Meeting Abstract
The risks of food limitation and ultimately starvation date back to the dawn of heterotrophy; yet, starvation remains a major factor in regulating modern animal populations. Researchers studying starvation over a century ago suggested that animals subjected to sublethal periods of food limitation are somehow more tolerant of subsequent starvation events. This possibility has received little attention over the past decades, yet is highly relevant to modern science for two reasons. First, animals in natural populations are likely to be exposed to bouts of food limitation once or more before they face prolonged starvation during which the risk of mortality becomes imminent. Second, our current approach to studying starvation physiology in the laboratory focuses on nourished animals with no previous exposure to nutritional stress. We examined the relationship between previous exposure to food limitation and potentially adaptive physiological responses to starvation in adult rats and found several significant differences. On two occasions rats were fasted until they lost 20% of their body mass maintained lower body temperatures, and had presumably lower energy requirements when subjected to prolonged starvation than their naïve cohort that never experienced food limitation. These rats that were ‘trained’ in starvation also had lower plasma glucose set-points and reduced their reliance on endogenous lipid oxidation. These findings underscore 1) the need for biologists to revisit the classic hypothesis that animals can adapt to starvation using a modern set of research tools and 2) the need to design controlled experiments of starvation physiology that more closely resemble the dynamic nature of food availability.
