Effect of diet on the deposition of n-3 fatty acids, conjugated linoleic and C18:1trans fatty acid isomers in muscle lipids of German Holstein bulls

Effect of Cooking with Superheated (SHS) vs. Standard Steam Oven on the Fatty Acids Profile of Different Kinds of Meat and Fish

We compared the effect of two different kinds of steam oven-a standard (SO) and a superheated steam (SHS) oven-on four different kinds of samples: hamburgers, bovine steaks, pork steaks, and salmon fillets. Ten samples of each meat/fish were divided into three parts. Then samples were analyzed as (i) raw, (ii) cooked with SO, and (iii) cooked with SHS. For each sample, we determined the proximate composition, fatty acid composition and thiobarbituric acid reactive substances (TBARS). The results of fatty acid composition were processed both with a linear model and with a multivariate approach by using three complementary discriminant analysis techniques: canonical (CAN), stepwise (St) and discriminant (DA). SHS was effective in degreasing hamburgers but not the other kinds of samples. Cooking methods selectively affected the fatty acid profile of samples, SHS being higher in MUFA and lower in PUFA n-3 than SO. This result was also confirmed by the discriminant analysis. Finally, samples cooked with SHS showed a lower fatty acid oxidation extent than SO, as the TBARS value was significantly lower in the SHS than in the SO, irrespective of the type of meat/fish cooked.

Fatty Acid Profile of Intramuscular Fat in the Longissimus Lumborum and Semimembranosus Muscles of Bulls Fed Diets Based on Virginia Fanpetals, Grass and Maize Silages

The aim of this study was to determine the effect of Virginia fanpetals (Sida hermaphrodita) silage on the fatty acid profile and the content of selected nutrients and vitamins in the Longissimus lumborum (LL) and Semimembranosus (SM) muscles of young bulls. Forty Polish Holstein-Friesian bulls aged 16 months were assigned to four dietary treatments (n=10) and were fed different types of silage during a 7-month fattening period. The proportion (g/kg dry matter) of silage in the diets was as follows: (1) grass silage (GS) (600); (2) Virginia fanpetals silage (VFS) (600); (3) VFS (300) and GS (300); and (4) VFS (300) and maize silage (MS) (300). Silage was supplemented with concentrate at 400 g/kg DM in each diet. The animals were slaughtered at the end of the fattening period. The intramuscular fat (IMF) of bulls fed GS had the highest (P<0.05) concentrations of n-3 polyunsaturated fatty acids (PUFAs) and linolenic acid (LNA), whereas the IMF of bulls receiving GS and VFS was characterized by the highest proportion of MUFAs, mostly oleic acid (C18:1 cis 9). In comparison with the LL muscle, the SM muscle contained less IMF (by 40%) with a more nutritionally desirable profile. The SM muscle was characterized by a more desirable mineral composition and a higher concentration of α-tocopherol.

Effects of xanthan gum, canning and storage period on fatty acid profile and cholesterol oxidation of restructured low-fat meat product of India

This study evaluated the impact of xanthan gum (XG), canning and storage on fatty acids (FAs) contents and formation of cholesterol oxidation products (COPs) in low-fat meat product (goshtaba) of Jammu and Kashmir (J&K), India. The FAs composition i.e. saturated FAs, monounsaturated FAs, polyunsaturated FAs and trans FAs during processing and storage showed non-significant difference in all goshtaba products (P > 0.05). The cholesterol content decreased significantly after canning in all products (P < 0.05) while, maximum reduction was observed in high-fat goshtaba (HFC). During storage all products exhibited significant decrease in cholesterol upto 6th month, thereafter showed non-significant variation. The COPs determined were 7-β-OH-ch, 5-ch-3β-ol-7-one and 25-OH-ch. After canning two COPs (7-β-OH-ch, 5-ch-3β-ol-7-one) were produced in all products. But during storage there was formation of 25-OH-ch, increase in 7-β-OH-ch and decrease in 5-ch-3β-ol-7-one and lower COPs were observed in low-fat goshtaba containing 1.5% XG. The results concluded that fat replacer (XG), processing and storage had no significant effect on the FAs compositions of all goshtaba products including HFC. However, cholesterol content exhibited significant variation and minimum reduction in cholesterol and formation of lower COPs were observed in low-fat goshtaba formulated with 1.5% XG.

