Fatty acid composition, conjugated linoleic acid isomers and cholesterol in beef from crossbred bullocks intensively produced and from Alentejana purebred bullocks reared according to Carnalentejana-PDO specifications

Evaluation of the Composition of the Cholesterol, Tocopherols, β-Carotene and Fatty Acids Profile of the Liver Tissue of Male Water Buffaloes (Bubalus bubalis) Managed in Different Ecosystems of the Eastern Amazon

The diet offered to animals has a great influence on the composition of tissues and, consequently, the quality. The objective of this study was to evaluate the influence of Amazonian ecosystems, in the dry and rainy periods of the year, on the composition of cholesterol, tocopherols, β-carotene and the fatty acid profile of the livers of water buffaloes (Bubalus bubalis) reared in the Eastern Amazon, in an extensive or intensive system. Total lipid content was influenced by the location and time of year (p < 0.05). Ninety-six male water buffaloes were used (12 per sampling period), aged between 24 and 36 months, with average weights of 432 kg (end of the rainy season) and 409 kg (end of the dry season). Total cholesterol, α-tocopherol and γ-tocopherol influenced the relationship between extensive vs intensive ecosystems, location, periods and the interaction between the location and period of the year (p < 0.05). Animals raised in a pasture ecosystem had the highest values of omega-3, and those raised in confinement, the highest values of omega-6 (p < 0.05). The proportions of n-6/n-3 and hypocholesterolemia (7.14) and hypercholesterolemia (3.08%) (h/H) were found in greater amounts in animals raised in confinement (p < 0.05). The atherogenic index (AI) had a higher value in the rainy season, in animals raised in Santarém (2.37%), with no difference between pasture and feedlot ecosystems, except in animals raised in the rainy season in Nova Timboteua, with a lower AI (1.53%). The thrombogenicity index (TI) was higher in the livers of confined animals (0.32%) and lower (0.18%) in those raised in Nova Timboteua (rainy season). Amazonian ecosystems influence the nutritional values of buffalo liver, with the best nutritional values in animals in the extensive system.

The Effect of Grazing Level and Ageing Time on the Physicochemical and Sensory Characteristics of Beef Meat in Organic and Conventional Production

This study investigated the influence of the production system (conventional vs. organic), the grass consumption level and the ageing period (7 and 14 days) on beef quality. Three groups of samples from Limousin × Avileña calves were analysed: F100, formed by animals fed 100% on forage; F74, formed by animals fed on an average amount of forage of 74%; and F35, formed by animals fed on straw fodder (35%) and concentrate (65%). The results showed that the higher the grass content, the lower the fat oxidation and the higher the n-3 content, but also the higher the SFA level, the initial Warner-Bratzler shear force (WBSF), and the more residue it leaves on chewing. As for the effect of production system, organic samples showed higher intramuscular fat content and lower moisture and MUFA content. These samples were darker and showed lower values for flavour quality. Among the organic samples, F100 had higher n-3 and CLA content and higher values for colour, hardness, odour and flavour quality. Increased ageing time may improve the sensory characteristics of the meat, especially in the case of the F100 samples. The results pointed out that F100 samples aged at least 14 days showed the best physico-chemical, nutritional and sensory characteristics.

Effects of grass- and concentrate-based finishing systems on the quality of meat from the M. longissimus thoracis of young Sarda bulls

