Thoroughbred mare's milk exhibits a unique and diverse free oligosaccharide profile.

The Thoroughbred is among the most valuable horse breeds, and its husbandry is a major industry. Mare's milk plays a major role in the health of neonatal foals. Although the main components of mare's milk are broadly characterized, free oligosaccharides (OS), which possess various bioactivities in many mammalian milks, have not been fully profiled in Thoroughbreds. The aim of this study was to identify and quantify OS in Thoroughbred mare's milk during the first week of lactation, when foals typically consume mare's milk exclusively. A total of 48 OS structures (including isomers and anomers), corresponding to 20 unique compositions, were identified by nano LC-Chip QToF-MS and confirmed by tandem mass spectrometry. Neutral OS were the most abundant glycans (58.3%), followed by acidic OS containing Neu5Ac (33.3%), a minor presence of fucosylated OS structures (6.25%) and one structure containing NeuGc (2.1%). Comparison with other well-characterized mammalian milks revealed that mare's milk shared 8 OS structures with human, bovine, pig and goat milk (i.e., 2 sialyllactose isomers, 3 hexose, LNH, LNT, and OS with the composition 3 Hex-1 Neu5Ac). Additionally, there were seven unique OS not previously found in other mammal milks. During the first 7 days of lactation, the percentage of neutral and fucosylated OS increased, whereas acidic OS decreased and the total OS concentration ranged from 217.8 mg·L-1 to 79.8 mg·L-1

Peptidomic and glycomic profiling of commercial dairy products: identification, quantification and potential bioactivities.

Peptidomics and glycomics are recently established disciplines enabling researchers to characterize functional characteristics of foods at a molecular level. Milk-derived bioactive peptides and oligosaccharides have garnered both scientific and commercial interest because they possess unique functional properties, such as anti-hypertensive, immunomodulatory and prebiotic activities; therefore, the objective of this work was to employ peptidomic and glycomic tools to identify and measure relative and absolute quantities of peptides and oligosaccharides in widely consumed dairy products. Specifically, we identified up to 2117 unique peptides in 10 commercial dairy products, which together represent the most comprehensive peptidomic profiling of dairy milk in the literature to date. The quantity of peptides, measured by ion-exchange chromatography, varied between 60 and 130 mg/L among the same set of dairy products, which the majority originated from caseins, and the remaining from whey proteins. A recently published bioactive peptide database was used to identify 66 unique bioactive peptides in the dataset. In addition, 24 unique oligosaccharide compositions were identified in all the samples by nano LC Chip QTOF. Neutral oligosaccharides were the most abundant class in all samples (66-91.3%), followed by acidic (8.6-33.7%), and fucosylated oligosaccharides (0-4.6%). Variation of total oligosaccharide concentration ranged from a high of 65.78 to a low of 24.82 mg/L. Importantly, characterizing bioactive peptides and oligosaccharides in a wider number of dairy products may lead to innovations that go beyond the traditional vision of dairy components used for nutritional purposes but that will rather focus on improving human health

Comparative composition, diversity, and abundance of oligosaccharides in early lactation milk from commercial dairy and beef cows.

Prebiotics are nondigestible dietary ingredients, usually oligosaccharides (OS), that provide a health benefit to the host by directly modulating the gut microbiota. Although there is some information describing OS content in dairy-source milk, no information is available to describe the OS content of beef-source milk. Given the different trait emphasis between dairy and beef for milk production and calf survivability, it is plausible that OS composition, diversity, and abundance differ between production types. The goal of this study was to compare OS in milk from commercial dairy and beef cows in early lactation. Early-lactation multiparous cows (5-12 d in milk) from 5 commercial Holstein dairy herds and 5 Angus or Angus hybrid beef herds were sampled once. Milk was obtained from each enrolled cow and frozen on the farm. Subsequently, each milk sample was assessed for total solids, pH, and OS content and relative abundance. Oligosaccharide diversity and abundance within and between samples was transformed through principal component analysis to reduce data complexity. Factors from principal component analysis were used to create similarity clusters, which were subsequently used in a multivariate logistic regression. In total, 30 OS were identified in early-lactation cow milk, including 21 distinct OS and 9 isomers with unique retention times. The majority of OS detected in the milk samples were present in all individual samples regardless of production type. Two clusters described distribution patterns of OS for the study sample; when median OS abundance was compared between the 2 clusters, we found that overall OS relative abundance was consistently greater in the cluster dominated by beef cows. For several of the structures, including those with known prebiotic effect, the difference in abundance was 2- to 4-fold greater in the beef-dominated cluster. Assuming that beef OS content in milk is the gold standard for cattle, it is likely that preweaning dairy calves are deprived of dietary-source OS. Although supplementing rations with OS is an approach to rectify this deficiency, understanding the health and productivity effects of improving OS abundance being fed to preweaning calves is a necessary next step before recommending supplementation. These studies should account for the observation that OS products are variable for both OS diversity and structural complexity, and some products may not be suitable as prebiotics

2'-fucosyllactose Supplementation Improves Gut-Brain Signaling and Diet-Induced Obese Phenotype and Changes the Gut Microbiota in High Fat-Fed Mice.

