Composition, structure and absorption of milk lipids: a source of energy, fat-soluble nutrients and bioactive molecules

A Liquid Chromatography-High Resolution Mass Spectrometry (LC-HRMS) Method for the Determination of Free Hydroxy Fatty Acids in Cow and Goat Milk

A liquid chromatography–high resolution mass spectrometry (LC-HRMS) method for the direct determination of various saturated hydroxy fatty acids (HFAs) in milk was developed for the first time. The method involves mild sample preparation conditions, avoids time-consuming derivatization procedures, and permits the simultaneous determination of 19 free HFAs in a single 10-min run. This method was validated and applied in 17 cow milk and 12 goat milk samples. This work revealed the existence of various previously unrecognized hydroxylated positional isomers of palmitic acid and stearic acid in both cow and goat milk, expanding our knowledge on the lipidome of milk. The most abundant free HFAs in cow milk were proven to be 7-hydroxystearic acid (7HSA) and 10-hydroxystearic acid (10HSA) (mean content values of 175.1 ± 3.4 µg/mL and 72.4 ± 6.1 µg/mL in fresh milk, respectively). The contents of 7HSA in cow milk seem to be substantially higher than those in goat milk.

Antioxidant activity toward fish oil triacylglycerols exerted by sphingoid bases isolated from butter serum with α-tocopherol

A mixture of sphingoid bases (SPGs) was prepared from butter serum, a by-product of anhydrous milk fat production. The mixture comprised seven types of SPGs with C16 to C19 alkyl chains. These milk SPGs inhibited the oxidation of fish oil triacylglycerol (TAG) more effectively than did a standard SPG (d18:1) with α-tocopherol. Reaction products were prepared from the combination of d18:0 or d18:1 with acrolein and propanal. Both sets of reaction products showed antioxidant activity toward fish oil TAG. Antioxidant activity of reaction products from d18:0 was stronger than that of reaction products from d18:1, suggesting that the molecule d18:0 may be a significant focus of the difference in antioxidant activity between milk SPGs and d18:1. To use SPGs as food additives in the future, an appropriate source of SPGs will be needed, and butter serum appears to have promise as a source of functional SPGs with strong antioxidant activity.

Effect of gestational age (preterm or full term) on lipid composition of the milk fat globule and its membrane in human colostrum

Human colostrum is the first milk secreted by the mother after birth and constitutes the ideal food for the newborn, because its chemical composition, rich in immunoglobulins, antimicrobial peptides, growth factors, bioactive lipids, and other important molecules, is perfectly adapted to the metabolic, digestive, and immunological immaturity of the newborn. An incomplete gestational period can affect the maturity of the mammary gland and its ability to secrete milk with the proper composition for the newborn's condition. Previous studies indicate that the mammary gland modulates the profiles of bioactive lipids present in the different phases of lactation from colostrum to mature milk. Given the key role played by the polar lipids (PL) (phospho- and sphingolipids) of the milk fat globule membrane (MFGM) in the immune system and cognitive development of the newborn, it is crucial to analyze whether the content and distribution of the PL are affected by gestation period. Therefore, this study aimed to determine the milk fat globule (MFG) and MFGM lipid compositions of human colostrum samples from 20 healthy preterm and full-term mothers. Lipid characterization using chromatographic techniques (gas chromatograph mass spectrometry and HPLC-evaporative light-scattering detection) revealed differences related to length of gestation in the profiles of lipid classes and fatty acid and triacylglyceride contents of colostrum. This comparative analysis leads to noteworthy outcomes about the changing roles of the PL, considering the preterm or full-term condition. We found a lack of correlation of some PL (such as phosphatidylcholine, phosphatidylinositol, and phosphatidylserine) with the delivery term; these could be denoted as structural category lipids. However, sphingomyelin and phosphatidyl-ethanolamine exhibited trends to decrease in full-term colostrum, indicating that in the final stage of pregnancy specific accretion of some PL occurs, which should be denoted as a nutritional redistribution.

Correlating Volatile Lipid Oxidation Compounds with Consumer Sensory Data in Dairy Based Powders During Storage

Lipid oxidation (LO) is a recognised problem in dairy powders due to the formation of volatile odour compounds that can negatively impact sensory perception. Three commercial dairy powders, fat-filled whole milk powder (FFWMP), skim milk powder (SMP), and infant milk formula (IMF), stored under different conditions (21 °C, 37 °C, or 25 °C with 50% humidity), were evaluated by consumer acceptance studies, ranked descriptive sensory analysis, and LO volatile profiling using headspace solid phase microextraction gas chromatography mass spectrometry (HS-SPME GCMS) over 16 weeks. Significant (p = 0.001) differences in the concentration of LO compounds and sensory perception were evident between sample types in the different storage conditions. The sensory acceptance scores for FFWMP and SMP remained stable throughout storage in all conditions, despite the increased perception of some LO products. The IMF sample was perceived negatively in each storage condition and at each time point. Overall increases in hexanal, heptanal, and pentanal correlated with “painty”, “oxidised”, “cooked”, and “caramelised” attributes in all samples. The concentration of some LO volatiles in the IMF was far in excess of those in FFWMP and SMP. High levels of LO volatiles in IMF were presumably due to the addition of polyunsaturated fatty acids (PUFA) in the formulation.

Development of a Liquid Chromatography-High Resolution Mass Spectrometry Method for the Determination of Free Fatty Acids in Milk

The determination of free fatty acids (FFAs) in milk is of importance for quality control, legislative purposes, authentication and product development. We present herein a liquid chromatography–high resolution mass spectrometry method for the direct determination of FFAs in milk. The method involves mild sample preparation, avoids time-consuming derivatization and allows the direct quantification of twenty-two FFAs in a 10-min single run. It was validated and applied in thirteen cow milk and seven goat milk samples. Saturated fatty acids C16:0, C18:0 and unsaturated C18:1 (n-9) were found to be the major components of milk FFAs at concentrations of 33.1 ± 8.2 μg/mL, 16.5 ± 5.3 μg/mL and 14.8 ± 3.8 μg/mL, respectively, in cow milk and at concentrations of 22.8 ± 1.8 μg/mL, 12.7 ± 2.8 μg/mL and 13.3 ± 0.3 μg/mL, respectively, in goat milk. Other saturated and unsaturated FFAs were found in significantly lower quantities. Saturated fatty acids C6:0, C8:0 and C10:0 were found in higher quantities in goat milk than in cow milk. The levels of the important (for human health) odd-chain FFAs C15:0 and C17:0 were estimated in cow and goat milk.

