The Effect of Starvation, Food Restriction, and Water Deprivation on Thermoregulation and Average Daily Metabolic Rates in Gerbillus pusillus

Publisher Website
Google Scholar
Abstract
Average daily metabolic rates (ADMRs) were monitored under several dietary conditions. Gerbillus pusillus demonstrated a 14-h cycle of metabolic activity in phase with the photoperiod. When food and water were provided ad lib., ADMR was 96.5% of the predicted value for a granivorous rodent. When deprived of water with an ad lib. supply of food, ADMR increased significantly. Unfavorable changes in these dietary regimes result in periodic bouts of hypothermia. Gerbils on a restricted food intake maintained their weight after an initial loss of 7.93%. This negligible weight loss implies that G. pusillus uses hypothermia to regulate its metabolic rate to the energy available. During periods of torpidity, metabolic rate was directly related to both ambient and body temperature. The gerbils were unable to arouse below 15 C. At this temperature coordination was poor. Metabolic rates of food-restricted animals with body temperatures greater than 34.0 C did not differ from the minimal resting postabsorptive rates under ad lib. food and water. At the natural burrow temperatures (30.0 C), torpid G. pusillus would expend 50% of the energy used by a euthermic resting gerbil at the same temperature. Employment of torpor in its natural milieu would, therefore, confer a considerable saving in both energy and water.