds have a diversity of factorial aerobic scopes similar to that exhibited by mammals.