Nutritional and physiologic significance of human milk proteins

Maternal breastmilk, infant gut microbiome and the impact on preterm infant health

AIM

This narrative review summarises the benefits of maternal breastmilk to both the infant and the mother, specifically the benefits that relate to modification of the infant microbiome, and how this might vary in the preterm infant.

METHODS

We used PubMed to primarily identify papers, reviews, case series and editorials published in English until May 2020. Based on this, we report on the components of breastmilk, their associated hypothesised benefits and the implications for clinical practice.

RESULTS

Breastmilk is recommended as the exclusive diet for newborn infants because it has numerous nutritional and immunological benefits. Additionally, exposure to the maternal breastmilk microbiome may confer a lasting effect on gut health. In the preterm infant, breastmilk is associated with a significant reduction in necrotising enterocolitis, an inflammatory gastrointestinal disease and reduction in other key morbidities, together with improved neurodevelopmental outcomes.

CONCLUSION

These impacts have long-term benefits for the child (and the mother) even after weaning. This benefit is likely due, in part, to modification of the infant gut microbiome by breastmilk microbes and bioactive components, and provide potential areas for research and novel therapies in preterm and other high-risk infants.

Priming for Life: Early Life Nutrition and the Microbiota-Gut-Brain Axis

Microbes colonize the human body during the first moments of life and coexist with the host throughout the lifespan. Intestinal microbiota and their metabolites aid in the programming of important bodily systems such as the immune and the central nervous system during critical temporal windows of development, with possible structural and functional implications throughout the lifespan. These critical developmental windows perinatally (during the first 1000 days) are susceptible timepoints for insults that can endure long lasting effects on the microbiota-gut-brain axis. Environmental and parental factors like host genetics, mental health, nutrition, delivery and feeding mode, exposure to antibiotics, immune activation and microbiota composition antenatally, are all factors that are able to modulate the microbiota composition of mother and infant and may thus regulate important bodily functions. Among all these factors, early life nutrition plays a pivotal role in perinatal programming and in the modulation of offspring microbiota from birth throughout lifespan. This review aims to present current data on the impact of early life nutrition and microbiota priming of important bodily systems and all the factors influencing the microbial coexistence with the host during early life development.

Bovine Colostrum: Its Constituents and Uses

Colostrum is the milk produced during the first few days after birth and contains high levels of immunoglobulins, antimicrobial peptides, and growth factors. Colostrum is important for supporting the growth, development, and immunologic defence of neonates. Colostrum is naturally packaged in a combination that helps prevent its destruction and maintain bioactivity until it reaches more distal gut regions and enables synergistic responses between protective and reparative agents present within it. Bovine colostrum been used for hundreds of years as a traditional or complementary therapy for a wide variety of ailments and in veterinary practice. Partly due to concerns about the side effects of standard Western medicines, there is interest in the use of natural-based products of which colostrum is a prime example. Numerous preclinical and clinical studies have demonstrated therapeutic benefits of bovine colostrum for a wide range of indications, including maintenance of wellbeing, treatment of medical conditions and for animal husbandry. Articles within this Special Issue of Nutrients cover the effects and use bovine colostrum and in this introductory article, we describe the main constituents, quality control and an overview of the use of bovine colostrum in health and disease.

Effect of human breast milk on innate immune response: Up-regulation of bacterial pattern recognition receptors and innate cytokines in THP-1 monocytic cells

Human breast milk (HBM) contains many bioactive components that protect infants from various microorganisms. Pattern recognition receptors on phagocytic cells recognize microbial pathogens and promote the innate immune system. This study aimed to evaluate the effect of HBM on the expression of pattern recognition receptors and innate cytokines in the monocytic cell line THP-1 and the phagocytic activity of RAW264.7 macrophages. Expression levels of specific mRNAs in THP-1 cells were quantitated using reverse transcription-polymerase chain reaction. Phagocytic activity was measured by fluorescence microscopy to detect the uptake of fluorescent dye-labeled carboxylate-modified polystyrene latex beads in RAW264.7 macrophages. HBM stimulated the phagocytic activity of RAW264.7 macrophages. HBM increased mRNA expression of pattern recognition receptors, including the cluster of differentiation 14 and toll-like receptor 2 and 4, and various innate cytokines, including tumor necrosis factor α, interleukin-1β, C-X-C motif chemokine 8, and C-C motif chemokine ligand 2, in THP-1 monocytic cells. Furthermore, milk oligosaccharides in HBM, such as lacto- N-fucopentaose I, enhanced the expression of pattern recognition receptors and various innate cytokines. HBM is able to modulate the innate immune response by upregulating the expression of pattern recognition receptors and various innate cytokines in monocytes/macrophages.

High-Temperature Short-Time Preserves Human Milk's Bioactive Proteins and Their Function Better Than Pasteurization Techniques With Long Processing Times

Donor human milk is generally processed by holder pasteurization (HoP) at 62. 5°C for 30 min. This temperature-time combination is sufficient for eliminating pathogens in donor milk, but also negatively affects several bioactive milk components. Long heating up times may further affect the bioactive properties of pasteurized milk. High-Temperature-Short-Time (HTST), a treatment with shorter processing times (72°C for 15 sec), was investigated as a suitable alternative to HoP. In addition, pasteurization methods that follow the same temperature regime but with varying heating up times were compared. Human milk samples from four different donors were combined into one pool, which was then used to perform all analyses. The effects of these methods on the levels and functionality of immunoglobulin A, lactoferrin, lysozyme and bile salt-stimulated lipase, were evaluated with LC-MS/MS-based proteomics and activity assays, while the pasteurization efficacy was evaluated with an alkaline phosphatase test. HoP, a treatment with long processing times, times, caused the highest reduction in all proteins studied (reduced by 50-98%). Compounds such as lactoferrin and bile salt-stimulated lipase that are more sensitive to heat treatments were better retained with HTST, but their levels and functionality were still significantly lower than those of untreated donor milk (52 and 81% reduction of lactoferrin and bile salt-stimulated lipase activity, respectively). Our findings showed that a treatment with considerably shorter processing times, such as HTST, may reduce the thermal damage caused to the bioactive proteins compared to HoP, without affecting pasteurization efficacy. Since the vast majority of the donor human milk banks that are currently operating on a global level apply HoP to donor milk, our findings may provide relevant information for the optimization of donor milk processing.

Do Thyroid Diseases during Pregnancy and Lactation Affect the Nutritional Composition of Human Milk?

OBJECTIVE

 To identify whether the effects of thyroid disease during pregnancy and lactation affect the nutritional composition of human milk.

METHODS

 Systematic review of the scientific literature using the Medical Literature Analysis and Retrieval System Online/MedLine databases to evaluate the association of thyroid diseases during pregnancy and lactation with the nutritional composition of human milk. There was no delimitation by period or by language, and the searches were completed in March 2019. The following descriptors were applied: human milk AND thyroid AND composition, using the preferred reporting items for systematic reviews and meta-analyses (PRISMA) protocol for data search, selection, and extraction. The flowchart proposed for bibliographic search resulted in 12 articles and, of these, four were selected.

RESULTS

 The articles elected for this review were published between 1976 and 2018. Two studies found significant differences in the nutritional composition of mothers' milk with hypothyroidism or overweight compared with the milk of those without hypothyroidism. Studies have shown that the presence of the disease led to changes in the nutritional composition of human milk, especially a higher concentration of human milk fat.

CONCLUSION

 It is extremely important that these women have continuous nutritional follow-up to minimize the impact of these morbidities on the nutritional composition of human milk.

