Milk and meat in our diet: good or bad for health?

Dietary combination of linseed and hazelnut skin as a sustainable strategy to enrich lamb with health promoting fatty acids

This study investigated the effect of the inclusion of extruded linseed and hazelnut skin on fatty acid (FA) metabolism in finishing lambs. Forty lambs were divided into 4 groups and fed for 60 d with: a conventional cereal-based diet, or the same diet with 8% of extruded linseed, or 15% of hazelnut skin, or 4% of linseed plus 7.5% of hazelnut skin as partial replacement of maize. Dietary treatments did not affect growth performances, carcass traits, and ruminal fermentation. The combined effect of linseed and hazelnut skin enriched the intramuscular fat with health promoting FA. Particularly, increases in α-linolenic acid (3.75-fold), and very long-chain n-3 poly-unsaturated FA (+ 40%) were attributed to the supplementation with linseed, rich in α-linolenic acid. In addition, increases in rumenic (+ 33%), and vaccenic (+ 59%) acids were attributed to hazelnut skin tannins modulating ruminal biohydrogenation and accumulating intermediate metabolites. The simultaneous inclusion of linseed and hazelnut skin can be a profitable strategy for enriching the intramuscular fat of lambs with health promoting FA, without adverse effects on ruminal fermentation and animal performance.

Effects of Agricultural Intensification on Mediterranean Diets: A Narrative Review

INTRODUCTION

Mediterranean diets (MedDiets) are linked to substantial health benefits. However, there is also growing evidence that the intensification of food production over the last 60 years has resulted in nutritionally relevant changes in the composition of foods that may augment the health benefits of MedDiets.

OBJECTIVE

To synthesize, summarize, and critically evaluate the currently available evidence for changes in food composition resulting from agricultural intensification practices and their potential impact on the health benefits of MedDiets.

METHODS

We summarized/synthesized information from (i) systematic literature reviews/meta-analyses and more recently published articles on composition differences between conventional and organic foods, (ii) desk studies which compared food composition data from before and after agricultural intensification, (iii) recent retail and farm surveys and/or factorial field experiments that identified specific agronomic practices responsible for nutritionally relevant changes in food composition, and (iv) a recent systematic literature review and a small number of subsequently published observational and dietary intervention studies that investigated the potential health impacts of changes in food composition resulting from agricultural intensification.

RESULTS AND DISCUSSION

There has been growing evidence that the intensification of food production has resulted in (i) lower concentrations of nutritionally desirable compounds (e.g., phenolics, certain vitamins, mineral micronutrients including Se, Zn, and omega-3 fatty acids, α-tocopherol) and/or (ii) higher concentrations of nutritionally undesirable or toxic compounds (pesticide residues, cadmium, omega-6 fatty acids) in many of the foods (including wholegrain cereals, fruit and vegetables, olive oil, dairy products and meat from small ruminants, and fish) that are thought to contribute to the health benefits associated with MedDiets. The evidence for negative health impacts of consuming foods from intensified conventional production systems has also increased but is still limited and based primarily on evidence from observational studies. Limitations and gaps in the current evidence base are discussed. Conclusions: There is now substantial evidence that the intensification of agricultural food production has resulted in a decline in the nutritional quality of many of the foods that are recognized to contribute to the positive health impacts associated with adhering to traditional MedDiets. Further research is needed to quantify to what extent this decline augments the positive health impacts of adhering to a traditional MedDiet.

Dairy product consumption and risk of non-alcoholic fatty liver disease: A systematic review and meta-analysis of observational studies

BACKGROUND AND AIMS

It is unclear whether regular consumption of dairy products is associated with the risk of developing non-alcoholic fatty liver disease (NAFLD). Thus, we conducted a systematic review followed by a meta-analysis of studies reporting on the association of dairy consumption with NAFLD risk.

METHODS AND RESULTS

We comprehensively searched PubMed, Web of Science, and Scopus for observational studies that evaluated the association between dairy intake and NAFLD likelihood that were published before September 1, 2022. The reported odds ratios (ORs) of fully adjusted models and their 95% confidence intervals (CIs) were pooled using a random-effects model for the meta-analysis. Out of 1206 articles retrieved, 11 observational studies, including 43,649 participants and 11,020 cases, were included. Pooled OR indicated a significant association between dairy intake and NAFLD (OR = 0.90; 95% CI: 0.83, 0.98; I² = 67.8%, n = 11). Pooled ORs revealed that milk (OR: 0.86; 95% CI: 0.78, 0.95; I² = 65.7%, n = 6), yogurt (OR: 0.88; 95% CI: 0.82; I² = 0.0%, n = 4), and high-fat dairy (OR: 0.38; 95% CI: 0.19, 0.75; I² = 0.0%, n = 5) consumption was inversely associated with NAFLD while cheese was not linked to NAFLD risk.

CONCLUSION

We observed that consumption of dairy products is linked to a reduced risk of developing NAFLD. Overall, the data in the source articles is of low to moderate quality; therefore, further observational studies are required to support the current findings (PROSPERO Reg. number: CRD42022319028).

Correlation between breeding values for milk fatty acids and Nordic Total Merit index traits for Danish Holstein and Danish Jersey

Milk fatty acid composition is gaining interest in the Danish dairy industry both to develop new dairy products and as a management tool. To be able to implement milk fatty acid (FA) composition in the breeding program, it is important to know the correlations with the traits in the breeding goal. To estimate these correlations, we measured milk fat composition in Danish Holstein (DH) and Danish Jersey (DJ) cattle breeds using mid-infrared spectroscopy. Breeding values were estimated for specific FA and for groups of FA. Correlations with the estimated breeding values (EBV) underlying the Nordic Total Merit index (NTM) were calculated within breed. For both DH and DJ, we showed that FA EBV had moderate correlations with the NTM and production traits. For both DH and DJ, the correlation of FA EBV and NTM were in the same direction, except for C16:0 (0 in DH, 0.23 in DJ). A few correlations differed between DH and DJ. The correlation between claw health index and C18:0 was negative in DH (-0.09) but positive in DJ (0.12). In addition, some correlations were not significant in DH but were significant in DJ. The correlations between udder health index and long-chain FA, trans FA, C16:0, and C18:0 were not significant in DH (-0.05 to 0.02), but were significant in DJ (-0.17, -0.15, 0.14, and -0.16, respectively). For both DH and DJ, the correlations between FA EBV and nonproduction traits were low. This implies that it is possible to breed for a different fat composition in the milk without affecting the nonproduction traits in the breeding goal.

