Content and Composition of Branched-Chain Fatty Acids in Bovine Milk Are Affected by Lactation Stage and Breed of Dairy Cow

Dietary sources of branched-chain fatty acids and their biosynthesis, distribution, and nutritional properties

Branched-chain fatty acids (BCFAs) consist of a wide variety of fatty acids with alkyl branching of methyl group. The most common BCFAs are the types with one methyl group (mmBCFA) on the penultimate carbon (iBCFA) or the antepenultimate carbon (aiBCFA). Long-chain mmBCFAs are widely existing in animal fats, milks and are mostly derived from bacteria in the diet or animal digestive system. Recent studies show that BCFAs benefit human intestinal health and immune homeostasis, but the connection between their content, distribution in the human and their nutritional functions are not well established. In this paper, we reviewed BCFAs from various dietary sources focused on their molecular species. The BCFAs biosynthesis in bacteria, Caenorhabditis elegans, mammals and their distribution in human tissues are summarized. This paper also discusses the nutritional properties of BCFAs including influences on intestinal health, immunoregulatory effects, anti-carcinoma, and anti-obesity activities, by highlighting the most recent research progress.

Branched-Long-Chain Monomethyl Fatty Acids: Are They Hidden Gems?

Branched-long-chain monomethyl fatty acids (BLCFA) are consumed daily in significant amounts by humans in all stages of life. BLCFA are absorbed and metabolized in human intestinal epithelial cells and are not only oxidized for energy. Thus far, BLCFA have been revealed to possess versatile beneficial bioactivities, including cytotoxicity to cancer cells, anti-inflammation, lipid-lowering, reducing the risk of metabolic disorders, maintaining normal β cell function and insulin sensitivity, regulation of development, and mitigating cerebral ischemia/reperfusion injury. However, compared to other well-studied dietary fatty acids like eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), BLCFA has received disproportionate attention despite their potential importance. Here we outlined the major food sources, estimated intake, absorption, and metabolism in human cells, and bioactive properties of BLCFA with a focus on the bioactive mechanisms to advocate for an increased commitment to BLCFA investigations. Humans were estimated to absorb 6-5000 mg of dietary BLCFA daily from fetus to adult. Notably, iso-15:0 inhibited the growth of prostate cancer, liver cancer and T-cell non-Hodgkin lymphomas in rodent models at the effective doses of 35-105 mg/kg/day, 70 mg/kg/day, and 70 mg/kg/day, respectively. Feeding formula prepared with 20% w/w BLCFA mixture to neonatal rats with enterocolitis mitigated the intestine inflammation. Iso-15:0 at doses of 10, 40, and 80 mg/kg relieved brain ischemia/reperfusion injury in rats. In the future, it is crucial to conduct research to establish the epidemiology of BLCFA intake and their impacts on health outcomes in humans as well as to fully uncover the underlying mechanisms for their bioactivities.

Molecular mechanisms in the miR-33a/LPPR4 pathway regulating unsaturated fatty acid synthesis in bovine mammary epithelial cells

The regulatory mechanisms governing metabolism of fatty acids in cow mammary gland are crucial for establishing relationships between milk quality and fatty acid content. Both, microRNAs (miRNAs) and protein-coding genes are important factors involved in the regulation of milk fat synthesis. In this study, high-throughput sequencing of miRNAs and mRNAs in bovine mammary gland tissue was performed during peak lactation (3 samples) and late lactation (3 samples) periods to characterize expression profiles. Differential expression (DE) analyses of miRNA and mRNA and miRNA-mRNA regulatory pathway screening were performed. Two-hundred eighty regulatory miRNA-mRNA pairs were identified, including the miR-33a-lipid phosphate phosphatase-related protein type 4 (LPPR4) pathway. Bioinformatics prediction, dual-luciferase reporter system detection, qRT-PCR, and Western blotting revealed that miR-33a can directly target LPPR4 and inhibit its expression. Experiments also revealed that miR-33a promotes the synthesis of triglycerides and increases the content of unsaturated fatty acids (UFAs) in bovine mammary epithelial cells (BMECs). These results indicate that miR-33a via LPPR4 plays an important role in the regulation of milk fat synthesis and UFA levels.

Caciocavallo Podolico Cheese, a Traditional Agri-Food Product of the Region of Basilicata, Italy: Comparison of the Cheese's Nutritional, Health and Organoleptic Properties at 6 and 12 Months of Ripening, and Its Digital Communication

Traditional agri-food products (TAPs) are closely linked to the peculiarities of the territory of origin and are strategic tools for preserving culture and traditions; nutritional and organoleptic peculiarities also differentiate these products on the market. One such product is Caciocavallo Podolico Lucano (CPL), a stretched curd cheese made exclusively from raw milk from Podolian cows, reared under extensive conditions. The objective of this study was to characterise CPL and evaluate the effects of ripening (6 vs. 12 months) on the quality and organoleptic properties, using the technological "artificial senses" platform, of CPL produced and sold in the region of Basilicata, Italy. Additionally, this study represents the first analysis of cheese-related digital communication and trends online. The study found no significant differences between 6-month- and 12-month-ripened cheese, except for a slight increase in cholesterol levels in the latter. CPL aged for 6 and 12 months is naturally lactose-free, rich in bioactive components, and high in vitamin A and antioxidants and has a low PUFA-n6/n3 ratio. The "artificial sensory profile" was able to discriminate the organoleptic fingerprints of 6-month- and 12-month-ripened cheese. The application of a socio-semiotic methodology enabled us to identify the best drivers to create effective communication for this product. The researchers recommend focusing on creating a certification mark linked to the territory for future protection.

