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

Abstract

The present study was conducted to obtain a comprehensive overview of oligosaccharides present in the milk of a variety of important domestic animals including cows, goats, sheep, pigs, horses and dromedary camels. Using an analytical workflow that included ultraperformance liquid chromatography -hydrophilic interaction liquid chromatography with fluorescence detection coupled to quadrupole time-of-flight MS, detailed oligosaccharide libraries were established. The partial or full characterisation of the neutral/fucosylated, phosphorylated and sialylated structures was facilitated by sequencing with linkage-and sugar-specific exoglycosidases. Relative peak quantification of the 2-aminobenzamide-labelled oligosaccharides provided additional information. Milk from domestic animals contained a much larger variety of complex oligosaccharides than was previously assumed, and thirteen of these structures have been identified previously in human milk. The direct comparison of the oligosaccharide mixtures reflects their role in the postnatal maturation of different types of gastrointestinal systems, which, in this way, are prepared for certain post-weaning diets. The potential value of animal milk for the commercial extraction of oligosaccharides to be used in human and animal health is highlighted.Key words: Domestic animal milk: Oligosaccharides: Ultra-performance liquid chromatography -hydrophilic interaction liquid chromatography with fluorescence detection -MS: 2-Aminobenzamide: Relative quantification Human milk and animal milk are rich sources of bioactive oligosaccharides, which are of great interest to the functional food industry. Many biological activities have been reported for certain milk oligosaccharides including prebiotic activity, anti-adhesion effects, anti-inflammatory properties, glycomemodifying activity, and a role in brain development and growth-related characteristics of intestinal cells (1 -4) . Milk oligosaccharides are typically composed of three to ten monosaccharide units, including glucose (Glc), galactose (Gal) and N-acetyl-glucosamine (GlcNAc) as well as fucose and sialic acids. The core unit present at the reducing end of milk oligosaccharides is either lactose (Gal(b1 -4)Glc) or N-acetyl-lactosamine (Gal(b1 -4)GlcNAc) (5) .As the biological activity of milk oligosaccharides is dependent on their individual structural characteristics, a detailed knowledge of their composition is necessary. Human milk is a rich source of oligosaccharides (20 mg/l in colostrum; 12 -13 mg/l in mature milk), and more than 200 structures have been identified so far (6,7) . Less is known about animal milk oligosaccharides as their concentration in milk is low. For example, the concentration of oligosaccharides in bovine colostrum is 1 g/l, whereas their concentration in mature milk is about 20-fold less (8,9) . Using a combination of advanced analytical techniques, structural libraries of up to forty and even more than fifty bovine milk oligosaccharides (10 -12) , twenty-nine porcine milk oligosacch...

Non-lysosomal Degradation of Singly Phosphorylated Oligosaccharides Initiated by the Action of a Cytosolic Endo-β-N-acetylglucosaminidase

“…3A) (10, 13), providing conclusive evidence that the putative DLO-degrading enzyme is a DLO-pyrophosphatase that splits the pyrophosphate bond of DLOs producing mono-phosphorylated POSs. Although mono-phosphorylated POSs have been identified by MS in bacteria (30) or in milk oligosaccharides (31), to the best of our knowledge this is the first example of the use of MS for the identification of DLO-derived POSs of mammalian origin.…”

Composition and enrichment of caprine milk oligosaccharides from New Zealand Saanen goat cheese whey

“…It is interesting to note that the formic acid adduct is only detected for the neutral sugars, not the acidic ones. Traces of other possible CMOs, previously described (Albrecht et al, 2014), lacto-Nneotetraose (m/z 706.27), lacto-N-novo pentaose (m/z 868.36) and diglycolyl-lactose (m/z 955.33), were also observed in the colostrum, regular milk, whey and the final purified product. Another feature of the MS profile were ions consistent with lactose phosphate (m/z 421), another compound produced during lactose and galactose metabolism (Benthin et al, 1994).…”

“…However, the level of lactose was still greater compared to the oligosaccharide levels (0.16 g L À1 ), thus the need for further purification. The inhibitory effect of higher concentrations of galactose in batch systems on lactose hydrolysis have been reported previously (Albrecht et al, 2014;Marino et al, 2011). Higher conversion rates may be achieved by continuous systems using immobilised b-galactosidase.…”

“…The number of oligosaccharides reported thus far in bovine milk (up to 40) (Marino et al, 2011;Tao et al, 2008), bovine colostrum (over 50) (Aldredge et al, 2013) and goat milk (40) (Albrecht et al, 2014) is less than the 200 different structures reported in human milk (Aldredge et al, 2013;German et al, 2008). Some of the predominant caprine milk oligosaccharides (CMO) and bovine milk oligosaccharides (BMO) are structurally similar to those in HMO suggesting that, to some extent, they may have identical or similar functions as described for HMO (Mehra and Kelly, 2006).…”

“…The oligosaccharide composition of goat and bovine milk has been intensely studied in the past decade (Albrecht et al, 2014;Tao et al, 2008). The number of oligosaccharides reported thus far in bovine milk (up to 40) (Marino et al, 2011;Tao et al, 2008), bovine colostrum (over 50) (Aldredge et al, 2013) and goat milk (40) (Albrecht et al, 2014) is less than the 200 different structures reported in human milk (Aldredge et al, 2013;German et al, 2008).…”