Context Recent heightened interest of consumers in the origins of their food, together with broader general awareness of environmental matters, has led to an increase in the demand for meat obtained from grazing systems. The importance of local breeds adapted to medium- and low-input production is fully recognised as a means of guaranteeing the sustainability of these farming methods. A finishing system based on pastures and the use of local breeds could both meet the demands of consumers and increase economic returns for Sardinian farmers. Aims The work evaluated the effects of different finishing treatments (pasture PAS-0C vs hay–concentrate-based diets HAY-C) on the quality of meat from young Sarda bulls and the usefulness of meat chemicals as markers to discriminate between finishing systems. Methods Twenty-eight young Sarda bulls were assigned randomly to the following two treatments: finished on natural pasture (PAS-0C group, n = 7), and fed on natural pasture hay ad libitum and concentrate (HAY-C group, n = 21). The latter group comprised three levels characterised by an increasing daily dose of concentrates, as follows: 2.5 kg/animal (HAY-2.5C), 3.3 kg/animal (HAY-3.3C), and ad libitum (HAY-ALC). After slaughter at a fixed age (416 ± 25 days), carcass yield, pH of the Longissimus thoracis (LT) muscle, colour parameters, cooking loss, proximate analysis, α-tocopherol and cholesterol concentration, and fatty acid composition of intramuscular fat of LT were all determined. The discriminating power of the meat chemicals between the two main finishing systems (PAS-0C vs HAY-C) and among the three groups receiving concentrates and hay (HAY-2.5C, HAY-3.3C and HAY-ALC) was assessed using linear discriminant analysis. Key results Pasture-based treatment decreased the intramuscular fat and increased the α-tocopherol concentration of meat and the proportion of some desirable fatty acids (α-linolenic acid and its derivatives eicosapentaenoic acid, docosapentaenoic acid), and improved the value of the ratio of n-6:n-3, without affecting the ultimate pH, colour parameters, and cooking loss. The discriminant procedure was able to discriminate accurately between the two main finishing systems and among the three groups receiving concentrate and hay (P &lt; 0.0001 and P &lt; 0.005 of the Hotelling’s T-squared test respectively). The concentration of α-tocopherol was key to the discrimination of the two main finishing systems, whereas the content of C17:0 and C18:0i were particularly effective in discriminating among the three groups fed with hay concentrate. Conclusions Grazing improves some of the meat traits of young Sarda bulls compared with the effects of a hay-concentrate-based finishing diet. The concentration of α-tocopherol in meat is an effective marker for discriminating the effects of pasture from those of a concentrate-based finishing diet Implications The results highlight the role of pasture-based diet in finishing young Sarda bulls, and could provide a wealth of knowledge for Sardinian beef farmers for delivering meat produce that stands out in the market and meets the demand of consumers more concerned about food origin and its healthiness.

Comparison of Muscle and Subcutaneous Tissue Fatty Acid Composition of Bangladeshi Nondescript Deshi Bulls Finished on Pasture Diet

The objective of this study was to characterize and compare the tissue-associated differences in the fatty acid profiles of intramuscular and subcutaneous fat from pasture fed nondescript deshi breed bulls of Bangladesh. The average chemical composition of thelongissimusmuscle was as follows: moisture74.65±0.48%, protein21.55±0.83%, intramuscular fat2.78±0.28%, and ash1.02±0.03%. There was significant evidence that the lipids oflongissimusmuscle from the nondescript deshi bulls had a lower content of saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), and conjugated linoleic acid (CLA) and a higher content of polyunsaturated fatty acids (PUFA) compared to subcutaneous fat. Intramuscular fat also showed the highest PUFA/SFA and∑n-6/∑n-3fatty acids ratios and total n-3 and n-6 PUFAs compared to subcutaneous tissue depots. Overall findings suggest that the meat from pasture fed nondescript deshi breed can be considered as lean meat and healthy for human consumption.

Nutritional Cues Tie Living Organisms to Their Environment and Its Sustainability

We connect modern, intensive agriculture's role in environmental degradation to its role in producing nutritionally unbalanced foods, and delineate specific approaches to reduce agriculture's environmental impact, while producing healthful foods. We call attention to recently discovered genetic programs used by all living organisms to respond to their environment, and present a model of how these programs change body composition and function (of humans and their crop plants and livestock alike) in response to environmental cues. We propose that production of nutritionally balanced crops and livestock requires careful consideration of how these plants and animals are grown; the composition of plant food is modulated by growing conditions, body composition of livestock reflects their feed; composition and function of human body and brain are strongly affected by how food plants and animals are produced. We selected four nutritional features not only involved in (i) governing human health by modulating these genetic programs, but (ii) also affected by agricultural practices. These nutritional features are fat composition (especially saturated fat and the ratio of polyunsaturated omega-6 oils to omega-3 oils), carbohydrate composition (especially the proportion of carbohydrates with a high glycemic index, such as sugars and quick-burning starches) and the level of antioxidant micronutrients. We not only outline threats to human health presented by the current environment, but also potential gains in quality-of-life in a future environment designed to optimize human wellness using insights into the gene-programing effect of diet- and other lifestyle-related factors. These gains could extend beyond optimal human physical and mental health to gains in workforce productivity. The same changes in agricultural practices required to achieve these gains in human health are also needed to support environmental health and sustainable food production. The resulting vision of optimal human health and environmental health, supported by sustainable practices, is intended as an inspiring image of what sustainability has to offer to individuals and society. Our goal is to provide a transparent overview and illustrations intelligible not only to non-experts in each of the other respective areas involved but also to policy makers and the public.