Isolation and identification of O- and N-linked glycoproteins in milk from different mammalian species and their roles in biological pathways which support infant growth

Milk serves as the sole nutrition for newborns, as well as a medium for the transfer of immunological components from the mother to the baby. This study reveals different glycoprotein profiles obtained from human, bovine, and caprine milk and their potential roles in supporting infant growth. Proteins from these three milk samples are separated and analyzed using two-dimensional gel electrophoresis (2-DE). Glycosylated proteins from all samples are enriched by affinity chromatography using lectins from the seeds of Artocarpus integer before analysis using LC/MS-QTOF. The glycoproteome profiling demonstrates that glycosylated proteins are higher in caprine milk compared to other samples. Analysis using LC/MS-QTOF identified 42 O-glycosylated and 56 N-glycosylated proteins, respectively. Among those identified, human milk has 17 glycoproteins, which are both O- and N-glycosylated, whereas caprine and bovine have 10 and 1, respectively. Only glycoproteins from human milk have shown positive matching to important human biological pathways, such as vesicle-mediated transport, immune system and hemostasis pathways. Human milk remains unique for human babies with the presence of antibodies in the form of immunoglobulins that are lacking in ruminant milk proteomes.

Whey Versus Casein as a Protein Source during the Weaning Period: Impact on Growth and Later Adiposity and Glucose Homeostasis in a Rat Model of Intrauterine Growth Restriction

The impact of early life protein source (whey vs. casein) on short- and long-term glucose homeostasis and adiposity is unknown and was investigated in this study. At the end of the suckling period, non-IUGR (intrauterine growth restriction) and IUGR pups were separated from dams and were randomized into four groups. From age 21-49 days, non-IUGR and IUGR pups were fed ad-libitum chow or a semi-synthetic diet (20% from protein; casein or whey) and from age 50-199 days, all groups were fed ad-libitum chow. Food intake, body composition, glucose, and insulin homeostasis were assessed. Among the chow groups, IUGR had slower growth and higher fasting glucose at age 42 days, as well as higher fasting and AUC glucose at age 192 days relative to non-IUGR. The whey IUGR group had a slower growth rate and higher fasting glycemia in early life (age 21-49 days) and higher HOMA-IR later in life (age 120-122 and 190-192 days) relative to casein IUGR. This study shows the potential advantage of casein relative to whey during weaning on short term energy intake, growth, and glucose homeostasis in an IUGR model and reveals, for the first time, its long term impact on insulin sensitivity, which may have implications for later metabolic health, particularly in small-for-gestational-age populations at risk of type 2 diabetes.

Mildly Pasteurized Whey Protein Promotes Gut Tolerance in Immature Piglets Compared with Extensively Heated Whey Protein

Human milk is the optimal diet for infant development, but infant milk formula (IMF) must be available as an alternative. To develop high-quality IMF, bovine milk processing is required to ensure microbial safety and to obtain a protein composition that mimics human milk. However, processing can impact the quality of milk proteins, which can influence gastro-intestinal (GI) tolerance by changing digestion, transit time and/or absorption. The aim of this study was to evaluate the impact of structural changes of proteins due to thermal processing on gastro-intestinal tolerance in the immature GI tract. Preterm and near-term piglets received enteral nutrition based on whey protein concentrate (WPC) either mildly pasteurized (MP-WPC) or extensively heated (EH-WPC). Clinical symptoms, transit time and gastric residuals were evaluated. In addition, protein coagulation and protein composition of coagulates formed during in vitro digestion were analyzed in more detail. Characterization of MP-WPC and EH-WPC revealed that mild pasteurization maintained protein nativity and reduced aggregation of β-lactoglobulin and α-lactalbumin, relative to EH-WPC. Mild pasteurization reduced the formation of coagulates during digestion, resulting in reduced gastric residual volume and increased intestinal tract content. In addition, preterm piglets receiving MP-WPC showed reduced mucosal bacterial adherence in the proximal small intestine. Finally, in vitro digestion studies revealed less protein coagulation and lower levels of β-lactoglobulin and α-lactalbumin in the coagulates of MP-WPC compared with EH-WPC. In conclusion, minimal heat treatment of WPC compared with extensive heating promoted GI tolerance in immature piglets, implying that minimal heated WPC could improve the GI tolerance of milk formulas in infants.

Faecal calprotectin levels during the first year of life in healthy children

AIM

A high faecal calprotectin (FC) level is a non-invasive marker for inflammatory bowel disease. Nevertheless, healthy infants have elevated levels of FC with large variations. The aim of our study was to determine the levels of FC and associated factors in healthy infants aged 0-12 months.

METHODS

Infants younger than 1 year of age were in the follow-up programme of the Well Child Unit. Data on the clinical characteristics, including birth, anthropometric measurements and feeding types of infants in the unit, were obtained from their personal health records. One fresh stool sample was collected from each infant. ELISA was used to measure FC.

RESULTS

We included 84 infants younger than 1 year of age. The median FC value was 313 μg/g. The FC levels were greater in the youngest (0-30 days) group of infants than in the oldest (181-365 days) group (P < 0.001). The FC levels were higher in infants delivered by caesarean section than in those delivered vaginally (P = 0.016). The levels were also higher in infants who were solely breastfed than in those who received mixed feeding (breast milk and formula) during the first 6 months of life (P = 0.030).

CONCLUSION

The FC levels in this group of infants were high, especially in the first month of life. Several birth and environmental factors influenced the FC values. Further studies with a larger cohort of infants and serial assessment of FC over time are required to better understand the patterns of this biomarker during infancy.

A comparison of macronutrient-based methods for deriving energy values in human milk

OBJECTIVE

Energy values for human milk are increasingly available clinically, though there are no standards for deriving these values. We compared published calorie methods using a common set of samples.

STUDY DESIGN

Ten human milk samples were measured for gross and digestible macronutrients using laboratory methods. Four calorie conversion factors were used: Atwater general (ATW-GEN); Atwater milk specific (ATW-MILK), human milk specific (HUM-MILK), and combustible conversions (COMBUST). Differences in derived calories were assessed using ANOVA.

RESULTS

There was a significant difference (P < 0.001) in calorie values between methods. Gross macronutrients with COMBUST conversion factors produced the highest calorie values (19.4 ± 1.4 kcal/ounce) whereas digestible macronutrients with HUM-MILK conversion factors produced the lowest calorie values (16.3 ± 1.3 kcal/ounce). Mean difference between these values was 3.1 kcal/ounce (95% CI 2.5, 3.7).

CONCLUSION

Mean calorie difference of 3.1 kcal/ounce is clinically important for preterm infants, suggesting the need for standardization.

Degradation of Proteins From Colostrum and Mature Milk From Chinese Mothers Using an in vitro Infant Digestion Model

This study provided insights into the degradation of human milk proteins in an in vitro infant digestion model by comparing colostrum (week 1) and mature milk (week 4) of 7 Chinese mothers individually. In this study, we adapted the exiting INFOGEST in vitro model, to conditions representative to infants (0 to 3 month-old). The level of undigested proteins was analyzed by LC-MS/MS after gel-electrophoretic separation and in-gel digestion. The BCA protein assay showed that the total undigested milk protein content decreased from the start to the end of digestion with variations between mothers, especially in the gastric phase (25–80%). Undigested proteins could also still be found after the intestinal phase, ranging from 0.5 to 4.2% of initial protein content. Based on LC-MS/MS analysis, milk protein digestion varied between the mothers individually, especially during the gastric phase. No differences could be observed between protein digestion from colostrum and mature milk after the intestinal phase. The highest levels of proteins remaining after intestinal digestion can be linked to the group immune-active proteins, for all mothers. The level of protease inhibitors and total protein content in the milk did not correlate with the overall proteolysis during digestion. The results also showed that milk serum proteins partly remained after the gastric phase, with 33% remaining from colostrum and 37% remaining from mature milk. More than 40 milk serum proteins were detected after the intestinal phase. Some of the highly abundant milk serum proteins (lactoferrin, serum albumin, bile salt-activated lipase, immunoglobulins, α₁-antichymotrypsin) were still partially present intact after the intestinal phase, for all mothers. Caseins were also not completely digested in the gastric phase, with 35% remaining from colostrum and 13% remaining from mature milk. Caseins, on the other hand, were almost completely digested after the intestinal phase. The complete degradation of caseins into peptides might be related to their structural features. Overall, this study showed that digestion differed for the various human milk proteins by adapting an in vitro digestion model to infant physiological conditions, with the main differences between digestion of the milk from individual mothers being observed after gastric digestion.

