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Type: Journal article
Title: Mistletoebirds and xylose: Australian frugivores differ in their handling of dietary sugars
Author: Napier, K.
Fleming, P.
McWhorter, T.
Citation: Physiological and Biochemical Zoology, 2014; 87(3):445-455
Publisher: University of Chicago Press
Issue Date: 2014
ISSN: 1522-2152
Statement of
Kathryn R. Napier, Patricia A. Fleming, Todd J. McWhorter
Abstract: 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 (AE*) 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 AE* 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.
Keywords: Animals
Dietary Carbohydrates
Biological Availability
Rights: © 2014 by The University of Chicago. All rights reserved.
DOI: 10.1086/675493
Appears in Collections:Animal and Veterinary Sciences publications
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