Murdoch University Research Repository

Welcome to the Murdoch University Research Repository

The Murdoch University Research Repository is an open access digital collection of research
created by Murdoch University staff, researchers and postgraduate students.

Learn more

Mistletoebirds and xylose: Australian frugivores differ in their handling of dietary sugars

Napier, K.R., Fleming, P.A.ORCID: 0000-0002-0626-3851 and McWhorter, T.J. (2014) Mistletoebirds and xylose: Australian frugivores differ in their handling of dietary sugars. Physiological and Biochemical Zoology, 87 (3). pp. 445-455.

PDF - Published Version
Download (352kB)
Link to Published Version:
*Subscription may be required


Carbohydrate-rich mistletoe fruits are consumed by a wide range of avian species. Small birds absorb a large portion of water-soluble nutrients, such as glucose, via the paracellular pathway. d-xylose, a pentose monosaccharide, is abundant in some nectars and mistletoe fruits consumed by birds, and it has been suggested that it is most likely absorbed via the paracellular pathway in birds. We measured apparent assimilation efficiency () and bioavailability (f) for d-xylose and d- and l-glucose in three frugivorous Australian bird species. Mistletoebirds, silvereyes, and singing honeyeaters showed significantly lower for d-xylose than for d-glucose. Across two diet sugar concentrations, silvereyes and singing honeyeaters significantly increased f of both l-glucose (a metabolically inert isomer of d-glucose commonly used to quantify paracellular uptake) and d-xylose on the more concentrated diet, probably because of increased gut processing time. By contrast, mistletoebirds (mistletoe fruit specialists) did not vary f of either sugar with diet concentration. Mistletoebirds also showed higher f for d-xylose than l-glucose and eliminated d-xylose more slowly than silvereyes and singing honeyeaters, demonstrating differences in the handling of dietary xylose between these species. Our results suggest that d-xylose may be absorbed by both mediated and nonmediated mechanisms in mistletoebirds.

Item Type: Journal Article
Murdoch Affiliation(s): School of Veterinary and Life Sciences
Publisher: University of Chicago Press
Copyright: © 2014 The University of Chicago Press
Item Control Page Item Control Page


Downloads per month over past year