Systematic examination of protein extraction, proteolytic glycopeptide enrichment and MS/MS fragmentation techniques for site-specific profiling of human milk N-glycoproteins

Human milk contains numerous N-glycoproteins with functions that provide protection to the infant. Increasing understanding of the functional role of human milk glycoproteins within the infant requires toolsets to comprehensively profile their site-specific glycosylation patterns. However, optimized methods for site-specific glycosylation analysis across the entire human milk proteome are not available. Therefore, we performed a systematic analysis of techniques for profiling the sites and compositions of N-glycans in human milk using liquid chromatography/mass spectrometry. To decrease interference from non-target molecules, we compared techniques for protein extraction, including ethanol (EtOH) precipitation, trichloroacetic acid precipitation, molecular weight cut-off filtration and techniques for tryptic glycopeptide enrichment, including C18-, porous graphitized carbon and hydrophilic interaction liquid chromatography (HILIC)-solid phase extraction (SPE) and acetone precipitation. We compared the capacity of higher-energy collision dissociation, electron-transfer dissociation and electron-transfer/higher-energy collision dissociation (EThcD) to produce fragment ions that would enable effective identification of the glycan composition, peptide sequence and glycosylation site. Of these methods, a combination of EtOH precipitation, HILIC-SPE and EThcD-fragmentation was the most effective for human milk N-glycopeptide profiling. This optimized approach significantly increased the number of N-glycopeptides and precursor N-glycoproteins (246 N-glycopeptides from 29 glycoproteins) compared with a more common extraction approach with no protein extraction and C18 clean-up (62 N-glycopeptides from 11 glycoproteins). The advancement in methods for human milk N-glycoproteins provided by this study represents a key step for better understanding the function of glycoproteins within the breast milk-fed infant.

Factors Associated with Anemia Among Children 6-23 Months of Age in Ethiopia: A Multilevel Analysis of Data from the 2016 Ethiopia Demographic and Health Survey

BACKGROUND

Anemia is disproportionately borne among children in the African regions including Ethiopia. In Ethiopia, there is limited information on the prevalence and factors associated with anemia among children aged 6-23 months. Therefore, the aim of this study was to identify individual- and community-level factors associated with anemia among children 6-23 months of age.

METHODS

The data were obtained from the 2016 Ethiopia Demographic and Health Survey, conducted from January to June 2016. A sample of 2554 children aged 6-23 months was included. Data were analyzed using STATA version 14. A multilevel ordinal logistic regression model was fitted and an adjusted odds ratio with a 95% confidence interval was obtained.

RESULTS

The prevalence of anemia among children 6-23 months of age was 72.3%; 27.5% mild, 41% moderate, and 3.8% severe anemia. child age 18-23 months (AOR: 0.76; 95%CI: 0.61-0.93), female sex (AOR: 0.84; 95%CI: 0.72-0.98), maternal anemia (AOR: 1.53; 95%CI: 1.28-1.82), exclusive breastfeeding (AOR: 0.73; 95%CI: 0.54-0.98), child fever (AOR: 1.41; 95%CI: 1.03-1.93), underweight children (AOR: 1.42; 95%CI: 1.17-1.73) and exposure to either newspaper, radio or television (AOR: 0.78; 95%CI: 0.61-0.99) were the individual-level factors associated with anemia. High community-poverty (AOR: 1.30; 95%CI: 1.01-1.67), living in the regions of Somali (AOR: 2.08; 95%CI: 1.31-3.29), Amhara (AOR: 0.65; 95%CI: 0.45-0.94), Benishangul (AOR: 0.39; 95%CI: 0.25- 0.61) and Harari (AOR: 1.97; 95%CI: 1.18-3.31) were the community-level factors associated with anemia.

CONCLUSION

This study showed that childhood anemia is affected both by the individual- and community-level factors. The strategies of promoting exclusive breastfeeding, addressing maternal anemia, child fever, giving special attention for underweight children, and targeting regions identified to have a high risk of anemia should be strengthened to reduce childhood anemia.

Nutritional and Non-nutritional Composition of Human Milk Is Modulated by Maternal, Infant, and Methodological Factors

Human milk (HM) is dynamic and shows a high inter- and intra-individual variability. To characterize HM with precision, it is necessary to understand the factors that modulate its composition. The objective of this narrative review is to summarize the maternal, infant and methodological factors that affect HM composition. We searched SCOPUS and PubMed databases for articles related to factors that are known to or could potentially influence HM composition and volume across lactation periods. Our comprehensive review encompasses various maternal-, infant-related, and methodological factors that modulate aspects of HM composition including macro- and micronutrients, vitamins and minerals, as well as volume. The most profound changes were observed in HM lipids and lipophiles. Evidence exists for many of the infant-related factors known to affect the nutritive and non-nutritive components of HM (e.g., birth weight, gestational age, infant age/stage of lactation). In contrast, less is known with respect to maternal factors; where there is either limited research or conflicting evidence (e.g., maternal lifestyle, obstetric history, medical conditions), except for the mother's diet, for which there is a relatively well-established understanding. Equally, although many of the methodological factors (e.g., HM sampling, handling and analytics) are known to impact HM composition, few studies have investigated this as a primary outcome, making it an important area of future research in HM. Here we propose a systematic capture of numerous maternal- and infant-related characteristics to facilitate associative comparisons of HM data within and across studies. Additionally, it would be prudent to standardize the methodological aspects known to affect HM composition in analytics, not only for HM lipids and lipophiles, but also for those nutrients whose variability is yet less well-understood. Defining the factors determining HM composition with accuracy will open perspectives for maternal intervention to optimize milk composition for specific needs of infants.

Insights on Health and Food Applications of Equus asinus (Donkey) Milk Bioactive Proteins and Peptides-An Overview

Due to its similarity with human milk and its low allergenic properties, donkey milk has long been used as an alternative for infants and patients with cow's milk protein allergy (CMPA). In addition, this milk is attracting growing interest in human nutrition because of presumed health benefits. It has antioxidant, antimicrobial, antitumoral, antiproliferative and antidiabetic activity. In addition, it stimulates the immune system, regulates the gastrointestinal flora, and prevents inflammatory diseases. Although all donkey milk components can contribute to functional and nutritional effects, it is generally accepted that the whey protein fraction plays a significant role. This review aims to highlight the active proteins and peptides of donkey milk in comparison with other types of milk, emphasizing their properties and their roles in different fields of health and food applications.

Factors Affecting the Composition of Expressed Fresh Human Milk

Breast milk is considered the ideal and preferred feeding for all infants through the first 4-6 months of life. It provides many short and long-term benefits to the infant and mother. In the absence of breastfeeding, expressed breast milk is the best way to provide nutrition. In the United States, the majority of breastfeeding mothers express milk at some point during the course of lactation. Breast milk is a dynamic fluid and its content changes with duration of lactation and varies between and among women. Many factors such as maternal diet and medications affect the constituents of breast milk. In addition, method of breast milk expression, handling, and storage can also influence its contents.