Effect of Breed on Transcriptional and Protein Expression of Lipogenic Enzymes in Tail and Subcutaneous Adipose Tissue from Two Grazing Breeds of Lambs

Simple Summary

An experiment to determine the effect of sheep breed on subcutaneous fatty acid composition was carried out at the Butalcura Research Station, Chiloé, Chile. To this end, two breeds of lambs were challenged to graze a typical, naturalized pasture of the Chiloé Archipelago, Chile, from 60 d to 120 d after birth. The animals were sacrificed to collect samples from subcutaneous fat (SCF) from the back, and tail fat (TF) to determine the effect of breed on transcriptional expression of lipogenic enzymes and fatty acid profile in these two fat depots. The results showed that although mRNA expression of enzymes was similar in both breeds, there were differences in certain protein levels in the SCF, partially related with the fatty acid profiles, thus affecting the selection of lamb breed either for human consumption or experimental purposes.

Abstract

This experiment was carried out to determine the effect of breed on mRNA and protein expression levels of lipogenic enzymes acetyl-CoA carboxylase α (ACC), fatty acid synthase (FAS), stearoyl-CoA desaturase 1 (SCD1) plus sterol regulatory element binding transcription factor 1c (SREBP1c) in the subcutaneous fat (SCF) from the back of the animal, and tail fat (TF) of both Chilota and Suffolk Down lambs grazing Calafatal. Eight Chilota and six Suffolk Down 2-month-old male lambs were allocated to graze a “Calafatal”, a typical secondary succession of Chiloé Archipelago, Chile. After 62 d, lambs were slaughtered according to Chile’s meat industry standards. Fatty acid profile, RT-qPCR, and Western blot analyses from SCF and TF samples were performed. Although the mRNA expression levels of ACC, FAS, SCD1 and SREBP1c in SCF did not differ significantly between breeds (p > 0.05), a trend to higher mRNA expression of FAS and SREBP1c in TF from Chilota lambs was observed (p = 0.06). On the other hand, FAS levels in SCF were higher in Chilota than in Suffolk Down lambs (p < 0.02), although Suffolk Down showed higher fat contents and saturated fatty acid (SFA) proportions than Chilota lambs (p < 0.01). The FAS protein expression in TF was similar in both breeds (p > 0.05). Although the fat content was higher in Suffolk Down than in Chilota lambs (p < 0.01), the SFA proportions were similar in both breeds. Finally, it can be concluded that although mRNA expression of enzymes was similar in both breeds, there were differences in some protein levels in the SCF, partially related with the fatty acid profiles, thus affecting the selection of lamb breed either for human consumption or experimental purposes.

Effect of Linseed Supplementation on Total Longissimus Muscle Lipid Composition and Shelf-Life of Beef From Young Maremmana Bulls

Twenty young Maremmana bulls were randomly allotted to two dietary groups during a finishing period (~90 days): C diet (without lipid supplementation), and L diet (with linseed supplementation, 20% concentrate feed). The aim was to investigate the effects of dietary linseed supplementation on the intramuscular fat composition, and the shelf-life of minced beef. The L diet did not alter the dressing rate and daily weight gain, whereas the C18:3n-3 content in the intramuscular fat significantly increased (from 0.85 to 1.78 g/100 g of total fatty acid, +109%), leading to a reduction in a n-6/n-3 ratio below four and an increase in the overall proportion of long chain n-3 fatty acids in beef lipids. These effects were principally related to differences in the distribution of fatty acids between the neutral and polar lipids. The results demonstrated that linseed supplementation modified the lipid composition of beef, without negatively impacting overall productivity, in the period from weaning the bull until its slaughter. However, the total amount of n-3 fatty acids in the beef of young bulls on the L diet, was not sufficient for the aliquot of humans' n-3 fatty acid requirements. This was mainly related to the low levels of fat in the beef. Comparing beef samples from animals on the L diet, with samples from animals on the C diet, the higher levels of n-3 polyunsaturated fatty acids led to a significant reduction of shelf-life starting after 2 days of storage at 4°C, because of fatty acid and cholesterol oxidation. The L diet group samples showed a higher level of TBARS (+80%) and COPs (+73%), two important parameters to estimate the oxidation level of beef. This suggests that enriching beef with n-3 fatty acids should be coupled with packaging techniques that consider the higher susceptibility to lipid oxidation. In conclusion, dietary linseed supplementation led to a higher proportion of n-3 fatty acids in beef lipids, however, the natural content of antioxidant substances was not able to protect intramuscular fat from oxidation during storage at 4°C.

