Abstract: The Daurian ground squirrel (Spermophilus dauricus) is a lipid storage hibernating animal, as a result, it does not eat any food and drink water during hibernation. However, it is not well known what the differences are in genes expression of Aquaporin (AQP) and activity of digestive enzymes between hibernating and non-hibernating periods. To investigate the adaptive response of small intestine at physiological and biochemical levels in hibernating rodents, the genes expression ofAQP1andAQP3and the activity of digestive enzymes (protease, sucrase, maltase and lipase) in the ileum of Daurian ground squirrels were examined during active (summer, July), hibernating (winter, December) and arousal (spring, March) periods. The results indicated the expression level ofAQP1gene in hibernating period was higher than that in active and arousal periods, while the expression level ofAQP3gene in hibernating period was lower than that in active and arousal periods. Total protease activity was higher in active period than that in hibernating and arousal periods. The activity of maltase and sucrase in hibernating period was lower than that in arousal period. The activity of lipase was relatively stable in these three periods.These results indicate that the ground squirrel regulates the water balance and nutrient by changing the AQP genes expression and the some enzymes activity of small intestine, which could acclimate to its hibernation habit and variations in energy demands.

Key words: Spermophilus dauricus, aquaporin, digestive enzyme, hibernation, small intestine