Implications of Organic Dairy Management on Herd Performance and Milk Fatty Acid Profiles and Interactions with Season

Interest in organic cows' milk has increased due to the perceived superior nutritional quality and improved sustainability and animal welfare. However, there is a lack of simultaneous assessments on the influence of organic dairy practices and dietary and breed drivers on productivity, feed efficiency, health parameters, and nutritional milk quality at the herd level. This work aimed to assess the impact of organic vs. conventional management and month on milk yield and basic composition, herd feed efficiency, health parameters, and milk fatty acid (FA) composition. Milk samples (n = 800) were collected monthly from the bulk tanks of 67 dairy farms (26 organic and 41 conventional) between January and December 2019. Data on breed and feeding practices were gathered via farm questionnaires. The samples were analyzed for their basic composition and FA profile using Fourier transform infrared spectroscopy (FTIR) and gas chromatography (GC), respectively. The data were analyzed using a linear mixed model, repeated measures design and multivariate redundancy analysis (RDA). The conventional farms had higher yields (kg/cow per day) of milk (+7.3 kg), fat (+0.27 kg), and protein (+0.25 kg) and higher contents (g/kg milk) of protein, casein, lactose, and urea. The conventional farms produced more milk (+0.22 kg), fat (+8.6 g), and protein (+8.1 g) per kg offered dry matter (DM). The organic farms produced more milk per kg of offered non-grazing and concentrate DM offered, respectively (+0.5 kg and +1.23 kg), and fat (+20.1 g and +51 g) and protein (+17 g and +42 g). The organic milk had a higher concentration of saturated fatty acid (SFA; +14 g/kg total FA), polyunsaturated fatty acid (PUFA; +2.4 g/kg total FA), and nutritionally beneficial FA alpha linolenic acid (ALNA; +14 g/kg total FA), rumenic acid (RA; +14 g/kg total FA), and eicosapentaenoic acid (EPA; +14 g/kg total FA); the conventional milk had higher concentrations of monounsaturated FA (MUFA; +16 g/kg total FA). Although the conventional farms were more efficient in converting the overall diet into milk, fat, and protein, the organic farms showed better efficiency in converting conserved forages and concentrates into milk, fat, and protein as a result of reduced concentrate feeding. Considering the relatively small differences in the FA profiles between the systems, increased pasture intake can benefit farm sustainability without negatively impacting consumer nutrition and health.

Associating changes in the bacterial community of rumen and faeces and milk fatty acid profiles in dairy cows fed high-starch or starch and oil-supplemented diets

The experiment reported in this research paper aimed to evaluate the effects of high-starch or starch and oil-supplemented diets on rumen and faecal bacteria, and explore links between the structure of bacterial communities and milk fatty acid (FA) profiles. We used four Holstein dairy cows in a 4 × 4 Latin square design. Cows were fed a diet rich in cereals (high-starch diet with 23% starch content on dry matter (DM) basis), a diet supplemented with saturated FA from Ca salts of palm oil + 18% DM starch, a diet with high content of monounsaturated FA (from extruded rapeseeds) + 18% DM starch or a diet rich in polyunsaturated FA (from extruded sunflower seeds) + 17% DM starch. At the end of each experimental period, cows were sampled for rumen and faecal contents, which were used for DNA extraction and amplicon sequencing. Partial least squares (PLS) regression analysis highlighted diet-related changes in both rumen and faecal bacterial structures. Sparse PLS discriminant analysis was further employed to identify biologically relevant operational taxonomical units (OTUs) driving these differences. Our results show that Butyrivibrio discriminated the high-starch diet and linked positively with higher concentrations of milk odd- and branched-chain FA. YS2-related OTUs were key taxa distinguishing diets supplemented with Ca salts of palm oil or sunflower seeds and correlated positively with linoleic acid in milk. Similarly, diets modulated faecal bacterial composition. However, correlations between changes in faecal and rumen bacteria were poor. With this work, we demonstrated that high-starch or lipid-supplemented diets affect rumen and faecal bacterial community structure, and these changes could have a knock-on effect on milk FA profiles.

Effects of Different Roughage Diets on Fattening Performance, Meat Quality, Fatty Acid Composition, and Rumen Microbe in Steers

This study aimed to evaluate different roughages on fatting performance, muscle fatty acids, rumen fermentation and rumen microbes of steers. Seventy-five Simmental crossbred steers were randomly divided into wheat straw group (WG), peanut vine group (PG) and alfalfa hay group (AG), with 5 replicates of 5 steers each. The results showed a highest average daily gain and lowest feed/gain ratio in AG group (P = 0.001). Steers fed alfalfa hay had the highest muscle marbling score and n-3 polyunsaturated fatty acid (PUFA), and also the rumen NH3-N and microbial protein (MCP) concentration among the three groups (P < 0.05). Correlation analysis showed that ruminal NH3-N and MCP were negatively correlated with muscle saturated fatty acid (SFA), while ruminal MCP was positively correlated with muscle PUFA and n-3 PUFA (P < 0.05). 16S rRNA analysis indicated that fed alfalfa hay decreased the abundance of Ruminococcaceae_UCG-001(P = 0.005). More importantly, muscle SFA deposition were positively correlated to the abundance of Ruminococcaceae_UCG-001 (P < 0.05), while the muscle PUFA and n-3 PUFA deposition were negatively correlated to it (P < 0.01). Therefore, alfalfa hay provides a better fattening effect on steers. Alfalfa rich in n-3 PUFA would reduce the abundance of Ruminococcaceae_UCG-001 involved in hydrogenation, increase the rumen protective effect of C18:3 n-3, which is beneficial to the deposition of muscle n-3 PUFA and PUFA.

