Effect of temperature on preference for dietary unsaturated fatty acids inthe Djungarian hamster (Phodopus sungorus)

Previous studies have shown that hibernators preparing for winter prefer a diet rich in unsaturated fat. This study was designed to determine if a dai ly heterotherm, the Djungarian hamster (Phodopus sungorus), shows a similar preference when given simultaneous access to two diets, one rich in satura ted fat and the other rich in unsaturated fat. In two experiments, hamsters that had been exposed to short days for 8-10 weeks were exposed to 8%C for 10 days. When half of these animals were moved to a warm environment (26-2 9%C), they developed a significantly lower preference for the unsaturated d iet than controls that remained at 8%C (P < 0.01). This difference in prefe rence disappeared when the experimental group was returned to 8%C (P = 0.4) . Although mean body temperature (T-b) was significantly lower (mean differ ence = 0.35%C) in experimental animals in the cold environment, most animal s did not enter daily torpor at any time during the experiment. Together, t hese results suggest that the large decreases in core T-b accompanying torp or, originally assumed to necessitate the incorporation of unsaturated fatt y acids into cell membranes of hibernators and daily heterotherms, are not necessary to stimulate changes in food choice.