Microbial digestion in the koala (Phascolarctos cinereus, Marsupialia), an arboreal folivore
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The rate of volatile fatty acid (VFA) production in the hindgut of three koalas (Phascolarctos cinereus) maintained onEucalyptus punctata foliage was measured by in vitro incubation.
VFA production in both the caecum and proximal colon was slow (11 μmole ml−1 h−1) and the contribution made by total daily VFA production was estimated to be only 9% of digestible energy intake. This is attributed primarily to the indigestible nature of the eucalypt-derived digesta entering the hindgut. Estimates of cell-wall digestion by koalas in associated experiments explained only 60–70% of the VFA production in vitro suggesting that some fermentation of other substrate occurred.
It is concluded that, despite its extreme development, the hindgut in koalas plays a relatively minor role in the extraction of energy from eucalypt foliage.
volatile fatty acids
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