Immunomodulatory Constituents of Human Donor Milk

Mother's own human milk is the best nutrition for infants, especially preterm very-low-birth-weight (VLBW) (≤1,500 g) infants, because of its immune-modulatory constituents that strengthen the infant's host defense, provide protection against infections, and decrease the risk of necrotizing enterocolitis (NEC). When mother's own milk is unavailable or insufficient, donor human milk is considered the best alternative, especially for preterm VLBW infants. However, to assure biological safety, donor milk must be pasteurized. This results in partial or complete inactivation of some of the immunomodulatory constituents of human milk, which confer host defense. This review summarizes the current evidence regarding the effects of pasteurization on the different immunological constituents of donor milk, and their clinical significance, especially in relation to prevention of NEC.

Formula Diet Alters the Ileal Metagenome and Transcriptome at Weaning and during the Postweaning Period in a Porcine Model

Exclusive breastfeeding impacts the intestinal microbiome and is associated with a better immune function than is seen with milk formula (MF) feeding in infants and yet with mechanisms poorly defined. The porcine model was used to evaluate the impact of MF on ileum microbial communities and gene expression relative to human milk (HM)-fed piglets. Fifty-two Dutch Landrace male piglets were fed an isocaloric diet of either HM (n = 26) or MF (n = 26) from day 2 through day 21 of age and weaned to a solid diet until day 51. Eleven piglets from each group were euthanized at day 21, while the remaining piglets (HM, n = 15; MF, n = 15) were euthanized at day 51 to collect ileal epithelium (EP) scrapings and ileal (IL) tissues. The epithelial mucosa was subjected to shotgun metagenome sequencing, and EP and IL tissues were used for transcriptome analysis. On day 21, transcriptome data revealed that the levels of pathways involved in inflammation and apoptosis were significantly higher in MF piglets than in HM piglets, whereas the levels of tight junctions and pathogen detection systems were lower in MF piglets than in HM piglets. The MF impacts on the small intestine were maintained over the postweaning period (day 51) as indicated by higher levels of Dialister invisus bacteria and higher levels of expression of genes associated with inflammation and apoptosis pathways relative to HM group. The current study demonstrated that MF might impact local intestinal inflammation, apoptosis, and tight junctions and might suppress pathogen recognition in the small intestine compared with HM.IMPORTANCE Exclusive human milk (HM) breastfeeding for the first 6 months of age in infants is recommended to improve health outcomes during early life and beyond. When women are unable to provide sufficient HM, milk formula (MF) is often recommended as a complementary or alternative source of nutrition. Previous studies in piglets demonstrated that MF alters the gut microbiome and induces inflammatory cytokine production. The links between MF feeding, gut microbiome, and inflammation status are unclear due to challenges associated with the collection of intestinal samples from human infants. The current report provides the first insight into MF-microbiome-inflammation connections in the small intestine compared with HM feeding using a porcine model. The present results showed that, compared with HM, MF might impact immune function through the induction of ileal inflammation, apoptosis, and tight junction disruptions and likely compromised immune defense against pathogen detection in the small intestine relative to piglets that were fed HM.

Investigation of amino acids and minerals in Chinese breast milk

BACKGROUND

The nutrients in human milk, particularly amino acids and minerals, are important for infant growth and development. Since there are few reports of amino acids and minerals in Chinese breast milk, we conducted this study to establish a representative preliminary database of breast milk nutrients in Chinese breast milk. In this study, we collected breast milk from healthy mothers in seven cities in western, southern and central China. The composition, content and proportion of total amino acids and ten elements (potassium, sodium, calcium, magnesium, iron, zinc, manganese, copper, selenium and phosphorus) in human milk in different lactation stages were investigated.

RESULTS

In this study, it was found that the content of total essential amino acids (671.47 mg 100 mL^-1 ) in Chinese breast milk was higher compared with the European Society for Paediatric Gastroenterology Hepatology and Nutrition (ESPGHAN) (574 mg 100 mL^-1 ), but the content of leucine (LEU) (129.01 mg 100 mL^-1 ) and cysteine (CYS) (20.31 mg 100 mL^-1 ) was much lower than that recommended by ESPGHAN. Moreover, it was found that the content of most of these ten elements decreased during lactation, and the content of calcium in Chinese breast milk was lower compared with ESPGHAN. In addition, the content of selenium (7.23-20.55 mg 1000 mL^-1 ) in breast milk from the three cities Nanchang, Shanghai and Guangzhou in China was much higher than that recommended by ESPGHAN.

CONCLUSIONS

In a word, amino acids and minerals in Chinese human milk showed a significant difference from other countries. Human milk meal or infant food should be regulated to meet the requirements of the infant and to maintain the balance of the amino acids and minerals. © 2020 Society of Chemical Industry.

Bovine Lactoferrin Supplementation Does Not Disrupt Microbiota Development in Preterm Infants Receiving Probiotics

OBJECTIVE

The aim of the study was to assess whether bovine lactoferrin (bLf) supplementation disrupts intestinal microbiota development in preterm infants less than 31 weeks gestational age receiving prophylactic probiotic administration.

METHODS

Subjects were recruited from the LACUNA trial (ISRCTN66482337), designed to assess bLf safety. These subjects were randomized to daily receive either probiotic supplements or probiotics supplemented with 100 mg bLf mixed with their feeds (human milk or formula). Stools were collected weekly from enrolled infants for 1 month and the microbiota characterized using V6-16S rRNA gene amplicon profiling.

RESULTS

Infants' microbiomes did not increase in alpha diversity over time in both feeding interventions. Infants receiving bLf supplementation had overall higher species richness as compared with those not receiving these supplements and lactoferrin supplementation had differing effects on infant microbiota species richness depending on the infant's gestational age. Principal co-ordinate analysis revealed that the infant microbiotas did not separate by intervention group, gestational age bracket at birth or sampling time and the main factor dictating sample clustering was infant identity. There were very few detectable differences in taxa relative abundance or functional gene content between the microbiotas in the 2 study groups.

CONCLUSIONS

Bovine lactoferrin supplementation has minimal impact on microbiota composition/function in preterm infants receiving probiotics, and therefore, is unlikely to disrupt microbiota development.

Early-Life Supplementation of Bovine Milk Osteopontin Supports Neurodevelopment and Influences Exploratory Behavior

INTRODUCTION

Osteopontin (OPN) is a whey protein found at high concentration in human milk and is involved in processes such as bone cell proliferation and differentiation. Milk OPN has shown to be involved in various aspects of development, including the immune system and gut health. However, the influence of dietary bovine milk OPN inclusion on brain and cognitive development has not been studied extensively until recently. This research examines whether dietary supplementation of bovine milk OPN supports brain and cognitive development in the translational pig model.

METHODS

From postnatal day (PND) 2 to 34, twenty-one intact male pigs were provided ad libitum access to one of two dietary treatments, a standard soy protein isolate-based milk replacer to serve as a control diet (n = 11) and the same base diet supplemented with bovine milk OPN to serve as a test diet (n = 10). In addition to growth and health outcomes, recognition memory was tested using the novel object recognition (NOR) task from PND 28 to 32, and magnetic resonance imaging was conducted at PND 34 to evaluate brain development.

RESULTS

No dietary effects were observed for growth performance or health indices. For the behavioral analysis, pigs that received the test diet exhibited shorter (p < 0.05) latency to the first object visited compared with pigs fed the control diet. Although the control group exhibited novelty preference, there was no difference in recognition index between dietary groups. Neuroimaging outcomes revealed increased (p < 0.05) relative brain volumes of the corpus callosum, lateral ventricle, left and right internal capsule, left and right putamen-globus pallidus, and right hippocampus, and right cortex in the test group. Diffusion tensor imaging revealed higher (p < 0.05) radial diffusivity in the corpus callosum and lower (p < 0.05) fractional anisotropy in pigs provided the test diet.

CONCLUSION

Dietary supplementation of bovine milk OPN increased the relative volume of several brain regions and altered behaviors in the NOR task. Underlying mechanisms of bovine milk OPN influencing the development of brain structures and additional behaviors warrant further investigation.