Can we improve the nutritional quality of meat?

The nutritional value of meat is an increasingly important factor influencing consumer preferences for poultry, red meat and processed meat products. Intramuscular fat content and composition, in addition to high quality protein, trace minerals and vitamins are important determinants of nutritional value. Fat content of meat at retail has decreased substantially over the past 40 years through advances in animal genetics, nutrition and management and changes in processing techniques. Evidence of the association between diet and the incidence of human non-communicable diseases has driven an interest in developing production systems for lowering total SFA and trans fatty acid (TFA) content and enrichment of n-3 PUFA concentrations in meat and meat products. Typically, poultry and pork has a lower fat content, containing higher PUFA and lower TFA concentrations than lamb or beef. Animal genetics, nutrition and maturity, coupled with their rumen microbiome, are the main factors influencing tissue lipid content and relative proportions of SFA, MUFA and PUFA. Altering the fatty acid (FA) profile of lamb and beef is determined to a large extent by extensive plant and microbial lipolysis and subsequent microbial biohydrogenation of dietary lipid in the rumen, and one of the major reasons explaining the differences in lipid composition of meat from monogastrics and ruminants. Nutritional strategies can be used to align the fat content and FA composition of poultry, pork, lamb and beef with Public Health Guidelines for lowering the social and economic burden of chronic disease.

Organic food consumption during pregnancy and its association with health-related characteristics: the KOALA Birth Cohort Study

OBJECTIVE

To investigate the associations of organic food consumption with maternal pre-pregnancy BMI, hypertension and diabetes in pregnancy, and several blood biomarkers of pregnant women.

DESIGN

Prospective cohort study.

SETTING

Pregnant women were recruited at midwives' practices and through channels related to consumption of food from organic origin.

SUBJECTS

Pregnant women who filled in FFQ and donated a blood sample (n 1339). Participant groups were defined based on the share of consumed organic products; to discriminate between effects of food origin and food patterns, healthy diet indicators were considered in some statistical models.

RESULTS

Consumption of organic food was associated with a more favourable pre-pregnancy BMI and lower prevalence of gestational diabetes. Compared with participants consuming no organic food (reference group), a marker of dairy products intake (pentadecanoic acid) and trans-fatty acids from natural origin (vaccenic and rumenic acids) were higher among participants consuming organic food (organic groups), whereas elaidic acid, a marker of the intake of trans-fatty acids found in industrially hydrogenated fats, was lower. Plasma levels of homocysteine and 25-hydroxyvitamin D were lower in the organic groups than in the reference group. Differences in pentadecanoic acid, vaccenic acid and vitamin D retained statistical significance when correcting for indicators of the healthy diet pattern associated with the consumption of organic food.

CONCLUSIONS

Consumption of organic food during pregnancy is associated with several health-related characteristics and blood biomarkers. Part of the observed associations is explained by food patterns accompanying the consumption of organic food.