Sphingolipids in food and their critical roles in human health

Sphingolipids (SLs) are ubiquitous structural components of cell membranes and are essential for cell functions under physiological conditions or during disease progression. Abundant evidence supports that SLs and their metabolites, including ceramide (Cer), ceramide-1-phosphate (C1P), sphingosine (So), sphingosine-1-phosphate (S1P), are signaling molecules that regulate a diverse range of cellular processes and human health. However, there are limited reviews on the emerging roles of exogenous dietary SLs in human health. In this review, we discuss the ubiquitous presence of dietary SLs, highlighting their structures and contents in foodstuffs, particularly in sea foods. The digestion and metabolism of dietary SLs is also discussed. Focus is given to the roles of SLs in both the etiology and prevention of diseases, including bacterial infection, cancers, neurogenesis and neurodegenerative diseases, skin integrity, and metabolic syndrome (MetS). We propose that dietary SLs represent a "functional" constituent as emerging strategies for improving human health. Gaps in research that could be of future interest are also discussed.

Fatty acids as biomarkers of total dairy and dairy fat intakes: a systematic review and meta-analysis

Context

Dairy intake in humans is commonly assessed using questionnaires, but the data collected are often biased. As a result, there is increasing interest in biomarkers of dairy fat. To date, there has been no overview of the fatty acids suitable for use as biomarkers of dairy fat intake.

Objective

This systematic review and meta-analysis of observational studies was performed to identify circulating fatty acids as biomarkers of total dairy and dairy fat intakes in the general population.

Data Sources

MEDLINE, Embase, and Web of Knowledge databases were searched for eligible studies published until June 2017.

Study Selection

Articles were included when a correlation between circulating dairy fatty acids and intakes of total dairy and dairy fat was found, as measured by dietary assessment tools.

Data Extraction

Two authors extracted data independently and assessed the risk of bias. An adapted form of the Newcastle-Ottawa Scale was used for quality assessment.

Results

Data were pooled using the random-effects model. Meta-analysis revealed that the fatty acids in plasma/serum were significantly correlated with intakes of total dairy (C14:0 [r = 0.15; 95%CI, 0.11 - 0.18], C15:0 [r = 0.20; 95%CI, 0.13 - 0.27], and C17:0 [r = 0.10; 95%CI, 0.03 - 0.16] and dairy fat (C14:0 [r = 0.16; 95%CI, 0.10 - 0.22], C15:0 [r = 0.33; 95%CI, 0.27 - 0.39], C17:0 [r = 0.19; 95%CI, 0.14 - 0.25], and trans-C16:1n-7 [r = 0.21; 95%CI, 0.14 - 0.29).

Conclusions

C14:0, C15:0, C17:0, and trans-C16:1n-7 were identified as biomarkers of total dairy and dairy fat intakes in the general population. In light of the suboptimal measurement techniques used in some studies, correlations with trans-C18:1n-7 and conjugated linoleic acid require further investigation.

Realization of breeding values for milk fatty acids in relation to seasonal variation in organic milk

Prediction of detailed milk fatty acid (FA) composition by mid-infrared spectroscopy (MIRS) offers possibilities for high-throughput indirect measurements of detailed milk compositional parameters through the milk testing system, which can be used to differentiate the FA profile by genetics or specific management or on dairies for milk quality evaluation. Since 2015, milk samples from all Danish dairy cows under milk testing have been recorded using MIRS. The MIRS software from the FOSS Application Note 64 was used to predict contents of 7 FA groups and 4 individual FA. Data generated from the application note have been used to estimate breeding values for sires for percentage of saturated fat (SFA%) in milk. To investigate whether extreme SFA% breeding values of sires were reflected in the detailed milk FA profile from their daughters, milk samples from 194 cows in 7 organic herds were collected and the detailed FA composition measured by gas chromatography. From each cow, milk samples were collected twice to explore specific seasonal effects of pasture-based diets in relation to sires' estimated breeding value (EBV) for MIRS-predicted SFA% (MIRS-SFA%). The results showed a significant difference in SFA% measured from GC (GC-SFA%) in milk from daughters of sires having high SFA% EBV compared with daughters of sires having low SFA% EBV. The EBV group (low or high) also significantly affected most FA except C13:0, C15:0, C17:0, and C18:1 trans-11. Contents of SFA with even chain-lengths were all higher in the high EBV group, whereas C14:1, C16:1, and the other unsaturated C18 FA had a higher content in the low EBV group. All FA were significantly affected by season. The SFA% decreased from indoor spring feeding to summer pasture, as did FA with chain length ≤16 carbons, whereas long-chain FA (>C17) all increased during summer pasture. The results show that use of MIRS-predicted EBV for SFA% will most likely display a correlated response on the detailed FA composition in milk. In the current study, the combined action of feeding and genetics resulted in a 10 percentage-point difference on average when comparing milk SFA% from daughters of high SFA% EBV sires during indoor spring feeding from one farm to milk SFA% from daughters of low SFA% EBV sires during summer from another farm.

TDP-43 facilitates milk lipid secretion by post-transcriptional regulation of Btn1a1 and Xdh

Milk lipid secretion is a critical process for the delivery of nutrition and energy from parent to offspring. However, the underlying molecular mechanism is less clear. Here we report that TDP-43, a RNA-binding protein, underwent positive selection in the mammalian lineage. Furthermore, TDP-43 gene (Tardbp) loss induces accumulation of large lipid droplets and severe lipid secretion deficiency in mammary epithelial cells to outside alveolar lumens, eventually resulting in lactation failure and pup starvation within three weeks postpartum. In human milk samples from lactating women, the expression levels of TDP-43 is positively correlated with higher milk output. Mechanistically, TDP-43 exerts post-transcriptional regulation of Btn1a1 and Xdh mRNA stability, which are required for the secretion of lipid droplets from epithelial cells to the lumen. Taken together, our results highlights the critical role of TDP-43 in milk lipid secretion, providing a potential strategy for the screening and intervention of clinical lactation insufficiency.

Milk lipid secretion is a critical process for the delivery of nutrition and energy from parent to offspring. Here the authors found that TDP-43, a RNA-binding protein, is required for milk lipid secretion by post-transcriptional regulation of Btn1a1 and Xdh mRNA stability.

Adipophilin and perilipin 3 positively correlate with total lipid content in human breast milk

Lipids are secreted into milk as bilayer-coated structures: milk fat globules (MFGs). Adipophilin (ADRP) and perilipin 3 (TIP47) are associated with MFGs in human breast milk; however, the role of these proteins in milk lipid secretion is not fully understood. The study aimed to investigate levels of ADRP, TIP47 and total lipid content in human breast milk, their mutual correlations, and dynamics during lactation. Milk samples from 22 healthy lactating women (Caucasian, Central European) were collected at five time points during lactation (1–3, 12–14, 29–30, 88–90 and 178–180 days postpartum). Mass spectrometry-based method was used for quantification of ADRP and TIP47 in the samples. The gravimetric method was used to determine milk total lipid content. We observed distinctive trends in ADRP, TIP47 levels and lipid content in human breast milk during the first six months of lactation. We also found a significant association between lipid content and ADRP, lipid content and TIP47, and ADRP and TIP47 concentrations in breast milk at all sampling points. A mass spectrometry-based method was developed for quantifying ADRP and TIP47 in human breast milk. Strong mutual correlations were found between ADRP, TIP47 and total lipid content in human breast milk.

