Histidine dipeptides HPLC-based test for the detection of mammalian origin proteins in feeds for ruminants

The present work is focused on the use of the relative amounts of carnosine and anserine for detecting the presence of proteins of mammalian origin in feeds for ruminants. The methodology is cheap and simple and may serve for the rapid screening of feeds. Animal protein additions to feeds as low as 0.5% can be easily detected based on the cation exchange HPLC determination of the carnosine and/or anserine dipeptides. Furthermore, the molar ratio of these dipeptides was found to be characteristic of the animal species and could be used to discriminate between mammalian and non-mammalian species eventually added to feeds. Feeds having carnosine/anserine molar ratios higher than 0.3 were strongly suspected of containing banned mammalian proteins. Those suspicious feeds might be later confirmed by more specific techniques. The exact source of feeds containing mixtures of animal proteins from different species could not be identified by this method even though the method was able to detect its mammalian origin.