Association of carcass weight with quality and functional properties of beef from Hanwoo steers

The association of carcass weight with quality and functional properties of Hanwoo (Korean native cattle) beef was investigated. The carcasses of 250 Hanwoo steers were categorised into light (<375 kg; n = 74), medium (375–425 kg; n = 76) and heavy (>425 kg; n = 100) groups and were evaluated for back fat thickness, rib eye area, and beef marbling score 24 h postmortem using the Korean carcass grading system. Rib eye area, back fat thickness, and marbling score significantly increased (P < 0.05) with increasing carcass weight. However, marbling score and intramuscular fat content showed only a little increase (P < 0.05) beyond a limit of 375 kg. Inosine-5′-monophosphate concentration was significantly higher (P < 0.05) in medium and heavy carcasses. Carnosine concentration was significantly higher in medium carcasses. Total saturated fatty acid content and n-6 : n-3 ratio decreased as carcass weight increased (P < 0.05). Medium and heavy carcasses had significantly higher (P < 0.05) scores for sensory quality parameters. Overall, medium carcasses of Hanwoo displayed optimal sensory and health benefits while minimising the economic disadvantages of growing cattle to heavier weights.

Carcass Characteristics and Meat Quality of Swamp Buffaloes (Bubalus bubalis) Fattened at Different Feeding Intensities

Twenty-four male 1-year old swamp buffaloes (Bubalus bubalis) were randomly allocated to 4 groups. One group grazed on guinea grass (GG) and another on guinea grass and the legume Stylosanthes guianensis (GL). The other two groups were kept in pens and fed freshly cut guinea grass and concentrate at an amount of 1.5% (GC1.5) and 2.0% (GC2.0) of body weight, respectively. The effect of the different feeding intensities on carcass characteristics and meat quality were assessed. The mean body weight at slaughter was 398 (±16) kg. Average daily gain was higher in concentrate-supplemented groups (570 and 540 g/d in GC1.5 and GC2.0, respectively) when compared to GG (316 g/d) and GL (354 g/d) (p<0.01). Likewise, the warm carcass weight was higher in GC1.5 and GC2.0 compared to GG and GL. Dressing percentage was 48.1% and 49.5% in GC1.5 and GC2.0 in comparison to 42.9% and 44.8% observed in GG and GL, respectively. Meat of Longissimus throracis from GC1.5 and GC2.0 was redder in color (p<0.01), while water holding capacity (drip and thawing loss) was improved in pasture-fed groups (p<0.05). Protein and fat content of Longissimus thoracis was higher in animals supplemented with concentrate (p<0.01), as was cholesterol content (p<0.05), whereas PUFA:SFA ratio was higher and n-6/n-3 ratio lower (p<0.01) in pasture-fed buffaloes. Results of the present study showed that the supplementation of pasture with concentrate enhances the growth and carcass characteristics of swamp buffaloes expressed in superior dressing percentage, better muscling, and redder meat with a higher content of protein and fat, whereas animals grazing only on pasture had a more favorable fatty acid profile and water holding capacity. In conclusion, the supplementation of concentrate at a rate of about 1.5% of body weight is recommended to improve the performance and carcass quality of buffaloes.

