Microbial studies of the intestinal microflora of the koala, Phascolarctos cinereus. II. Pap, a special maternal faeces consumed by juvenile koalas
Osawa, R, Blanshard, WH & O’Callaghan, PG 1993, Australian Journal of Zoology, pp. 611-620.
The presence of tannin-protein-complex-degrading enterobacteria (T-PCDE) present in ‘pap’, a faecal substance ingested by juvenile koalas, was found to be a prerequisite to obtaining protein from tannin-rich eucalyptus leaves. Microflora present in the faeces of female koalas during the production of pap was found to have a higher water content and pH (81.8%, 7.0 respectively) than faeces produced prior to the beginning of the pap feeding process (54.6-56.4%, 5.5). Counts of viable T-PCDE were found to be higher in pap while normal faeces contained less, with some samples testing negative for T-PCDE altogether.
Preliminary studies presumed the source of pap was the caecum, a fibre-digesting intestinal tract. Given the significant increase in pH and water content from normal faecal samples to pap faecal samples, it is now confirmed that pap is directly obtained from the caecum and further sustains viable T-PCDE for the purpose of tannin metabolism. Anaerobic koala (AK) bacteria were also found to increase between normal faecal samples to T-PCDE viable pap samples. This bacterium fosters the degradation of gallic acid, a major constituent of tannin-rich plants, to pyrogallol. Ultimately the coexistence of AK bacteria with T-PCDE aids digestive function in koalas despite the presence of tannins in Eucalyptus spp. Without T-PCDE and AK bacteria, tannin-protein complexes would not be degraded and the transition from milk to eucalyptus would not be achievable.
Exclusively feeding on Eucalyptus spp. necessitates a unique method to ingest proteins otherwise unobtainable without the activity of T-PCDE and AK bacteria. Mammalian species lack the ability to degrade tannin-protein complexes (T-PCs) and therefore the capacity to obtain protein from such food items. The unique activity of pap feeding allows the juvenile koala to extract dietary protein from T-PCs.
This study complements preliminary studies on the importance of pap feeding for juveniles to gain dietary independence and consume Eucalyptus spp.
Summarised by Lauren Mousley
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