Meeting Abstract

43.3  Jan. 6  Protein Conservation in Spontaneous and Facultative Hibernators: the White-tailed Prairie Dog (Cynomys leucurus) and the Black-tailed Prairie Dog (Cynomys ludovicianus) COTTON, C.J.; University of Wyoming, Laramie ccotton@uwyo.edu

White-tailed prairie dogs are spontaneous hibernators that undergo regular, low temperature torpor bouts throughout the winter, while black-tailed prairie dogs are facultative hibernators that utilize sporadic, moderate temperature torpor bouts during the winter. The primary objectives of this study were to assess the abilities of these two species to 1) conserve skeletal muscle morphology, protein and strength, and 2) utilize labile protein in the small intestine and liver during the winter season of reduced activity and food intake. Masses and protein concentrations of the extensor digitorum longus (EDL), soleus, liver, and small intestine were compared before and after hibernation in both species. Skeletal muscle strength and fiber morphology were also analyzed for the EDL and soleus in all groups. Despite utilizing vastly different hibernation strategies, both species experienced a similar extent of muscle atrophy and strength loss during the hibernation season. After examining 17 parameters related to muscle atrophy and labile protein use during the hibernation season, only the change in cross-sectional area of slow oxidative fibers was found to differ significantly between the two species. Therefore, it appears that hibernation strategy has little effect on protein use and the retention of skeletal muscle strength during the winter season. Our findings do, however, show that both hibernation strategies permit a high degree of skeletal muscle conservation, especially when compared to muscle disuse atrophy models.