Preliminary Microscopic Investigations of the Digesta Derived From Foliage of Eucalyptus-Ovata (Labill) in the Digestive-Tract of the Common Ringtail Possum, Pseudocheirus-Peregrinus (Marsupialia)

Abstract

A method is described that stabilizes vacuolar tannins in unchewed leaves of Eucalyptus ovata. This method, with light microscopy and electron microscopy, was used to study the fate of digesta in the gut of the common ringtail possum Pseudocheirus peregrinus. Normal animals (fed fresh foliage and practising coprophagy) were compared with animals denied access either to fresh foliage or to soft faecal pellets in the week before they were killed. Both manipulations appear to disturb gut function and create a need for caution in interpreting the observations. Nonetheless the results demonstrate some tanning of leaf cytoplasts in the ringtail possum, but the quantitative significance of the dietary losses so incurred is difficult to estimate. Partial digestion of cell walls and tanned cytoplasts occurs in the caecum, where massive populations of micro-organisms become attached to digestion-resistant tissue components. These 'microbial rafts' are reingested as soft pellets by coprophagy and the bacteria largely digested.