MicroRNA Milk Exosomes: From Cellular Regulator to Genomic Marker

Recent advances in ruminants' milk-derived exosomes (EXO) have indicated a role of microRNAs (miRNAs) in cell-to-cell communication in dairy ruminants. The miRNAs EXO retain peculiar mechanisms of uptake from recipient cells, which enables the selective delivery of cargos, with a specific regulation of target genes. Although many studies have been published on the miRNAs contained in milk, less information is available on the role of miRNAs EXO, which are considered stable over time and resistant to digestion and milk processing. Several miRNAs EXO have been implicated in the cellular signaling pathway, as in the regulation of immune response. Moreover, they exert epigenetic control, as extenuating the expression of DNA methyltransferase 1. However, the study of miRNAs EXO is still challenging due to the difficulty of isolating EXO. In fact, there are not agreed protocols, and different methods, often time-consuming, are used, making it difficult to routinely process a large number of samples. The regulation of cell functions in mammary glands by miRNAs EXO, and their applications as genomic markers in livestock, is presented.

Milk‑derived hexapeptide PGPIPN prevents and attenuates acute alcoholic liver injury in mice by reducing endoplasmic reticulum stress

Bioactive peptides are an emerging area of biomedical research in the study of numerous human diseases, including acute alcoholic liver injury (AALI). To study the role and mechanism of the milk-derived hexapeptide Pro-Gly-Pro-Ile-Pro-Asn (PGPIPN) in preventing and reducing AALI, the present study established a mouse model of AALI. PGPIPN was used as a therapeutic drug, and glutathione (GSH) was used as a positive control. The body and liver weights of mice were measured, and the liver indexes were calculated to observe mice health. The pathological morphology of liver tissues stained with hematoxylin and eosin were examined to analyze hepatic injury, and hepatocyte apoptosis was measured with a TUNEL assay. The concentrations or activities of alanine aminotransferase (ALT), aspartate aminotransferase, tumor necrosis factor-α, interleukin (IL)-1β, IL-6, triglyceride, total cholesterol, malondialdehyde, superoxide dismutase and GSH peroxidase (GSH-PX) were detected in serum and/or liver homogenates. The 78 kDa glucose-regulated protein (GRP78), protein kinase R-like (PKR) endoplasmic reticulum kinase (PERK), phosphorylated (p)-PERK, eukaryotic initiation factor 2α (eIF-2α), p-eIF-2α, inositol-requiring enzyme 1α (IRE-1α), spliced X-box binding protein 1 (XBP-1s), C/EBP homologous protein (CHOP), caspase-3 and cleaved caspase-3 proteins associated with endoplasmic reticulum stress in hepatocytes were assessed by western blotting, and RNA levels of XBP-1s, CHOP and caspase-3 genes were assessed by reverse transcription-quantitative PCR. The results suggested that PGPIPN attenuated alcoholic hepatocyte damage in animal models and reduced hepatocyte oxidative stress in a dose-dependent manner. Moreover, PGPIPN reduced endoplasmic reticulum stress by regulating the expression levels of p-PERK, p-eIF-2α, XBP-1s, CHOP, caspase-3 and cleaved caspase-3. Collectively, the present results indicated that PGPIPN, as a potential therapeutic drug for AALI, exerted a protective effect on the liver and could reduce liver damage.

Evaluation of Bioactivities of the Bovine Milk Lactoferrin-Osteopontin Complex in Infant Formulas

Human milk contains several bioactive proteins, including lactoferrin (LF) and osteopontin (OPN). These two proteins have been shown to form a complex, which shows increased bioactivities. Bovine LF and OPN can also form such a complex. We assessed bioactivities of the bovine LF-OPN complex (at molar ratios of LF:OPN = 3:1, 5:1, or 8:1) in a formula protein matrix, including LF, OPN, bovine whey protein hydrolysate, and α-lactalbumin. Our results show that the bovine LF-OPN complex together with formula proteins is resistant to in vitro digestion, stimulates intestinal cell proliferation (by 15-50%) and differentiation (by 30-50%), increases antibacterial activity (by 25-50%), and enhances intestinal immunity. The 3:1 ratio of LF to OPN exhibits the most potent effects, as compared with the other two ratios. In conclusion, adding bovine LF and OPN to infant formulas may result in increased stability of the two components and enhanced bioactivities, possibly improving outcomes in formula-fed infants.

Macro- and Micronutrients in Milk from Healthy Cambodian Mothers: Status and Interrelations

BACKGROUND

Except for low thiamin content, little is known about vitamins or macronutrients in milk from Cambodian mothers, and associations among milk nutrients.

OBJECTIVES

We measured fat-soluble vitamins (FSVs) and water-soluble vitamins (WSVs), and macronutrients, and explored internutrient associations in milk from Cambodian mothers.

METHODS

Milk from women (aged 18-45 y, 3-27 wk postpartum, n = 68) who participated in a thiamin-fortification trial were analyzed for vitamins B-2 (riboflavin, FAD), B-3 (nicotinamide), B-5, B-6 (pyridoxal, pyridoxine), B-7, B-12, A, E [α-tocopherol and γ-tocopherol (γ-TPH)], carotenoids, carbohydrate (CHO), fat, and protein. Milk vitamin B-1 [thiamin, thiamin monophosphate (TMP), thiamin pyrophosphate (TPP)] was previously assessed for fortification effects. Milk nutrient concentrations were compared with the Adequate Intake (AI) values for infants aged 0-6 mo. Pearson correlation was used to examine internutrient associations after excluding nutrients affected by fortification.

RESULTS

Fortification increased thiamin and B-1 and decreased γ-TPH. Less than 40% of milk samples met the AIs for all vitamins, and 10 samples did not reach any AI values for the analyzed nutrients. CHO, fat, and energy values were met in 1.5-11.8%, and protein in 48.5%, of the samples. Whereas fat, protein, and energy were related (all r < 0.5; P < 0.001) and associated with FSVs and WSVs, CHO correlated only with some WSVs. TPP was not correlated with B-1 vitamers, but with other WSVs (r = 0.28-0.58; P < 0.019). All FSVs, except α-carotene, were correlated with each other (r = 0.42-0.98; P < 0.002). TPP, FAD, B-2, and B-3 were associated with almost all FSVs (r = 0.24-0.63; P < 0.044).

CONCLUSIONS

Cambodian women might not provide sufficient nutrients to their exclusively breastfeeding infants. Besides thiamin, all other vitamins measured were much lower than the AI. There were many strong correlations among macronutrients and vitamins; the extent to which these are explained by maternal diet, milk volume, maternal physiology, or genetics requires additional exploration.

Protein content of infant formula for the healthy full-term infant

Healthy full-term breastfed infants show a different growth pattern compared to formula fed infants and this can reduce the risk of obesity and metabolic syndrome later in life. The increasing knowledge of breast milk composition led to the hypothesis that high dietary protein intake derived from formula milk feeding could have a role in determining the different growth rates and body composition of formula-fed infants compared to breastfed infants. In efforts to simulate human milk, many studies have investigated the safety of infant formulas with reduced protein levels. Nevertheless, feeding a "very-low" protein infant formula may cause limited protein synthesis during a phase of rapid growth. For this reason, using a low-protein formula with an amino acid composition modified according on the estimated infant requirements was suggested. In this edition of the American Journal of Clinical Nutrition, Kouwenhoven et al. concluded that the use of a modified low protein formula (1.7 g protein/100 kcal) is safe. Therefore, if this data is confirmed by longer follow up, the current European legal standards for protein amount in infant formula could be reduced with a potential reduction of the later risk of childhood obesity.