Combined use of milk infrared spectra and genotypes can improve prediction of milk fat composition

It has been shown that milk infrared (IR) spectroscopy can be used to predict detailed milk fat composition. In addition, polymorphisms with substantial effects on milk fat composition have been identified. In this study, we investigated the combined use of milk IR spectroscopy and genotypes of dairy cows on the accuracy of predicting milk fat composition. Milk fat composition data based on gas chromatography and milk IR spectra were available for 1,456 Dutch Holstein Friesian cows. In addition, genotypes for the diacylglycerol acyltransferase 1 (DGAT1) K232A and stearoyl-CoA desaturase 1 (SCD1) A293V polymorphisms and a SNP located in an intron of the fatty acid synthase (FASN) gene were available. Adding SCD1 genotypes to the milk IR spectra resulted in a considerable improvement of the prediction accuracy for the unsaturated fatty acids C10:1, C12:1, C14:1 cis-9, and C16:1 cis-9 and their corresponding unsaturation indices. Adding DGAT1 genotypes to the milk IR spectra resulted in an improvement of the prediction accuracy for C16:1 cis-9 and C16 index. Adding genotypes of the FASN SNP to the IR spectra did not improve prediction of milk fat composition. This study demonstrated the potential of combining milk IR spectra with genotypic information from 3 polymorphisms to predict milk fat composition. We hypothesize that prediction accuracy of milk fat composition can be further improved by combining milk IR spectra with genomic breeding values.

Food Safety through Natural Antimicrobials

Microbial pathogens are the cause of many foodborne diseases after the ingestion of contaminated food. Several preservation methods have been developed to assure microbial food safety, as well as nutritional values and sensory characteristics of food. However, the demand for natural antimicrobial agents is increasing due to consumers' concern on health issues. Moreover, the use of antibiotics is leading to multidrug resistant microorganisms reinforcing the focus of researchers and the food industry on natural antimicrobials. Natural antimicrobial compounds from plants, animals, bacteria, viruses, algae and mushrooms are covered. Finally, new perspectives from researchers in the field and the interest of the food industry in innovations are reviewed. These new approaches should be useful for controlling foodborne bacterial pathogens; furthermore, the shelf-life of food would be extended.

31P NMR-Based Phospholipid Fingerprinting of Powdered Infant Formula

Infant formula (IF), regarded as the optimal substitute for human breast milk, is very important for infant growth and development. Phospholipids (PLs) are ubiquitous components of infant formula as they have good emulsifier properties in addition to their nutritional and biological functions. In this study, the PL contents in four different commercial IF brands (indicated as A, M, O, and W) were characterized and quantified using optimized ³¹P NMR spectroscopy. PLs (nine) were identified and quantified, and among these, phosphatidylethanolamine and sphingomyelin occurred at lower concentrations (5.72 and 8.89 mg/100 g, respectively) in IFs from brand O, whereas phosphatidic acid was higher (2.83 mg/100 g) in IFs from brand W. In summary, ³¹P NMR spectroscopy, combined with the multivariate data analysis, proved to be an effective analytical toolbox for evaluating the PL contents in IF and the comparative differences between IF brands.

[Nutritional value of dairy products and recommended daily consumption]

INTRODUCTION

Objective: messages that are given recently have encouraged to reduce the consumption of dairy products, by noting them as dispensable or even harmful in relation to certain pathologies. The objective of this present work is to review the nutritional value of this group of foods and their recommended consumption. Methods: bibliographic search related to the topic. Results: dairy products provide proteins of high biological value, vitamins and minerals, especially calcium and vitamins B2 and B12, as well as essential fatty acids, and some antioxidants, among other nutrients. Although its fat is mostly saturated (65%), it does not seem to adversely affect cardiovascular risk and may even have a slight protective effect. More than 75% of individuals have calcium intakes lower than recommended, and since more than 50% of the calcium in the diet comes from dairy products, increasing their consumption may be recommended. Moderate milk intake during pregnancy is positively associated with birth weight and length of the offspring and bone mineral content during childhood. In adults, dairy consumption it is associated with a lower risk of metabolic syndrome, coronary heart disease and myocardial infarction, colorectal and gallbladder cancer, and type 2 diabetes. Moreover in older people it is associated with a lower risk of sarcopenia and vertebral fractures. Conclusions: the population ignores what is the nutritional value of dairy products and their advisable consumption (2-4 servings / day). The latest studies support the need to have an adequate consumption in all stages of life due to its relationship with the prevention and control of chronic diseases. Dairy consumption is less than 2 servings / day in 37.1% of children and 42.3% of adults, so it would be desirable to improve this situation.

The Function and Alteration of Immunological Properties in Human Milk of Obese Mothers

Maternal obesity is associated with metabolic changes in mothers and higher risk of obesity in the offspring. Obesity in breastfeeding mothers appears to influence human milk production as well as the quality of human milk. Maternal obesity is associated with alteration of immunological factors concentrations in the human milk, such as C-reactive protein (CRP), leptin, IL-6, insulin, TNF-Alpha, ghrelin, adiponectin, and obestatin. Human milk is considered a first choice for infant nutrition due to the complete profile of macro nutrients, micro nutrients, and immunological properties. It is essential to understand how maternal obesity influences immunological properties of human milk because alterations could impact the nutrition status and health of the infant. This review summarizes the literature regarding the impact of maternal obesity on the concentration of particular immunological properties in the human milk.

Impact of the rumen microbiome on milk fatty acid composition of Holstein cattle

Background

Fatty acids (FA) in bovine milk derive through body mobilization, de novo synthesis or from the feed via the blood stream. To be able to digest feedstuff, the cow depends on its rumen microbiome. The relative abundance of the microbes has been shown to differ between cows. To date, there is little information on the impact of the microbiome on the formation of specific milk FA. Therefore, in this study, our aim was to investigate the impact of the rumen bacterial microbiome on milk FA composition. Furthermore, we evaluated the predictive value of the rumen microbiome and the host genetics on the composition of individual FA in milk.