Predicted essential fatty acid intakes for a group of dairy cows also apply at individual animal level

The ruminant requirements for essential fatty acids (EFAs), particularly linoleic acid (LA) and alpha-linolenic acid (ALA), have not been fully determined, although evidence suggests that an adequate supply of polyunsaturated fatty acids (FAs) could improve immunity and reproduction in transition cows. In previous studies, we predicted EFA intake for a group of cows based on animal characteristics and milk EFA secretions. However, to support precision livestock feeding, we need to match the nutrient requirements and intakes of each cow as closely as possible. Our group-level predictions may not be accurate enough to estimate the EFA intake of an individual cow, due to inter-individual variations in EFA digestion and metabolism related to differences in feed intake, intake patterns, and the composition and functioning of the rumen microbiota. To address this issue, here we set out to establish specific equations that predict EFA intake for an individual cow based on the difference (i.e. the residuals) between observed EFA intake and the predicted EFA intake based on our group-level equations. We studied a database of individual dairy cows (26 experiments; 503 datapoints from three research teams) and we predicted the residuals from (1) dietary and animal-related factors (i.e. full predictions) and (2) animal-related factors only (i.e. field predictions), which are considered more field-amenable. The variance of predicted LA and log ALA intake was explained to 68% by observed LA intake and 66% by observed log ALA intake, respectively. The residuals of LA intake were predicted by dietary ALA content, total FA intake, BW, milk yield and fat content in full predictions, and by BW, feeding level, milk yield and fat content, and sum of milk C4:0 to C14:0 FA in field predictions. The log residuals of ALA intake were predicted by dietary NDF and total FA contents, NDF intake, BW, milk protein, LA and ALA contents, and fat yield in full predictions, and by BW, DM intake, milk LA and ALA contents, and fat yield in field predictions. The field predictions showed a moderate loss of accuracy compared to full predictions based on RMSE of prediction (from 38 to 54 g/d for LA and from 0.090 to 0.12 log (g/d) for ALA). This work is the first to predict the EFA intake of an individual cow based on previously established group-level predictions of EFA intake adjusted for dietary and animal-related factors.

Monomethyl branched-chain fatty acids: Health effects and biological mechanisms

Branched-chain fatty acids (BCFA) are a group of lipids that are widely present in various organisms; they take part in numerous biochemical processes and affect multiple signaling pathways. However, BCFA are not well explored in terms of their effects on human health. Recently, they have been gaining interest, especially in relation to various human diseases. This review describes the occurrence of BCFA, their dietary sources, their potential health effects, and the current state of knowledge concerning their mechanism(s) of action. Many studies have been conducted so far in cellular and animal models, which reveal potent anti-cancer, lipid lowering, anti-inflammatory and neuroprotective actions. Research in humans is scarce. Therefore, further studies on animals and humans should be performed to confirm and expand these findings, and improve our understanding of the potential relevance of BCFA to human health and disease.

Monitoring the Milk Composition, Milk Microbiota, and Blood Metabolites of Jersey Cows throughout a Lactation Period

This study aimed to determine how milk composition, milk microbiota, and blood metabolites may change during the lactation period in Jersey cows. Milk and jugular blood samples were collected from eight healthy cows every other month from the beginning to the end of their lactation period. Samples of airborne dust were also collected to determine whether the cowshed microbiota could affect milk microbiota. Milk yield peaked in the first two months and gradually decreased as the lactation period progressed. Milk fat, protein, and solids-not-fat contents were low in the first month, and then increased during the middle and late lactation periods. In the first month, plasma non-esterified fatty acids (NEFA), haptoglobin (Hp), and aspartate transaminase (AST) levels were elevated, and high abundances of Burkholderiaceae and Oxalobacteraceae were observed in milk and airborne dust microbiota. The finding that contamination of the environmental microbiota in milk was coupled with elevated plasma NEFA, Hp, and AST levels indicated that impaired metabolic function during the early lactation period may increase the invasion of opportunistic bacteria. This study can affirm the importance of feeding and cowshed management and should provide a helpful addition to improving Jersey cow farming.

Preservation of high pressure pasteurised milk by hyperbaric storage at room temperature versus refrigeration on inoculated microorganisms, fatty acids, volatile compounds and lipid oxidation

High pressure pasteurised (HPP) milk was stored by hyperbaric storage at room temperature (HS/RT) (50-100 MPa at 20 °C) and compared with refrigeration (RF), to assess the effect on two pathogens surrogates and a pathogenic, up to 120 days, and on fatty acids, volatile organic compounds (VOCs) and secondary lipid oxidation over 60 days. HS/RT (75-100 MPa) was able to inactivate at least 6.68/6.31/6.03 log CFU/mL of Escherichia coli/Listeria innocua/Salmonella Senftenberg (to below the detection limit), while RF resulted only in minor changes. Overall, fatty acids profile remained stable under HS/RT, although secondary lipid oxidation showed slightly higher values. In addition, both HS/RT and RF showed stable and similar VOCs profiles and off-flavour indicative compounds were not detected, except for the lowest pressure (50 MPa) after 40 days. HS/RT preserved HPP milk with enhanced microbial safety, shelf-life and quality compared to RF, being in addition quasi-energetically costless and more sustainable than RF.