Performance and milk quality parameters of Jersey crossbreds in low-input dairy systems

Previous work has demonstrated some benefit from alternative breeds in low-input dairying, although there has been no systematic analysis of the simultaneous effect of Jersey crossbreeding on productivity, health, fertility parameters or milk nutritional quality. This work aimed to understand the effects of, and interactions/interrelations between, dairy cow genotypes (Holstein-Friesian (HF), Holstein-Friesian × Jersey crossbreds (HF × J)) and season (spring, summer, autumn) on milk yield; basic composition; feed efficiency, health, and fertility parameters; and milk fatty acid (FA) profiles. Milk samples (n = 219) and breed/diet data were collected from 74 cows in four UK low-input dairy farms between March and October 2012. HF × J cows produced milk with more fat (+ 3.2 g/kg milk), protein (+ 2.9 g/kg milk) and casein (+ 2.7 g/kg milk); and showed higher feed, fat, and protein efficiency (expressed as milk, fat and protein outputs per kg DMI) than HF cows. Milk from HF × J cows contained more C4:0 (+ 2.6 g/kg FA), C6:0 (+ 1.9 g/kg FA), C8:0 (+ 1.3 g/kg FA), C10:0 (+ 3.0 g/kg FA), C12:0 (+ 3.7 g/kg FA), C14:0 (+ 4.6 g/kg FA) and saturated FA (SFA; + 27.3 g/kg milk) and less monounsaturated FA (MUFA; -23.7 g/kg milk) and polyunsaturated FA (− 22.3 g/kg milk). There was no significant difference for most health and fertility parameters, but HF × J cows had shorter calving interval (by 39 days). The superior feed, fat and protein efficiency of HF × J cows, as well as shorter calving interval can be considered beneficial for the financial sustainability of low-input dairy farms; and using such alternative breeds in crossbreeding schemes may be recommended. Although statistically significant, it is difficult to determine if differences observed between HF and HF × J cows in fat composition are likely to impact human health, considering average population dairy fat intakes and the relatively small difference. Thus, the HF × J cow could be used in low-input dairying to improve efficiency and productivity without impacting milk nutritional properties.

Docosahexaenoic acid-rich algae oil supplementation on breast milk fatty acid profile of mothers who delivered prematurely: a randomized clinical trial

Preterm infants are deficient in long-chain polyunsaturated fatty acids, especially docosahexaenoic acid (DHA), a fatty acid (FA) associated with an increase in bronchopulmonary dysplasia (BPD). In two previous randomized control trials, DHA supplementation did not reduce the risk of BPD. We examined the breast milk FA profile, collected 14 days after birth, of mothers who delivered before 29 weeks of gestation and who were supplemented with DHA-rich algae oil or a placebo within 72 h after birth as part of the MOBYDIck trial. Milk FA were analyzed by gas chromatography. The total amount of FA (mg/mL) was similar in both groups but the supplementation increased DHA (expressed as % of total FA, mean ± SD, treatment vs placebo, 0.95 ± 0.44% vs 0.34 ± 0.20%; P < 0.0001), n-6 docosapentaenoic acid (DPA) (0.275 ± 0.14% vs 0.04 ± 0.04%; P < 0.0001) and eicosapentaenoic acid (0.08 ± 0.08% vs 0.07 ± 0.07%; P < 0.0001) while decreasing n-3 DPA (0.16 ± 0.05% vs 0.17 ± 0.06%; P < 0.05). Supplementation changed the ratio of DHA to arachidonic acid (1.76 ± 1.55% vs 0.60 ± 0.31%; P < 0.0001) and n-6 to n-3 FA (0.21 ± 0.06% vs 0.17 ± 0.04%; P < 0.0001). DHA-rich algae supplementation successfully increased the DHA content of breast milk but also included secondary changes that are closely involved with inflammation and may contribute to changing clinical outcomes.

A quantitative review of on-farm feeding practices to enhance the quality of grassland-based ruminant dairy and meat products

In the last decades, a large body of evidence has highlighted the major role of feeding management practices in improving specific nutritional, technological and sensory quality traits of ruminant products. However, results have been mostly obtained under controlled conditions, and have been rarely validated on-farm. Therefore, a quantitative review was conducted to quantify the effects of on-farm feeding management practices on carotenoids, fat-soluble vitamins, colour, fatty acids (FAs), terpenes and sensory properties in the main animal product categories (PCs): dairy products from cattle (DC), sheep (DS) and goat (DG), and meat from cattle (MC) and sheep (MS). Four feeding scenarios were selected according to the consistency of on-farm studies in the literature: (a) feeding "Fresh herbage" instead of conserved forages; (b) ban any form of silage ("Silage-free"); (c) ban maize silage ("Maize silage-free"); (d) feeding forages from permanent grasslands rich in species or plant secondary metabolites (PSMs) ("PSM-rich permanent grassland"). Feeding fresh herbage increased the concentration of carotenoids, fat-soluble vitamin, n-3 FA, rumenic acid, and branched chain FA (BCFA), and reduced the concentration of saturated FA, for all PC, with overall stronger effect for dairy products than for meat. The texture of meat and dairy products was marginally affected, whereas feeding fresh herbage decreased lactic and increased vegetal notes in DC. The "Silage-free" feeding scenario resulted in increased vaccenic acid, rumenic acid, BCFA, and C18:3n-3 in DC. The "Maize silage-free" feeding scenario lowered n-6 FA whereas increased n-3, rumenic acid and BCFA concentrations in DC. Feeding ruminants with forages from "PSM-rich permanent grasslands" increased monounsaturated FA, n-3 FA and rumenic acid and decreased n-6 FA in dairy products, and only marginally affected meat FA composition. The DC from "PSM-rich permanent grasslands" showed higher intense, spicy and animal notes. Overall, the differences between feeding management practices observed on farm were smaller than those observed under controlled trials. Several confounding factors, not controlled when operating under on-farm conditions, could be at the origin of these divergences (i.e. mixed diets, forage characteristics, animal-related factors). This review confirmed that farming practices may differently affect several quality traits of ruminant products. It also highlighted the uneven knowledge on the effect of feeding management depending on the PC: larger for milk than for meat and decreasing when moving from cattle to sheep and from sheep to goat.

