Divergent Selection for Heat Loss in Mice: II. Correlated Responses in Feed Intake, Body Mass, Body Composition, and Number Born Through Fifteen Generations

M. K. Nielsen, B. A. Freking, L. D. Jones, S. M. Nelson, T. L. Vorderstrasse, B. A. Hussey

Research output: Contribution to journalArticle

55 Scopus citations

Abstract

Divergent selection for heat loss (kcal·kg-.75·d-1), measured in 9- to 11-wk-old male mice, was conducted for 15 generations. Selection for high (MH) and low (ML) heat loss and unselected control (MC) occurred in each of three replicates for a total of nine unique lines. Feed intake in males was measured during Generations 9 through 15. Body mass at commencement of mating in females and at time of measurement of heat loss in males was recorded. Body fat percentage at 12 wk for animals of Generations 6, 10, and 14 was predicted as a function of electrical conductivity and body mass. Litter size was recorded for all generations, and components of litter size were evaluated at Generation 11 in one replicate and Generation 12 in the other two replicates. Feed intake changed in the same direction as heat loss for the MH and ML selections; at Generation 15, the difference between MH and ML (P < .002) was 20.6% of the MC mean. Body mass did not change with selection for heat loss. Differences in body fat percentage were not significant in earlier generations, but at Generation 14, MH and ML were significantly (P < .01) different with MH mice having the lowest fat percentage; MC was intermediate. Selection had a significant (MH vs ML; P < .01) effect on litter size, causing an increase in MH and a decrease in ML. This difference was explained by a difference (P < .01) in ovulation rate. There was no asymmetry of response in feed intake, fatness, litter size, or number of ovulations.

Original languageEnglish (US)
Pages (from-to)1469-1476
Number of pages8
JournalJournal of animal science
Volume75
Issue number6
DOIs
Publication statusPublished - Jun 1997

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Keywords

  • Body Composition
  • Feed Intake
  • Heat Loss
  • Litter Size
  • Mice
  • Selection

ASJC Scopus subject areas

  • Food Science
  • Animal Science and Zoology
  • Genetics

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