Maintenance of a fully functional digestive system during hibernation in the European hamster, a food-storing hibernator

International audienceSome small mammals limit energy expenditure during winter conditions through torpor bouts, which are characterizedby a decrease in body temperature and metabolic rate. Individuals arise periodically from torpor to restorecritical functions requiring euthermia. Althoughmost of the species involved do not feed during hibernationand rely on body reserves to fulfil energy requirements (fat-storing species), others hoard food in a burrow(food-storing species) and can feed during interbout euthermy. Whereas fat-storing species undergo a markedatrophy of the digestive tract, food-storing species have to maintain a functional digestive system during hibernation.Our study aimed to evaluate the absorption capacities of a food-storing species, the European hamster,throughout the annual cycle. In vivo intestinal perfusions were conducted in different groups of hamsters(n = 5) during the different life periods, namely before hibernation, in torpor, during interbout euthermy, andduring summer rest. The triglyceride, non-esterified free fatty acid, starch, glucose and protein composition ofthe perfusate was evaluated before and after the 1 h perfusion of a closed intestinal loop. Triglyceride, starchand protein hydrolysis rates were similar in hibernating (torpid and euthermic) and non-hibernating hamsters.Intestinal absorption of free fatty acid was also similar in all groups. However, glucose uptake rate was higherduring hibernation than during the summer. In contrastwith fat-storing species, the intestinal absorption capacitiesof food-storing species are fully maintained during hibernation to optimize nutrient assimilation duringshort interbout euthermy. In particular, glucose uptake rate is increased during hibernation to restore glycaemiaand ensure glucose-dependent pathways