A comparative study of free oligosaccharides in the milk of domestic animals

Abstract

This study was conducted to provide a comprehensive analysis of the oligosaccharides in the milk of a variety of important domestic animals including cow, goat, sheep, pig, horse, and dromedary camel. Using an analytical workflow which included ultra-performance hydrophilic interaction liquid chromatography with fluorescence detection (UPLC-HILIC-FLD) and coupling to a quadrupole time of flight (qTOF) mass spectrometer (MS), detailed oligosaccharide libraries were established. The partial or full characterization of the neutral/fucosylated, phosphorylated and sialylated structures was facilitated by sequencing with linkage- and sugar- specific exoglycosidases. Relative peak quantification of the 2-AB labelled oligosaccharides provided additional information. Milks from domestic animals contained a much larger variety of complex oligosaccharides than was previously assumed and thirteen of these structures were previously identified in human milk. The direct comparison of the oligosaccharide mixtures could contribute to a better understanding of possible differences in their biological effects and highlight the potential value of animal milks for commercial oligosaccharide extraction.