Odd- and branched-chain fatty acids in milk fat from Holstein dairy cows are influenced by physiological factors

Dairy products are the major source of odd- and branched-chain fatty acids (OBCFAs), a group of nutrients with emerging health benefits. The animal diet is known to influence milk fat OBCFAs of dairy cows; however, little is known about the effects of physiological factors. The objective of this study was to investigate the effects of parity and lactation stage on OBCFAs in milk fat of dairy cows. Holstein dairy cows (n = 157) were selected according to parity (first, second, third, or greater) and days in milk (DIM) (≤21 DIM, 21 < DIM ≤ 100, 100 < DIM ≤ 200, >200 DIM). All cows were fed the same total mixed ration for three weeks. Milk samples were collected during the last three days of each lactation stage for fatty acid (FA) analyses via gas chromatography. Results showed that first- and second-parity cows displayed significantly higher proportions and yields of iso-14:0, iso-15:0, iso-16:0, total iso-FA, and total branched-chain FA (P < 0.05) compared with other parities. The proportions of C17:0 and C17:1 cis-9 were also greater in first-parity cows (P < 0.05), while the yields of C17:0 and C17:1 cis-9 were similar among different parities (P > 0.05). The proportions of total OBCFAs were greater in first- and second-parity cows (P < 0.05), whereas the highest yield was observed in second-parity cows. Lactation dairy cows in ≤ 21 DIM group displayed lower proportions of iso-13:0, anteiso-13:0, C13:0, iso-14:0, C15:0, iso-16:0, total iso-FA, and total OBCFAs compared with that of the other groups (P < 0.05), and also lower yields of iso-14:0 and iso-16:0 (P < 0.05). In contrast, C17:0 and C17:1 cis-9 proportions and yields were higher in dairy cows with ≤ 21 DIM (P < 0.05). Iso-17:0 and anteiso-17:0 were not affected by lactation stage (P > 0.05). Taken together, our data showed that both parity and lactation stage have considerable effects on milk fat OBCFAs of dairy cows. In summary, first- and second-parity cows had higher milk OBCFAs compared with later parity cows, and OBCFAs with medium chain lengths were lower in dairy cows with ≤ 21 DIM, while C17:0 and C17:1 cis-9 were higher. These findings show that milk OBCFA contents are differentially modulated by physiological state. They will be useful in future studies that seek to alter OBCFA composition of Holstein dairy cow milk fats.

Unraveling structural and conformational dynamics of DGAT1 missense nsSNPs in dairy cattle

Cattle are domestic animals that have been nourishing humans for thousands of years. Milk from cattle represents a key source of high-quality protein, fat, and other nutrients. The nutritional value of milk and dairy products is closely associated with the fat content, providing up to 30% of the total fat consumed in the human diet. The fat content in cattle milk represents a major concern for the scientific community due to its association with human health. The relationship between milk fat content and diacylglycerol o-acyltransferase 1 gene (DGAT1) is well described in literature. Several studies demonstrated the difference in fat contents and other milk production traits in a wide range of cattle breeds, to be associated with missense non-synonymous single nucleotide polymorphisms (nsSNPs) of the DGAT1 gene. As a result, an nsSNPs analysis is crucial for unraveling the DGAT1 structural and conformational dynamics linked to milk fat content. DGAT1-nsSNPs are yet to be studied in terms of their structural and functional impact. Therefore, state-of-the-art computational and structural genomic methods were used to analyze five selected variants (W128R, W214R, C215G, P245R, and W459G), along with the wild type DGAT1. Significant structural and conformational changes in the variants were observed. We illustrate how single amino acid substitutions affect DGAT1 function, how this contributes to our understanding of the molecular basis of variations in DGAT1, and ultimately its impact in improving fat quality in milk.

Milk Fatty Acid Profile of Holstein Cows When Changed from a Mixed System to a Confinement System or Mixed System with Overnight Grazing

This study is aimed at comparing the milk fatty acid profile (FAP) of cows that changed from a mixed system (MS) of double grazing plus total mixed ration (TMR) to a total confinement system (TCS, 100% TMR) with cows that changed to another MS with one overnight grazing plus TMR and compare with cows that were kept unchanged in TCS. The diet change was made in the second month of lactation. The milk samples were collected at one (M1-spring) and three months of lactation (M3-summer). Three treatments are as follows (each n = 10): confined cows fed with TMR throughout the period (GTMR), cows that changed from MS with double grazing plus TMR in M1 to TCS in M3 (GCHD), and cows that changed from a MS with double grazing plus TMR in M1 to a MS with overnight grazing plus TMR in M3 (GTMR+P). Unlike GTMR+P, GCHD improved milk production after change (increased 14% from M1 to M3), but milk FAP was impaired. In M3, conjugated linoleic acid (C18 : 2-CLA) in GTMR and GCHD was lower than GTMR+P (p < 0.05), and linolenic (C18 : 3-n-3) was lower in GCHD than GTMR+P. Maintaining grazing in summer overnight sustained milk fat quality, evidenced by higher C18 : 3 (n-3); C18 : 2 (CLA); and n-6/n-3 ratio than cows that changed to TCS.

Identification of High and Low Branched-Chain Fatty Acid-Producing Phenotypes in Holstein Cows following High-Forage and Low-Forage Diets in a Crossover Designed Trial

BACKGROUND

Branched-chain fatty acids (BCFAs) are rumen-derived fatty acids comprising ∼2% of bovine-milk fatty acids. BCFAs possess anti-inflammatory properties and enriching the BCFA content of bovine milk may provide human health benefits.

OBJECTIVE

We determined whether forage content impacts the BCFA content of milk from Holstein cows and identified fatty acid phenotypes in high vs. low BCFA-containing milks.

METHODS

Holstein cows (n = 62), fed for 67 d in a crossover design, consumed a diet with high forage and low concentrate (HF:C) and a diet with low forage and high concentrate (LF:C). Milk samples were collected at the end of each treatment period and fatty acid content determined. Paired t-tests, 1-factor ANOVA, sparse partial least-squares discriminant analysis (sPLSDA), and Pearson's correlation analysis were used to analyze the data.