Addition of an extract of lucerne (Medicago sativa L.) to cattle diets - Effects on fatty acid profile, meat quality and eating quality of the M. longissimus muscle

There is considerable interest in enhancing beneficial fatty acids, particularly 18:3n-3, conjugated linoleic acid and long chain n-3 fatty acids such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), in beef to provide benefits to human health. Here, the potential to enhance these fatty acids by feeding a n-3 polyunsaturated fatty acid (PUFA)-rich plant extract (PX) from lucerne is presented. Cattle (n=8/diet) were assigned to the following finishing diets: straw and concentrate (S-CC); straw and concentrate containing 25% PX and 2000IUvitaminE/kg PX-concentrate (S-PXC); grass silage (GS); GS plus 75gPX/kg dry matter intake (DMI) (GS-LPX) or GS plus 150g PX/kg DMI (GS-HPX). Addition of PX to concentrates or GS increased the n-3 fatty acid content of loin muscle and had favourable effects on the n-6:n-3 PUFA ratio (P<0.05), without detrimental effects on loin muscle sensory characteristics.

Strategies for Producing and Incorporating Conjugated Linoleic Acid–Rich Oils in Foods

Conjugated linoleic acid (CLA) is in ruminant-derived foods and is known to combat obesity-related diseases. However, CLA levels in a healthy diet are too low to produce a clinical effect. Therefore, CLA has been produced by linoleic isomerization through fermentation and chemical catalysis. Many of these techniques are not practical for food production, but a recent development has enabled production of CLA-rich triglyceride vegetable oils from high linoleic acid oils by a minor modification of conventional food-oil processing techniques. These oils were used to produce common lipid-based food, such as margarine, shortenings, and salad dressings, whose quality was enhanced by the presence of CLA-rich oil and provided a significant CLA source. Meat and egg CLA content and subsequent food quality can also be increased by addition of dietary CLA. However, consumer awareness of CLA benefits needs to increase prior to commercial-scale production of CLA-rich oil.

Impact of ground soybean and starch levels on the quality of meat from feedlot young Nellore bulls

Twenty-eight young Nellore bulls (395±32kg initial body weight) were assigned to a completely randomized design (2×2 factorial design with 7 animals per treatment) to evaluate effects on the quality of meat. Diet treatments consisted of high (about 25%) or low (about 16%) starch levels, with or without ground soybean addition. Shear force was decreased in the meat from animals fed a low-starch diet (P=0.0016). Meat from animals fed a high-starch diet had increased total concentrations of unsaturated (P=0.0029) and monounsaturated fatty acids (P=0.0253). Polyunsaturated fatty acid content increased in the meat from animals fed a diet containing soybean (P=0.0121). High starch diets (>25%) decreased the concentration of saturated fatty acids and increased the amount of unsaturated fatty acids in the meat from young Nellore bulls.

Comparison of fatty acids in beef tissues from conventional, organic and natural feeding systems in western Canada

Turner, T. D., Jensen, J., Pilfold, J. L., Prema, D., Donkor, K. K., Cinel, B., Thompson, D. J., Dugan, M. E. R. and Church, J. S. 2015. Comparison of fatty acids in beef tissues from conventional, organic and natural feeding systems in western Canada. Can. J. Anim. Sci. 95: 49–58. The effect of production system on intramuscular and associated trim fatty acid (FA) profiles of retail ribeye steaks from conventional and niche market organic and natural (grain- or grass-fed) beef were compared. Meat from organic grain- and grass-fed systems was leaner, containing greater proportions of polyunsaturated FA, i.e., 18:3n-3, 20:5n-3, 22:5n-3, 22:6n-3. Correspondingly, the n-6/n-3 ratios of organic grain- and grass-fed systems were 3:1, while conventional and natural grain systems had ratios of 8:1. High forage-to-grain ratio production systems increased proportions of desirable biohydrogenation intermediates (BI), including t11-18:1 and c9,t11-18:2, whereas conventional and natural grain systems elevated t10-18:1. Trim fat was similarly affected by production system, and was a relatively richer source of BI. Overall, proportions of desirable FAs, including n-3 and BI, were greater for organic grain- and grass-fed systems, emphasizing the importance of a high forage-to-grain ratio to enhance the healthfulness of beef, whereas conventional and natural grain-fed systems were largely equivalent.