Results

Our results show that the proportion of variance explained by the rumen bacteria composition (termed microbiability or \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$h_{B}^{2}$$\end{document}hB2) was generally smaller than that of the genetic component (heritability), and that rumen bacteria influenced most C15:0, C17:0, C18:2 n-6, C18:3 n-3 and CLA cis-9, trans-11 with estimated \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$h_{B}^{2}$$\end{document}hB2 ranging from 0.26 to 0.42. For C6:0, C8:0, C10:0, C12:0, C16:0, C16:1 cis-9 and C18:1 cis-9, the variance explained by the rumen bacteria component was close to 0. In general, both the rumen microbiome and the host genetics had little value for predicting FA phenotype. Compared to genetic information only, adding rumen bacteria information resulted in a significant improvement of the predictive value for C15:0 from 0.22 to 0.38 (P = 9.50e−07) and C18:3 n-3 from 0 to 0.29 (P = 8.81e−18).

Conclusions

The rumen microbiome has a pronounced influence on the content of odd chain FA and polyunsaturated C18 FA, and to a lesser extent, on the content of the short- and medium-chain FA in the milk of Holstein cattle. The accuracy of prediction of FA phenotypes in milk based on information from either the animal’s genotypes or rumen bacteria composition was very low.

Electronic supplementary material

The online version of this article (10.1186/s12711-019-0464-8) contains supplementary material, which is available to authorized users.

The mTORC1/4EBP1/PPARγ Axis Mediates Insulin-Induced Lipogenesis by Regulating Lipogenic Gene Expression in Bovine Mammary Epithelial Cells

4EBP1 is a chief downstream factor of mTORC1, and PPARγ is a key lipogenesis-related transcription factor. mTORC1 and PPARγ are associated with lipid metabolism. However, it is unknown which effector protein connects mTORC1 and PPARγ. This study investigated the interaction between 4EBP1 with PPARγ as part of the underlying mechanism by which insulin-induced lipid synthesis and secretion are regulated by mTORC1 in primary bovine mammary epithelial cells (pBMECs). Rapamycin, a specific inhibitor of mTORC1, downregulated 4EBP1 phosphorylation and the expression of PPARγ and the following lipogenic genes: lipin 1, DGAT1, ACC, and FAS. Rapamycin also decreased the levels of intracellular triacylglycerol (TAG); 10 types of fatty acid; and the accumulation of TAG, palmitic acid (PA), and stearic acid (SA) in the cell culture medium. Inactivation of mTORC1 by shRaptor or shRheb attenuated the synthesis and secretion of TAG and PA. In contrast, activation of mTORC1 by Rheb overexpression promoted 4EBP1 phosphorylation and PPARγ expression and upregulated the mRNA and protein levels of lipin 1, DGAT1, ACC, and FAS, whereas the levels of intracellular and extracellular TAG, PA, and SA also rose. Further, 4EBP1 interacted directly with PPARγ. Inactivation of mTORC1 by shRaptor prevented the nuclear location of PPARγ. These results demonstrate that mTORC1 regulates lipid synthesis and secretion by inducing the expression of lipin 1, DGAT1, ACC, and FAS, which is likely mediated by the 4EBP1/PPARγ axis. This finding constitutes a novel mechanism by which lipid synthesis and secretion are regulated in pBMECs.

mTORC2 Regulates Lipogenic Gene Expression through PPARγ to Control Lipid Synthesis in Bovine Mammary Epithelial Cells

The mechanistic target of rapamycin complex 2 (mTORC2) primarily functions as an effector of insulin/PI3K signaling to regulate cell proliferation and is associated with cell metabolism. However, the function of mTORC2 in lipid metabolism is not well understood. In the present study, mTORC2 was inactivated by the ATP-competitive mTOR inhibitor AZD8055 or shRNA targeting RICTOR in primary bovine mammary epithelial cells (pBMECs). MTT assay was performed to examine the effect of AZD8055 on cell proliferation. ELISA assay and GC-MS analysis were used to determine the content of lipid. The mRNA and protein expression levels were investigated by RT/real-time PCR and western blot analysis, respectively. We found that cell proliferation, mTORC2 activation, and lipid secretion were inhibited by AZD8055. RICTOR was knocked down and mTORC2 activation was specifically attenuated by the shRNA. Compared to control cells, the expression of the transcription factor gene PPARG and the lipogenic genes LPIN1, DGAT1, ACACA, and FASN was downregulated in RICTOR silencing cells. As a result, the content of intracellular triacylglycerol (TAG), palmitic acid (PA), docosahexaenoic acid (DHA), and other 16 types of fatty acid was decreased in the treated cells; the accumulation of TAG, PA, and DHA in cell culture medium was also reduced. Overall, mTORC2 plays a critical role in regulating lipogenic gene expression, lipid synthesis, and secretion in pBMECs, and this process probably is through PPARγ. This finding provides a model by which lipogenesis is regulated in pBMECs.

Bioaccessibility of carotenoids from plant and animal foods

The frequent consumption of carotenoid-rich foods has been associated with numerous health benefits, such as the supply of provitamin A. To exert these health benefits, carotenoids need to be efficiently liberated from the food matrix, micellized in the small intestine, taken up by the enterocytes and absorbed into the human blood stream. Enormous efforts have been made to better understand these processes. Because human studies are costly, labor-intense and time-consuming, the evaluation of carotenoid liberation and micellization at the laboratory scale using simulated in vitro digestion models has proven to be an important tool for obtaining preliminary results prior to conducting human studies. In particular, the liberation from the food matrix and the intestinal micellization can be mimicked by simulated digestion, yielding an estimate of the so-called bioaccessibility of a carotenoid. In the present review, we provide an overview of the carotenoid digestion process in vivo, the currently used in vitro digestion models and the outcomes of previous bioaccessibility studies, with a special focus on correlations with concomitantly conducted human studies. Furthermore, we advocate for the on-going requirement of better standardized digestion protocols and, in addition, we provide suggestions for the complementation of the acquired knowledge and current nutritional recommendations. © 2018 Society of Chemical Industry.

MicroRNA-106b Regulates Milk Fat Metabolism via ATP Binding Cassette Subfamily A Member 1 ( ABCA1) in Bovine Mammary Epithelial Cells

Research on the mechanisms that regulate milk fat synthesis in dairy cows is essential to identify potential molecular targets that in the long term can help develop appropriate molecular breeding programs. Although some studies have revealed that microRNA (miRNA) affect lipid metabolism by targeting specific genes, joint analysis of miRNA and target mRNA data from bovine mammary tissue has revealed few clues regarding the underlying mechanisms controlling milk fat synthesis. The objective of the present study was to use high-throughput sequencing and bioinformatics analysis to identify miRNA and mRNA pairs and explore further their potential roles in regulating milk fat synthesis. A total of 233 pairs of negatively associated miRNA and mRNA pairs were detected. Among those, there were 162 pairs in which the miRNAs were down-regulated and the target mRNAs were up-regulated. Among the identified miRNA, miR-106b can bind the 3'-UTR of the ATP binding cassette subfamily A member 1 ( ABCA1), a gene previously identified as having a positive association with bovine milk fat synthesis. The overexpression of miR-106b in bovine mammary epithelial cells caused a decrease in triglyceride and cholesterol content while the inhibition of miR-106b increased triglyceride and cholesterol content, confirming its role in lipid metabolism. The present study allowed for the construction of a miR-106b- ABCA1 regulatory network map, thus providing a theoretical basis to target this gene in the molecular breeding of dairy cows.

