Lipid metabolism in hibernators: the importance of essential fatty acids

Abstract

Two polyunsaturated essential fatty acids, linoleic acid and linolenic acid, are important for their inherent energy during lipid oxidation. In addition, they influence the length of hibernation bouts and the metabolic rates of mammals that hibernate. Hibernators that lack linoleic acid in their diet or that are fed a diet high in saturated fatty acids have significantly shorter bouts of hibernation and have a higher mass specific metabolic rate. The decrease in the length of a bout of hibernation is significant because the animal arouses from hibernation more frequently, using more of its energy stores. This could resuit in a decreased chance of survival. How the essential fatty acids exert their actions in hibernators is just beginning to be elucidated. Essential fatty acids are the sole precursors for the eicosanoids that influence thermoregulation. Thus, studies of eicosanoid function during hibernation are warranted. The recent discovery and characterization of the protein leptin, which can regulate energy balance and may be regulated by polyunsaturated fatty acids, may prove to be important to hibernation and the regulation of body mass. Future investigations of the regulation of body mass during hibernation should consider the fatty acid composition of the diet and the effect of the essential fatty acids on gene transcription.