Manipulating dietary PUFA in animal feed: implications for human health

Milk, meat and eggs tend not to be regarded as an important source of PUFA. They are disproportionally high in SFA compared with their PUFA content, especially those from cattle and sheep, since their rumen microbes are responsible for the loss of over 90% of PUFA intake by livestock. This need not necessarily be the case since the relative proportion of PUFA in these foods is dictated by livestock management, especially feeding, and this can be manipulated to boost their content of crucial long-chain n-3 fatty acids and conjugated linoleic fatty acids. The present paper considers the fatty acid composition in animal-derived foods and how these can be manipulated to be more conducive for consumers' health. The importance of recognising the effect of livestock production systems on fat composition is also highlighted along with the fact that we may have to compromise between intensive, high levels of production and this particular aspect of food quality.

Influence of alternative lifestyles on self-reported body weight and health characteristics in women

BACKGROUND

Alternative lifestyles are often associated with distinct practices with respect to nutrition, physical activity, smoking, alcohol use and usage of complementary medicine. Evidence concerning effects of these lifestyle-related practices on health status is still fragmentary.

OBJECTIVE

To describe maternal health characteristics related to alternative lifestyles, with emphasis on body-weight status, during pregnancy and maternity periods.

METHODS

We compared self-reported health-related features of mothers with alternative lifestyles and conventional lifestyles during pregnancy and maternity period in the KOALA Birth Cohort Study. This cohort comprises two recruitment groups of mother-infant pairs, one with a conventional (no selection based on lifestyle, n = 2333), the other with an alternative lifestyle (selected via organic food shops, anthroposophic clinicians and midwives, anthroposophic under-five clinics, Rudolf Steiner schools and relevant magazines, n = 485). Mothers in the alternative group more frequently chose organic foods, adhered to specific living rules, practised vegetarianism and identified themselves with anthroposophy.

RESULTS

Mothers in the alternative group showed lower BMI and lower prevalence of overweight and obesity than the conventional group, before pregnancy as well as 4-5 years after delivery. This difference was partly retained after adjusting for potential confounders. Furthermore, women in the alternative group had a lower prevalence of pregnancy-related hypertension, more often started breastfeeding and gave exclusive and prolonged breastfeeding for a longer period. Finally, they smoked less often, but more often drunk alcohol during pregnancy.

CONCLUSION

The results suggest that an alternative lifestyle is associated with favourable body weight and with several differences in other health features.

The effect of slaughter season on the Fatty Acid profile in four types of fat deposits in crossbred beef bulls

The objective of this study was to determine the effect of slaughter season on the fatty acid profile in four types of fat deposits in crossbred (Polish Holstein Friesian Black-and-White×Limousine) beef bulls. The percentage share of fatty acids was determined by gas chromatography and were divided into the following categories of fatty acids: saturated (SFAs), unsaturated (UFAs), monounsaturated (MUFAs), polyunsaturated (PUFAs), desirable hypocholesterolemic (DFAs) and undesirable hypercholesterolemic (OFAs), n-3 and n-6. Perinephric fat was characterized by the highest SFA concentrations (59.89%), and subcutaneous fat had the highest MUFA content (50.63%). Intramuscular fat was marked by a high percentage share of PUFAs and the highest PUFA/SFA ratio. The slaughter season had a significant effect on the levels of C18:3, C20:4 (p≤0.01) and conjugated linoleic acid (p≤0.05). There was an interaction between the slaughter season and fat type for the content of C20:4 (p≤0.01) and C20:5 (p≤0.05). The results of this study show that beef from cattle slaughtered in the summer season has a higher nutritional value and more health-promoting properties.