Reprint of "Postprandial lipemia and fecal fat excretion in rats is affected by the calcium content and type of milk fat present in Cheddar-type cheeses"

The aim of this study was to better understand the effect of calcium on the bioavailability of milk lipids from a cheese matrix using a rat model. Cheddar-type cheeses were manufactured with one of three types of anhydrous milk fat, control, olein or stearin, and salted with or without CaCl₂. The cheeses were fed to rats and postprandial lipemia was monitored. Feces were analyzed to quantify fatty acids excreted as calcium soaps. Higher calcium concentration in cheese caused a higher and faster triacylglycerol peak in blood, except for cheeses containing stearin. Furthermore, calcium soaps were more abundant in feces when the ingested cheese had been enriched with calcium and when the cheese was prepared with stearin. Increased lipid excretion was attributable to the affinity of saturated long-chain fatty acids for calcium. Results showed that lipid bioaccessibility can be regulated by calcium present in Cheddar cheese. This study highlights the nutritional interaction between calcium and lipids present in the dairy matrix and confirms its physiological repercussions on fatty acid bioavailability.

Circulating fatty acids as biomarkers of dairy fat intake: data from the lifelines biobank and cohort study

Background: C14:0, C15:0, C17:0 and trans-C16:1(n-7) are often used as biomarkers for dairy fat intake. Trans-C18:1(n-7) and CLA, two fatty acids which are also present in dairy, have hardly been explored. We investigated whether trans-C18:1(n-7) and CLA can enrich the existing biomarker portfolio. Methods: Data were obtained from Lifelines (n = 769). Dairy fat intake was determined by FFQ. Fatty acids were measured in fasting plasma triglycerides (TG), phospholipids (PL) and cholesterol esters (CE). Results: Median (25th-75th percentile) intakes of dairy and dairy fat were 322(209-447) and 12.3(8.4-17.4) g/d respectively. A pilot study showed that trans-C18:1(n-7) and CLA were only detectable in TG and PL. Of the established markers, TG C15:0 was most strongly associated with dairy fat intake (standardized β (std.β) = 0.286, R² = 0.111). Of the less established markers, TG trans-C18:1(n-7) was most strongly associated with dairy fat intake (Std.β = 0.292, R² = 0.115), followed by PL CLA (Std.β = 0.272, R² = 0.103) and PL trans-C18:1(n-7) (Std.β = 0.269, R² = 0.099). In TG, a combination of C15:0 and trans-C18:1(n-7) performed best (R² = 0.128). In PL, a combination of C14:0, C15:0, trans-C18:1(n-7) and CLA performed best (R² = 0.143). Conclusion: Trans-C18:1(n-7) and CLA can be used as biomarkers of dairy fat intake. Additionally, combining established with less established markers allowed even stronger predictions for dairy fat intake.

Milk-derived mammary epithelial cells as non-invasive source to define stage-specific abundance of milk protein and fat synthesis transcripts in native Sahiwal cows and Murrah buffaloes

The molecular physiology of milk production of two important dairy species; Sahiwal cows (Bos indicus) and Murrah buffaloes (Bubalus bubalis) are not fully understood due to constraints in obtaining mammary tissue samples because of sacred and ethical reasons. The present study suggests the use of milk-derived mammary epithelial cells (MECs) as a non-invasive method to understand molecular aspects of lactation biology in dairy animals. A total of 76 MECs were collected from five different lactation periods viz. colostrum (0-2), early (5-20), peak (30-50), mid (90-140) and late lactation (> 215 days) stages from Sahiwal cows and Murrah buffaloes to study the transcription kinetics of milk protein, fat synthesis, and their regulatory genes. Significant changes were observed in milk composition of both dairy species with lactation stages. High mRNA abundance of all milk protein and fat synthesis genes was observed in MECs of Murrah buffaloes as compared to Sahiwal cows. The mRNA abundance of caseins (CSN1S1, CSN1S2, CSN2, and CSN3) and whey protein (LALBA, LF) were higher in early lactation stage. Similarly, the expression of milk fat synthesis genes (SCD, BTN1A1, ACACA, GPAM, FAPB3, FASN) was also high in early lactation stage. The relative abundance of 4 regulatory genes (JAK2, STAT5, SREBF1 and EIF4BP41) remained high during early lactation indicating their regulatory roles in lactogenesis process. Overall, results suggested a significant effect of lactation stages on milk composition and transcription abundance of milk protein and fat synthesis genes. The present study establishes the fact that milk-derived MECs could be utilized as a valuable source to understand mammary gland functioning of native cows and buffaloes.

Insights into the role of bacteria in vitamin A biosynthesis: Future research opportunities

Significant efforts have been made to address the hidden hunger challenges due to iron, zinc, iodine, and vitamin A since the beginning of the 21st century. Prioritizing the vitamin A deficiency (VAD) disorders, many countries are looking for viable alternative strategies such as biofortification. One of the leading causes of VAD is the poor bioconversion of β-carotene into retinoids. This review is focused on the opportunities of bacterial biosynthesis of retinoids, in particular, through the gut microbiota. The proposed hypothesis starts with the premise that an animal can able to store and timely convert carotenoids into retinoids in the liver and intestinal tissues. This theory is experimental with many scientific insights. The syntrophic metabolism, potential crosstalk of bile acids, lipocalins and lipopolysaccharides of gut microbiota are reported to contribute significantly to the retinoid biosynthesis. The gut bacteria respond to these kinds of factors by genetic restructuring driven mainly by events like horizontal gene transfer. A phylogenetic analysis of β-carotene 15, 15'-mono (di) oxygenase enzymes among a selected group of prokaryotes and eukaryotes was carried out to validate the hypotheses. Shedding light on the probiotic strategies through non-genetically modified organism such as gut bacteria capable of synthesizing vitamin A would address the VAD disorders.

