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Science 10 February 1989:
Vol. 243. no. 4892, pp. 794 - 796
DOI: 10.1126/science.2916126
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Articles

Science, Vol 243, Issue 4892, 794-796
Copyright © 1989 by American Association for the Advancement of Science

articles

Physiological constraint on feeding behavior: intestinal membrane disaccharidases of the starling

C Martinez del Rio and BR Stevens

Department of Zoology, University of Florida, Gainesville 32611.

Animals clearly choose what they eat and can even choose among chemically different sugars. The physiological and biochemical mechanisms that constrain feeding choices are largely unknown. In this study, European starlings (Sturnus vulgaris) preferred mixture solutions of D-glucose plus D-fructose to equimolar (double molar caloric value) solutions of sucrose. Intubation feeding of sucrose did not increase blood glucose levels. Sucrose is a useless energy source for these birds because they lack a single digestive enzyme (sucrase) on the small intestinal brush border membrane. However, the membranes possessed separate maltase and isomaltase disaccharidases. This expression pattern and expression patterns of membrane disaccharidases among mammals suggest a role for intestinal enzymes in the coevolutionary interactions between vertebrates and their plant food sources.


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Evolutionary associations between nectar properties and specificity in bird pollination systems.
S. D Johnson and S. W Nicolson (2008)
Biol Lett 4, 49-52
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