母乳低聚糖与婴幼儿健康关系研究进展

母乳低聚糖在促进婴幼儿生长发育上发挥重要作用,目前已报道的母乳低聚糖超过200种。文章综述了母乳低聚糖的种类与结构、对婴幼儿肠道健康的影响、免疫调节作用及促进大脑发育等相关研究成果,总结了母乳低聚糖的应用现状,展望了未来母乳低聚糖工业化生产及其应用的可能性和必要性。     

食用菌多糖调控肠道菌群研究进展

多糖是食用菌的主要活性物质之一,具有抗氧化、抗肿瘤、抗炎、免疫调节等生物活性。文章从食用菌多糖的功效与结构、人体肠道菌群组成、分布与功能以及食用菌多糖如何调控肠道菌群影响人体健康方面进行了综述,同时对食用菌多糖的后续研究提出了建议。     

Considerable variation in the concentration of osteopontin in human milk, bovine milk, and infant formulas

Osteopontin (OPN) is a multifunctional bioactive protein that is implicated in numerous biological processes such as bone remodeling, inhibition of ectopic calcification, and cellular adhesion and migration, as well as several immune functions. Osteopontin has cytokine-like properties and is a key factor in the initiation of T helper 1 immune responses. Osteopontin is present in most tissues and body fluids, with the highest concentrations being found in milk. In the present study, ELISA for human and bovine milk OPN were developed and OPN concentration in human breast milk, bovine milk, and infant formulas was measured and compared. The OPN concentration in human milk was measured to approximately 138 mg/L, which corresponds to 2.1% (wt/wt) of the total protein in human breast milk. This is considerably higher than the corresponding OPN concentrations in bovine milk (∼18 mg/L) and infant formulas (∼9 mg/L). Moreover, bovine milk OPN is shown to induce the expression of the T helper 1 cytokine IL-12 in cultured human lamina propria mononuclear cells isolated from intestinal biopsies. Finally, the OPN concentration in plasma samples from umbilical cords, 3-mo-old infants, and pregnant and nonpregnant adults was measured. The OPN level in plasma from 3-mo-old infants and umbilical cords was found to be 7 to 10 times higher than in adults. Thus, the high levels of OPN in milk and infant plasma suggest that OPN is important to infants and that ingested milk OPN is likely to induce cytokine production in neonate intestinal immune cells.     

人乳寡糖体外合成研究进展

人乳寡糖的益生作用被确定之后,其合成方法的研究也受到越来越多的重视。本文将人乳寡糖(HMOs)的合成方法分为化学法和生物法,详细阐述了每种合成方法的研究进展,并分析了其优劣势。通过对人乳寡糖合成方法的深入了解,将为实现人乳寡糖的工业化生产奠定坚实的基础。     

不同阶段母乳中10种游离低聚糖的检测及含量分析

目的检测不同阶段母乳中10种游离母乳低聚糖(human milk oligosaccharides,HMOS)的含量,并比较其在不同阶段母乳中的变化。方法分别采集产后0~7 d(初乳)、产后8~15 d(过渡乳)、产后16~180 d(成熟乳)的母乳,采用荧光标记HMOS,通过超高效液相色谱-荧光检测法和标准曲线定量10种HMOS。采用Person相关比较不同泌乳时间与HMOS含量的相关性,3个泌乳阶段的组间差异采用单因素方差分析。结果在选定的色谱条件下,10种HMOS可完全分离并定量。10种HMOS中,2'岩藻糖乳糖(2'FL)、3'唾液酸乳糖(3'SL)、6'唾液酸乳糖(6'SL)、乳糖-N-四糖(LNT)、乳糖-N-新四糖(LNn T)、乳糖-N-五糖I(LNFP-I)与泌乳时间存在负相关关系,3'岩藻糖乳糖(3'FL)与泌乳时间存在正相关关系,上述7种HMOS在不同阶段母乳中差异有统计学意义(P0.05),而α-四糖(P_I)、乳糖-N-五糖V(LNFP-V)、乳糖-N-新五糖(LNnFP-V)与泌乳时间无明显相关关系,在不同阶段母乳中含量差异无统计学意义(P0.05)。结论不同阶段母乳中HMOS的含量不同。10种HMOS中,7种HMOS与泌乳时间具有相关关系并且在不同泌乳阶段差异有统计学意义(P0.05)。     

母乳低聚糖与婴儿肠道菌群相关性研究进展

母乳中含有丰富的母乳低聚糖(human milk oligosaccharides HMOs),可以刺激新生儿肠道中有益细菌的生长从而起到益生元的作用.目前我国允许添加到婴幼儿配方奶粉中的低聚糖在结构上与HMOs不同,因此,它们无法模拟HMOs的某些结构特异性效应.本文综述了HMOs的组成、结构以及在母乳中的含量,重点...     