Analyses of consumers' preferences and of the correspondence between direct and indirect label claims and the fatty acid profile of milk in large retail chains in northern Italy

Combined results from 2 survey studies were used to obtain information useful for the industries and retailers involved in the milk production and selling chain in North Italy. The first survey identified different clusters of fluid milk purchasers by examining their preferences and attitudes toward 12 intrinsic-extrinsic and credence milk attributes, by applying best-worst scaling methodology, whereas the second survey characterized the fatty acid (FA) profiles of commercial milk sold by large-scale retailers to verify the correspondence between the actual FA profile and the direct and indirect claims on the labels. To summarize information about the FA profile of milk, which may be considered an advanced attribute of milk quality, the milk FA index (MFAI) was calculated for each milk sample. A total of 130 milk samples (around 85% of the labels in northern Italy) and a total of 502 participants who answered a face-to-face questionnaire were considered in the 2 surveys. The milk samples were 13.1% organic, 9.2% certified as being of mountain origin, and over 50% noncertified but linked to cow grazing or to a mountain environment on their labels. The FA profiles showed a wide range of variation, with saturated FA ranging from 63.4 to 71.8, and polyunsaturated FA from 2.76 to 5.85. The FA profile and MFAI index of certified milk (organic or mountain-derived) were significantly different from the profiles of noncertified milk, whereas no correspondence was observed between the retail price and milk quality. When ranked on the basis of MFAI, which proved to be a good discriminating tool, the certified milks presented a bimodal distribution, indicating that certification does not always guarantee a real difference. The consumers chose milk considering the origin of the product, brand, expiration date, and process certification as the most important attributes, whereas they rated price and organic certification as the least important attributes. The study showed that about 20% of the consumers had a high propensity to buy milk on the basis of its quality. However, this attribute is often incorrectly indicated or not indicated at all on the milk label, with misleading images or claims that do not correspond to the actual FA quality of the milk. Having a clear index that offers information about the FA profile could thus be an interesting tool to improve the awareness of buyers and to valorize and differentiate milk products.

Nutritional Regulation of Mammary Gland Development and Milk Synthesis in Animal Models and Dairy Species

In mammals, milk is essential for the growth, development, and health. Milk quantity and quality are dependent on mammary development, strongly influenced by nutrition. This review provides an overview of the data on nutritional regulations of mammary development and gene expression involved in milk component synthesis. Mammary development is described related to rodents, rabbits, and pigs, common models in mammary biology. Molecular mechanisms of the nutritional regulation of milk synthesis are reported in ruminants regarding the importance of ruminant milk in human health. The effects of dietary quantitative and qualitative alterations are described considering the dietary composition and in regard to the periods of nutritional susceptibly. During lactation, the effects of lipid supplementation and feed restriction or deprivation are discussed regarding gene expression involved in milk biosynthesis, in ruminants. Moreover, nutrigenomic studies underline the role of the mammary structure and the potential influence of microRNAs. Knowledge from three lactating and three dairy livestock species contribute to understanding the variety of phenotypes reported in this review and highlight (1) the importance of critical physiological stages, such as puberty gestation and early lactation and (2) the relative importance of the various nutrients besides the total energetic value and their interaction.

Unravelling the Role of Rumen Microbial Communities, Genes, and Activities on Milk Fatty Acid Profile Using a Combination of Omics Approaches

Milk products are an important component of human diets, with beneficial effects for human health, but also one of the major sources of nutritionally undesirable saturated fatty acids (SFA). Recent discoveries showing the importance of the rumen microbiome on dairy cattle health, metabolism and performance highlight that milk composition, and potentially milk SFA content, may also be associated with microorganisms, their genes and their activities. Understanding these mechanisms can be used for the development of cost-effective strategies for the production of milk with less SFA. This work aimed to compare the rumen microbiome between cows producing milk with contrasting FA profile and identify potentially responsible metabolic-related microbial mechanisms. Forty eight Holstein dairy cows were fed the same total mixed ration under the same housing conditions. Milk and rumen fluid samples were collected from all cows for the analysis of fatty acid profiles (by gas chromatography), the abundances of rumen microbiome communities and genes (by whole-genome-shotgun metagenomics), and rumen metabolome (using 500 MHz nuclear magnetic resonance). The following groups: (i) 24 High-SFA (66.9-74.4% total FA) vs. 24 Low-SFA (60.2-66.6%% total FA) cows, and (ii) 8 extreme High-SFA (69.9-74.4% total FA) vs. 8 extreme Low-SFA (60.2-64.0% total FA) were compared. Rumen of cows producing milk with more SFA were characterized by higher abundances of the lactic acid bacteria Lactobacillus, Leuconostoc, and Weissella, the acetogenic Proteobacteria Acetobacter and Kozakia, Mycobacterium, two fungi (Cutaneotrichosporon and Cyphellophora), and at a lesser extent Methanobrevibacter and the protist Nannochloropsis. Cows carrying genes correlated with milk FA also had higher concentrations of butyrate, propionate and tyrosine and lower concentrations of xanthine and hypoxanthine in the rumen. Abundances of rumen microbial genes were able to explain between 76 and 94% on the variation of the most abundant milk FA. Metagenomics and metabolomics analyses highlighted that cows producing milk with contrasting FA profile under the same diet, also differ in their rumen metabolic activities in relation to adaptation to reduced rumen pH, carbohydrate fermentation, and protein synthesis and metabolism.

