NEW APPROACHES TO INVESTIGATE FEEDING AND DIGESTIVE-SYSTEM IN HERBIVOROUS MAMMALS

To elucidate the mechanism of assimilating the cellulose-rich food by small mammals, morphofunctional investigations were supplemented by bi ochemical evaluation of digestive functions of symbiocenoses in fore-s tomach and caecum as well as by experimental determination of food pas sage rate and degree of cellulose fibers reduction in the digestive tr act. Two model species of rodents having hemiglandular stomachs, great gerbil Rhombomys opimus and bank vole Clethrionomys glareolus were in vestigated. The success in cellulose assimilation in these rodents is related to careful grinding of fibers by teeth, that is accompanied in gerbils by fiber separation in the digestive tract: coarse and thick fibers are quickly evacuated, whereas small and thin ones are fermente d in the caecum. In voles thick fibers are also destroyed as the cellu lase enzymatic complex starts functioning already in the forestomach. The obtained results permit to calculate that in C. glareolus 24-30% o f the cellulose assimilated are fermented in the forestomach.