RESULTS

The total milk fatty acid concentration for cows fed the HF:C diet was greater than that of cows fed the LF:C diet (4.2 ± 0.7 g/100 mL vs. 3.9 ± 0.9 g/100 mL). sPLSDA demonstrated separation of the dietary treatments, with BCFAs and odd-chain fatty acids as primary determinants. Total BCFA content in milk fat was elevated by HF:C intake compared with LF:C intake (1.80 vs. 1.68%). Quintile separation of high vs. low BCFA milks resulted in 4 groups: HF:C /low BCFAs, HF:C /high BCFAs; LF:C /low BCFAs, and LF:C /high BCFAs. Milks from the high BCFA quintiles had lower palmitic acid content (29.6% vs. 34.4%) but higher oleic acid content than milks from the low BCFA quintiles (19.7% vs. 17.0%). Some cows were identified as high BCFA producers or low BCFA producers regardless of diet.

CONCLUSIONS

BCFA content of milk is diet-sensitive but variation in responses exists. The potential to produce milk with high BCFA content and lower SFA content needs further study.

Milk Odd and Branched Chain Fatty Acids in Dairy Cows: A Review on Dietary Factors and Its Consequences on Human Health

This review highlights the importance of odd and branched chain fatty acids (OBCFAs) and dietary factors that may affect the content of milk OBCFAs in dairy cows. Historically, OBCFAs in cow milk had little significance due to their low concentrations compared to other milk fatty acids (FAs). The primary source of OBCFAs is ruminal bacteria. In general, FAs and OBCFAs profile in milk is mainly affected by dietary FAs and FAs metabolism in the rumen. Additionally, lipid mobilization in the body and FAs metabolism in mammary glands affect the milk OBCFAs profile. In cows, supplementation with fat rich in linoleic acid and α-linolenic acid decrease milk OBCFAs content, whereas supplementation with marine algae or fish oil increase milk OBCFAs content. Feeding more forage rather than concentrate increases the yield of some OBCFAs in milk. A high grass silage rate in the diet may increase milk total OBCFAs. In contrast to saturated FAs, OBCFAs have beneficial effects on cardiovascular diseases and type II diabetes. Furthermore, OBCFAs may have anti-cancer properties and prevent Alzheimer's disease and metabolic syndrome.

Milk Fatty Acid Profiles in Different Animal Species: Focus on the Potential Effect of Selected PUFAs on Metabolism and Brain Functions

Milk contains several important nutrients that are beneficial for human health. This review considers the nutritional qualities of essential fatty acids (FAs), especially omega-3 (ω-3) and omega-6 (ω-6) polyunsaturated fatty acids (PUFAs) present in milk from ruminant and non-ruminant species. In particular, the impact of milk fatty acids on metabolism is discussed, including its effects on the central nervous system. In addition, we presented data indicating how animal feeding—the main way to modify milk fat composition—may have a potential impact on human health, and how rearing and feeding systems strongly affect milk quality within the same animal species. Finally, we have presented the results of in vivo studies aimed at supporting the beneficial effects of milk FA intake in animal models, and the factors limiting their transferability to humans were discussed.

Functional Odd- and Branched-Chain Fatty Acid in Sheep and Goat Milk and Cheeses

The inverse association between the groups of odd-chain (OCFA) and branched-chain (BCFA) and the development of diseases in humans have generated interest in the scientific community. In experiment 1, the extent of the passage of odd- and branched-chain fatty acids (OBCFA) from milk fat to fresh cheese fat was studied in sheep and goats. Milk collected in two milk processing plants in west Sardinia (Italy) was sampled every 2 weeks during spring (March, April and May). In addition, a survey was carried out to evaluate the seasonal variation of the OBCFA concentrations in sheep and goats’ cheeses during all lactation period from January to June. Furthermore, to assess the main differences among the sheep and goat cheese, principal component analysis (PCA) was applied to cheese fatty acids (FA) profile. Concentrations of OBCFA in fresh cheese fat of both species were strongly related to the FA content in the unprocessed raw milk. The average contents of OBCFA were 4.12 and 4.13 mg/100 mg of FA in sheep milk and cheese, respectively, and 3.12 and 3.17 mg/100 mg of FA in goat milk and cheese, respectively. The OBCFA concentration did no differed between milk and cheese in any species. The content of OBCFA was significantly higher in sheep than goats’ dairy products. The OBCFA composition of the cheese was markedly affected by the period of sampling in both species: odd and branched FA concentrations increased from March to June. The seasonal changes of OBCFA in dairy products were likely connected to variations in the quality of the diet. The PCA confirmed the higher nutritional quality of sheep cheese for beneficial FA, including OBCFA compared to the goat one, and the importance of the period of sampling in the definition of the fatty acids profile.