人乳中低聚糖的含量及其常用分析方法的研究进展

人乳低聚糖（human milk oligosaccharides,HMOs）是母乳中的一类重要组分,迄今为止已经确定了200多种结构不同的HMOs。HMOs能在肠道微生物的作用下产生短链脂肪酸,对婴儿健康产生有益影响,这是母乳与配方粉的主要区别之一。研究表明,不同种类的肠道微生物利用不同机制来识别和消化不同结构的HMOs,维持肠道菌群平衡。同时,HMOs还具有缓解过敏症状,预防坏死性小肠结肠炎等多种功能。本文对HMOs的结构、种类与含量、与婴儿肠道菌群的互作及其免疫调节功能进行了综述。HMOs可促进婴儿肠道菌群的定植与生长,并通过多种方式直接或间接调节婴儿免疫功能。本文为HMOs在婴幼儿食品中的应用提供理论支持,对其未来研发方向提供新思路。

     

Correlations between oligosaccharides in breast milk and the composition of the gut microbiome in breastfed infants

The composition of the microbiome in the early stages of life can directly affect the health of developing infants, and prior evidence suggests that human milk oligosaccharides (HMO) are critical regulators in the maintenance of a healthy gut microbiota in infants. Herein, we conducted an analysis of the gut microbiota of 1-mo-old breastfed infants from Jining and Harbin, China, and a corresponding analysis of the HMO profiles in samples of maternal breast milk. Quantification of HMO was conducted via liquid chromatography-mass spectrometry, and bacterial DNA sequencing was employed for characterization of the fecal microbiota. The abundances of total neutral oligosaccharides, lactodifucotetraose, lacto-N-fucopentaose I, and disialyl-lacto-N-tetraose were significantly increased in samples from the Jining group relative to the Harbin group. Bifidobacterium were the predominant microbial species in infants from both Harbin and Jining, with these levels being significantly higher in the former set. Correlation analyses evaluating microbes and 19 different HMO indicated that HMO were beneficial to the development of the gut microbiota in young infants. The predominance of Bifidobacterium in these microbial communities suggests that their ability to efficiently utilize HMO can contribute to the homeostasis of the gut microflora, with breast milk-derived HMO being critical to the shaping of the gut microbiota in breastfed infants.     

柱前衍生—高效液相色谱荧光检测法测定乳制品中6种母乳寡糖

目的：建立一种普及性强、灵敏度高,并能同时测定乳制品中6种母乳寡糖的高效液相色谱—荧光检测分析方法。方法：样品经冰醋酸沉淀,滤纸过滤后,经2-氨基苯甲酰胺溶液衍生,离心后经有机滤膜过滤,用AdvanceBio Glycan Map色谱柱分离,以乙腈-50 mmol/L甲酸铵溶液（pH 4.4）为流动相,梯度洗脱分离,并使用荧光检测器检测。结果：6种母乳寡糖在1.00～400.0 mg/L质量浓度范围内线性关系良好,相关系数均＞0.999,方法检出限为4.1～10.9 mg/kg,回收率为71.3%～90.2%,日内相对标准偏差（RSD）为1.0%～6.3%,日间相对标准偏差＜10.0%。结论：该方法简单、快捷,可有效降低衍生峰的干扰,适用于乳制品中3′-岩藻糖基乳糖、2′-岩藻糖基乳糖、乳糖-N-四糖、乳糖-N-新四糖、3′-唾液乳糖和6′-唾液乳糖6种母乳寡糖的日常检测。     

母乳和不同婴儿配方乳粉中蛋白质消化性研究

以母乳为对照,模拟婴儿胃肠消化环境对两种普通婴儿配方乳粉和一种适度水解蛋白婴儿配方乳粉中的蛋白质进行体外模拟消化研究,测定其体外胃、肠以及胃肠总消化率和消化液中的氨基酸含量。结果表明体外胃消化率、肠消化率及胃肠总消化率从高到低依次均为:母乳>适度水解蛋白婴儿配方乳粉>婴儿配方乳粉B>婴儿配方乳粉A,且母乳中蛋白质的体外消化率均显著高于适度水解蛋白婴儿配方乳粉和两种普通婴儿配方乳粉(p<0.05)。此外,在体外胃肠总消化液中,适度水解蛋白婴儿配方乳粉中的必需氨基酸总量显著高于母乳和婴儿配方乳粉A、B(p<0.05),母乳和适度水解蛋白婴儿配方乳粉中的氨基酸总量显著高于婴儿配方乳粉A、B(p<0.05)。与两种普通婴儿配方乳粉相比,适度水解蛋白婴儿配方乳粉中蛋白质能更好的被机体消化利用,营养价值更高。      

Public health risks and benefits associated with breast milk and infant formula consumption

