Analysis of the Milk Oligosaccharides Spectrum and Sialylation Status of Milk from West African Dwarf Goat and East Friesian Sheep.

Milk oligosaccharides (MOs) modulate multiple physiological processes, including gut health and pathogen defense. However, most research has focused on cows, and comparatively little is known about the structural diversity of MOs in the milk of other farm animals, which are commonly used for milk production, such as goats and sheep. For this reason, we used LC-MS to characterize the MOs in West African dwarf goat and East Friesian sheep milk. The analyses revealed the presence of numerous bioactive MOs. In total, 40 different MO structures were detected. Interestingly, all sheep MOs were also identified in goat milk. As especially sialylated MOs have profound functions on supporting gut health and pathogen defense in the offspring of mammals, we also quantitated the overall concentration of the sialic acids N-acetylneuraminic acid (Neu5Ac) and N-glycolylneuraminic acid (Neu5Gc), as well as the ratio of sialic acids attached to MOs, using an HPLC approach. While Neu5Gc is the dominant sialic acid in the MOs of East Friesian sheep, with Neu5Ac present only in very low concentrations, in the West African dwarf goat milk the sialic acids where more equally distributed. The obtained results are important not only for the optimization of livestock breeding, but also for humans. In this regard, Neu5Gc is particularly noteworthy, as it is supposed to induce proinflammatory effects in humans.