Short communication: Odd-chain and branched-chain fatty acid concentrations in bovine colostrum and transition milk and their stability under heating and freezing treatments

Although odd-chain fatty acids (OCFA) and branched-chain fatty acids (BCFA) are found in bovine milk and have some positive influences on human and animal health, their concentrations in bovine colostrum and transition milk have not been reported. In this study, we reported the OCFA and BCFA concentrations in colostrum and transition milk and their stability after heating or freezing treatments (or both), which are processes commonly applied in dairy calf management. Milk samples were collected from 12 Holstein dairy cows (6 primiparous and 6 multiparous) at the first milking (colostrum), fifth milking (transition milk), and ninth milking (mature milk) after calving, respectively, and were used for fatty acid analysis using gas chromatography. The sum concentration of OCFA and BCFA (termed OBCFA) was 134 mg/100 g of milk in the colostrum, which was 24% and 35% lower than that in the transition milk and mature milk, respectively. Among these fatty acids detected, C15:0 and C17:0 were the top 2 abundant fatty acids in all milk types, accounting for 20 to 25% and 21 to 24% of the total concentration of OBCFA, respectively. Additionally, anteiso-C17:0 was the most abundant BCFA, followed by iso-C17:0, anteiso-C15:0, iso-C16:0, iso-C15:0, iso-C18:0, and iso-C14:0 in 3 types of milk. Significant interactions between milk type and cow parity were observed for all OCFA and BCFA concentrations. The milk samples were also treated with heating (at 65°C for 60 min), freezing (at -20°C for 30 d), and heating and freezing (at 65°C for 60 min and then at -20°C for 30 d), and milk OCFA and BCFA concentrations were similar between these treatments. In conclusion, the OBCFA concentration was lower in colostrum, compared with transition and mature milks, and it remained stable after heating and freezing treatments.

Branched-Chain Fatty Acids-An Underexplored Class of Dairy-Derived Fatty Acids

Dairy fat and its fatty acids (FAs) have been shown to possess pro-health properties that can support health maintenance and disease prevention. In particular, branched-chain FAs (BCFAs), comprising approximately 2% of dairy fat, have recently been proposed as bioactive molecules contributing to the positive health effects associated with the consumption of full-fat dairy products. This narrative review evaluates human trials assessing the relationship between BCFAs and metabolic risk factors, while potential underlying biological mechanisms of BCFAs are explored through discussion of studies in animals and cell lines. In addition, this review details the biosynthetic pathway of BCFAs as well as the content and composition of BCFAs in common retail dairy products. Research performed with in vitro models demonstrates the potent, structure-specific properties of BCFAs to protect against inflammation, cancers, and metabolic disorders. Yet, human trials assessing the effect of BCFAs on disease risk are surprisingly scarce, and to our knowledge, no research has investigated the specific role of dietary BCFAs. Thus, our review highlights the critical need for scientific inquiry regarding dairy-derived BCFAs, and the influence of this overlooked FA class on human health.

A comparative study on milk composition of Jersey and Holstein dairy cows during the early lactation

Recently, Jersey cattle was introduced and produced by embryo transfer to Korea. This study was conducted to investigate the differences of milk compositions between Jersey and Holstein cows and the relationship between days in milk (DIM) and milk compositions during early lactation. Data were collected from twelve lactating cows from Department of Animal Resources Development at National Institute of Animal Science. Cows in parity 1 were used, and calved at spring from April to March of 2017. All cows were housed in two sections within a free-stall barn, which divided into six from each breed, and received a basal total mixed ration. Milk samples of each cow were collected at 3 DIM and 30 DIM for analyzing the milk compositions, including fatty acids (FA), amino acids and minerals. Total solids, citrate, and milk urea nitrogen level were differed between the breeds (p < 0.05). As DIM went from 3 to 30, milk protein, total solids, and somatic cell count decreased (p < 0.05), but lactose increased in all breed milk (p < 0.05). Citrate and free fatty acid (FFA) elevated in Jersey milk (p < 0.05), whereas reduced in Holstein milk (p < 0.05). Proportions of some individual FA varied from the breeds. Myristic (C14:0), palmitic (C16:0), and arachidonic acid (C20:4) in milk from all cows were higher at 3 DIM than at 30 DIM (p < 0.05). Also, stearic (C18:0) and oleic acid (C18:1) were lower at 3 DIM than at 30 DIM (p < 0.05), and the C18:1 to C18:0 ratio was significantly differed in DIM × breed interactions (p < 0.05). The contents of the individual amino acids did not differ from the breeds. Calcium, phosphorous, magnesium, and zinc (Zn) contents was significantly increased in Holstein milk than Jersey milk at 3 DIM. Also, K and Zn concentrations were higher in Holstein milk than in Jersey milk at 30 DIM (p < 0.05). It was concluded that Jersey cows would produce more effective milk in processing dairy products and more proper energy status compared with Holstein cows in early lactation under the same environmental and nutritional conditions.

Milk fat: opportunities, challenges and innovation

Milk fat is a high-value milk component that is processed mainly as butter, cheese, cream and whole milk powder. It is projected that approximately 35 million tonnes of milk fat will be produced globally by 2025. This surplus, enhances the need for diversification of milk fat products and the milk pool in general. Infant milk formula producers, for instance, have incorporated enzyme modified ("humanised") milk fat and fat globule phospholipids to better mimic human milk fat structures. Minor components like mono- and di-glycerides from milk fat are increasingly utilized as emulsifiers, replacing palm esters in premium-priced food products. This review examines the chemistry of milk fat and the technologies employed for its modification, fractionation and enrichment. Emerging processing technologies such as ultrasound, high pressure processing, supercritical fluid extraction and fractionation, can be employed to improve the nutritional and functional attributes of milk fat. The potential of recent developments in biological intervention, through dietary manipulation of milk fatty acid profiles in cattle also offers significant promise. Finally, this review provides evidence to help redress the imbalance in reported associations between milk fat consumption and human health, and elucidates the health benefits associated with consumption of milk fat and dairy products.

Impact of SNPs in ACACA, SCD1, and DGAT1 Genes on Fatty Acid Profile in Bovine Milk with Regard to Lactation Phases

Simple Summary

Fatty acids are an important component of milk fat. Because of their wide spectrum of effects on human health, it is important to better understand the regulation of their profile in milk. This study aims to analyzing the relation between selected genes with milk fatty acid content. As increased concentration of unhealthy fatty acids and lower concentration of healthy ones in less frequent homozygotes and a strong influence of the genes on fatty acids with 18 carbon atoms were observed, these findings could be useful in future dairy cattle selection aiming production of more healthy milk.

