EFFECTS OF AMBIENT-TEMPERATURE, DIET QUALITY, AND FOOD RESTRICTION ONBODY-COMPOSITION DYNAMICS OF THE PRAIRIE VOLE, MICROTUS-OCHROGASTER

We manipulated diet quality, food availability, and ambient temperatur e to investigate the role of these variables in fat deposition by grow ing prairie voles (Microtus ochrogaster) and fat use by adult voles. E xposure to either 5 degrees C or a high-fiber diet reduced fat deposit ion by growing voles and also reduced growth as measured by body lengt h. Adult voles on the high-fiber diet reduced fat content, but exposur e to 5 degrees C had no effect on body composition. Both the high-fibe r diet and exposure to 5 degrees C caused increased food intake and re duced diet digestibility for adult voles. Restricting access to food r esulted in reduced lipid mass of all adult voles and reduced fat-free mass of those held at 5 degrees C. When faced with poor food quality o r cold ambient temperature, voles will increase food intake rather tha n catabolize lipid tissue. When food availability is limited, however, voles will use fat stores to meet the balance of their energy require ments.