Study On Adaptation Strategies Of Eothenomys Miletus At Different Areas Of Hengduan Mountain Regions In Winter

The physiological regulation of body mass and energy metabolism is the main strategy for small mammals to cope with environmental changes.Animals must acquire and assimilate energy for survival.Under high altitude conditions,animals show a variety of adaptive changes,such as body mass,thermogenic characteristics,physiological indicators,phenotypic characteristics and blood indicators.Hengduan Mountain regions is located in southwest China,which has a large difference in altitude,small annual temperature difference and large daily temperature difference.E.miletus was a inherent species in Hengduan Mountain regions.In order to study the survival and adaptation mechanism of E.miletus in Hengduan Mountain regions,previous studies in our group analyzed the characteristics and physiological indexes of E.miletus of different altitudes in summer,the changes of food quality on physiological indexes and activity behaviors of E.miletus in winter,and the different adaptation of physiology and behavior affected by high-fat and high-sugar food in E.miletus.On this basis,the scientific problem were proposed in this study under the harsher conditions of winter environment: What are the coping strategies of E.miletus under different altitude conditions in Hengduan Mountain regions in winter? Through the study of its energetics and morphological characteristics,the closely related indexes energy metabolism were determined to clarify the countermeasures of energy metabolism heat production and phenotypic adaptation of E.miletus in different areas,and finally reveal the survival adaptation mechanism to environmental changes of E.miletus in Hengduan Mountain regions.This paper consists of two parts:(1)Body mass regulation by Eothenomys miletus at different areas of the Hengduan Mountain regions in winterWe studied body mass regulation in E.miletus at different areas of the Hengduan Mountain regions in winter based on samples collected from Deqin(DQ),Xianggelila(XGLL),Li-jiang(LJ),Jianchuan(JC)and Ailao Mountain(ALS).Body mass,wet mass of body composition,gastrointestinal mass,serum leptin levels and hypothalamic neuropeptide Y(NPY),agoutirelated peptide(Ag RP),pro-opiomelanocortin(POMC),cocaine and amphetamine regulatedtranscript peptide(CART)were measured.The results showed that body mass,serum leptin levels,stomach mass,liver mass,caecum mass,NPY and Ag RP expressions at XGLL and DQ were significantly higher than at the other three areas,other masses of body composition,diges-tive tract,POMC and CART expressions were similar among areas.All of the results suggested that E.miletus adapted to environmental variation by changing body mass,mass of liver,large intestine and cecum,serum leptin levels and hypothalamic trophic neuropeptide expressions.(2)Comparative study on MC1 R gene expression,UCP1,Hb and Mb contents Eothenomys miletus at different altitude in winterIn order to explore the variations of coat color,physiological and blood indexes in E.miletus is at different elevations from Hengduan Mountain regions in winter,samples were collected from Deqin(DQ),Xianggelila(XGLL),Li-jiang(LJ),Jianchuan(JC)and Ailao mountain(ALS)from north to south,gene sequence of melanocortisn recertor1(MC1R)was amplified by PCR,expression of MC1 R gene in skin was determined by FQ-PCR,and contents of uncoupling Protein 1(UCP1)in brown adipose tissue,hemoglobin(Hb)and myoglobin(Mb)in serum by measured by enzyme-linked immunoassay(ELISA).The results showed that the amplified MC1 R fragment was a partial sequence about 200 bp.MC1R gene expression in ALS and JC was significantly higher than that in LJ,XGLL and DQ.Contents of UCP1 and Mb in DQ and XGLL were significantly higher than that in ALS,JC and LJ.But Hb content showed no significant difference among the five regions.All of the above results showed that E.miletus could change the coat color by changing the expression of MC1 R gene,and increase the thermogenesis capacity by elevating the content of Mb and UCP1,so as to adapt to the environmental changes at different altitudes from Hengduan Mountains regions.In conclusion,E.miletus adapts to high altitude and low temperature environment in the high altitudes in Hengduan Mountain regions in winter by increasing the weight of liver,caecum,relative expression levels of hypothalamus neuropeptides NPY and AGRP,UCP1,Hb and Mb contents.reduce the body mass,stomach weight,serum leptin content and MC1 R gene expression.Finally,it adapts to the diverse environment of different altitude in Hengduan Mountain regions in winter by adjusting energy metabolism,morphology and important physiological indicators.