Abstract

Milk fat is a dietary source of fatty acids (FA), which can be health promoting or can increase risks of some diseases. FA profile composition depends on many factors, among them gene polymorphism. This study analyzed the relation between polymorphism of acetyl-CoA carboxylase α (ACACA), stearoyl-CoA desaturase 1 (SCD1), diacylglycerol acyltransferase 1 (DGAT1) genes with FA profile in milk from Polish Holstein-Friesian cattle and determined changes of FA percentage during lactation with regard to polymorphism. Milk samples were collected twice: during the first phase of lactation (<90 Days in milk; DIM) and at the end of lactation (>210 DIM). During the first milk collection, blood samples were taken to analyze three chosen single nucleotide polymorphisms (SNPs): AJ312201.1g.1488C > G SNP in ACACA gene, A293V SNP in SCD1 gene, and K232A SNP in DGAT1 gene. Increased concentration of FA that are less beneficial for human health and have lower concentration of healthy FA in homozygotes: GG in ACACA, VV in SCD1, and KK in DGAT1 were observed, as well as a strong influence of the analyzed genes on FA with 18C atoms was also found. Moreover, it was demonstrated that lactation phase significantly affected FA percentage in milk depending on the phenotype. These results may contribute their part to knowledge toward obtaining more beneficial milk composition.

Relations of Ruminal Fermentation Parameters and Microbial Matters to Odd- and Branched-Chain Fatty Acids in Rumen Fluid of Dairy Cows at Different Milk Stages

Simple Summary

The objective of this study was to determine the relationships between milk odd- and branched-chain fatty acids (OBCFAs) and ruminal fermentation parameters, microbial populations, and base contents. Significant relationships existed between the concentrations of C11:0, iso-C15:0, anteiso-C15:0, C15:0, and anteiso-C17:0 in rumen and milk. The total OBCFA content in milk was positively related to the acetate molar proportion but negatively correlated with isoacid levels. The adenine/N ratio was negatively related to milk OBCFA content but positively associated with the iso-C15:0/iso-C17:0 ratio.

Abstract

The purpose of this research was to evaluate whether relationships exist between odd- and branched-chain fatty acids (OBCFAs) originating from milk fat and the corresponding data of ruminal fermentation parameters, microbial populations, and base contents that were used to mark microbial protein in rumen. Nine lactating Holstein dairy cows with similar body weights and parity were selected in this study, and the samples of rumen and milk were collected at the early, middle, and late stages, respectively. The rumen and milk samples were collected over three consecutive days from each cow, and the ruminal and milk OBCFA profiles, ruminal fermentation parameters, bacterial populations, and base contents were measured. The results showed that the concentrations of OBCFAs, with the exception of C11:0 and C15:0, were significantly different between milk and rumen (p < 0.05). The concentrations of anteiso-fatty acids in milk were higher than those in rumen, and the contents of linear odd-chain fatty acids were higher than those of branched-chain fatty acids in both milk and rumen. Significant relationships that existed between the concentrations of C11:0, iso-C15:0, anteiso-C15:0, C15:0, and anteiso-C17:0 in rumen and milk (p < 0.05). The total OBCFA content in milk was positively related to the acetate molar proportion but negatively correlated with isoacid contents (p < 0.05). The populations of Ruminococcus albus, R. flavefacients, and Eubacterium ruminantium were significantly related to milk C13:0 contents (p < 0.05). The adenine/N ratio was negatively related to milk OBCFA content (p < 0.05) but positively associated with the iso-C15:0/iso-C17:0 ratio (p < 0.05). Milk OBCFAs were significantly correlated with ruminal fermentation parameters, ruminal bacterial populations, and base contents. Milk OBCFAs had the potential to predict microbial nitrogen flow, and the prediction equations for ruminal microbial nitrogen flow were established for OBCFAs in dairy milk.

Branched chain fatty acid composition of yak milk and manure during full-lactation and half-lactation

BACKGROUND

Branched chain fatty acids (BCFA) are bioactive food compounds and are well known to be essential components of human, cow and caprine milk. In Qinghai-Tibet plateau, yaks are domesticated in large numbers and their milk in addition to meat are commercially important to millions of Tibetans and Chinese.

OBJECTIVE

We tested the hypotheses that concentrations of BCFA in yak milk and manure differ between lactation periods and evaluated gene expression levels of certain genes involved in the biosynthesis and elongation of fatty acids.

DESIGN

Fresh milk and manure were collected from each yak and their fatty acid compositions compared with emphasis on BCFA.

PARTICIPANTS/SETTING

Yak milk and manure samples from the full lactation (October, 2015) and half lactation periods (March, 2016) were collected and BCFA levels were analyzed in detail by GC-FID and structures verified by GC-EI-MS/MS. Gene expression studies were carried out by semi-quantitative real time PCR method.

STATISTICAL ANALYSES PERFORMED

The difference between full lactation and half lactation was tested using student's t-test. Linear regression model was modelled in Excel and its significance was tested by ANOVA. Statistical significance was determined by performing student's t-test for gene expression studies.

RESULTS

BCFA ranged from 3-6% of total fatty acids in yak milk samples. The half-lactation yak milk contained higher levels of BCFA (5.29 ± 0.53) than the full-lactation milk (4.00 ± 0.46). The total BCFA in yak manure was found to be 14.67 ± 1.21, high in anteiso-15:0 and anteiso-17:0. ELOVL1 enzyme involved in the elongation of saturated C18 to C26 acyl-CoA substrates and MCAT enzyme involved in the transfer of a malonyl group to the mitochondrial acyl carrier protein are significantly upregulated in full-lactation milk.

