Profiling, quantification and structure elucidation of non-human mammalian milk oligosaccharides by mass spectrometry

Oligosaccharides are a class of bioactive molecules that are receiving increasing commercial attention for their roles in stimulating the growth of beneficial bacteria in the intestine and inhibiting specific pathogen binding by acting as decoy receptors. Together these functions act to create a protective intestinal environment that contribute to gut health. The foundation for these benefits is attributed to the effects of breast milk on the health of infants, whose gut microflora are dominated by bifidobacterium species.;Although the importance of breast milk has been widely recognized, the technology to analyze milk is still lacking thereby limiting our understanding of the various components. The goal of this research is to determine the similarities and differences between human milk and milk from domesticated animals, such as bovine and porcine. The hope is that human milk can be approximated by other milk. Bovine milk may provide similar benefits as that of human milk and may provide more than the basic essential nutrients to non-breastfed infants. Analysis of primate milk oligosaccharides were also included in this thesis since primates may be the best animal models for medical and food control studies difficult to perform on human beings.;Recently, in our lab, we proposed new methods employing high performance mass spectrometry and nanoflow HPLC on chip-based devices[1]. In addition, new tandem MS methods such as infrared multiphoton dissociation (IRMPD) yield critical structural information. In this report, we systematically examined the oligosaccharides in bovine, porcine, and primates by employing microchip LC separation and high performance mass spectrometry including Fourier transform ion cyclotron resonance and time-of-flight analyzer. We obtained structures on both neutral and ionic oligosaccharides, as well as relevant information to identify specific oligosaccharides.;Results from this study show that bovine and porcine milk have up to 80% sialylated oligosaccharides in abundance with none or little fucosylation occurring. These results were extremely different from that of human milk, which has over 70% fucosylation and up to 20% sialylation. In primates, on the other hand, oligosaccharide types and abundances vary differently among species. However, primates are the closest species to human milk beings.