Mandarin Vole Energy Metabolism And The Digestive Tract To Adapt To The Characteristics Of The Study

Objective: we choosed mandarin vole (microtus mandarinus) as the animal model,we studied the morphological and histological characteristic and the NOS neurons in theMyenteric plexus of the alimentary tract, also we studied the energy metabolic rate ofmales, nonlactating females and lactating females in order to understand the relationsamong the energy demands, adaptive change and the traits of life-histoty. Methods:Firstly, we observed the characteristic of alimentary tract with the normal morphologicaland histological methods, the comparison study of NOS neurons of myenteric plexus ingastrointestinal tract was also done. Then the daily metabolic rate (DMR) were estimatedby means of feeding trials and the resting metabolic rate (RMR) were estimated frommeasurements of oxygen comsumption. At last, we measured the length, mass) functionalvolume and the perimeter, mocosal thickness of each digestive tract organs. Therelationship among the energy demands, adaptive strategies and the traits of life-histotywere analysed. Result: 1 The morphological and histological characteristic of digestivetract included: (1) Enamel of the molar teeth form complicated loop. (2) Esophagus haskeratinized stratified squanous epithelium: and the muscularis externa in esophagus wasstriated muscle. (3) The epithelium in the cardiac part and fundus of stomach waskeratinized stratified squamous epithelime, but the body of stomach and pyloric parthas simple columnar epitheliun. (4) The intestinal villi changed lower and lower as itextended to the ileum. (5) The cecum has thin tract wall and spiral cecal folds. (6) Thececum and the large intestine were relative long. (7) The gut associated lymphoid tissues(GALT) was abundence, the Peyer's patches were obviously. 2 The dense of NOS positiveneurons trends to add as the gut extended to the colon. The ganglion and nerve strarldform complex net. 3 The DMR of mandarin vole was 77.26 KJ/animal/day (2.387 KJ/g/day).The DMR of males, nonlactating females and lactating females were 62.82 KJ/animal/day(2.003 KJ/g/ddy), 65.06 KJ/animal/day (2.04l KJ/g/day), l06.32 KJ/aniinal/day (3.l8KJ/g/day), respectively. The average digestibility was 78.06%. 4 The RMR inthermoneutral zone was 2. 4601ml0₂/g/h, it was l75.70% of expectant. The RMR of males,nonlactating females and lactating females were 2.3949m10₂/g/h, 2. 3477ml0₂/g/h, 2.5843m10₂/g/h, respectively. They were l65.37%, l64.92%, l90.68% of each expectant. The meanthermal conductance (Cm) is 0.1797 ml0₂/g/h℃. It is 105.96% of the expectant Cm. 5In many cases, the lactating females had the largest length, mass, ard perimeter. mocosalthickness (folded helight) of each (ligestive tract organs after controlling for effectsof body mass. Compared wi th tlle lliales, tIle fema1e mandarin vo1es had the much longera1imentary tract. Conc I us i on: 1fIle amrpIlologica1 and )l is to1ogical structure of tf lea1imentary tract of mandarin vo1e is fadapted to its feeding habit and physiologicalfunction. Mandarin yo1es had lower energy metabolic rate in rodents, but higher thanthe norma1 small manmals. Mandarin voles had relatively 1ow cost of 1actation, that 'maybe adaPt to its 1if e--history traits, such as 1onger lactation periods, smaller littersizes, s1ower rates of postnatal growth, poorer cold toJerance. The adaptive chaWesof alimentary tract was re1ated to the e11ergy demands, but there had interspecies andintrnypecies differences. The digestive tract of tuandarin voles had the poor abil.ityof adaPtive -changes, so its meta.bolic rate changed slight1y when the energy demands' added, that may be the cause of sotue life--Ilistory traits.