The safety and quality of infant milk, whether it is breast milk (BM) or infant formula (IF), are a major concern for parents and public health authorities. BM is recommended as the gold standard at WHO level. However, nowadays IF appears as an essential alternative in Western countries, challenging producers to optimize nutritional quality and safety of IF. The aim of the present article is to give an overview on the assessment and comparison of risks and benefits associated with BM and IF consumption. To date, this intensively debated subject has been mainly investigated. It has been shown that both diets could be sources of beneficial health effects in terms of nutrition and also risks in terms of chemical safety. Moreover, microbiologists have demonstrated that IF consumption can cause illness due to product contamination or inappropriate milk preparation. The article concludes on the bottlenecks and gaps that should be investigated to further progress the quantification of the impact of early diet on infant health. Performing a multi-disciplinary risk-benefit assessment with DALY as endpoint might be a future option to help prioritize management options.     

Effects of goat milk enriched with oligosaccharides on microbiota structures,and correlation between microbiota and short-chain fatty acids in the large intestine of the mouse

In this study, we explored the effects of combining goat milk and oligosaccharides on the large intestine environment of mice. A combination of goat milk with each of 3 oligosaccharides—stachyose, fructo-oligosaccharide (FOS), and a prebiotics mix—were independently fed to mice. We investigated composition changes in the microbiota of the large intestine using 16S rRNA gene sequencing; measured short-chain fatty acid content using gas chromatography–mass spectrometry; and performed a Spearman correlation analysis between microorganisms and short-chain fatty acids. Our results showed that microbial diversity in the large intestine decreased significantly in the FOS group. In terms of α diversity, microbial richness significantly declined in all 3 treatment groups; in terms of β diversity, the intestinal microbial structures clearly changed in the FOS group. The abundance of Bifidobacterium and Lactobacillus increased markedly in the FOS group compared with the other groups. Functional predictions showed that FOS reduced intestinal bacterial infections and improved the endocrine and immune systems. Spearman correlation analysis showed that propionic, isobutyric, and valeric acids were all positively correlated with certain microbiota. Our findings suggest that FOS-enriched goat milk is beneficial for improving the large intestine environment in the host.     

Non-digestible carbohydrates in infant formula as substitution for human milk oligosaccharide functions: Effects on microbiota and gut maturation

Human milk (HM) is the golden standard for nutrition of newborn infants. Human milk oligosaccharides (HMOs) are abundantly present in HM and exert multiple beneficial functions, such as support of colonization of the gut microbiota, reduction of pathogenic infections and support of immune development. HMO-composition is during lactation continuously adapted by the mother to accommodate the needs of the neonate. Unfortunately, for many valid reasons not all neonates can be fed with HM and are either totally or partly fed with cow-milk derived infant formulas, which do not contain HMOs. These cow-milk formulas are supplemented with non-digestible carbohydrates (NDCs) that have functional effects similar to that of some HMOs, since production of synthetic HMOs is challenging and still very expensive. However, NDCs cannot substitute all HMO functions. More efficacious NDCs may be developed and customized for specific groups of neonates such as pre-matures and allergy prone infants. Here current knowledge of HMO functions in the neonate in view of possible replacement of HMOs by NDCs in infant formulas is reviewed. Furthermore, methods to expedite identification of suitable NDCs and structure/function relationships are reviewed as in vivo studies in babies are impossible.     

Gangliosides in human milk and infant formula: A review on analytical techniques and contents

Gangliosides (GGs) are important bioactive compounds that offer beneficial anti-infective, anti-inflammatory, and neuronal development effects. The present work reviews the techniques used to determine the GG content in human milk and infant formula. In the case of conventional techniques (thin-layer chromatography (TLC) and spectroscopy), extraction and purification steps are more laborious than for the current techniques (liquid chromatography-mass spectrometry (LC-MS)). The new methodologies allow the identification of the ceramide and oligosaccharide forming the GGs, which is of interest considering their structural differences among human milk and infant formula. This information could be used to incorporate GGs into infant formula in such a way as to more closely resemble human milk regarding total contents and profile.     

Comparison of the antipathogenic effect toward Staphylococcus aureus of N-linked and free oligosaccharides derived from human,bovine, and goat milk

N-linked oligosaccharides (N-glycans) derived from milk were recently found to be antipathogenic. This study compares the antimicrobial activity of N-linked glycans and free oligosaccharides from human, bovine, and goat milk against Staphylococcus aureus. Milk N-glycans showed a bactericidal/bacteriostatic effect on the pathogen when compared to free milk oligosaccharides, evidenced by the clear zone from the halo assay, with the order of human milk >goat milk >bovine milk. None of the free milk oligosaccharide samples were bactericidal/bacteriostatic, despite its positive results in growth curve and minimum inhibitory concentration (MIC) assays which are believed to be related to hyperosmosis. Both N-glycans and free milk oligosaccharides can reduce the adhesion of Staphylococcus aureus to Caco-2 cells, however, N-glycans worked significantly more effective than free milk oligosaccharides. Structural analysis of all free oligosaccharide and N-glycan samples showed the obvious interspecies differences, and the structure/function relationship of the respected N-glycans is of interest for future study. The significant bactericidal/bacteriostatic activity possessed by human, bovine, and goat milk N-linked glycans holds great potential as a novel substitute for antibiotics.     

