Edinburgh Napier University

  Studies of wild callitrichids reveal limited data about their complex diets. As insectivorous primates it is likely that they can digest chitin. Using the common marmoset, Callithrix jacchus, as a model, this study assessed chitin digestibility and whether or not a variety of zoo-housed callitrichid species display a preference for particular insect types. The presence of chitinolytic microorganisms in the faeces of Goeldi's monkey, Callimico goeldii, was investigated using both culture-based and molecular techniques and a preliminary evaluation of the faecal bacterial population was made.
The measurement of faecal acid detergent fibre in C. jacchus showed that they did digest insect chitin and furthermore Goeldi's monkeys; cotton-topped tamarins, Saguinus oedipus, Geoffroy's marmosets, Callithrix geoffroyi and pygmy marmosets, Cebuella pygmaea, showed significant preferences for particular insect types. The presence of chitinolytic microorganisms in the faeces of C. goeldii, was confirmed with Cellulosimicrobium spp being among a number of chitinolytic microorganisms isolated. Using a range of agar media targeted to specific bacterial genera, Bacteroides, Lactobacillus, Bifidobacterium, Clostridium and coliforms were found in the faecal samples and numbers present estimated. As expected the highest count was for total anaerobes, with Bacteroides and Clostridium species present in high numbers. Molecular analysis resulted in the isolation of 113 16S rDNA sequences which matched existing entries in the GenBank database. Eighty five % of the isolates were matched to clones of unassigned phylotype but clones from the genera Howardella, Escherichia, Shigella, Prevotella, Megasphaera and Bifidobacterium were identified.
The evidence resulting from this investigation will inform diet development and aid in the future health management of callitrichids in captivity. Additionally, the isolation of novel chitinolytic microorganisms could have potential industrial applications where the degradation of chitin is of interest.