Total and sn-2 fatty acid profile of breast milk from women delivering preterm infants under the influence of maternal characteristics

Data on the total fatty acid (FA) profile and position-specific triacylglycerides (TAGs) in preterm infants' maternal milk are essential for establishing the recommended requirement of FA in preterm infants in China. We aimed to determine the composition and positional distribution of FAs in preterm infants' maternal milk in China and further investigate the effect of maternal background on the FA composition. Breast milk samples (4, 11, 30, 60, and 90 (all ±3) days post-partum) were collected from 59 healthy women delivering preterm infants. The total and sn-2 milk FA composition was determined using gas chromatography. The multivariate statistical analysis showed significant differences in the FA profiles of milk with different lactation times, gestational ages and maternal ages. In particular, the content of linoleic and linolenic acid (ALA) was much higher, whereas the content of docosahexaenoic (DHA) and arachidonic acid were lower in the preterm milk from the Wuxi district than that from America and countries in Europe. The content of sn-2 polyunsaturated FAs (ALA: p = 0.013 and DHA: p = 0.003) were lower in the preterm colostrum from women aged over 30 years. Overall, these results suggest that the European and American standards of preterm formula may not be suitable for Chinese preterm infants, and polyunsaturated FA fortification in the maternal diet or preterm formula is needed for women with advanced age.

Postprandial lipemia and fecal fat excretion in rats is affected by the calcium content and type of milk fat present in Cheddar-type cheeses

The aim of this study was to better understand the effect of calcium on the bioavailability of milk lipids from a cheese matrix using a rat model. Cheddar-type cheeses were manufactured with one of three types of anhydrous milk fat, control, olein or stearin, and salted with or without CaCl₂. The cheeses were fed to rats and postprandial lipemia was monitored. Feces were analyzed to quantify fatty acids excreted as calcium soaps. Higher calcium concentration in cheese caused a higher and faster triacylglycerol peak in blood, except for cheeses containing stearin. Furthermore, calcium soaps were more abundant in feces when the ingested cheese had been enriched with calcium and when the cheese was prepared with stearin. Increased lipid excretion was attributable to the affinity of saturated long-chain fatty acids for calcium. Results showed that lipid bioaccessibility can be regulated by calcium present in Cheddar cheese. This study highlights the nutritional interaction between calcium and lipids present in the dairy matrix and confirms its physiological repercussions on fatty acid bioavailability.

Breast Milk Lipidome Is Associated with Early Growth Trajectory in Preterm Infants

Human milk is recommended for feeding preterm infants. The current pilot study aims to determine whether breast-milk lipidome had any impact on the early growth-pattern of preterm infants fed their own mother's milk. A prospective-monocentric-observational birth-cohort was established, enrolling 138 preterm infants, who received their own mother's breast-milk throughout hospital stay. All infants were ranked according to the change in weight Z-score between birth and hospital discharge. Then, we selected infants who experienced "slower" (n = 15, -1.54 ± 0.42 Z-score) or "faster" (n = 11, -0.48 ± 0.19 Z-score) growth; as expected, although groups did not differ regarding gestational age, birth weight Z-score was lower in the "faster-growth" group (0.56 ± 0.72 vs. -1.59 ± 0.96). Liquid chromatography-mass spectrometry lipidomic signatures combined with multivariate analyses made it possible to identify breast-milk lipid species that allowed clear-cut discrimination between groups. Validation of the selected biomarkers was performed using multidimensional statistical, false-discovery-rate and ROC (Receiver Operating Characteristic) tools. Breast-milk associated with faster growth contained more medium-chain saturated fatty acid and sphingomyelin, dihomo-γ-linolenic acid (DGLA)-containing phosphethanolamine, and less oleic acid-containing triglyceride and DGLA-oxylipin. The ability of such biomarkers to predict early-growth was validated in presence of confounding clinical factors but remains to be ascertained in larger cohort studies.

Impact of crossbreeding Holstein and Brown Swiss cows on milk yield, composition, and fatty acid profiles in subtropics

Milk yield (MY), composition, and fatty acid profiles of purebred Holstein (HO) cows, Brown Swiss (BS), and their F₁ crossbreds (HS) were compared under subtropical climate in Egypt. Pure HO had significantly greater 305-MY, total-MY, and daily-MY (p < 0.05) than pure BS and crossbred HS. Furthermore, HO and HS had significantly higher peak-MY (44.2 and 43.3 kg, respectively) than BS (36.1 kg). In comparison with HO, BS had significantly higher milk fat, protein, total solids, and solid-not-fat % (p < 0.05); however, no significant differences were observed between BS and HS for milk fat %. The milk fat of BS had higher concentrations of saturated (C17:0 and C18:0) fatty acids (FA) than that of the HO and HS (p = 0.001 and 0.008, respectively). Content of C4:0, C6:0, C8:0, C12:0, and C15.0 FA did not differ between genotypes. Milk from HO and BS had significantly higher concentrations of unsaturated (C20:1 and C20:5) FA than that from HS (p < 0.05). C14:1 (myristoleic), C16:1 (palmitoleic), and C18:2 (linoleic) FA contents were similar for all genotypes. In conclusion, BS surpassed HO for all milk composition traits and some FA components; however, HS had comparable milk fat percentage with BS. There appears to be an opportunity to modify the concentration of certain FA by breeding.

Milk fat components with potential anticancer activity-a review

During many years, the milk fat has been unfairly undervalued due to its association with higher levels of cardiovascular diseases, dyslipidaemia or obesity, among others. However, currently, this relationship is being re-evaluated because some of the dairy lipid components have been attributed potential health benefits. Due to this, and based on the increasing incidence of cancer in our society, this review work aims to discuss the state of the art concerning scientific evidence of milk lipid components and reported anticancer properties. Results from the in vitro and in vivo experiments suggest that specific fatty acids (FA) (as butyric acid and conjugated linoleic acid (CLA), among others), phospholipids and sphingolipids from milk globule membrane are potential anticarcinogenic agents. However, their mechanism of action remains still unclear due to limited and inconsistent findings in human studies.

Argan Oil-Mediated Attenuation of Organelle Dysfunction, Oxidative Stress and Cell Death Induced by 7-Ketocholesterol in Murine Oligodendrocytes 158N

