AJP - Regulatory, Integrative and Comparative Physiology, Vol 268, Issue 3 658-R665, Copyright © 1995 by American Physiological Society
Dietary obesity in the mouse: interaction of strain with diet composition
D. B. West, J. Waguespack and S. McCollister
Obesity, Diabetes, and Metabolism Section, Pennington Biomedical Research Center, Louisiana State University, Baton Rouge 70808.
The effect of varying dietary macronutrient content on the body composition
of AKR/J and SWR/J mice was examined. Dietary fat was fed at three levels
(45, 30, and 15 kcal%), while dietary protein also was varied across three
levels (10, 20, and 30 kcal%). All mice were placed on the defined diets at
5 wk of age and maintained on these diets for 12 wk. AKR/J mice were
significantly larger and had a significantly greater carcass fat content
compared with SWR/J mice in all dietary conditions. There was a clear
dose-response effect of dietary fat on body fat in the AKR/J mice. In
contrast, SWR/J mice showed an increase of body fat only when fed the diet
containing the highest level of dietary fat and the lowest protein
concentration. High levels of dietary protein (30 kcal%) resulted in a
significant decrease of carcass fat in the AKR/J mice compared with diets
containing either 20 or 10 kcal% protein. This effect of protein was not
observed in the SWR/J mice except in the groups fed the 45 kcal% fat diets.
These findings demonstrate a strong interaction of genetic background and
macronutrient content of the diet on body composition. The AKR/J strain of
mouse has a greater percentage of carcass fat and is more responsive to the
effects of dietary fat composition compared with the SWR/J strain.