Emerging Genetic Tools to Investigate Molecular Pathways Related to Heat Stress in Chickens: A Review

Simple Summary

New genomic tools have been used as an instrument in order to assess the molecular pathway involved in heat stress resistance. Local chicken breeds have a better attitude to face heat stress. This review aims to summarize studies linked to chickens, heat stress, and heat shock protein.

Abstract

Chicken products are the most consumed animal-sourced foods at a global level across greatly diverse cultures, traditions, and religions. The consumption of chicken meat has increased rapidly in the past few decades and chicken meat is the main animal protein source in developing countries. Heat stress is one of the environmental factors which decreases the productive performance of poultry and meat quality. Heat stress produces the over-expression of heat shock factors and heat shock proteins in chicken tissues. Heat shock proteins regulate several molecular pathways in cells in response to stress conditions, changing the homeostasis of cells and tissues. These changes can affect the physiology of the tissue and hence the production ability of chickens. Indeed, commercial chicken strains can reach a high production level, but their body metabolism, being comparatively accelerated, has poor thermoregulation. In contrast, native backyard chickens are more adapted to the environments in which they live, with a robustness that allows them to survive and reproduce constantly. In the past few years, new molecular tools have been developed, such as RNA-Seq, Single Nucleotide Polymorphisms (SNPs), and bioinformatics approaches such as Genome-Wide Association Study (GWAS). Based on these genetic tools, many studies have detected the main pathways involved in cellular response mechanisms. In this context, it is necessary to clarify all the genetic and molecular mechanisms involved in heat stress response. Hence, this paper aims to review the ability of the new generation of genetic tools to clarify the molecular pathways associated with heat stress in chickens, offering new perspectives for the use of these findings in the animal breeding field.

Comparison of the Potential Abilities of Three Spectroscopy Methods: Near-Infrared, Mid-Infrared, and Molecular Fluorescence, to Predict Carotenoid, Vitamin and Fatty Acid Contents in Cow Milk

The objective of this work is to compare the ability of three spectroscopy techniques: molecular fluorescence, near-infrared (NIR), and mid-infrared with attenuated total reflectance (MIR-ATR) spectroscopy to predict the concentrations of 8 carotenoids, 6 vitamins and 22 fatty acids (FA) in cow’s milk. A dataset was built through the analysis of 242 frozen milk samples from different experiments. The milk compounds were analysed using reference methods and by NIR, MIR-ATR, and fluorescence to establish different predictive models. NIR spectroscopy allowed for better prediction of cis9-β-carotene, β-cryptoxanthin and the sum of carotenoids than the other techniques, with a coefficient of cross-validation in calibration (R²CV) > 0.60 and a coefficient of determination in validation (R²V) > 0.50. Their standard errors of prediction (SEP) were equal to 0.01, except for the sum of carotenoids (SEP = 0.15). However, MIR-ATR and fluorescence seem usable for the prediction of lutein and all-trans-β-carotene, respectively. These three spectroscopy methods did not allow us to predict (R²CV < 0.30) vitamin contents except, for vitamin A (the best R²CV = 0.65 with NIR and SEP = 0.15) and α-tocopherol (the best R²CV = 0.56 with MIR-ATR and SEP = 0.41), but all R²V were <0.30. NIR spectroscopy yielded the best prediction of the selected milk FA.

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.

Livestock diversity in shifting cultivation area of North Eastern Hill states in India

The breed of animals and birds reared by the jhumia were mostly non-descript and the method of rearing was traditional or backyard farming. Local breeds are an important self-replicating asset of almost all jhumia people and fulfill functions that go far beyond the output of products. At one end of the spectrum are breeding and production systems in which animals are kept in natural environments and are exposed to a large degree of natural selections imposed by the elements. Such systems are prevalent in ecologically marginal areas and typically practiced by pastoralists for whom adaptation traits are more crucial than production traits. Considering the distinctive features of animal genetic resources, as well as the urgent need for maintaining and conserving domestic animal diversity for future generations, it is necessary to promote more productive and sustainable livestock management.

Dairy Product Intake in Older Adults across Europe Based On the SHARE Database

Objective: To evaluate dairy intake patterns in older adults across Europe. Methods: We conducted cross-sectional analysis using data from the fourth wave (2011/2012) of the Survey of Health, Aging and Retirement in Europe (SHARE) database. Prevalence rates regarding the number of weekly servings of dairy in individuals ≥50 years old were calculated for 16 European countries. Results: The overall prevalence rate of daily dairy product intake in Europe was 66.95% (CI95%: 66.28-67.63%). Global prevalence in men was 63.35% (CI95%:62.37-64.35%) and in women 69.80% (CI95%:68.86-70.71%). Among men, this type of intake was highest in Denmark (84.89% [CI95%: 79.11-90.66%]) and lowest in Poland (26.15% [CI95%: 22.71-29.58%]). Among women, the highest prevalence was found in Spain (89.51% [CI95%: 85.16-93.86%]) and the lowest in Poland (31.33% [CI95%: 27.05-35.61%]). The overall prevalence rate of dairy product intake less than once a week was 3.99% (CI95%: 3.83-4.16%). In terms of gender, men in Hungary (11.02% [CI95%: 9.16-12.89%]) and women in Slovenia (8.76% [CI95%: 7.26-10.25%]) had the lowest such intake. Conclusions: Dairy intake is very heterogeneous across Europe, with overall intake levels lower than recommended. Differences were also observed between genders, with a lower intake in men, and with age, with the intake lower in older individuals.