Genetic background and diet impact beef fatty acid composition and stearoyl-CoA desaturase mRNA expression

The intramuscular fat composition of ruminant meats influences the quality of the final product, which explains the increasing interest in assessing the fatty acid profile of meat from different production systems. In this study, it was hypothesized that there are breed- and diet-induced variations on lipid metabolism in the muscle, which may be, at least partially, modulated by the stearoyl-CoA desaturase (SCD) gene expression levels. Forty purebred young bulls from two phylogenetically distant autochthonous cattle breeds, Alentejana and Barrosã (n = 20 for each breed), were assigned to two different diets (low vs. high silage) and slaughtered at 18 months of age. Meat fatty acid composition, including the detailed conjugated linoleic acid (CLA) isomeric profile, was determined along with the SCD mRNA levels. Meat from Barrosã bulls fed the low silage diet was richer in monounsaturated fatty acids, CLA and trans fatty acids, when compared to that from Alentejana bulls. The meat content in polyunsaturated fatty acids was similar across experimental groups. Moderate positive correlations between the SCD mRNA levels and the products of this enzyme activity were found, although they were not reflected on the calculated desaturase indices. Overall, these findings highlight the importance of taking into account the genetic background while devising feeding strategies to manipulate beef fatty acid composition.

Effect of low- and high-forage diets on meat quality and fatty acid composition of Alentejana and Barrosã beef breeds

This study investigated the effects of genotype and diet on meat fat composition and palatability obtained from Alentejana (AL) and Barrosã (BA) breeds. Herein, 20 males from each breed allocated at 11 months of age were fed ad libitum a low-forage diet or a high-forage diet and slaughtered at 18 months of age. Trained sensory panel analysis found that the longissimus lumborum (Ll) muscle from BA had higher tenderness, juiciness and overall acceptability scores than the AL breed. The highest scores for those attributes were observed in the BA breed fed the high-forage diet. Regarding the semitendinosus (St) muscle, breed was a source of variation of tenderness scores. In contrast to the Ll muscle, the highest tenderness scores for the St muscle were observed in the AL breed. The intramuscular fat (IMF) content was positively correlated with tenderness, juiciness and overall acceptability in Ll muscle and negatively correlated with flavour in the St muscle. The levels of 14:0 and 16:0, 16:1c9, 18:1c9 and 18:1c11 were positively correlated to juiciness, tenderness and overall acceptability in the Ll muscle. These correlations were not observed in the St muscle, which may be related to its low IMF content. Nonetheless, negative correlations were observed for the St muscle between flavour and 14:0, 16:0 and 18:0 FA contents.The IMF varied widely in the Ll but not in the St muscle. The latter had higher levels of 16:1c9 and trans fatty acids (∑TFA) in the BA than in the AL breed. Regarding the Ll muscle, the BA had higher amounts of 14:0, 16:0, 16:1c9, 18:0, 18:1c9, 18:1c11, saturated fatty acids (∑SFA), cis monounsaturated fatty acids (∑cis MUFA), ∑TFA and n-3 polyunsaturated fatty acids (∑n-3 PUFA) than the AL breed. The diet exerted an influence on the IMF content and on the levels of 14:0, 16:0, 16:1c9, 18:0, 18:1c9, 18:1c11, ∑SFA, ∑cis MUFA and ∑TFA in both Ll and St muscles. Moreover, the levels of ∑n-3 PUFA in the Ll muscle and 18:2n-6, 20:4n-6, ∑n-6 PUFA and ∑PUFA in the St muscle were influenced by diet. The results obtained in this study, with two Portuguese breeds, confirm that genetic background plays a major role in the determination of meat eating quality.

