Metabolomic biomarkers identify differences in milk produced by Holstein cows and other minor dairy animals.

Several milk metabolites are associated with breeds or species of dairy animals. A better understanding of milk metabolites from different dairy animals would advance their use in evaluating milk traits and detecting milk adulteration. The objective of this study was to characterize the milk metabolite profiles of Chinese Holstein, Jersey, yak, buffalo, goat, camel, and horse and identify any differences using non-targeted metabolomic approaches. Milk samples were tested using nuclear magnetic resonance (NMR) spectroscopy and liquid chromatography–tandem mass spectrometry (LC-MS). Data were analyzed using a multivariate analysis of variance and differences in milk metabolites between Holstein and the other dairy animals were assessed using orthogonal partial least-squares discriminant analysis. Differential metabolites were identified and some metabolites, such as choline and succinic acid, were used to distinguish Holstein milk from that of the other studied animals. Metabolic pathway analysis of different metabolites revealed that glycerophospholipid metabolism as well as valine, leucine, and isoleucine biosynthesis were shared in the other ruminant animals (Jersey, buffalo, yak, and goat), and biosynthesis of unsaturated fatty acids was shared in the non-ruminant animals (camel and horse). These results can be useful for gaining a better understanding of the differences in milk synthesis between Holstein and the other dairy animals.