Obesity is characterized by fat accumulation, chronic inflammation and impaired satiety signaling, which may be due in part to gut microbial dysbiosis. Manipulations of the gut microbiota and its metabolites are attractive targets for obesity treatment. The predominant oligosaccharide found in human milk, acts as a prebiotic with beneficial effects on the host. However, little is known about the beneficial effects of 2'-FL in obesity. The aim of this study was to determine the beneficial effects of 2'-FL supplementation on the microbiota-gut-brain axis and the diet-induced obese phenotype in high fat (HF)-fed mice. Male C57/BL6 mice (n = 6/group; six weeks old) were counter-balanced into six weight-matched groups and fed either a low-fat (LF; 10% kcal as fat), HF (45% kcal as fat) or HF diet with 2'-FL (HF_2'-FL) at 1, 2, 5 and 10% (w/v) in drinking water for six weeks. General phenotypes (body weight, energy intake, fat and lean mass), cecal microbiome and metabolites, gut-brain signaling, intestinal permeability and inflammatory and lipid profiles were assessed. Only 10% 2'-FL, but not 1, 2 or 5%, decreased HF diet-induced increases in energy intake, fat mass and body weight gain. A supplementation of 10% 2'-FL changed the composition of cecal microbiota and metabolites compared to LF- and HF-fed mice with an increase in Parabacteroides abundance and lactate and pyruvate, respectively, whose metabolic effects corresponded to our study findings. In particular, 10% 2'-FL significantly reversed the HF diet-induced impairment of cholecystokinin-induced inhibition of food intake. Gene expressions of interleukin (IL)-1β, IL-6, and macrophage chemoattractant protein-1 in the cecum were significantly downregulated by 10% 2'-FL compared to the HF group. Furthermore, 10% 2'-FL suppressed HF diet-induced upregulation of hepatic peroxisome proliferator-activated receptor gamma, a transcription factor for adipogenesis, at the gene level. In conclusion, 10% 2'-FL led to compositional changes in gut microbiota and metabolites associated with improvements in metabolic profiles and gut-brain signaling in HF-fed mice. These findings support the use of 2'-FL for modulating the hyperphagic response to HF diets and improving the microbiota-gut-brain axis

Studying Lactoferrin N-Glycosylation.

Lactoferrin is a multifunctional glycoprotein found in the milk of most mammals. In addition to its well-known role of binding iron, lactoferrin carries many important biological functions, including the promotion of cell proliferation and differentiation, and as an anti-bacterial, anti-viral, and anti-parasitic protein. These functions differ among lactoferrin homologs in mammals. Although considerable attention has been given to the many functions of lactoferrin, its primary nutritional contribution is presumed to be related to its iron-binding characteristics, whereas the role of glycosylation has been neglected. Given the critical role of glycan binding in many biological processes, the glycan moieties in lactoferrin are likely to contribute significantly to the biological roles of lactoferrin. Despite the high amino acid sequence homology in different lactoferrins (up to 99%), each exhibits a unique glycosylation pattern that may be responsible for heterogeneity of the biological properties of lactoferrins. An important task for the production of biotherapeutics and medical foods containing bioactive glycoproteins is the assessment of the contributions of individual glycans to the observed bioactivities. This review examines how the study of lactoferrin glycosylation patterns can increase our understanding of lactoferrin functionality

A genome-wide association study reveals specific transferases as candidate loci for bovine milk oligosaccharides synthesis.

