Defense Against Dietary Tannin in Herbivores: a Survey for Proline Rich Salivary Proteins in Mammals
S. Mole1, L.G. Butler1, and G. IASON2
1Department of Biochemistry, Purdue University, W. Lafayette, IN 47907, USA
2Department of Zoology, Aberdeen University, Scotland, UK
Recent experiments with laboratory animals have indicated that mammalian herbivores may have an innate defensive mechanism against polyphenolics consumed in their diet. This defense involves the secretion of proline rich salivary proteins (PRPs) which specifically bind to polyphenolics such as tannins. This report presents survey data for PRPs in a phylogenetically broad range of mammals. PRPs are reported in marsupials for the first time and in previously unsurveyed species of the Lagomorpha and Artiodactyla. In some taxa PRPs which do not have high affinities for tannin binding are reported while in others PRP levels are so low as to be insignificant as a defense against polyphenolics. We conclude that PRPs are most able to act as a defense against tannins in the Rodentia and Lagomorpha.