Effect Of Energy Coerce On Fattening And Change Mechanism Of Pivotal Enzyme Before And After Hibernation In Daurian Ground Squirrels

Hibernation is a spontaneous physiology phenomenon for small mammals to adapt energy shortages in winter.Keeping fat hibernation animals mainly depend on consume fat accumulated in the fall as overwinter energy source. Thus, energy accumulation in summer has prodigious effect on wintering survival rate of animals when energy was insufficient. Keeping fat hibernation animals mainly regard sugar from food as energy source in summer. While during hibernation, they survival by their stored fat in the fall. This transform of energy utilization from sugar to fat is created through the change of metabolic enzyme associated with fat and carbohydrate. This study was focus on Daurian ground squirrels(Spermophilus dauricus). First, we Analyzed the effect of energy stress on fattening. Second, content change of key enzymes of sugar metabolism[hexokinase(HK), phosphofructokinase(PFK), pyruvate kinase(PK) from the beginning of fatten to ending of hibernation were measured. There was five critical period[fattening phase(F), before the maximum of body mass phase(B-BMmax), maximum of body mass phase(BMmax), post-fattening phase(P-F) and hibernation(H) Here are the main results: 1. The weight of animals increased significantly during fattening and the differencebetween groups is remarkable. Energy stress decrease the fatten rate duringenergy accumulation period. 2. Food intake of animals under low temperature is lower than normal temperatureafter three days acclimation. Even after 3 weeks cold temperature acclimation,The intake energy, digestible energy and metabolizable energy were not increased.This indicated animals didn’t accumulate energy by rise the use efficient of foodand the digestive efficiency reached maximum during fattening. 3. Body temperature of ground squirrels decreased significantly after 3 weeks lowtemperature treatment. This result suggests animals can remit energy expend byreduce temperature when they face environment deteriorate. 4. HK, PFK, PK content have significant difference among five critical periods. HK,PFK, PK content increased during fattening, indicating that these enzymesparticipated in the process of transformation of carbohydrates into fat. PK contentdecreased before hibernation, suggesting that PK play an important role inceasing carbohydrates metabolism in the hibernating period.