BackgroundHuman milk oligosaccharides (OS) play a key role in brain and gut microbiota development of the neonate, but the underlying biosynthetic steps of OS in the mammary gland are still largely unknown. As bovine milk contains OS with somewhat similar structures and functionalities there is increased interest in further understanding the genetic basis underlying the OS content of milk for eventual extraction and generation of value-added ingredients for infant formulas and nutraceuticals. The present study is the first to report on genetic parameter estimation as well as on a genome wide association study (GWAS) from the largest bovine milk OS dataset analyzed to date.ResultsIn total 15 different bovine milk OS were monitored. Heritabilities ranged from 0 to 0.68 in Danish Holstein and from 0 to 0.92 in Danish Jersey. The GWAS identified in total 1770 SNPs (FDR < 0.10) for five different OS in Danish Holstein and 6913 SNPs (FDR < 0.10) for 11 OS in Danish Jersey. In Danish Holstein, a major overlapping QTL was identified on BTA1 for LNH and LNT explaining 24% of the variation in these OS. The most significant SNPs were associated with B3GNT5, a gene encoding a glycosyltransferase involved in glycan synthesis. In Danish Jersey, a very strong QTL was detected for the OS with composition 2 Hex 1 HexNAc (isomer 1) on BTA11. The most significant SNP had -log10(P-value) of 52.88 (BOVINEHD1100030300) and was assigned to ABO, a gene encoding ABO blood group glycosyltransferases. This SNP has been reported to be a missense mutation and explains 56% of the OS variation. Other candidate genes of interest identified for milk OS were ALG3, B3GALNT2, LOC520336, PIGV, MAN1C1, ST6GALNAC6, GLT6D1, GALNT14, GALNT17, COLGALT2, LFNG and SIGLEC.ConclusionTo our knowledge, this is the first study documenting a solid breeding potential for bovine milk OS and a strong indication of specific candidate genes related to OS synthesis underlying this genetic influence. This new information has the potential to guide breeding strategies to achieve production of milk with higher diversity and concentration of OS and ultimately facilitate large-scale extraction of bovine milk OS

Novel High-Molecular Weight Fucosylated Milk Oligosaccharides Identified in Dairy Streams

peer-reviewedOligosaccharides are the third largest component in human milk. This abundance is remarkable because oligosaccharides are not digestible by the newborn, and yet they have been conserved and amplified during evolution. In addition to encouraging the growth of a protective microbiota dominated by bifidobacteria, oligosaccharides have anti-infective activity, preventing pathogens from binding to intestinal cells. Although it would be advantageous adding these valuable molecules to infant milk formula, the technologies to reproduce the variety and complexity of human milk oligosaccharides by enzymatic/organic synthesis are not yet mature. Consequently, there is an enormous interest in alternative sources of these valuable oligosaccharides. Recent research has demonstrated that bovine milk and whey permeate also contain oligosaccharides. Thus, a thorough characterization of oligosaccharides in bovine dairy streams is an important step towards fully assessing their specific functionalities. In this study, bovine milk oligosaccharides (BMOs) were concentrated by membrane filtration from a readily available dairy stream called “mother liquor”, and analyzed by high accuracy MALDI FT-ICR mass spectrometry. The combination of HPLC and accurate mass spectrometry allowed the identification of ideal processing conditions leading to the production of Kg amount of BMO enriched powders. Among the BMOs identified, 18 have high-molecular weight and corresponded in size to the most abundant oligosaccharides present in human milk. Notably 6 oligosaccharides contained fucose, a sugar monomer that is highly abundant in human milk, but is rarely observed in bovine milk. This work shows that dairy streams represent a potential source of complex milk oligosaccharides for commercial development of unique dairy ingredients in functional foods that reproduce the benefits of human milk.This project was supported by the University of California Discovery Program (05GEB01NHB), the National Institute of Environmental Health Sciences (P42ES004699), the National Institutes of Health award R01AT00707, the California Dairy Research Foundation (08 GEB-04 NH) and the CHARGE study (P01 ES11269). The authors acknowledge financial support from the Irish Department of Agriculture, Fisheries and Food through the Food Institutional Research Measure (FIRM–05/R&D/TD/368)

Characterization of recombinant human lactoferrin N-glycans expressed in the milk of transgenic cows.

Lactoferrin (LF) is one of the most abundant bioactive glycoproteins in human milk. Glycans attached through N-glycosidic bonds may contribute to Lactoferrin functional activities. In contrast, LF is present in trace amounts in bovine milk. Efforts to increase LF concentration in bovine milk led to alternative approaches using transgenic cows to express human lactoferrin (hLF). This study investigated and compared N-glycans in recombinant human lactoferrin (rhLF), bovine lactoferrin (bLF) and human lactoferrin by Nano-LC-Chip-Q-TOF Mass Spectrometry. The results revealed a high diversity of N-glycan structures, including fucosylated and sialylated complex glycans that may contribute additional bioactivities. rhLF, bLF and hLF had 23, 27 and 18 N-glycans respectively with 8 N-glycan in common overall. rhLF shared 16 N-glycan with bLF and 9 N-glycan with hLF while bLF shared 10 N-glycan with hLF. Based on the relative abundances of N-glycan types, rhLF and hLF appeared to contain mostly neutral complex/hybrid N-glycans (81% and 52% of the total respectively) whereas bLF was characterized by high mannose glycans (65%). Interestingly, the majority of hLF N-glycans were fucosylated (88%), whereas bLF and rhLF had only 9% and 20% fucosylation, respectively. Overall, this study suggests that rhLF N-glycans share more similarities to bLF than hLF