SELECTION FOR SERUM CHOLESTEROL, VOLUNTARY PHYSICAL ACTIVITY, 56-DAY BODY WEIGHT AND FEED INTAKE IN RANDOMBRED MICE. I. DIRECT RESPONSES

Abstract

A five-generation selection experiment was conducted with randomly bred ICR mice. Lines were developed for high (CH) and low (CL) serum cholesterol (SC), voluntary physical activity (lines AH and AL), 56-day body weight (lines WH and WL), and feed intake (lines IH and IL). An unselected randomly bred control line was maintained with each pair of selection lines (CC, AC, WC and IC, respectively). Selection was based on individual performance in SC, activity and weight lines, and on within-sex, among full-sib family selection in intake lines. Genetic responses (selected line generation means deviated from control line generation means and regressed on generation number) were different from zero (P<0.05) in CH males and females, CL males, AH males and females, AL males, WH males and females, WL males and females, and IH females. Realized heritabilities which did not differ (P<0.05) between sexes were: 0.43±0.05 (line CH), 0.37±0.06 (line CL), 0.26±0.08 (line AH), 0.16±0.04 (line AL), 0.33±0.05 (line WH), 0.40±0.05 (line WL), 0.42±0.06 (line IH). In Line IL heritabilities of males and females differed (P<0.05) from each other (0.08±0.06 and 0.29±0.06, respectively).