Meeting Abstract

P1.222  Wednesday, Jan. 4  Post-weaning dynamics of the cecal microbial communities of arctic ground squirrels STEVENSON, T.J.*; BUCK, C.L.; QUINLAN, B.A.; DUDDLESTON, K.N.; University of Alaska Anchorage

The arctic ground squirrel (Urocitellus parry) has evolved the most extreme phenotype of any hibernator. The short arctic summer allows only 2-3 months to acquire sufficient energy stores (primarily fat) to survive the hibernation season (7-9 months). Most fat gain (5 to 45% increase) occurs during the 3 weeklong pre-hibernation fattening period. Research in mice and humans shows the gut microflora of obese individuals is more efficient in extracting energy from carbohydrates than that of leaner individuals, and sends signals that predispose the host to storage of triglycerides into adipose tissue. The gut microbiota may play a key role in assisting the arctic ground squirrel to acquire sufficient fat mass to survive hibernation. In order to study the development of the gut microbial community, captive-born juvenile arctic ground squirrels and their ceca were sampled at 4 time points (n=10; weaning and 4,6 and 8 weeks post-weaning) across the active season. Average squirrel mass increased linearly throughout the active season (R2= 0.9652), while average abdominal white fat mass increased exponentially (n= 10; R2 = 0.9982). Cecal content peaked at 6 weeks post-weaning (15g ± 4.75). The percent live cells increased linearly from 63.31% ± 3.84 to 80.04% ± 5.00 throughout the active season (n=8, R2= 0.9989), while percent dead and injured cells decreased linearly, 28.77% ± 3.93 to 17.14% ± 5.67 and 7.87% ± 1.64 to 2.76% ± 0.84, respectively (n= 8; R2= 0.9804 and 0.9899, respectively). These results suggest that microbial cell viability increases throughout development and pre-hibernation fattening. Additional analyses of the microbial community conducted includes terminal restriction fragment length polymorphism and 16s rDNA clone libraries to investigate microbial community diversity, and short chain fatty acid analysis to investigate microbial metabolic activity.