Comparison of Milk Oligosaccharides Pattern in Colostrum of Different Horse Breeds

Colostrum oligosaccharides are known to exhibit prebiotic and immunomodulatory properties. Oligosaccharide composition is species-specific, and equine colostrum has been reported to contain unique oligosaccharides. Therefore, equine oligosaccharides (EMOS) from colostrum from different horse breeds were analyzed by CE-LIF, CE-MS^<i>n</i>, HILIC-MS^<i>n</i>, and exoglycosidase degradation. Sixteen EMOS were characterized and quantified, of which half were neutral and half were acidic. EMOS showed about 63% structural overlap with human milk oligosaccharides, known for their bioactivity. Seven EMOS were not reported before in equine oligosaccharides literature: neutral Gal­(β1–4)­HexNAc, Gal­(β1–4)­Hex-Hex, β4′-galactosyllactose, and lactose-<i>N</i>-hexaose, as well as acidic 6′-Sialyl-Hex-Ac-HexNAc, sialyllacto-<i>N</i>-tetraose-a, and disialylacto-<i>N</i>-tetraose (isomer not further specified). In all colostrum samples, the average oligosaccharide concentration ranged from 2.12 to 4.63 g/L; with β 6′and 3′- galactosyllactose, 3′-sialyllactose, and disialyllactose as the most abundant of all oligosaccharides (27–59, 16–37, 1–8, and 1–6%, respectively). Differences in presence and in abundance of specific EMOS were evident not only between the four breeds but also within the breed