Sialyloligosaccharides in Human and Bovine Milk and in Infant Formulas: Variations with the Progression of Lactation

Abstract

Several lines of research support a role for human milk oligosaccharides in the defense of breast-fed infants against pathogens. Some ofthese oligosaccharides contain at least one moiety of sialic acid and are, thus, termed sialyloligosaccharides. These constitute a significant component (>1 g/L) of human milk. It is well established that milk composition varies among species, and previous reports have indicated that one ofthe differences between human and bovine milk is precisely their contents of sialyloligosaccharides. Because most infant formulas are manufactured with bovine milk components, it follows that formula-fed and breast-fed infants ingest dissimilar quantities of these carbohydrate structures. To ascertain these differences and their impact along lactation, the contents of oligosaccharide-bound sialic acids and major sialyloligosaccharides in samples of human and bovine milk (obtained at different lactation stages) were determined. In addition, infant formulas were assayed for their sialyloligosaccharide contents. Seven sialyloligosaccharides were identified in human milk; namely, 3'-sialyl-3-fucosyllactose and sialyllacto-N-tetraoses (a and b+c), the predominant structures at all lactation stages. Five sialyloligosaccharides were identified in bovine milk, of which 6'-sialyllactosamine and 3'-sialyllactose were the most abundant. In addition, sialyloligosaccharides in human and bovine milk decreased along lactation, and infant formulas did not contain significant amounts of sialyloligosaccharides. The results point to the general conclusion that regarding both qualitative and quantitative aspects, milk from humans and cows and infant formulas have different oligosaccharide contents. In this sense, bottle-fed infants are subject to reduced sialyloligosaccharide intake as compared to breast-fed infants.

Simultaneous quantification of sialyloligosaccharides from human milk by capillary electrophoresis

“…The range of our CE results overlaps with the range of oligosaccharides reported by Kunz et al [8] for LST c, 6′-SL, and DSLNT (Table 7). Our range of results also overlaps with the results of the report of Martin-Sosa et al [28] for 6′-SL, 3′-SL, and DSLNT. There was a wide discrepancy between the values for LST a between these other two reports.…”

“…Although this method allowed simultaneous analysis of both acidic and neutral species, many of the individual oligosaccharides could not be resolved. Martin-Sosa and associates described a method in 2003 of desialylating sialyloligosaccharides with neuraminidase, resolving them on an amino column, and detecting them at 206 nm [28]. Eight peaks were detected and quantified, but isomers of sialic acid attachment could not be resolved after desialylation, and the samples required extensive manipulation before analysis.…”

“…A technique more commonly employed for native milk oligosaccharide resolution and quantification is high pH anion exchange chromatography with pulsed amperometric detection [17,[23][24][25][26], but the electrochemical response factors for anionic sialyloligosaccharides by this technique are not consistent, and differ by the linkage position of the sialic acid [23]. Reverse-or normal-phase chromatography was able to resolve derivatized or reduced acidic oligosaccharides, with detection by UV absorbance or spectrofluorimetry as the basis for quantification [27,28]. In our laboratory, capillary electrophoresis with detection at 205 nm was shown to be able to resolve human milk sialyloligosaccharides effectively, and to have a linear response factor over a wide range of concentrations.…”

Composition and properties of bovine colostrum: a review

“…In one study, the total number of oligosaccharides in colostrum from individual cows ranged between 14 and 32 (Barile et al 2010). 3′ Sialylactose (3′SL), 6′ sialylactose (6′SL), 6′ sialylactosamine (6′SLN) and disialyllactose (DSL) are the predominant oligosaccharides in colostrum, with 3′SL accounting for 70% of the total oligosaccharide content (Martin-Sosa et al 2003;Nakamura et al 2003;McJarrow and van Amelsfort-Schoonbeek 2004;Tao et al 2009;Urashima et al 2009). Nakamura et al (2003 reported that levels of 3′SL, 6′SL and 6′SLN in colostrum were highest immediately following parturition and decreased rapidly by 48 h post-partum, whereas levels of neutral oligosaccharides increased.…”

Human milk: composition and health benefits

“…17 However, HMO specific composition is markedly affected by maternal genetic factors. 11,18,19 Different structures of oligosaccharides depend on the presence of specific transferase enzymes expressed in the lactocytes. The two genes involved in shaping the specific composition are the Secretor and the Lewis Blood Group genes.…”