Argan oil is widely used in Morocco in traditional medicine. Its ability to treat cardiovascular diseases is well-established. However, nothing is known about its effects on neurodegenerative diseases, which are often associated with increased oxidative stress leading to lipid peroxidation and the formation of 7-ketocholesterol (7KC) resulting from cholesterol auto-oxidation. As 7KC induces oxidative stress, inflammation and cell death, it is important to identify compounds able to impair its harmful effects. These compounds may be either natural or synthetic molecules or mixtures of molecules such as oils. In this context: (i) the lipid profiles of dietary argan oils from Berkane and Agadir (Morocco) in fatty acids, phytosterols, tocopherols and polyphenols were determined by different chromatographic techniques; and (ii) their anti-oxidant and cytoprotective effects in 158N murine oligodendrocytes cultured with 7KC (25-50 µM; 24 h) without and with argan oil (0.1% v/v) or α-tocopherol (400 µM, positive control) were evaluated with complementary techniques of cellular and molecular biology. Among the unsaturated fatty acids present in argan oils, oleate (C18:1 n-9) and linoleate (C18:1 n-6) were the most abundant; the highest quantities of saturated fatty acids were palmitate (C16:0) and stearate (C18:0). Several phytosterols were found, mainly schottenol and spinasterol (specific to argan oil), cycloartenol, β-amyrin and citrostadienol. α- and γ-tocopherols were also present. Tyrosol and protocatechic acid were the only polyphenols detected. Argan and extra virgin olive oils have many compounds in common, principally oleate and linoleate, and tocopherols. Kit Radicaux Libres (KRL) and ferric reducing antioxidant power (FRAP) tests showed that argan and extra virgin olive oils have anti-oxidant properties. Argan oils were able to attenuate the cytotoxic effects of 7KC on 158N cells: loss of cell adhesion, cell growth inhibition, increased plasma membrane permeability, mitochondrial, peroxisomal and lysosomal dysfunction, and the induction of oxiapoptophagy (OXIdation + APOPTOsis + autoPHAGY). Altogether, our data obtained in 158N oligodendrocytes provide evidence that argan oil is able to counteract the toxic effects of 7KC on nerve cells, thus suggesting that some of its compounds could prevent or mitigate neurodegenerative diseases to the extent that they are able to cross the blood-brain barrier.

Mediterranean Diet and Prevention of Chronic Diseases

A large body of research data suggests that traditional dietary habits and lifestyle unique to the Mediterranean region (Mediterranean diet, MD) lower the incidence of chronic diseases and improve longevity. These data contrast with troubling statistics in the United States and other high income countries pointing to an increase in the incidence of chronic diseases and the projected explosion in cost of medical care associated with an aging population. In 2013, the MD was inscribed by UNESCO in the "Representative List of the Intangible Cultural Heritage of Humanity." The 2015-2020 Dietary Guidelines for Americans included the MD as a healthy dietary pattern. Therefore, specific objectives of this article are to provide an overview of the nutritional basis of this healthful diet, its metabolic benefits, and its role in multiple aspects of disease prevention and healthy aging. Whereas recommendations about the MD often focus on specific foods or bioactive compounds, we suggest that the eating pattern as a whole likely contributes to the health promoting effects of the MD.

Heat Stress in Dairy Cattle Alters Lipid Composition of Milk

Heat stress, potentially affecting both the health of animals and the yield and composition of milk, occurs frequently in tropical, sub-tropical and temperate regions. A simulated acute heat stress experiment was conducted in controlled-climate chambers and milk samples collected before, during and after the heat challenge. Milk lipid composition, surveyed using LC-MS, showed significant changes in triacylglycerol (TAG) and polar lipid profiles. Heat stress (temperature-humidity index up to 84) was associated with a reduction in TAG groups containing short- and medium-chain fatty acids and a concomitant increase in those containing long-chain fatty acids. The abundance of five polar lipid classes including phosphatidylethanolamine, phosphatidylserine, phosphatidylcholine, lysophosphatidylcholine and glucosylceramide, was found to be significantly reduced during heat stress. Lysophosphatidylcholine, showing the greatest reduction in concentration, also displayed a differential response between heat tolerant and heat susceptible cows during heat stress. This phospholipid could be used as a heat stress biomarker for dairy cattle. Changes in TAG profile caused by heat stress are expected to modify the physical properties of milk fat, whereas the reduction of phospholipids may affect the nutritional value of milk. The results are discussed in relation to animal metabolism adaptation in the event of acute heat stress.

Patterns of dairy food intake, body composition and markers of metabolic health in Ireland: results from the National Adult Nutrition Survey

Background:

Studies examining the association between dairy consumption and metabolic health have shown mixed results. This may be due, in part, to the use of different definitions of dairy, and to single types of dairy foods examined in isolation.

Objective:

The objective of the study was to examine associations between dairy food intake and metabolic health, identify patterns of dairy food consumption and determine whether dairy dietary patterns are associated with outcomes of metabolic health, in a cross-sectional survey.

Design:

A 4-day food diary was used to assess food and beverage consumption, including dairy (defined as milk, cheese, yogurt, cream and butter) in free-living, healthy Irish adults aged 18–90 years (n=1500). Fasting blood samples (n=897) were collected, and anthropometric measurements taken. Differences in metabolic health markers across patterns and tertiles of dairy consumption were tested via analysis of covariance. Patterns of dairy food consumption, of different fat contents, were identified using cluster analysis.

Results:

Higher (total) dairy was associated with lower body mass index, %body fat, waist circumference and waist-to-hip ratio (P<0.001), and lower systolic (P=0.02) and diastolic (P<0.001) blood pressure. Similar trends were observed when milk and yogurt intakes were considered separately. Higher cheese consumption was associated with higher C-peptide (P<0.001). Dietary pattern analysis identified three patterns (clusters) of dairy consumption; 'Whole milk', 'Reduced fat milks and yogurt' and 'Butter and cream'. The 'Reduced fat milks and yogurt' cluster had the highest scores on a Healthy Eating Index, and lower-fat and saturated fat intakes, but greater triglyceride levels (P=0.028) and total cholesterol (P=0.015). conclusion: Overall, these results suggest that while milk and yogurt consumption is associated with a favourable body phenotype, the blood lipid profiles are less favourable when eaten as part of a low-fat high-carbohydrate dietary pattern. More research is needed to better understand this association.

Conclusion:

Overall, these results suggest that although milk and yogurt consumption is associated with a favourable body phenotype, the blood lipid profiles are less favourable when eaten as part of a low-fat high-carbohydrate dietary pattern. More research is needed to better understand this association.

Human Milk Fatty Acid Composition: Comparison of Novel Dried Milk Spot Versus Standard Liquid Extraction Methods

Accurate assessment of the long chain polyunsaturated fatty acid (LC-PUFA) content of human milk (HM) provides a powerful means to evaluate the FA nutrient status of breastfed infants. The conventional standard for FA composition analysis of HM is liquid extraction, trans-methylation, and analyte detection resolved by gas chromatography. This standard approach requires fresh or frozen samples, storage in deep freeze, organic solvents, and specialized equipment in processing and analysis. Further, HM collection is often impractical for many studies in the free living environment, particularly for studies in developing countries. In the present study, we compare a novel and more practical approach to sample collection and processing that involves the spotting and drying ~50 μL of HM on a specialized paper stored and transported at ambient temperatures until analysis. Deming regression indicated the two methods aligned very well for all LC-PUFA and the abundant HM FA. Additionally, strong correlations (r > 0.85) were observed for DHA, ARA, EPA, linoleic (LA), and alpha-linolenic acids (ALA), which are of particular interest to the health of the developing infant. Taken together, our data suggest this more practical and inexpensive method of collection, storage, and transport of HM milk samples could dramatically facilitate studies of HM, as well as understanding its lipid composition influences on human health and development.