Effect of weight at slaughter and breed on beef intramuscular lipid classes and fatty acid profile

The effect of slaughter weight and breed on the composition of intramuscular fat (IMF) of seven Spanish cattle breeds was studied. Lipid classes and fatty acids were evaluated in young bulls of seven local Spanish cattle breeds, Asturiana, Avileña, Morucha, Parda Alpina, Pirenaica, Retinta and Rubia Gallega, slaughtered at a live weight of 320 kg (veal type) and 550 kg (yearling bull type). Higher slaughter weight and early maturating breeds produced higher IMF content in the longissimus muscle (P < 0.001), which was linked to a reduction in phospholipids, monoglycerides, diglycerides, cholesterol and free-fatty acids content, but an increase in triacylglycerols. Besides, heavier animals displayed a higher percentage of saturated and monounsaturated fatty acids (MUFA), but a lower polyunsaturated fatty acids (PUFA) percentage (P < 0.001). The increase in triglycerides (TG), saturated fatty acids (SFA) and MUFA illustrates the increasing importance of lipid storage as fattening proceeds and the acquisition of ruminal functionality. The feeding system based on cereals had a strong influence on the fatty acid profile, giving the studied beef a relatively high PUFA/SFA and n-6/n-3 ratios.

Effect of slaughter season and muscle type on the fatty acid composition, including conjugated linoleic acid isomers, and nutritional value of intramuscular fat in organic beef

BACKGROUND

Consumer awareness regarding the intake of beef of organic origin is strongly associated with the beneficial outcomes to human health, the environment and animal welfare. In this paper the effects of slaughter season and muscle type on the fatty acid composition, conjugated linoleic acid (CLA) isomeric profile, total cholesterol, α-tocopherol and β-carotene contents and nutritional quality of intramuscular fat in organic beef (n = 30) are reported for the first time.

RESULTS

Organic beef showed a very low total lipid content, with seasonal changes in the levels of some fatty acids, CLA isomers, n-6/n-3 polyunsaturated fatty acid (PUFA) ratio, total cholesterol and β-carotene. In addition, differences between longissimus lumborum (relatively red) and semitendinosus (relatively white) muscles were found for many fatty acids, specific CLA contents, many CLA isomers and both PUFA/saturated fatty acid (SFA) and n-6/n-3 ratios. However, in spite of the seasonal and carcass variations, all organic meats analysed had values of beef similar to pasture-fed cattle.

CONCLUSION

From a nutritional perspective, organic meat from both slaughter seasons seems to have high CLA contents, PUFA/SFA and n-6/n-3 indices within the recommended values for the human diet. The data indicate that intramuscular fat in organic meat has a high nutritional value throughout the year.

Contrasting cellularity and fatty acid composition in fat depots from Alentejana and Barrosã bovine breeds fed high and low forage diets

During the finishing phase of bovines, large amounts of subcutaneous and visceral fats are deposited leading to production inefficiencies with major impact on meat quality. A better understanding of the cellularity features of the main fat depots could provide strategies for adipose tissue manipulation. This study assessed the effect of feeding diets with distinct forage to concentrate ratios on the cellularity of two fat depots of beef cattle and their implications on the fatty acid profile. Thus, two phylogenetically distant Portuguese bovine breeds, Alentejana and Barrosã, were selected. The results did not show differences in subcutaneous fat deposition nor in visceral fat depots partitioning. Plasma adipokines concentration failed to show a consistent relationship with fatness, as leptin remained constant in all experimental groups, whereas interleukin-6 was influenced by breed. Fat depot seems to determine the area and number of adipocytes, with larger adipocytes and a lower number of cells in subcutaneous fat than in mesenteric fat. Neither breed nor diet influenced adipocytes area and number. The contents of total fatty acids, partial sums of fatty acids and conjugated linoleic acid isomeric profile were affected by breed and fat depot. The incorporation of saturated fatty acids (SFA), trans fatty acids, polyunsaturated fatty acids (PUFA) and branched chain fatty acids (BCFA) was higher in mesenteric fat depot, whereas subcutaneous fat depot had greater percentages of monounsaturated fatty acids (MUFA). In addition, SFA and MUFA proportions seem to be breed-related. In spite of the less relevant role of diet, the percentages of PUFA and BCFA were influenced by this factor. Under these experimental conditions, the effect of fat depot on cellularity and fatty acid composition prevails over breed or diet, as reinforced by the principal component analysis.