Reliability of genomic prediction for milk fatty acid composition by using a multi-population reference and incorporating GWAS results

Background

Large-scale phenotyping for detailed milk fatty acid (FA) composition is difficult due to expensive and time-consuming analytical techniques. Reliability of genomic prediction is often low for traits that are expensive/difficult to measure and for breeds with a small reference population size. An effective method to increase reference population size could be to combine datasets from different populations. Prediction models might also benefit from incorporation of information on the biological underpinnings of quantitative traits. Genome-wide association studies (GWAS) show that genomic regions on Bos taurus chromosomes (BTA) 14, 19 and 26 underlie substantial proportions of the genetic variation in milk FA traits. Genomic prediction models that incorporate such results could enable improved prediction accuracy in spite of limited reference population sizes. In this study, we combine gas chromatography quantified FA samples from the Chinese, Danish and Dutch Holstein populations and implement a genomic feature best linear unbiased prediction (GFBLUP) model that incorporates variants on BTA14, 19 and 26 as genomic features for which random genetic effects are estimated separately. Prediction reliabilities were compared to those estimated with traditional GBLUP models.

Results

Predictions using a multi-population reference and a traditional GBLUP model resulted in average gains in prediction reliability of 10% points in the Dutch, 8% points in the Danish and 1% point in the Chinese populations compared to predictions based on population-specific references. Compared to the traditional GBLUP, implementation of the GFBLUP model with a multi-population reference led to further increases in prediction reliability of up to 38% points in the Dutch, 23% points in the Danish and 13% points in the Chinese populations. Prediction reliabilities from the GFBLUP model were moderate to high across the FA traits analyzed.

Conclusions

Our study shows that it is possible to predict genetic merits for milk FA traits with reasonable accuracy by combining related populations of a breed and using models that incorporate GWAS results. Our findings indicate that international collaborations that facilitate access to multi-population datasets could be highly beneficial to the implementation of genomic selection for detailed milk composition traits.

Electronic supplementary material

The online version of this article (10.1186/s12711-019-0460-z) contains supplementary material, which is available to authorized users.

Dairy Consumption and Cardiometabolic Diseases: Systematic Review and Updated Meta-Analyses of Prospective Cohort Studies

PURPOSE OF REVIEW

Dairy products contain both beneficial and harmful nutrients in relation to cardiometabolic diseases. Here, we provide the latest scientific evidence regarding the relationship between dairy products and cardiometabolic diseases by reviewing the literature and updating meta-analyses of observational studies.

RECENT FINDINGS

We updated our previous meta-analyses of cohort studies on type 2 diabetes, coronary heart disease (CHD), and stroke with nine studies and confirmed previous results. Total dairy and low-fat dairy (per 200 g/d) were inversely associated with a 3-4% lower risk of diabetes. Yogurt was non-linearly inversely associated with diabetes (RR = 0.86, 95% CI: 0.83-0.90 at 80 g/d). Total dairy and milk were not associated with CHD (RR~1.0). An increment of 200 g of daily milk intake was associated with an 8% lower risk of stroke. The latest scientific evidence confirmed neutral or beneficial associations between dairy products and risk of cardiometabolic diseases.

Effect of substituting fresh-cut perennial ryegrass with fresh-cut white clover on bovine milk fatty acid profile

BACKGROUND

Including forage legumes in dairy systems can help address increasing environmental/economic concerns about perennial ryegrass monoculture pastures. This work investigated the effect of substituting fresh-cut grass with increasing quantities of fresh-cut white clover (WC) on milk fatty acid (FA) profile and transfer efficiency of dietary linoleic (LA) and α-linolenic (ALNA) acids to milk fat. Three groups of three crossbred dairy cows were used in a 3 × 3 crossover design. Dietary treatments were 0 g kg^-1 WC + 600 g kg^-1 grass, 200 g kg^-1 WC + 400 g kg^-1 grass, and 400 g kg^-1 WC + 200 g kg^-1 grass. All treatments were supplemented with 400 g kg^-1 concentrates on a dry matter basis. Cows had a 19-day adaptation period to the experimental diet before a 6-day measurement period in individual tie stalls.

RESULTS

Increasing dietary WC did not affect dry matter intake, milk yield or milk concentrations of fat, protein or lactose. Milk polyunsaturated FA concentrations (total n-3, total n-6, LA and ALNA) and transfer efficiency of LA and ALNA were increased with increasing dietary WC supply.

CONCLUSION

Inclusion of WC in pastures may increase concentrations of nutritionally beneficial FA, without influencing milk yield and basic composition, but any implications on human health cannot be drawn. © 2018 The Authors. Journal of the Science of Food and Agriculture published by JohnWiley & Sons Ltd on behalf of Society of Chemical Industry.

Short-Communication: A Comparison of the In Vitro Angiotensin-1-Converting Enzyme Inhibitory Capacity of Dairy and Plant Protein Supplements

The consumption of supplements based on dairy or plant proteins may be associated with bioactive potential, including angiotensin-1-converting enzyme inhibitory (ACE-1i) activity, which is linked with blood pressure reduction in vivo. To gain insight into this proposed mechanism, the ACE-1i potential of protein-based supplements, including a selection of dairy (n = 10) and plant (n = 5) proteins were in vitro digested. The total digest was filtered and permeate and retentate were obtained. ACE-1i activity was measured as the ability of proteins (pre-digestion, ‘gastric’, permeate, and retentate) to decrease the hydrolysis of furanacroloyl-Phe-Glu-Glu (FAPGG) substrate for the ACE-1 enzyme. Permeate and retentate of dairy proteins exerted a significantly higher ACE-1i activity (mean of 10 proteins: 27.05 ± 0.2% and 20.7 ± 0.2%, respectively) compared with pre-digestion dairy proteins (16.7 ± 0.3%). Plant protein exhibited high ACE-1i in ‘gastric’ and retentate fractions (mean of five proteins: 54.9 ± 0.6% and 35.7 ± 0.6%, respectively). The comparison of the in vitro ACE-1i activity of dairy and plant proteins could provide valuable knowledge regarding their specific bioactivities, which could inform their use in the formulation of specific functional supplements that would require testing for blood pressure control in human randomly-controlled studies.

Could predicting fatty acid profile by mid-infrared reflectance spectroscopy be used as a method to increase the value added by milk production chains?

