Meeting Abstract
91.6 Wednesday, Jan. 7 Do polyunsaturated fatty acids play a role in mammalian hibernator overwinter survival? SCHORR, R.A.*; FLORANT, G.L.; Colorado State University; Colorado State University robert.schorr@colostate.edu
Prior to hibernation, mammalian hibernators typically increase dietary polyunsaturated fatty acid (PUFA), which alters PUFA composition in a variety of tissues. This change can have a profound effect on a hibernator’s ability to prepare for and reduce energy costs during hibernation. In particular, increased PUFA content can increase torpor bout length, decrease body temperature, and reduce the rate of body mass loss. These obvious benefits to a hibernator have led us to hypothesize that increased PUFA content prior to hibernation will increase overwinter survival for the hibernator. Currently, there is little empirical evidence that supports the theory that increased acquisition and accumulation of PUFAs leads to a greater probability of survival. We used four years of mark-recapture data from a meadow jumping mice (Zapus hudsonius) population in central Colorado and modeled overwinter survival probability using individual serum fatty acid composition. Survival models were analyzed in Program MARK using the robust design model. Compared to post-hibernating mice, pre-hibernating mice had increased serum arachidonic acid serum levels. Most other serum fatty acids showed little seasonal changes in relative composition; however α-linolenic acid (ALA) was an important predictor of overwinter survival. Using ALA content to predict overwinter survival suggested that increasing ALA by 1% increased overwinter survival by 63%. From our findings we concluded that seasonal changes in relative PUFA levels may not be as important as the availability of particular fatty acids for season-specific needs. The role ALA plays in increasing overwinter survival has not been established, but this fatty acid has been implicated as one of the essential fatty acids invaluable for maintaining low body temperature and decreasing body mass loss.
