Day-to-day variability in voluntary wheel running among genetically differentiated lines of mice that vary in activity level

Abstract

This study examined the day-to-day variability in voluntary wheel-running behavior among three genetically distinct lines of young male and female mice. Daily wheel revolutions were recorded at an age of 6-8 weeks in 10 males and 10 females from each of 3 lines: selectively bred line for high wheel running (Line 8), selectively bred for high wheel-running activity and fixed for a Mendelian recessive allele that reduces hind-limb muscle mass by 50% (Line 3), non-selected control (Line 2). There were significant mean differences in revolutions/day among weeks (P = 0.003), but the effect size was small (10%). Significant main effects for wheel running were also revealed for sex and line (P < 0.001). The grand mean +/- SD for the coefficient of variation (CV) of intra-individual wheel running was 23.0 +/- 10.8%. Although a significant main effect for the CV was found for week, the effect size was low (7%) (age 6 weeks, 23.4 +/- 10.9%; age 7 weeks, 25.1 +/- 13.2%; age 8 weeks, 20.1 +/- 7.8%). The overall mean CV was similar between females (21.4 +/- 9.8%) and males (24.4 +/- 12.0%) and among lines (Line 2, 23.4 +/- 9.8%; Line 3, 20.4 +/- 7.6%; and Line 8, 25.0 +/- 14.4%). These findings are consistent with our previous work in young humans and lend further support for the hypothesis that biological mechanisms influence daily levels of physical activity.

Spontaneous activity rates and resting metabolism: Support for the allocation model of energy management at the among‐individual level

“…For example, differences among selected lines of fish show positive correlations between activity, RMR and growth (Allen, Rosenfeld, & Richards, 2016;Biro, Abrahams, Post, & Parkinson, 2006;Scott, Dhillon, Schulte, & Richards, 2014) consistent with the "performance" model (see above). Similarly, studies on selected lines of rodents also show positive correlations between activity and RMR (Eisenmann et al, 2009;Meek et al, 2009;Rezende et al, 2009;Sadowska et al, 2013;Waters et al, 2008).…”

“…For example, differences among selected lines of fish show positive correlations between activity, RMR and growth (Allen, Rosenfeld, & Richards, ; Biro, Abrahams, Post, & Parkinson, ; Scott, Dhillon, Schulte, & Richards, ) consistent with the “performance” model (see above). Similarly, studies on selected lines of rodents also show positive correlations between activity and RMR (Eisenmann et al, ; Meek et al, ; Rezende et al, ; Sadowska et al, ; Waters et al, ). These experiments, together with several similar studies comparing across selected lines in domestic animals that differ in metabolic rate and behavior (reviewed by Biro & Stamps, ), suggest that among‐individual (and genetic) correlations are generally positive.…”

“…That is, we assume individuals are intrinsically energy limited under the ad libitum food conditions in the laboratory, limited by individual variation in their ability to consume and process food into energy, and that activity and daily energy expenditure are positively correlated (Meek, Lonquich, Hannon, & Garland, 2009;Rezende, Gomes, Chappell, & Garland, 2009;Sadowska, Gębczyński, & Konarzewski, 2013). Therefore, any correlations between spontaneous activity and measures of metabolism should exist due to functional and genetic links between metabolism and behavior, as demonstrated by artificial selection studies under ad lib food conditions (Eisenmann, Wickel, Kelly, Middleton, & Garland, 2009;Meek et al, 2009;Rezende et al, 2009;Sadowska et al, 2013;Waters et al, 2008).…”

Architecture of energy balance traits in emerging lines of the Collaborative Cross

“…Suggestive QTL for spontaneous locomotor activity have been identified on Chr 3, 8, 12, 13, and 19 (56), while noveltyand stress-induced locomotor activity are associated with loci on Chr 1,4,5,8,9,13,14,and 19 (17). Mice examined in the aforementioned studies consisted of F2, BC, and AIL populations with only one strain (C57BL6/J) in common with those used to generate the pre-CC; thus, the suggestive QTL in the pre-CC may be attributed to allele-specific effects not present in the other genetic crosses.…”

Metabolic Scope as a Proximate Constraint on Individual Behavioral Variation: Effects on Personality, Plasticity, and Predictability

“…Of course, because research on the among-individual relationships between metabolism and behavior is still not extensive, some of our predictions are necessarily based on empirical results for which clear and consistent trends are not yet apparent. Furthermore, because we are not aware of any existing study linking aerobic scope to individual variation in behavioral plasticity or predictability, we reanalyze a published data set (Eisenmann et al 2009) on selectively bred lines of laboratory house mice that differ in aerobic scope and behavior to provide some first (tentative) data in support of our ideas.…”