CONCLUSIONS

BCFA in yak manure especially anteiso BCFA are positively correlated with yak milk from the same animal, indicating that these BCFA come from dietary sources. Yak milk delivers 777 mg BCFA compared to 158 mg per cup of whole U.S. dairy milk. QTP herders known to consume up to 2 kg of yak yogurt take in an estimated 3,500-5,000 mg BCFA per day. We conclude that BCFA intake for yak milk consumers is among the highest known in the world, higher when drawn from half lactating yaks.

Dairy Fat Consumption and the Risk of Metabolic Syndrome: An Examination of the Saturated Fatty Acids in Dairy

Lifestyle is a key modifiable risk factor involved in the manifestation of metabolic syndrome and, in particular, diet plays a pivotal role in its prevention and development. Current dietary guidelines discourage the consumption of saturated fat and dietary sources rich in saturated fat, such as dairy products, despite data suggesting that full-fat dairy consumption is protective against metabolic syndrome. This narrative review assessed the recent epidemiological and clinical research that examined the consumption of dairy-derived saturated fatty acids (SFA) on metabolic syndrome risk. In addition, this review evaluated studies of individual SFA to gain insight into the potential mechanisms at play with intake of a diet enriched with these dairy-derived fatty acids. This work underscores that SFA are a heterogenous class of fatty acids that can differ considerably in their biological activity within the body depending on their length and specific chemical structure. In summary, previous work on the impact of dairy-derived SFA consumption on disease risk suggests that there is currently insufficient evidence to support current dietary guidelines which consolidate all dietary SFA into a single group of nutrients whose consumption should be reduced, regardless of dietary source, food matrix, and composition.

Iso- but Not Anteiso-Branched Chain Fatty Acids Exert Growth-Inhibiting and Apoptosis-Inducing Effects in MCF-7 Cells

The present study compared the growth-inhibitory effects of four common branched chain fatty acids (BCFAs) found in beef and dairy fats including iso 15:0, anteiso 15:0, iso 17:0, and anteiso 17:0. MCF-7 human breast cancer cells were exposed for 72 h to media containing increasing doses (50 to -400 μM) of the four BCFA. Cell viability was not affected by any of the BCFA treatments at doses less than 200 μM. Culturing cells with 200 μM of iso-15:0 or iso-17:0 reduced cell viability by 27 ± 2.8 and 43 ± 8.3% at 24 h, 35 ± 4.6 and 49 ± 9.1% at 48 h, and 44 ± 6.8 and 57 ± 8.8% at 72 h posttreatment. In contrast, culturing cells with 200 μM of anteiso-15:0 or anteiso-17:0 did not affect cell viability for any durations tested. The incorporation of iso 15:0 and iso 17:0 into cells (19.1 ± 1.3 and 21.2 ± 1.4 μmol/mg protein, respectively) was greater (P < 0.01) than that of anteiso 15:0 and anteiso 17:0 (11.8 ± 0.7 and 13.8 ± 0.8 μmol/mg protein, respectively). Iso-15:0 and iso-17:0 downregulated (P < 0.01) the expression of antiapoptotic Bcl-2 (0.71 ± 0.6-fold and 0.64 ± 0.09-fold, respectively) and upregulated (P < 0.01) the expression of proapoptotic Bax (1.72 ± 0.14-fold and 2.15 ± 0.24-fold, respectively) compared to the control, whereas their corresponding anteiso isomers did not affect the expression of any apoptosis-related genes. Our findings suggest that the branching structure influences anticarcinogenic effects of BCFAs, with iso being more potent than anteiso.

The single nucleotide polymorphism g.133A>C in the stearoyl CoA desaturase gene (SCD) promoter affects gene expression and quali-quantitative properties of river buffalo milk

The stearoyl-CoA desaturase (SCD) gene has been investigated in depth in ruminants because of its effect on milk fat composition. In river buffalo, the single nucleotide polymorphism (SNP) g.133A>C in the gene promoter has been associated with milk quality and yield. However, the biological reason for such effects remains unexplored. In this study, we combined mRNA profile analysis, an electromobility shift assay, and quantitative PCR to elucidate the role of this SNP on gene transcription and its effects on milk fat traits. A preliminary genotyping of g.133A>C was carried out on a group of 303 river buffaloes to choose individuals for the downstream applications. Analysis of allele frequencies showed an increase in the minor allele C (0.25) compared with previous findings (0.16). Six animals (2 for each genotype) were chosen for cloning and 216 positive cDNA recombinant clones for SCD (72 per genotype) were analyzed by PCR. All clones showed the same length on agarose gel; therefore, random clones were chosen for sequencing. No qualitative differences were found and all gene transcripts assembled correctly. An electrophoretic mobility shift assay was performed to evaluate the binding of the transcription factor Sp1 to DNA sequences including g.133A>C. Genotype CC showed a higher binding (mean ± standard error of the mean) than genotype AA in 2 different conditions [Enzo buffer (EB), Enzo Life Science Inc., Farmingdale, NY: 201.77 ± 4.06 vs. 141.65 ± 3.77 band intensity values and Poletto buffer (PB): 95.90 ± 1.15 vs. 67.30 ± 2.14 band intensity values]. The subsequent quantitative PCR confirmed the upregulation of the CC genotype compared with the AA and AC genotypes. The association study with milk fat traits revealed a favorable effect of allele C. The heterozygous genotype had the highest values for monounsaturated fatty acids, oleic acid (C18:1 cis-9), polyunsaturated fatty acids, and odd- and branched-chain fatty acids, and the lowest values for saturated fatty acids and atherogenic and thrombogenic indices; the heterozygous genotype differed significantly from the AA genotype. The AC genotype has previously been associated with higher milk yield. Therefore, the g.133A>C SNP is a marker with dual effects and is an interesting candidate for assisted selection programs in river buffalo. These data clarified the biological role of the SNP g.133A>C in the SCD promoter and how it affects gene function, providing important knowledge on the genetic background of lipid metabolism, including the future possibility of selecting alleles with quantitatively or qualitatively favorable effects.

