Permanent URL to this publication: http://dx.doi.org/10.5167/uzh-2349
Clauss, M; Gehrke, J; Hatt, J M; Dierenfeld, E S; Flach, E J; Hermes, R; Castell, J; Streich, W J; Fickel, J (2005). Tannin-binding salivary proteins in three captive rhinoceros species. Comparative Biochemistry and Physiology - Part A: Molecular and Integrative Physiology, 140(1):67-72.
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Tannin-binding salivary proteins (TBSP) are considered to be counter-defences acquired in the course of evolution by animals whose natural forage contains such tannins. As tannins mostly occur in browse material but not in grasses, it is assumed that grazers do not have a need for TBSP. Whereas it has been shown in several non-ungulate species that TBSP can be induced by dietary tannins, their presence or absence in ungulates has, so far, been shown to be a species-specific characteristic independent of dietary manipulations. We investigated saliva from three rhinoceros species from zoological gardens fed comparable, conventional zoo diets. As expected, saliva from white rhinoceroses (Ceratotherum simum, grazer) had lower tannin-binding capacities than that from black rhinoceroses (Diceros bicornis, browser). Surprisingly, however, Indian rhinoceroses (Rhinoceros unicornis), commonly regarded as grazers as well, displayed the highest tannin-binding capacities of the three species investigated. It is speculated that this discrepancy might be a result of an evolutionarily recent switch to a grass-dominated diet in Indian rhinoceroses, and that the black rhinoceros, which is closer related to the white rhinoceros than the Indian species, has evolved an inducible mechanism of TBSP production. In separate trials during which the tannin content of the diets of black rhinoceroses was increased by the addition of either tannic acid or quebracho, the tannin-binding capacity of black rhinoceros saliva was increased to levels within the same range as that of Indian rhinoceroses on the conventional diets. While induction trials in white and Indian rhinoceroses remain to be performed for a full understanding of salivary anti-tannin defence in rhinoceroses, these results are the first report of an induced salivary response to increased dietary tannin levels in an ungulate species.
|Item Type:||Journal Article, refereed, original work|
|Communities & Collections:||05 Vetsuisse Faculty > Veterinary Clinic > Department of Small Animals > Clinic for Zoo Animals, Exotic Pets and Wildlife|
|DDC:||570 Life sciences; biology|
|Deposited On:||11 Apr 2008 13:57|
|Last Modified:||27 Nov 2013 19:23|
|Citations:||Web of Science®. Times Cited: 28|
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