Early infant adipose deposition is positively associated with the n-6 to n-3 fatty acid ratio in human milk independent of maternal BMI

Background/Objectives

Excessive infant weight gain in the first 6-months of life is a powerful predictor of childhood obesity and related health risks. In mice, omega-6 fatty acids (FA) serve as potent ligands driving adipogenesis during early development. The ratio of omega-6 relative to omega-3 (n-6/n-3) FA in human milk (HM) has increased 3-fold over the last 30 years, but the impact of this shift on infant adipose development remains undetermined. This study investigated how maternal obesity and maternal dietary FA (as reflected in maternal red blood cells (RBC) composition) influenced HM n-6 and n-3 FAs, and whether the HM n-6/n-3 ratio was associated with changes in infant adipose deposition between 2-weeks and 4-months postpartum.

Subjects/Methods

Forty-eight infants from normal-weight (NW), overweight (OW) and obese (OB) mothers were exclusively or predominantly breastfed over the first 4 months of lactation. Mid-feed HM and maternal RBC were collected at either transitional (2-weeks) or established (4-months) lactation, along with infant body composition assessed using air-displacement plethysmography. The FA composition of HM and maternal RBC was measured quantitatively by lipid mass spectrometry.

Results

In transitional and established HM, DHA was lower (P=0.008; 0.005) and the AA/DHA+EPA ratio was higher (P=0.05; 0.02) in the OB relative to the NW group. Maternal prepregnancy BMI and AA/ DHA+EPA ratios in transitional and established HM were moderately correlated (P=0.018; 0.001). Total infant fat mass was increased in the upper AA/DHA+EPA tertile of established HM relative to the lower tertile (P=0.019). The amount of changes in infant fat mass and % body fat were predicted by AA/EPA+DHA ratios in established HM (P=0.038; 0.010).

Conclusions

Perinatal infant exposures to a high AA/EPA+DHA ratio during the first 4-months of life, which is primarily reflective of maternal dietary FA, may significantly contribute to the way infants accumulate adipose.

A mixture of milk and vegetable lipids in infant formula changes gut digestion, mucosal immunity and microbiota composition in neonatal piglets

PURPOSE

Although composition of infant formula has been significantly improved during the last decade, major differences with the composition and structure of breast milk still remain and might affect nutrient digestion and gut biology. We hypothesized that the incorporation of dairy fat in infant formulas could modify their physiological impacts by making their composition closer to that of human milk. The effect of milk fat and milk fat globule membrane (MFGM) fragments in infant formulas on gut digestion, mucosal immunity and microbiota composition was evaluated.

METHODS

Three formulas containing either (1) vegetable lipids stabilized only by proteins (V-P), (2) vegetable lipids stabilized by a mixture of proteins and MFGM fragments (V-M) and (3) a mixture of milk and vegetable lipids stabilized by a mixture of proteins and MFGM fragments (M-M) were automatically distributed to 42 newborn piglets until slaughter at postnatal day (PND) 7 or 28, and compared to a fourth group of sow's suckling piglets (SM) used as a breast-fed reference.

RESULTS

At both PND, casein and β-lactoglobulin digestion was reduced in M-M proximal jejunum and ileum contents compared to V-P and V-M ones leading to more numerous β-Cn peptides in M-M contents. The IFNγ cytokine secretion of ConA-stimulated MLN cells from M-M piglets tended to be higher than in V-P ones at PND 7 and PND 28 and was closer to that of SM piglets. No dietary treatment effect was observed on IL-10 MLN cell secretion. Changes in faecal microbiota in M-M piglets resulted in an increase in Proteobacteria and Bacteroidetes and a decrease in Firmicutes phyla compared to V-P ones. M-M piglets showed higher abundances of Parabacteroides, Escherichia/Shigella and Klebsiella genus.

CONCLUSIONS

The incorporation of both milk fat and MFGM fragments in infant formula modifies protein digestion, the dynamic of the immune system maturation and the faecal microbiota composition.

Immunology of breast milk

Summary In the critical phase of immunological immaturity of the newborn, particularly for the immune system of mucous membranes, infants receive large amounts of bioactive components through colostrum and breast milk. Colostrum is the most potent natural immune booster known to science. Breastfeeding protects infants against infections mainly via secretory IgA (SIgA) antibodies, but also via other various bioactive factors. It is striking that the defense factors of human milk function without causing inflammation; some components are even anti-inflammatory. Protection against infections has been well evidenced during lactation against, e.g., acute and prolonged diarrhea, respiratory tract infections, including otitis media, urinary tract infection, neonatal septicemia, and necrotizing enterocolitis. The milk’s immunity content changes over time. In the early stages of lactation, IgA, anti-inflammatory factors and, more likely, immunologically active cells provide additional support for the immature immune system of the neonate. After this period, breast milk continues to adapt extraordinarily to the infant’s ontogeny and needs regarding immune protection and nutrition. The need to encourage breastfeeding is therefore justifiable, at least during the first 6 months of life, when the infant’s secretory IgA production is insignificant.

Rapamycin Inhibits Expression of Elongation of Very-long-chain Fatty Acids 1 and Synthesis of Docosahexaenoic Acid in Bovine Mammary Epithelial Cells

Mammalian target of rapamycin complex 1 (mTORC1) is a central regulator of cell growth and metabolism and is sufficient to induce specific metabolic processes, including de novo lipid biosynthesis. Elongation of very-long-chain fatty acids 1 (ELOVL1) is a ubiquitously expressed gene and the product of which was thought to be associated with elongation of carbon (C) chain in fatty acids. In the present study, we examined the effects of rapamycin, a specific inhibitor of mTORC1, on ELOVL1 expression and docosahexaenoic acid (DHA, C22:6 n-3) synthesis in bovine mammary epithelial cells (BMECs). We found that rapamycin decreased the relative abundance of ELOVL1 mRNA, ELOVL1 expression and the level of DHA in a time-dependent manner. These data indicate that ELOVL1 expression and DHA synthesis are regulated by mTORC1 in BMECs.

Advances in research on cis-9, trans-11 conjugated linoleic acid: a major functional conjugated linoleic acid isomer

Conjugated linoleic acid (CLA) consists of a group of positional and geometric conjugated isomers of linoleic acid. Since the identification of CLA as a factor that can inhibit mutagenesis and carcinogenesis, thousands of studies have been conducted in the last several decades. Among the many isomers discovered, cis-9, trans-11 CLA is the most intensively studied because of its multiple, isomer-specific effects in humans and animals. This paper provides an overview of the available data on cis-9, trans-11 CLA, including its isomer-specific effects, biosynthesis, in vivo/in vitro research models, quantification, and the factors influencing its content in ruminant products.