Lysozyme in the treatment of non-infectious sore throat

Sore throat is a common reason for seeking medical help [1]. It can have infectious and non-infectious aetiology [2]. The term “sore throat” is usually associated with an infectious agent (bacteria, viruses, and less commonly fungi) [1,3,4]. The terms “throat discomfort“,“throat irritation“ or “functional dysphonia due to the occupational diseases“ (which represents voice disorder) are often used in the same sense as a non-infectious sore throat [2,3]. It is identified by the exclusion of infectious aetiology symptoms accompanied by persistent sore throat symptoms (tingling and scratching sensation in the throat, hoarseness or muffled voice, foreign body sensation in the throat, coughing, difficulty in swallowing accompanied by pain) [2,5]. Read the full text [PDF]

Interactions of probiotics and prebiotics with the gut microbiota

The gut microbiota (GM) composition varies among individuals and is influenced by intrinsic (genetics, age) and extrinsic (environment, diet, lifestyle) factors. An imbalance or dysbiosis is directly associated with the development of several illnesses, due to the potential increase in intestinal permeability leading to a systemic inflammation triggered by higher levels of circulating lipopolysaccharides and changes in the immune response caused by an overgrowth of a specific genus or of pathogens. These mechanisms may increase symptoms in gastrointestinal disorders or reduce glucose tolerance in metabolic diseases. Diet also has a significant impact on GM, and functional foods, namely prebiotics and probiotics, are a novel approach to reestablish the indigenous microbiota. Prebiotics, like inulin and polyphenols, are selectively utilized by GM, releasing short-chain fatty acids (SCFA) and other metabolites which may reduce the intestinal lumen pH, inhibit growth of pathogens, and enhance mineral and vitamin bioavailability. Probiotic microorganism may increase the microbial diversity of GM and improve the integrity of the intestinal barrier, leading to an improvement of baseline and pathologic inflammation. In this chapter, we will discuss the potential roles of prebiotics and probiotics in health and diseases throughout an individual's lifetime and proposed mechanisms of action.

SERPINA1 gene identified in RNA-Seq showed strong association with milk protein concentration in Chinese Holstein cows

The detection of candidate genes and mutations associated with phenotypic traits is important for livestock animals. A previous RNA-Seq study revealed that SERPINA1 gene was a functional candidate that may affect milk protein concentration in dairy cows. To further confirm the genetic effect of SERPINA1 on milk protein traits, genetic polymorphisms were identified and genotype-phenotype associations were performed in a large Chinese Holstein cattle population. The entire coding region and the 5′-regulatory region (5′-UTR) of SERPINA1 was sequenced using pooled DNA of 17 unrelated sires. Association studies for five milk production traits were performed using a mixed model with a population encompassing 1,027 Chinese Holstein cows. A total of four SNPs were identified in SERPINA1, among which rs210222822 and rs41257068 presented in exons, rs207601878 presented in an intron, and rs208607693 was in the 5′-UTR. Analyses of pairwise D′ measures of linkage disequilibrium (LD) showed strong linkage among these four SNPs (D′ = 0.99–1.00), and a 9 Kb haplotype block involving three main haplotypes with GTGT, CCCC and CCGT was inferred. An association study revealed that all four single SNPs and their haplotypes had significant genetic effects on milk protein percentage, milk protein yield and milk yield (P = 0.0458 −  < 0.0001). The phenotypic variance ratio for all 11 significant SNP-trait pairs ranged from 1.01% to 7.54%. The candidate gene of SERPINA1 revealed by our previous RNA-Seq study was confirmed to have pronounced effect on milk protein traits on a genome level. Two SNPs (rs208607693 and rs210222822) presented phenotypic variances of approximately 7% and may be used as key or potential markers to assist selection for new lines of cows with high protein concentration.

Comparative milk proteome analysis of Kashmiri and Jersey cattle identifies differential expression of key proteins involved in immune system regulation and milk quality

BACKGROUND

Exploration of the bioactive components of bovine milk has gained global interest due to their potential applications in human nutrition and health promotion. Despite advances in proteomics profiling, limited studies have been carried out to fully characterize the bovine milk proteome. This study explored the milk proteome of Jersey and Kashmiri cattle at day 90 of lactation using high-resolution mass spectrometry based quantitative proteomics nano-scale LC-MS/Q-TOF technique. Data are available via ProteomeXchange with identifier PXD017412.

RESULTS

Proteins from whey were fractionated by precipitation into high and low abundant proteins. A total of 81 high-abundant and 99 low-abundant proteins were significantly differentially expressed between Kashmiri and Jersey cattle, clearly differentiating the two breeds at the proteome level. Among the top differentiating proteins, the Kashmiri cattle milk proteome was characterised by increased concentrations of immune-related proteins (apelin, acid glycoprotein, CD14 antigen), neonatal developmental protein (probetacellulin), xenobiotic metabolising enzyme (flavin monooxygenase 3 (FMO3), GLYCAM1 and HSP90AA1 (chaperone) while the Jersey milk proteome presented higher concentrations of enzyme modulators (SERPINA1, RAC1, serine peptidase inhibitor) and hydrolases (LTF, LPL, CYM, PNLIPRP2). Pathway analysis in Kashmiri cattle revealed enrichment of key pathways involved in the regulation of mammary gland development like Wnt signalling pathway, EGF receptor signalling pathway and FGF signalling pathway while a pathway (T-cell activation pathway) associated with immune system regulation was significantly enriched in Jersey cattle. Most importantly, the high-abundant FMO3 enzyme with an observed 17-fold higher expression in Kashmiri cattle milk seems to be a characteristic feature of the breed. The presence of this (FMO3) bioactive peptide/enzyme in Kashmiri cattle could be economically advantageous for milk products from Kashmiri cattle.

CONCLUSION

In conclusion, this is the first study to provide insights not only into the milk proteome differences between Kashmiri and Jersey cattle but also provides potential directions for application of specific milk proteins from Kashmiri cattle in special milk preparations like infant formula.

Nutrient and hormone composition of milk is altered in rodent dams post-bariatric surgery

Although bariatric surgery is approved for a woman of child-bearing age with an interest in subsequent pregnancy, reports of in utero growth issues during pregnancy have garnered a closer look at the impact of maternal surgical weight loss on the pre- and postpartum periods. Offspring of dams having received vertical sleeve gastrectomy (VSG) are born small-for-gestational age and have increased risk for metabolic syndrome later in life. Here, we aimed to determine whether the postnatal catch-up growth trajectory of bariatric offspring may be affected by milk composition. Milk samples were collected at postnatal day 15/16 from dams having received VSG surgery and fed a high-fat diet (HFD) (H-VSG), Sham surgery and fed chow (C-Sham), or Sham surgery and fed HFD (H-Sham). Milk obtained from H-VSG dams had elevated glucose (P < 0.05) and significantly reduced triglyceride content (P < 0.01). Milk from H-Sham dams had the lowest amount of milk protein (P < 0.05). Fatty acid composition measured by fractionation was largely not affected by surgery but rather maternal diet. No difference was observed in milk leptin levels; however, insulin, adiponectin, and growth hormone levels were significantly increased in milk from H-VSG animals. H-Sham had the lowest level of immunoglobulin (Ig)A, whereas IgG was significantly reduced in H-VSG. Taken together, the quality of milk from H-VSG dams suggests that milk composition could be a factor in reducing the rate of growth during the lactation period.

Neonatal Microbiome and Its Relationship to Necrotizing Enterocolitis: A Review of the Science

Necrotizing enterocolitis (NEC) occurs in many premature infants hospitalized in the neonatal intensive care unit. About 3% to 15% of very low-weight premature infants develop NEC, with an estimated 30% mortality rate for the cases requiring surgery. Currently, there is no known pathogenesis for NEC in the patient's populations. However, one of the most widely accepted hypotheses is having an abnormal fetal gut microbiome. The purpose of this review is to discuss some current methods of dysbiosis in the neonatal microbiome, such as maternal health, breastfeeding, and delivery method, and then to connect these to the occurrence of NEC in the infant and finally discuss some possibilities for limiting the occurrence of NEC in the future.

