Metabolic Adaptations to Prolonged Food Deprivation by the American Badger Taxidea taxus

Henry J Harlow

doi:10.1086/physzool.54.3.30159942

Abstract

Energy expenditures for food processing, maintenance, and activity requirements were determined in the laboratory on the American badger, Taxidea taxus, both with ad lib. food and starved for 7, 20, and 30 days. Body weight decreased at about 76 g per day, resulting in a respiratory quotient (RQ) of 0.83 after 30 days of starvation. Energy requirements were calculated from V̇o2, values. A 24.2%, 19.7%, and 26.3% reduction in total metabolism was observed at 7, 20, and 30 days, respectively, without food because of reduced maintenance and activity requirements. As a result, badgers were able to conserve approximately 17 g of tissue per day after 30 days without food. Part of the lower maintenance metabolism was accounted for by a 1.7 C reduction in body temperature. Activity was most depressed the first week of starvation but progressively increased after 20 and 30 days without food.

Highlights

The effects of caloric restriction on activity and metabolism have not been investigated on wild animals which are seasonally subjected to food scarcity
The total metabolism of badgers decreased 45%, 42.5%, and 54% when deprived of food for 7, 20, and 30 days, respectively
19.5% of the total metabolism during feeding trials was attributed to the cost of processing food

Summary

Introduction

The effects of caloric restriction on activity and metabolism have not been investigated on wild animals which are seasonally subjected to food scarcity. The American badger, Taxidea taxus, is a solitary carnivore with opportunistic feeding habits (Errington 1937; Jense 1968; Lindzey 1971). It is found at northern latitudes where severe cold winters and reduced food availability are common (Long 1972; Lampe 1976). Starvation quickly becomes critical at low air temperatures because metabolic requirements for thermoregulation are high. Metabolic changes during starvation which reduce energy requirements would, be advantageous to winter survival. Total metabolic requirements of an animal are expressed as the sum of ex-

Methods

Results

Conclusion