Maximal metabolic rates during voluntary exercise, forced exercise, and cold exposure in house mice selectively bred for high wheel-running

Enrico L. Rezende, Mark A. Chappell, Fernando R. Gomes, Jessica L. Malisch, Theodore Garland

Research output: Contribution to journalArticle

72 Citations (Scopus)

Abstract

Selective breeding for high wheel-running activity has generated four lines of laboratory house mice (S lines) that run about 170% more than their control counterparts (C lines) on a daily basis, mostly because they run faster. We tested whether maximum aerobic metabolic rates (V̇O2max) have evolved in concert with wheel-running, using 48 females from generation 35. Voluntary activity and metabolic rates were measured on days 5+6 of wheel access (mimicking conditions during selection), using wheels enclosed in metabolic chambers. Following this, V̇O2max was measured twice on a motorized treadmill and twice during cold-exposure in a heliox atmosphere (HeO2). Almost all measurements, except heliox V̇ O2max, were significantly repeatable. After accounting for differences in body mass (S<C) and variation in age at testing, S and C did not differ in V̇O2max during forced exercise or in heliox, nor in maximal running speeds on the treadmill. However, running speeds and V̇O2max during voluntary exercise were significantly higher in S lines. Nevertheless, S mice never voluntarily achieved the V̇ O2max elicited during their forced treadmill trials, suggesting that aerobic capacity per se is not limiting the evolution of even higher wheel-running speeds in these lines. Our results support the hypothesis that S mice have genetically higher motivation for wheel-running and they demonstrate that behavior can sometimes evolve independently of performance capacities. We also discuss the possible importance of domestication as a confounding factor to extrapolate results from this animal model to natural populations.

Original languageEnglish
Pages (from-to)2447-2458
Number of pages12
JournalJournal of Experimental Biology
Volume208
Issue number12
DOIs
Publication statusPublished - Jun 2005

Keywords

  • Artificial selection
  • Exercise
  • Experimental evolution
  • Locomotor activity
  • Maximum oxygen consumption
  • Mouse
  • Running performance
  • Thermogenesis

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Agricultural and Biological Sciences (miscellaneous)
  • Animal Science and Zoology
  • Aquatic Science
  • Molecular Biology
  • Insect Science
  • Ecology, Evolution, Behavior and Systematics
  • Physiology

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