How selected tissues of lactating holstein cows respond to dietary polyunsaturated fatty acid supplementation

The effect of a 10-week supplementation with polyunsaturated fatty acids [via sunflower oil/DHA-rich algae (SUNA) or linseed oil/DHA-rich algae (LINA) enriched diets] versus saturated fatty acids (SAT) of lactating German Holstein dairy cows in mid-lactation on expression patterns of lipid metabolism-associated genes and gene products in hepatic, longissimus muscle and subcutaneous/perirenal/omental adipose tissue was assessed. Most pronounced transcriptomic responses to dietary PUFA were obtained in hepatic [down-regulated ACACA (FC = 0.83, SUNA; FC = 0.86, LINA), FADS1 (FC = 0.60, SUNA; FC = 0.72, LINA), FADS2 (FC = 0.64, SUNA; FC = 0.79, LINA), FASN (FC = 0.64, SUNA; FC = 0.72, LINA), SCD (FC = 0.37, SUNA; FC = 0.47, LINA) and SREBF1 (FC = 0.79, SUNA, LINA) expression] and omental adipose [up-regulated ACACA (FC = 1.58, SUNA; FC = 1.22, LINA), ADFP (FC = 1.33, SUNA; FC = 1.32, LINA), CEBPA (FC = 1.75, SUNA; FC = 1.40, LINA), FASN (FC = 1.57, SUNA; FC = 1.21, LINA), LPL (FC = 1.50, SUNA; FC = 1.20, LINA), PPARG (FC = 1.36, SUNA; FC = 1.12, LINA), SCD (FC = 1.41, SUNA; FC = 1.17, LINA) and SREBF1 (FC = 1.56, SUNA; FC = 1.18, LINA) expression] tissue. Interestingly, gene/gene product associations were comparatively low in hepatic and omental adipose tissue compared with longissimus muscle, perirenal adipose and subcutaneous adipose tissue, indicating matches only in regard to minor concentrations of SCD product 18:1c9, FADS1 product 20:4n-6 and FADS2 product 18:3n-6 in hepatic tissue, and higher concentrations of ACACA and FASN gene products 12:0 and 14:0 and SCD product 18:2c9,t11 in omental adipose tissue. Whereas all analyzed tissues accumulated dietary PUFA and their ruminally generated biohydrogenation products, tissue-divergent preferences for certain fatty acids were identified. This descriptive study reports tissue-divergent effects of dietary PUFA and outlines the significance of a PUFA intervention with regard to dairy cows' nutritional management.

Fatty acid composition of adipose tissue and muscle from Jersey steers was affected by finishing diet and tissue location

To determine the impacts of finishing diet and tissue type and location on fatty acid composition and palatability of Jersey beef, twenty steers were assigned to a factorial treatment design with initial weight (Light vs. Heavy) and finishing diet (70 vs. 85% concentrate) as treatments. Ribeye steaks were collected for sensory evaluation. Muscle, seam and subcutaneous (s.c.) fat from steaks, kidney fat (KF) and omental fat (OMF) were collected for fatty acid analysis. Initial weight and finishing diet had little impact on beef palatability. The 85% concentrate decreased polyunsaturated fatty acids (PUFA) in muscle and increased trans fatty acids in all tissues (P<0.05). The monounsaturated:saturated fatty acid ratio (MUFA:SFA) was highest in s.c. fat, intermediate in muscle and seam fat, and lowest in KF and OMF. The PUFA:SFA was highest in muscle, intermediate in s.c. and seam fat, and lowest in KF and OMF. Fatty acid composition differed greatly among tissues and the lower concentrate diet increased omega-3 and PUFA percentages in muscle.

Review:Trans-forming beef to provide healthier fatty acid profiles

Dugan, M. E. R., Aldai, N., Aalhus, J. L., Rolland, D. C. and Kramer, J. K. G. 2011. Review: Trans- forming beef to provide healthier fatty acid profiles. Can. J. Anim. Sci. 91: 545–556.Trans fatty acids are found naturally in foods, particularly in those derived from ruminant animals, such as beef and dairy cattle. Over the past few decades, human consumption of trans fatty acids has increased, but this has been mainly from products containing partially hydrogenated vegetable oils. The correlation of trans fatty acid consumption with diseases such as coronary heart disease has been cause for concern, and led to recommendations to reduce their consumption. Trans fatty acids, however, have differing effects on human health. Therefore, in foods produced from ruminant animals, it is important to know their trans fatty acid composition, and how to enrich or deplete fatty acids that have positive or negative health effects. This review will cover the analysis of trans fatty acids in beef, their origin, how to manipulate their concentrations, and give a brief overview of their health effects.