The microbiome of Escherichia coli and culture-negative nonsevere clinical mastitis: Characterization and associations with linear score and milk production

Culture-negative and Escherichia coli cases are uncommonly treated in pathogen-based protocols for nonsevere mastitis. High-throughput 16S rRNA sequencing might reveal the presence of other pathogens and can provide information on microbial diversity. The objective was to explore the milk microbiome at the time of the mastitis event (enrollment) and its association with survival in the herd, milk production, and postevent linear score (LS) for cows with clinical mastitis characterized as negative or E. coli by culture. Fifty E. coli-positive and 35 culture-negative samples from cases were enrolled. No cases were treated with antimicrobials. All E. coli-positive quarters were characterized as transient; microbiological culture of samples taken 15 d postmastitis were negative for this organism. However, a difference in α-diversity (Shannon index) was present between enrollment and follow-up samples (3.8 vs. 5.1). When α-diversity was explored for enrollment E. coli samples, no relationship was observed between the Shannon indices of these samples and postmastitis LS. Alpha-diversity of the enrollment samples was lower for E. coli-positive cows that subsequently had greater losses in milk production. This difference was explained by a greater relative abundance of the family Enterobacteriaceae (67.8 vs. 38.4%) for cows that dropped in production. Analysis of composition of the microbiome identified one phylum, Proteobacteria, that differed between E. coli-positive cows that dropped in production and those that did not. Evaluation of β -diversity found no statistical relationship between postmastitis LS and the microbiome. When evaluating α- and β-diversities and composition of the microbiomes for culture-negative quarters, no associations were found for milk production changes and postmastitis LS. Three cows did not remain in the herd, limiting the ability to analyze survival. The findings suggest that a contributing factor to negative outcomes in E. coli-positive cows is relative abundance of this pathogen, and that no single or collective group of bacterial families is associated with milk production changes or postmastitis LS in culture-negative quarters. Although additional studies should be performed, the absence of associations between outcomes explored and microbial profiles in this study suggests that we are not missing opportunities by not treating nonsevere E. coli or culture-negative mastitis cases.     

Size distribution of fat globules in human colostrum, breast milk, and infant formula

Only a few results are available on the size of human milk fat globules (MFG), despite its significance regarding fat digestion in the infant, and no data are available at <24 h postpartum (PP). We measured the MFG size distribution in colostrum and transitional human milk in comparison with fat globules of mature milk and infant formula. Colostrum and transitional milk samples from 18 mothers were collected regularly during 4 d PP and compared with mature milk samples of 17 different mothers and 4 infant formulas. The size distribution was measured by laser light scattering. For further characterization, the ζ-potential of some mature MFG was measured by laser Doppler electrophoresis. The MFG diameter decreased sigmoidally in the first days. At <12 h PP, the mode diameter was 8.9 ± 1.0 μm vs 2.8 ±0.3 μm at 96 h PP. Thus, the surface area of MFG increased from 1.1 ±0.3 to 5.4 ±0.7 m²/g between colostrum and transitional milk. In mature milk, the MFG diameter was 4 μm on average and increased with advancing lactation, whereas the droplets in infant formula measured 0.4 μm. The ζ potential of mature MFG was −7.8 ± 0.1 mV. The fat globules are larger in early colostrum than in transitional and mature human milk and in contrast with the small-sized fat droplets in infant formula. Human MFG also have a low negative surface charge compared with bovine globules. These structural differences can be of nutritional significance for the infant.     

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.     

我国母乳脂肪和婴儿配方奶粉油脂研究现状

婴儿最理想的食品是母乳。我国对母乳脂肪的研究主要聚焦于母乳脂肪酸的分析研究,以及关注母乳中长链多不饱和脂肪酸(如AA和DHA)对婴儿健康的影响。国内婴儿配方奶粉油脂目前的设计也限于模仿母乳脂肪酸含量,而没有充分注意到母乳脂肪酸在甘三酯中的位置分布对婴儿消化吸收的重要影响,也没有注意到母乳中含有的脂肪酶能更好地促进消化吸收。综述了近年来国内外母乳脂肪和婴儿配方奶粉油脂研究现状,试图给婴儿配方奶粉企业提供一些参考。