Impact of Donor Human Milk in the Preterm Very Low Birth Weight Gut Transcriptome Profile by Use of Exfoliated Intestinal Cells

Background: Own mother’s milk (OMM) is the optimal nutrition for preterm infants. However, pasteurized donor human milk (DHM) is a valid alternative. We explored the differences of the transcriptome in exfoliated epithelial intestinal cells (EEIC) of preterm infants receiving full feed with OMM or DHM. Methods: The prospective observational study included preterm infants ≤ 32 weeks’ gestation and/or ≤1500 g birthweight. Total RNA from EEIC were processed for genome-wide expression analysis. Results: Principal component analysis and unsupervised hierarchical clustering analysis revealed two clustered groups corresponding to the OMM and DHM groups that showed differences in the gene expression profile in 1629 transcripts. The OMM group overexpressed lactalbumin alpha gene (LALBA), Cytochrome C oxidase subunit I gene (COX1) and caseins kappa gene (CSN3), beta gene (CSN2) and alpha gene (CSN1S1) and underexpressed Neutrophil Cytosolic Factor 1 gene (NCF1) compared to the DHM group. Conclusions: The transcriptomic analysis of EEIC showed that OMM induced a differential expression of specific genes that may contribute to a more efficient response to a pro-oxidant challenge early in the postnatal period when preterm infants are at a higher risk of oxidative stress. The use of OMM should be strongly promoted in preterm infants.

Milk in the prevention and management of type 2 diabetes: The potential role of milk proteins

Globally, diabetes mellitus is not only considered a leading cause of mortality and morbidities but has also created a substantial economic burden. There is growing evidence that foods and their components can be implemented in the prevention and management of type 2 diabetes mellitus (T2DM). Increased dairy consumption has been linked to a lower risk of T2DM. The protective role of dairy foods in the development of T2DM is thought to be largely attributable to dairy nutrients, one of them being dairy protein. There is considerable evidence that milk proteins increase the postprandial insulin response and lower the postprandial blood glucose response in both healthy subjects and patients with T2DM. The exact mechanisms by which milk proteins lower postprandial glucose levels are yet to established; however, the amino acids and bioactive peptides derived from milk proteins are thought to modify a physiological milieu, which includes delayed gastric emptying and the enhancement of incretin and insulin responses, consequently leading to lower postprandial glucose levels. The present review will focus on providing a clear presentation of the potential implementation of milk proteins as a dietary supplement in the prevention and management of T2DM by summarizing the relevant supporting evidence for this particular topic.

Glycerol Monolaurate Contributes to the Antimicrobial and Anti-inflammatory Activity of Human Milk

Human milk has antimicrobial compounds and immunomodulatory activities. We investigated glycerol monolaurate (GML) in human milk versus bovine milk and infant formula for antimicrobial and anti-inflammatory activities. Human milk contained approximately 3000 µg/ml of GML, compared to 150 μg/ml in bovine milk and none in infant formula. For bacteria tested (Staphylococcus aureus, Bacillus subtilis, Clostridium perfringens, Escherichia coli), except Enterococcus faecalis, human milk was more antimicrobial than bovine milk and formula. The Enterococcus faecalis strain, which was not inhibited, produced reutericyclin, which is an analogue of GML and functions as a growth stimulant in bacteria that produce it. Removal of GML and other lipophilic molecules from human milk by ethanol extraction resulted in a loss of antibacterial activity, which was restored by re-addition of GML. GML addition caused bovine milk to become antimicrobial. Human milk but not bovine milk or formula inhibited superantigen and bacterial-induced IL-8 production by model human epithelial cells. GML may contribute beneficially to human milk compared to bovine milk or infant formula.

Human Milk Retains Important Immunologic Properties After Defatting

BACKGROUND

In neonatal chylothorax, thoracic lymphatic drainage is ineffective. The resultant effusions often require drainage, leading to a loss of immune components. Affected infants can be managed with formula or defatted human milk feedings low in long-chain triglycerides to decrease lymph production. We hypothesized that there is no significant difference in the immunological profile or antibacterial effect of full-fat and defatted human milk.

METHODS

Milk from lactating mothers was divided into 1 aliquot that was defatted via centrifugation with the full-fat aliquot as control. Macronutrient content was analyzed with mid-infrared spectroscopy. Flow cytometry was used to measure immune cell populations. Lactoferrin, lysozyme, immunoglobulin (Ig)A, and IgG values were determined using enzyme-linked immunosorbent assay. The antibacterial properties were determined by inoculating paired full-fat and defatted milk samples with Escherichia coli or Streptococcus pneumoniae bacteria and performing colony counts.

RESULTS

Compared with full-fat milk, defatted milk demonstrated decreased total energy and fat and increased carbohydrate concentrations. Defatted milk demonstrated a significant decrease in all immune cell populations. There was no difference in IgA, IgG, lysozyme, or lactoferrin concentrations. Both aliquots demonstrated equivalent growth inhibition of E. coli and S. pneumoniae.

CONCLUSIONS

Unexpectedly, defatted human milk contained significantly less leukocytes than full-fat milk. IgA, IgG, lysozyme, and lactoferrin concentrations were preserved. The ability of defatted milk to inhibit bacterial growth was unaffected, suggesting that the antibacterial benefits of human milk remain after the defatting process. Further investigation regarding the clinical effect of leukocyte loss in defatted milk is warranted.

Temporal development of the infant gut microbiome

The majority of organisms that inhabit the human body reside in the gut. Since babies are born with an immature immune system, they depend on a highly synchronized microbial colonization process to ensure the correct microbes are present for optimal immune function and development. In a balanced microbiome, symbiotic and commensal species outcompete pathogens for resources. They also provide a protective barrier against chemical signals and toxic metabolites. In this targeted review we will describe factors that influence the temporal development of the infant microbiome, including the mode of delivery and gestational age at birth, maternal and infant perinatal antibiotic infusions, and feeding method-breastfeeding versus formula feeding. We will close by discussing wider environmental pressures and early intimate contact, particularly between mother and child, as they play a pivotal role in early microbial acquisition and community succession in the infant.

N-Glycosylation Plays an Essential and Species-Specific Role in Anti-Infection Function of Milk Proteins Using Listeria monocytogenes as Model Pathogen

The released milk N-glycome has been found to possess antipathogenic activity. Natively, they are covalently linked onto proteins. Whether the conjugated N-glycans still have antipathogenic properties and how the glycosylation influences the antipathogenic activity of proteins remain unclear. Herein, we compared the quantitative differences of milk protein N-glycosylation and the antilisterial differences of native milk proteins, released N-glycan pools, and deglycosylated proteins between human and bovine milk. N-glycosylation exhibited to be quantitatively species-specific. The entire growth inhibitory activity and the majority of the antiadhesive activity against Listeria monocytogenes of milk whey proteins, although not as high as the released N-glycans, are attributed to N-glycosylation. Moreover, all N-glycan-bearing samples from human milk showed better growth inhibitory activities than those from bovine milk. Generally, N-glycosylation significantly contributes to the antilisterial function of milk proteins and to the functional differences between species. This gives novel insights into the role of these glycoconjugates in nature.

Macronutrient Analysis of Modified-Fat Breast Milk Produced by 3 Methods of Fat Removal

BACKGROUND

Infants with chylothorax after congenital heart disease surgery are commonly treated using modified-fat breast milk. The effect of fat removal on breast milk macronutrients remains unclear. We compared macronutrient content of breast milk with breast milk skimmed using 3 methods, including a novel device, a cream separator.

METHODS

Thawed frozen breast milk samples from 30 women were defatted using refrigerated centrifuge, cream separator, and manual separation after refrigeration. We used standard assays to measure energy, protein, and fat content of breast milk samples.