Long chain n-3 polyunsaturated fatty acid concentration and color and lipid stability of muscle from heifers offered a ruminally protected fish oil supplement

Beef heifers (n = 48) were offered, daily, a 1.5 kg ration that contained 0, 69, 138, and 275 g of ruminally protected fish oil (RPFO) fortified with vitamin E (5000 IU/kg). The fatty acid profile of neutral (NL) and polar lipids (PL) of neck muscle was analyzed by GC-FID. Minced muscle was displayed in an 80% O(2):20% CO(2) atmosphere under simulated retail display conditions. Muscle α-tocopherol concentrations did not differ. For PL, the proportions of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) increased (P < 0.05, linearly and quadratically, respectively). For NL, the proportion of EPA was not affected but DHA increased linearly and quadratically (P < 0.05). Supplementation did not affect color stability of ground beef, but lipid oxidation was higher (P < 0.001) for 275 g of RPFO on day 10 of display. In conclusion, supplementation with RPFO increased muscle EPA and DHA with no effect on color stability while lipid oxidation was increased only at the highest level of supplementation, after prolonged display.

Enhancing fatty acid composition of milk and meat through animal feeding

In ruminants, extensive ruminal biohydrogenation of unsaturated fatty acids (FA) results in numerous cis and trans isomers of 18:1 and of conjugated and non-conjugated 18:2, the incorporation of which into ruminant products depends on the composition of the diet (forage vs concentrate) and of dietary lipid supplements. The low amount of 18:3n-3 (α-linolenic acid) absorbed explains its limited incorporation in meat and milk lipids. Its protection against hydrogenation has been an objective for several decades, but only encapsulation in a protein matrix is efficient. In non-ruminants, the FA composition of products is determined by dietary FA, despite minor differences in digestibility and in metabolic activity. Physicochemical differences in intestinal absorption processes between ruminants and non-ruminants can explain the lower FA digestibility in non-ruminants, especially for saturated FA. Unlike in non-ruminants, FA digestibility in ruminants does not depend on FA intake, except for 18:0. The decrease in cow butterfat, especially with concentrate diets, is generally attributed to t10–18:1 or t10,c12–18:2, but the regulation is probably more complex. Differences in terms of butterfat content and FA composition of milk between cow, ewe and goat responses to the amount and composition of ingested lipids are due to between-species variations in mammary metabolism. In animals bred for meat production, dietary 18:3n-3 results in increases in this FA and in n-3 long-chain polyunsaturated FA (20:5n-3, 22:5n-3) in muscles. The extent of this increase depends both on animal and nutritional factors. Grass is a source of 18:3n-3, which contributes to increased 18:3n-3 in muscle of ruminants as well as of pigs. Conjugated linoleic acids are mainly present in fat tissues and milk due to t11–18:1 desaturation. Their concentration depends on tissue type and on animal species. Non-ruminants fed synthetic conjugated linoleic acids incorporate them in significant amounts in muscle, depending on the isomer. All dietary manipulations favouring polyunsaturated FA incorporation in milk and meat lipids increase the risk of lipoperoxidation, which can be efficiently prevented by use of dietary combined hydro- and lipophilic antioxidants in the diet. Putative effects on organoleptic and technological quality of products deserve further studies.

Trans-18:1 and conjugated linoleic acid profiles after the inclusion of buffer, sodium sesquicarbonate, in the concentrate of finishing steers

Ninety-six European crossbred steers were fed a barley-based finishing diet for differing lengths of time (34-104 days) to investigate if adding dietary buffer (sodium sesquicarbonate at 1.5% as fed) could improve the trans-18:1 (GC-FID) and CLA (Ag(+)-HPLC-DAD) content and isomeric profile of beef produced. Results indicate that the addition of buffer to diets of cattle fed high concentrate diets has limited effects on the overall fatty acid composition of backfat and muscle tissues. However, buffer addition can help to prevent a 10t- shift by maintaining a better (higher) 11t-/10t-18:1 ratio in both meat and backfat during the first 30-60 days of feeding a high grain diet. Over time, however, the effect is lost becoming equal in tissues from animals with or without buffer addition to their diets.

