Radiographic Studies on the Structure and Function of the Gastrointestinal Tract of Two Species of Potoroine Marsupials.

The structure and function of the gastrointestinal tracts of 2 potoroine marsupials, Aepyprymnus rufescens, the rufous rat-kangaroo, and Potorous tridactylus, the long-nosed potoroo, were examined by the use of radiographic and fluoroscopic techniques. In both species barium sulphate given by mouth entered the sacciform forestomach within 20 min of dosing, but in the same time the hindstomach and duodenum were clearly outlined. Contrast medium reached the hindgut within 1 to 2 h, but was retained there for at least 24 h. A proportion of radio-opaque particles given by mouth also bypassed the sacciform forestomach, but those that entered the gastric region were retained there for up to 93 h. The stomach constituted 50% of total gut capacity, and the hindgut (caecum and colon) 35%. The sacciform forestomach was the largest gastric region. It is concluded that, on the basis of anatomy and digesta movements, the forestomach may be less important, and the hindgut more important, in fermentative digestion in the Potoroinae than in the Macropodidae.