RESULTS

All fat removal methods yielded skimmed breast milk with substantially lower fat and energy content. Mean energy content in breast milk skimmed by centrifuge (36.7 [SD 3.6] kcal/100 mL) was similar to that from cream separator (38.8 [3.5] kcal/100 mL). Both centrifuge and cream separator methods removed almost all fat and substantially more fat than the manual fat removal method. For unprocessed milk, energy and fat content estimated by creamatocrit was similar to reference method measurements; in skimmed milk, the creamatocrit significantly overestimated fat content. Mean protein content of skimmed breast milk was similar to unprocessed breast milk (mean 1.25 [0.31] g/100 mL).

CONCLUSION

Breast milk fat removal did not significantly alter protein levels. In skimmed breast milk, the overestimation of fat content using creamatocrit method suggests a need for more accurate bedside methods to assess macronutrient content. The similar macronutrient composition of breast milk skimmed by cream separator and centrifuge suggests the potential for cream separator use as a new, portable defatting method for hospitals and families.

Acidification effects on isolation of extracellular vesicles from bovine milk

Bovine milk extracellular vesicles (EVs) attract research interest as carriers of biologically active cargo including miRNA from donor to recipient cells to facilitate intercellular communication. Since toxicity of edible milk seems to be negligible, milk EVs are applicable to use for therapeutics in human medicine. Casein separation is an important step in obtaining pure EVs from milk, and recent studies reported that adding hydrochloric acid (HCl) and acetic acid (AA) to milk accelerates casein aggregation and precipitation to facilitate EV isolation and purification; however, the effects of acidification on EVs remain unclear. In this study, we evaluated the acidification effects on milk-derived EVs with that by standard ultracentrifugation (UC). We separated casein from milk by either UC method or treatment with HCl or AA, followed by evaluation of EVs in milk serum (whey) by transmission electron microcopy (TEM), spectrophotometry, and tunable resistive pulse sensing analysis to determine EVs morphology, protein concentration, and EVs size and concentration, respectively. Moreover, we used anti-CD9, -CD63, -CD81, -MFG-E8, -HSP70, and -Alix antibodies for the detection of EVs surface and internal marker proteins by western blot (WB). Morphological features of EVs were spherical shape and similar structure was observed in isolated EVs by TEM. However, some of the EVs isolated by HCl and AA had shown rough surface. Although protein concentration was higher in whey obtained by UC, EV concentration was significantly higher in whey following acid treatment. Moreover, although all of the targeted EVs-marker-proteins were detected by WB, HCl- or AA-treatments partially degraded CD9 and CD81. These findings indicated that acid treatment successfully separated casein from milk to allow efficient EV isolation and purification but resulted in partial degradation of EV-surface proteins. Our results suggest that following acid treatment, appropriate EV-surface-marker antibodies should be used for accurate assess the obtained EVs for downstream applications. This study describes the acidification effects on EVs isolated from bovine milk for the first time.

Site-specific integration of rotavirus VP6 gene in rabbit β-casein locus by CRISPR/Cas9 system

Rotavirus (RV) is the leading cause of viral gastroenteritis in neonates and VP6 protein has been discussed as a potential candidate vaccine. CRISPR/Cas9 was the latest generation of gene editing tools that can mediate the site-specific knock-in of exogenous genes, providing strong support for the expression of recombinant proteins. Here, seeking to design a rotavirus vaccine that would be suitable for both mammary-gland-based production and milk-based administration, rabbit β-casein (CSN2) locus was chosen as the target site to integrate the VP6 gene. The efficiency of inducing mutations in different target sites of rabbit CSN2 locus was analyzed and g4 site seems to be the best one to generate mutations (g4 72.76 ± 0.32% vs g1 30.14 ± 1.93%, g2 38.53 ± 0.75%, g3 52.26 ± 1.16%, P < 0.05). We further compared the knock-in efficiency through cytoplasmic injection of two group mixtures (containing 100 ng/μL Cas9 mRNA or Cas9 protein, 20 ng/μL sgRNA4, and 100 ng/μL donor vector) in rabbit zygotes, though the Cas9 mRNA group induced an HDR efficiency as high as 20.0% ± 2.6% than Cas9 protein group (10.3% ± 3.1%), 37.5% of the knock-in events were partial integration in the target site, when Cas9 protein used in the CRISPR/Cas9 system, all of the positive blastocysts showed completely integrated, results showed that the use of Cas9 protein is better than Cas9 mRNA to integrate the correct exogenous gene into the target site. Moreover, the transgenic rabbit that harbored correct integration of VP6 gene was obtained using Cas9 protein group and was used to produce an experimental milk-based rotavirus vaccine. Our research provides a novel strategy to produce rotavirus subunit vaccine and make a foundation for building broader milk-based vaccine protection against other pathogens.

The Functional Power of the Human Milk Proteome

Human milk is the most complete and ideal form of nutrition for the developing infant. The composition of human milk consistently changes throughout lactation to meet the changing functional needs of the infant. The human milk proteome is an essential milk component consisting of proteins, including enzymes/proteases, glycoproteins, and endogenous peptides. These compounds may contribute to the healthy development in a synergistic way by affecting growth, maturation of the immune system, from innate to adaptive immunity, and the gut. A comprehensive overview of the human milk proteome, covering all of its components, is lacking, even though numerous analyses of human milk proteins have been reported. Such data could substantially aid in our understanding of the functionality of each constituent of the proteome. This review will highlight each of the aforementioned components of human milk and emphasize the functionality of the proteome throughout lactation, including nutrient delivery and enhanced bioavailability of nutrients for growth, cognitive development, immune defense, and gut maturation.

Early-Life Iron Deficiency and Subsequent Repletion Alters Development of the Colonic Microbiota in the Pig

Background: Iron deficiency is the most prevalent micronutrient deficiency worldwide, affecting over two billion people. Early-life iron deficiency may alter the developing microbiota, which may or may not be reversible with subsequent dietary iron repletion. Thus, the aim of this study was to determine whether early-life iron deficiency and subsequent repletion alter colonic microbial composition and fermentation end-product concentrations in pigs. Methods: Forty-two male pigs received either control (CONT, 21.3 mg Fe/L) or iron-deficient (ID, 2.72 mg Fe/L) milk replacer treatments from postnatal day (PND) 2 to 32. Subsequently, 20 pigs continued through a series of age-appropriate, iron-adequate diets from PND 33 to 61. Contents from the ascending colon (AC) and rectum (feces) were collected at PND 32 and/or 61. Assessments included microbiota composition by 16S rRNA sequencing and volatile fatty acid (VFA) concentrations by gas chromatography methods. Data were analyzed using a 1-way ANOVA and PERMANOVA to assess the main effects of early-life iron status on all outcomes. Results: In AC samples, 15 genera differed (P < 0.05) between ID and CONT pigs, while 27 genera differed (P < 0.05) in fecal samples at PND 32. Early-life ID pigs had higher (P = 0.012) relative abundance of Lactobacillus in AC samples compared with CONT pigs. In feces, ID pigs had lower (P < 0.05) relative abundances of Bacteroides and Clostridium from the families of Clostridiaceae, Lachnospiraceae, and Ruminococcaceae. At PND 61, only two genera differed between treatment groups in AC samples, with ID pigs having a higher (P = 0.043) relative abundance of Bifidobacterium and lower (P = 0.047) relative abundance of Prevotella. Beta diversity differed at PND 32 in both AC and feces between CONT and ID pigs but no differences remained at PND 61. At PND 32, the total VFA concentration was higher in ID pigs compared with CONT pigs in both AC (P = 0.003) and feces (P = 0.001), but no differences in VFA concentrations persisted to PND 61. Conclusion: Early-life iron status influenced microbial composition and VFA concentrations within the large intestine, but these differences were largely normalized following subsequent dietary iron repletion.