Digestive plasticity of the small intestine and the fermentative hindgut in a marsupial herbivore, the tammar wallaby (Macropus eugenii)
Adam J. Munn A C , Peter Banks B and Ian D. Hume AA Institute of Wildlife Research, School of Biological Sciences A08, University of Sydney, NSW 2006, Australia.
B School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW 2052, Australia.
C Corresponding author. Email: a.munn@unswalumni.com
Australian Journal of Zoology 54(4) 287-291 https://doi.org/10.1071/ZO06004
Submitted: 9 January 2006 Accepted: 13 June 2006 Published: 11 August 2006
Abstract
We investigated the effects of a ground, pelleted diet versus natural forage on the gross morphology of the gastrointestinal tract of a medium-sized (5–7 kg body mass) macropodid marsupial, the tammar wallaby (Macropus eugenii). The empty wet mass (g) of the small intestine of tammar wallabies maintained on a pelleted diet for 6 weeks was 22% greater than that of animals maintained on natural forage, once body mass was taken into account by ANCOVA. Similarly, the body-mass-adjusted length of the tammar wallaby caecum and proximal colon combined was 25% longer in animals maintained on the pelleted diet compared with those maintained on forage. Our data suggest that food particle size may be directly involved in controlling the size of the post-gastric alimentary tract in tammar wallabies, and thus in their diet choice and nutritional ecology. Notably, this is the first study that links phenotypic plasticity of the gut directly to diet in a marsupial and we conclude that the tammar wallaby is an excellent model for exploring the causes and consequences of digestive plasticity in macropodid marsupials.
Acknowledgments
Thanks to Jan Nedved and the University of New South Wales Cowan Research Station for providing assistance with animal handling and husbandry and the infrastructure for this project. Frank Hemmings of the University of New South Wales’ John T. Waterhouse herbarium kindly provided expert identification of grasses. This work was carried out under a NSW NPWS licence A33 and with the approval of the University of New South Wales Animal Care and Ethics Committee (ACEC04/13). Sincere thanks must go to Tania Rose for assistance with animal dissections.
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