The aims of this work were (1) to develop prediction equations from mid-infrared spectroscopy (MIRS) to establish a detailed fatty acid (FA) composition of milk; (2) to propose a milk FA index, utilizing MIRS-developed equations, in which the precision of the FA-prediction equations is taken into account to increase the value of milk; and (3) to show application examples. A total of 651 bulk cow milk samples were collected from 245 commercial farms in northwest Italy. The results of the 651 gas chromatography analyses were used to establish (421 samples) and to validate (230 samples) the outcomes of the FA composition prediction that had been obtained by MIRS. A class-based approach, in which the obtained MIRS equations were used, was proposed to define a milk classification. The method provides a numerical index [milk FA index (MFAI)] that allows a premium price to be quantified to increase the value of a favorable FA profile of milk. Ten FA were selected to calculate MFAI, according to their relevance for human health and potential cheese sensory properties, and animal welfare and environmental sustainability were also considered. These factors were selected as dimensions of MFAI. A statistical analysis and expert judgment aggregation were performed on the selected FA by weighting the FA and normalizing the dimensions to reduce redundancy. A class approach was applied, using the precision of the MIRS equations to establish the classes. The median FA concentration of the data set was set as a reference value of class 0. The width, number, and limits of classes above and below the median were calculated using the 95% confidence level of the standard error of prediction, corrected with the bias of each FA. A progressive number and a positive or negative sign were assigned to each FA class above or below the median according to their role in the above mentioned dimensions. The sum of the numbers of each class, associated with its sign for each FA, was used to generate MFAI. The MFAI was applied to dairy farms characterized by different feeding strategies, all of which deliver milk to a commercial dairy plant. The MFAI values ranged from 0.7 to 4.2, and large variations, which depended on the cows' diet and forage quality, were observed for each feeding system. The proposed method has been found to be flexible and adaptable to several contexts on both intensive and extensive dairy farms.

Production of trans and conjugated fatty acids in dairy ruminants and their putative effects on human health: A review

Consumption of milk and dairy products is important in Western industrialised countries. Fat content is an important constituent contributing to the nutritional quality of milk and dairy products. In order to improve the health of consumers, there is high interest in improving their fatty acid (FA) composition, which depends principally on rumen and mammary metabolism. This paper reviews the lipid metabolism in ruminants, with a particular focus on the production of trans and conjugated linoleic acids (CLA) and conjugated linolenic acids (CLnA) in the rumen. After the lipolysis of dietary lipids, an extensive biohydrogenation of unsaturated FA occurs by rumen bacteria, leading to numerous cis and trans isomers of 18:1, non-conjugated of 18:2, CLA and CLnA. The paper examines the different putative pathways of ruminal biohydrogenation of cis9-18:1, 18:2n-6, 18:3n-3 and long-chain FA and the bacteria implicated. Then mechanisms relative to the de novo mammary synthesis are presented. Ruminant diet is the main factor regulating the content and the composition of milk fat. Effects of nature of forage and lipid supplementation are analysed in cows and small ruminants species. Finally, the paper briefly presents the effects of these FA on animal models and human cell lines. We describe the properties of ruminant trans 18:1, when compared to industrial trans 18:1, CLA and CLnA on human health from meta-analyses of intervention studies and then explore the underlying mechanisms.

Effects of dietary oil blend on fatty acid composition, oxidative stability and physicochemical properties of Longissimus thoracis et lumborum muscle in goats

This study examined the effects of dietary blend of 80% canola oil and 20% palm oil (BCPO) on the physicochemical properties, antioxidant status, oxidative stability and fatty acid composition of Longissimus thoracis et lumborum (LTL) muscle from goats during chill storage. Over a 14-week feeding trial, 24 Boer bucks were randomly assigned to and supplemented with diets containing 0, 4 or 8% BCPO on a dry matter basis, slaughtered and the LTL was subjected to a 7 day chill storage. Neither diet nor post mortem ageing influenced (P > 0.05) antioxidant enzyme activities, chemical composition and cholesterol. Diet had no effect on the carbonyl content, free thiol content, water-holding capacity, tenderness, pH and glycogen. Oil-supplemented goats had higher (P < 0.05) C18:1 trans-11, C18:3n-3 and C20:5n-3, carotenoid, tocopherol and redness, and lower thiobarbituric acid reactive substances values than the control goats. Post mortem ageing decreased (P < 0.05) shear force and oxidative stability of chevon. No significant (P > 0.05) changes were found in the proportion of individual fatty acids throughout storage. Total polyunsaturated fatty acids (PUFA) decreased while total saturated fatty acids increased as storage progressed. Dietary BCPO enhanced n-3 PUFA without compromising the quality attributes of chevon.

The influence of grass silage-to-maize silage ratio and concentrate composition on methane emissions, performance and milk composition of dairy cows

It is well-established that altering the proportion of starch and fibre in ruminant diets can alter ruminal and post-ruminal digestion, although quantitative evidence that this reduces enteric methane (CH4) production in dairy cattle is lacking. The objective of this study was to examine the effect of varying grass-to-maize silage ratio (70 : 30 and 30 : 70 DM basis), offered ad libitum, with either a concentrate that was high in starch or fibre, on CH4 production, intake, performance and milk composition of dairy cows. A total of 20 cows were allocated to one of the four experimental diets in a two-by-two factorial design run as a Latin square with each period lasting 28 days. Measurements were conducted during the final 7 days of each period. Cows offered the high maize silage ration had a higher dry matter intake (DMI), milk yield, milk energy output and lower CH4 emissions when expressed per kg DMI and per unit of ingested gross energy, but there was no difference in total CH4 production. Several of the milk long-chain fatty acids (FA) were affected by forage treatment with the most notable being an increase in 18:0, 18:1 c9, 18:2 c9 c12 and total mono unsaturated FA, observed in cows offered the higher inclusion of maize silage, and an increase in 18:3 c9 c12 c15 when offered the higher grass silage ration. Varying the composition of the concentrate had no effect on DMI or milk production; however, when the high-starch concentrate was fed, milk protein concentration and milk FAs, 10:0, 14:1, 15:0, 16:1, increased and 18:0 decreased. Interactions were observed for milk fat concentration, being lower in cows offered high-grass silage and high-fibre concentrates compared with the high-starch concentrate, and FA 17:0, which was the highest in milk from cows fed the high-grass silage diet supplemented with the high-starch concentrate. In conclusion, increasing the proportion of maize silage in the diets of dairy cows increased intake and performance, and reduced CH4 production, but only when expressed on a DM or energy intake basis, whereas starch-to-fibre ratio in the concentrate had little effect on performance or CH4 production.

