Limits to sustained energy intake. XV. Effects of wheel running on the energy budget during lactation

Zhi Jun Zhao, Elzbieta Krol, Sophie Moille, Yuko Gamo, John R. Speakman*

*Corresponding author for this work

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

The capacity of animals to dissipate heat may constrain sustained energy intake during lactation. We examined these constraints at peak lactation in MF1 mice that had ad libitum access to food, or that had to run a pre-set target on running wheels to obtain ad libitum access to food. The voluntary distance run decreased sharply during pregnancy and peak lactation. When lactating females were provided with 80% of their estimated food requirements, and had to run pre-set distances of 2, 4 or 6. km before given access to additional ad libitum food, most of them did not complete the running target during late lactation and the mice with the highest targets failed to reach their targets earlier in lactation. There were consequently significant group differences in asymptotic food intake (2 km, 16.97 +/- 0.40 g day(-1); 4 km, 14.29 +/- 0.72 g day(-1); and 6 km, 12.65 +/- 0.45 g day(-1)) and weaned litter masses (2 km, 71.11 +/- 2.39 g; 4 km, 54.63 +/- 4.28 g and 6 km, 47.18 +/- 2.46 g). When the females did run sufficiently to gain ad libitum food access, their intake did not differ between the different distance groups or from controls that were not required to run. Thus, despite being physically capable of running the distances, mice could not exercise sufficiently in lactation to gain regular ad libitum access to food, probably because of the risks of hyperthermia when combining heat production from exercise with thermogenesis from lactation.

Original languageEnglish
Pages (from-to)2316-2327
Number of pages12
JournalJournal of Experimental Biology
Volume216
Issue number12
DOIs
Publication statusPublished - Jun 2013

Keywords

  • reproductive performance
  • pregnancy
  • heat dissipation limitation
  • programming
  • food intake
  • activity
  • growth
  • body temperature
  • dissipation limitation hypothesis
  • voles lasiopodomys-brandtii
  • hamsters phodopus-sungorus
  • life-history evolution
  • resting metabolic-rate
  • in-house mice
  • mus musculus
  • laboratory mice
  • oxidative damage
  • food-intake

Cite this