三种啮齿动物的消化道形态特征

Digestive Tract Morphology in Three Rodent Species

对棕背(Clethrionomys rufocanus)、林姬鼠(Apodemus speciosus)和黑线姬鼠(A.agrarius)夏季的消化道形态进行了比较。3种啮齿动物总消化道的长度及重量(含内容物重和总干组织重),各器官的长度,胃、小肠和盲肠等长度,小肠和盲肠含内容物重,盲肠和大肠去内容物重,小肠、盲肠和大肠总干组织重等均存在明显的种间差异。以植物为食的棕背的总消化道、小肠、盲肠和大肠的长度或重量明显长于或重于其他两种鼠类。后肠可作为衡量草食性动物食物质量的指标。3种啮齿动物可通过消化道形态改变以适应不同的食性。

The animals＇ gut morphology is closed related to food habit, food quality and energy need. In order to investigate the relationship between food habits and digestive tract morphology, the lengths of gastrointestinal tracts of three species of rodents with different food habits were compared. Gray Red-backed Vole （Clethrionomys rufocanus）, Large Japanese Field Mouse （Apodemus speciosus） and Striped Field Mouse （A. agrarius） were live-trapped in the forest regions at Nehe County, Heilongjiang Province in June 2002. The entire digestive tract of animals were removed, carefully stripped the connective tissues and lipids, then extended to their full length on a dissecting plate with physiological saline, and the lengths of stomach, small intestine, large intestine, and caecum were measured to the nearest 1 mm and weighed to the nearest 0.1 mg. In order to remove the effect of body mass, analysis of covariance was used to analyze the data, using body mass as the covariate, and followed by least significant difference （LSD） multiple comparisons. We found significant differences in the length, mass with content and dry mass of total gut, stomach length, length, mass with content and dry mass of small intestine and caecum, and the mass without content and dry mass of large intestine among these species.The strict herbivores, C. rufocanus, had the largest length and/or mass of total alimentary, small intestine, caecum and large intestine. Our results suggest that the hind gut be more important to herbivorous than to granivorous/omnivorous rodents and can be a relative reliable indicator for food habits. C. rufocanus, A. speciosus and A. agrarius can coexist through the separation of food resource and changing the digestive tract morphology for adaptation.