Impact of US Brown Swiss genetics on milk quality from low-input herds in Switzerland: interactions with grazing intake and pasture type

This study investigated the effect of, and interactions between, contrasting crossbreed genetics (US Brown Swiss [BS] × Improved Braunvieh [BV] × Original Braunvieh [OB]) and feeding regimes (especially grazing intake and pasture type) on milk fatty acid (FA) profiles. Concentrations of total polyunsaturated FAs, total omega-3 FAs and trans palmitoleic, vaccenic, α-linolenic, eicosapentaenoic and docosapentaenoic acids were higher in cows with a low proportion of BS genetics. Highest concentrations of the nutritionally desirable FAs, trans palmitoleic, vaccenic and eicosapentaenoic acids were found for cows with a low proportion of BS genetics (0-24% and/or 25-49%) on high grazing intake (75-100% of dry matter intake) diets. Multivariate analysis indicated that the proportion of OB genetics is a positive driver for nutritionally desirable monounsaturated and polyunsaturated FAs while BS genetics proportion was positive driver for total and undesirable individual saturated FAs. Significant genetics × feeding regime interactions were also detected for a range of FAs.

Let’s talk about health: shoppers’ discourse regarding health while food shopping

Objective

The present study aimed to examine the role of health in consumers’ food purchasing decisions through investigating the nature of people’s discourse regarding health while conducting their food shopping.

Design

The study employed the think-aloud technique as part of an accompanied shop. All mentions of health and terms relating to health were identified from the data set. Inductive thematic analysis was conducted to examine how health was talked about in relation to people’s food choice decisions.

Setting

Supermarkets in Dublin, Republic of Ireland and Belfast, Northern Ireland.

Subjects

Participants (n50) were aged over 18 years and represented the main household shopper.

Results

Responsibility for others and the perceived need to illicit strict control to avoid ‘unhealthy’ food selections played a dominant role in how health was talked about during the accompanied shop. Consequently healthy shopping was viewed as difficult and effort was required to make the healthy choice, with shoppers relating to product-based inferences to support their decisions.

Conclusions

This qualitative exploration has provided evidence of a number of factors influencing the consideration of health during consumers’ food shopping. These results highlight opportunities for stakeholders such as public health bodies and the food industry to explore further ways to help enable consumers make healthy food choices.

Scd1 mammary-specific vector constructed and overexpressed in goat fibroblast cells resulting in an increase of palmitoleic acid and oleic acid

Stearoyl-CoA desaturase-1 (Scd1) is a rate-limiting enzyme in the biosynthesis of monounsaturated fatty acids. Overexpression of Scd1 in transgenic animals would modify the nutritional value of ruminant-derived foods by increasing the monounsaturated fatty acid (MUFA) and decreasing the saturated fatty acid (SFA) content. The aim of this study was to develop an effective Scd1 vector that is specifically expressed in dairy goat mammary glands. We successfully amplified the goat full length Scd1 cDNA and evaluated its activity in goat ear skin-derived fibroblast cells (GEFCs) by lipid analysis. In addition, we constructed a mammary gland-specific expression vector and confirmed efficient expression of Scd1 in goat mammary epithelial cells (GMECs) by qRT-PCR and Western blot analysis. Fatty acid analysis showed that Scd1-overexpression resulted in an increase in levels of palmitoleic acid (16:1n-7) and oleic acid (18:1n-9), from 1.73 ± 0.02% to 2.54 ± 0.02% and from 27.25 ± 0.13% to 30.37 ± 0.04%, respectively (both p<0.01) and the ratio of MUFA to SFA was increased. This work lays a foundation for the generation of Scd1 transgenic goats.

Genetic parameters for milk fatty acids in Danish Holstein cattle based on SNP markers using a Bayesian approach

Background

For several years, in human nutrition there has been a focus on the proportion of unsaturated fatty acids (UFA) and saturated fatty acids (SFA) found in bovine milk. The positive health-related properties of UFA versus SFA have increased the demand for food products with a higher proportion of UFA. To be able to change the UFA and SFA content of the milk by breeding it is important to know whether there is a genetic component underlying the individual FA in the milk. We have estimated the heritability for individual FA in the milk of Danish Holstein. For this purpose we used information of SNP markers instead of the traditional pedigree relationships.

Results

Estimates of heritability were moderate within the range of 0.10 for C18:1 trans-11 to 0.34 for C8:0 and C10:0, whereas the estimates for saturated fatty acids and unsaturated fatty acids were 0.14 and 0.18, respectively. Posterior standard deviations were in the range from 0.07 to 0.17. The correlation estimates showed a general pattern of two groups, one group mainly consisting of saturated fatty acids and one group mainly consisting of unsaturated fatty acids. The phenotypic correlation ranged from −0.95 (saturated fatty acids and unsaturated fatty acids) to 0.99 (unsaturated fatty acids and monounsaturated fatty acids) and the genomic correlation for fatty acids ranged from −0.29 to 0.91.

Conclusions

The heritability estimates obtained in this study are in general accordance with heritability estimates from studies using pedigree data and/or a genomic relationship matrix in the context of a REML approach. SFA and UFA expressed a strong negative phenotypic correlation and a weaker genetic correlation. This is in accordance with the theory that SFA is synthesized de novo, while UFA can be regulated independently from the regulation of SFA by the feeding regime.