Effects of Ambient Temperature, Diet Quality, and Food Restriction on Body Composition Dynamics of the Prairie Vole,Microtus ochrogaster

Abstract

We manipulated diet quality, food availability, and ambient temperature to investigate the role of these variables in fat deposition by growing prairie voles (Microtus ochrogaster) and fat use by adult voles. Exposure to either 5 degrees C or a high-fiber diet reduced fat deposition by growing voles and also reduced growth as measured by body length. Adult voles on the high-fiber diet reduced fat content, but exposure to 5 degrees C had no effect on body composition. Both the high-fiber diet and exposure to 5 degrees C caused increased food intake and reduced diet digestibility for adult voles. Restricting access to food resulted 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 or cold ambient temperature, voles will increase food intake rather than catabolize lipid tissue. When food availability is limited, however, voles will use fat stores to meet the balance of their energy requirements.

The energy budget, thermogenic capacity and behavior in Swiss mice exposed to a consecutive decrease in temperatures

“…Consistently, in the present study Swiss mice showed significant decreases in body mass after being exposed to -8°C to -15°C, during which body mass was lower by 21.9% in the mice at -15°C than controls. It has been well established that changes in body mass are the result of the imbalance between energy intake and expenditure, and decrease in body mass is generally due to a negative energy state (Voltura and Wunder, 1998;Speakman, 2000;Merritt et al, 2001;Li et al, 2005). Here, body fat mass was, on average, 3.3g in mice exposed to 8°C and 1.3g in -15°C, suggesting that 2g fat was proximately mobilized.…”

“…It has been reported that many small mammals such as Brandt's voles (Lasiopodomys brandtii), meadow voles (Microtus pennsylvanicus), prairie voles (M. ochrogaster), Djungarian hamster (Phodopus sungorus), South American field mice (Abrothrix andinus) and laboratory mice (Iverson and Turner, 1974;Steinlechner et al, 1983;Bozinovic et al, 1990;Toloza et al, 1991;Konarzewski and Diamond, 1994;Voltura and Wunder, 1998;Li and Wang, 2005) respond to low temperature environments by reducing body mass. Consistently, in the present study Swiss mice showed significant decreases in body mass after being exposed to -8°C to -15°C, during which body mass was lower by 21.9% in the mice at -15°C than controls.…”

Diet, phylogeny, and basal metabolic rate in phyllostomid bats

“…At the level of phenotypic plasticity rather than evolutionary adaptation, although some mammals downregulate BMR when faced with low-quality diet, the universality of this response has been contested (review in Speakman, 2000). Moreover, when faced with a lowquality diet, some mammals do not downregulate BMR but, instead, increase food intake (e.g., Thompson, 1992;Voltura and Wunder, 1998), in order to maintain a relatively constant intake of nutrients and energy. Increase in food intake leads to a decrease in digestive efficiency, and to compensate for such decrease, some mammals alter their gastrointestinal tract (Piersma and Lindström, 1997;Speakman, 2000).…”

Suppression of kisspeptin expression and gonadotropic axis sensitivity following exposure to inhibitory day lengths in female Siberian hamsters

“…Many mammals have evolved strategies for partitioning energy reserves to essential physiological processes and inhibiting nonessential processes during these unfavorable climatic conditions (Bronson, 1985;Bronson, 1991;Voltura and Wunder, 1998;Wade and Schneider, 1992). One such adaptive strategy employed by many small rodent species occupying variable environments is the complete cessation of reproductive activity by inhibition of the reproductive axis (Nelson et al, 1990).…”