Remarkable genetic diversity detected at river buffalo prolactin receptor (PRLR) gene and association studies with milk fatty acid composition

Prolactin is an anterior pituitary peptide hormone involved in many different endocrine activities and is essential for reproductive performance. This action is mediated by its receptor, the prolactin receptor, encoded by the PRLR gene. In this study, we sequenced and characterized the Mediterranean river buffalo PRLR gene (from exon 3 to 10), and we found remarkable genetic diversity. In particular, we found 24 intronic polymorphisms and 13 exonic SNPs, seven of which were non-synonymous. Furthermore, the polymorphisms identified in the 3'-UTR were investigated to establish their possible influence on microRNA binding sites. Considering all the amino acid changes and the observed allelic combinations, it is possible to deduce at least six different translations of the buffalo prolactin receptor and, consequently, the presence at the PRLR gene of at least six alleles. Furthermore, we identified a deletion of a CACTACC heptamer between nucleotides 1102 and 1103 of exon 10 (3'-UTR), and we developed an allele-specific PCR to identify the carriers of this genetic marker. Finally, the SNP g.11188A>G, detected in exon 10 and responsible for the amino acid replacement p.His328Arg, was genotyped in 308 Italian Mediterranean river buffaloes, and an association study with milk fat traits was carried out. The statistical analysis showed a tendency that approached significance for the AA genotype with higher contents of odd branched-chain fatty acids. Thus, our results suggest that the PRLR gene is a good candidate for gene association studies with qualitative traits related to buffalo milk production.

Dairy Products, Dairy Fatty Acids, and the Prevention of Cardiometabolic Disease: a Review of Recent Evidence

PURPOSE OF REVIEW

To examine recent literature on dairy products, dairy fatty acids, and cardiometabolic disease. Primary questions of interest include what unique challenges researchers face when investigating dairy products/biomarkers, whether one should consume dairy to reduce disease risk, whether dairy fatty acids may be beneficial for health, and whether one should prefer low- or high-fat dairy products.

RECENT FINDINGS

Dairy composes about 10% of the calories in a typical American diet, about half of that coming from fluid milk, half coming from cheese, and small amounts from yogurt. Most meta-analyses report no or weak inverse association between dairy intake with cardiovascular disease and related intermediate outcomes. There is some suggestion that dairy consumption was inversely associated with stroke incidence and yogurt consumption was associated with lower risk of type 2 diabetes. Odd chain fatty acids (OCFAs) found primarily in dairy (15:0 and 17:0) appear to be inversely associated with cardiometabolic risk, but causation is uncertain. Substitution analyses based on prospective cohorts suggested that replacing dairy fat with vegetable fat or polyunsaturated fat was associated with significantly lower risk of cardiovascular disease. Current evidence suggests null or weak inverse association between consumption of dairy products and risk of cardiovascular disease. However, replacing dairy fat with polyunsaturated fat, especially from plant-based foods, may confer health benefits. More research is needed to examine health effects of different types of dairy products in diverse populations.

Invited review: The anti-inflammatory properties of dairy lipids

Dairy product consumption is often associated with negative effects because of its naturally high levels of saturated fatty acids. However, recent research has shown that dairy lipids possess putative bioactivity against chronic inflammation. Inflammation triggers the onset of several chronic diseases, including cardiovascular disease, type 2 diabetes mellitus, obesity, and cancer. This review discusses the anti-inflammatory properties of dairy lipids found in milk, yogurt, and cheese, and it examines them in relation to their implications for human health: their protective effects and their role in pathology. We also consider the effect of lipid profile alteration in dairy products-by using ruminant dietary strategies to enrich the milk, or by lipid fortification in the products. We critically review the in vivo, in vitro, ex vivo, and epidemiological studies associated with these dairy lipids and their role in various inflammatory conditions. Finally, we discuss some suggestions for future research in the study of bioactive lipids and dairy products, with reference to the novel field of metabolomics and epidemiological studies.

Environmental and genetic factors influence the vitamin D content of cows’ milk

Vitamin D is obtained by cattle from the diet and from skin production via UVB exposure from sunlight. The vitamin D status of the cow impacts the vitamin D content of the milk produced, much like human breast milk, with seasonal variation in the vitamin D content of milk well documented. Factors such as changes in husbandry practices therefore have the potential to impact the vitamin D content of milk. For example, a shift to year-round housing from traditional practices of cattle being out to graze during the summer months and housed during the winter only, minimises exposure to the sun and has been shown to negatively influence the vitamin D content of the milk produced. Other practices such as changing dietary sources of vitamin D may also influence the vitamin D content of milk, and evidence exists to suggest genetic factors such as breed can cause variation in the concentrations of vitamin D in the milk produced. The present review aims to provide an overview of the current understanding of how genetic and environmental factors influence the vitamin D content of the milk produced by dairy cattle. A number of environmental and genetic factors have previously been identified as having influence on the nutritional content of the milk produced. The present review highlights a need for further research to fully elucidate how farmers could manipulate the factors identified to their advantage with respect to increasing the vitamin D content of milk and standardising it across the year.