Dietary fat quality and coronary heart disease prevention: A unified theory based on evolutionary, historical, global, and modern perspectives

A large and growing body of evidence indicates that dietary fatty acids regulate crucial metabolic processes involved in the pathogenesis of coronary heart disease (CHD). Despite this evidence, optimal dietary fatty acid intakes for CHD prevention remain unclear. Significant gaps in the modern nutrition literature and contradictions in its interpretation have precluded broad consensus. These shortcomings can be addressed through the incorporation of evolutionary, historical, and global perspectives. The objective of this review is to propose a unified theory of optimal dietary fatty acid intake for CHD prevention that integrates critical insights from evolutionary, historical, global, and modern perspectives. This broad approach may be more likely than previous methods to characterize optimal fatty acid intakes.

Fatty acid and vitamin E composition of intramuscular fat in cattle reared in different production systems

The aim of this study was to evaluate the fatty acid composition of intramuscular fat and the vitamin E content of beef from different production systems. Four cattle production systems were used: cattle reared under intensive conditions and fed concentrate (INT1) from Spain, cattle raised at pasture and supplemented with concentrate (SUP1) from the United Kingdom, cattle raised at pasture and on corn silage (SUP2) from Germany and cattle reared under extensive conditions slaughtered at two and three years old (EXT2 and EXT3) from Uruguay. The highest proportion and content (mg per 100g of muscle) of linoleic acid (C18:2n-6) and arachidonic acid (C20:4n-6) and the lowest saturated fatty acids (SFA) was found in INT1 beef. In contrast, beef reared under extensive conditions showed the highest proportion and content of linolenic acid (C18:3n-3), docosapentaenoic acid (DPA, C22:5n-3) and eicosapentaenoic acid (EPA, C20:5n-3), and SUP1 and SUP2 beef showed the highest level of palmitic acid (C16:0) and SFA. Beef from intensive system (INT1) had the lowest P/S (PUFA/SFA) ratio, whereas beef from extensive system (EXT2 and EXT3) had the lowest n-6/n-3 ratio. The results of the PCA (principal components analysis) of fatty acid composition showed that beef from intensive system (INT1) was clearly differentiated from the other meats and was located with the C18:2n-6 and C20:4n-6 and the n-6/n-3 ratio. EXT2 and EXT3 beef were located with C18:3n-3 and long chain fatty acids. Beef from extensive systems had the highest concentration of vitamin E (3.91mg α-tocopherol/kg muscle).

Authentication of organic milk using delta13C and the alpha-linolenic acid content of milk fat

The carbon stable isotope ratio (delta(13)C) and the alpha-linolenic acid (C18:3omega3) content of milk fat were analyzed to examine their applicability as general markers for the authentication of organic retail milk in Germany. To record the variable effect of feeding, including the seasonal influence on milk composition, three conventionally and three organically produced brands of retail milk were collected biweekly during a period of 18 months. Altogether 286 milk samples were analyzed. Threshold values for the identification of German organic milk were established and allowed to delimit almost all conventional samples. Organic retail milk was always above a minimum C18:3omega3 content of 0.50% and below a maximum delta(13)C of -26.5 per thousand. The universal and strongly negative correlation (r = -0.93) between C18:3omega3 and delta(13)C impedes the intentional manipulation of conventional milk. Conventional milk can naturally exceed the C18:3omega3 limit under atypical and rare conditions, but differentiation from organic milk can be improved by time-resolved comparison of data. In contrast with the general opinion, organic milk did not generally contain more c9,t11-C18:2 (CLA) than conventional milk. The proposed limits may deviate with dairy products containing milk from foreign countries.