Studies on the Nutrition of Macropodine Marsupials. 3. The Flow of Digesta Through the Stomach and Intestine of Macropodines and Sheep.

Abstract

3. The two markers 51chromium EDTA and 103ruthenium were used to examine and compare digesta flow in the eastern grey kangaroo (Macropus giganteus), the red-necked pademelon (Thylogale thetis), the tammar wallaby (M. eugenii), the eastern wallaroo (M. robustus robustus) and in sheep fed on chopped lucerne hay, and in T. thetis and M. eugenii fed on fresh grass (Phalaris aquatica). The markers were also used to define the kinetics of digesta flow in the intestine, and to estimate the flow of fluid and DM through defined regions of the stomach and intestines of T. thetis and M. eugenii fed on the lucerne diet. The pattern of digesta flow and the degree of differential flow of the 2 markers observed in the macropodines differed markedly from those in sheep and were attributed solely to the mode of transport through the elongated stomach. In the macropodines it was apparent that total mixing of forestomach contents did not occur; rather, digesta flowed slowly along the tubiform forestomach. The relationship of this mode of transport, defined as tubular flow, to stomach structure, and the possible effects on digestion in the forestomach, are discussed.