Dietary conjugated linoleic acid isomers change the unsaturation degree of hepatic fatty acids in neutral lipids but not in polar lipids

The fatty acid composition of phospholipids plays a key role in the structural and functional properties of cellular membrane. In this study, it was hypothesized that conjugated linoleic acid (CLA) isomer supplementation changes the unsaturation degree of the fatty acids of neutral lipids (NLs) but not those of polar lipids (PLs). Thus, the main goal was to determine the pattern of fatty acid incorporation into hepatic PL and NL fractions. Wistar male rats were fed cis(c)9,trans(t)11 and t10,c12 CLA isomers, separately or as a mixture. Whereas the t10,c12 isomer incorporation in the PL fraction was similar when supplemented either individually or as a mixture, the c9,t11 isomer reached the highest values of incorporation when combined with t10,c12. In the PL fraction, the linoleic acid did not change; but the arachidonic acid decreased, especially in the rats given the mixture. Also in this fraction, the t10,c12 isomer, either separately or as a mixture, decreased the amounts of n-6 long-chain (LC) polyunsaturated fatty acids (PUFA) and increased those of the n-3 LC PUFA relative to the control. In the NL fraction, linoleic acid incorporation followed the diet composition, whereas the arachidonic acid was similar among treatments. Facing CLA isomer supplementation, the present study suggests that fatty acid incorporation into phospholipids, through the balance between n-6 and n-3 LC PUFA, is dependent upon maintaining the unsaturation degree of cellular membrane.

Restricting the intake of a cereal-based feed in free-range-pastured poultry: effects on performance and meat quality

Pastures are assumed to be good sources of alpha-linolenic acid (ALA) and other bioactive compounds. In this study, we evaluated the effects of restricting the intake of a cereal-based feed on the consumption of a legume-based pasture, and consequently on poultry performance and meat quality. Broilers of the RedBro Cou Nu x RedBro M genotype were fed a cereal-based feed at different intake restriction levels (100, 75, or 50% of ad libitum intake) in portable floorless pens located on a subterranean clover (Trifolium subterraneum) pasture. Control birds were maintained at the same site in identical pens but had no access to pasture. The results revealed that, although the growth rate achieved was below the levels expected for the genotype, restriction of cereal-based feed intake had a significant impact on broiler weight gain and feed conversion while leading to an increase in relative leguminous pasture intake (from 1.6 to 4.9% of the total intake, on a DM basis). In addition, bird performance was positively influenced by pasture consumption. The capacity of ingested pasture to modulate carcass characteristics, broiler meat fatty acid profiles, and the meat content of total cholesterol, tocopherols, and to-cotrienols was investigated in broiler chickens slaughtered on d 64. Pasture intake decreased carcass yield (P < 0.05) and meat pH (P < 0.001) and improved breast skin pigmentation (P < 0.001). Consumption of the leguminous pasture had a marginal effect in the vitamin E profiles and cholesterol contents of broiler meat (P < 0.05), although it significantly affected the meat fatty acid profile. Although pasture intake did not influence the linoleic acid content of poultry meat, the levels of n-3 polyunsaturated fatty acids in breast meat [ALA (P < 0.001), eicosapentaenoic acid (P < 0.001), docosapentaenoic acid (P < 0.001), and docosahexaenoic acid (P < 0.001)] were significantly greater in birds consuming the leguminous biomass. Overall, the data suggest an important deposition of ALA and some conversion of ALA to its derivatives in pastured broilers subjected to a restriction of cereal-based feed.

Influence of pasture intake on the fatty acid composition, and cholesterol, tocopherols, and tocotrienols content in meat from free-range broilers

Over the last centuries, Western diets acquired a dramatic imbalance in the ratio of polyunsaturated fatty acids (PUFA) to saturated fatty acids (SFA) with a concomitant reduction in the dietary proportion of n-3 PUFA. Pastures are a good source of n-3 fatty acids, although the effect of forage intake in the fatty acid profile of meat from free-range chicken remains to be evaluated. In addition, it is unknown if consumer interest in specialty poultry products derived from free-range or organic production systems is accompanied by a greater nutritional quality of these products. In this study, broilers of the RedBro Cou Nu x RedBro M genotype were fed on a cereal-based diet in portable floorless pens located either on subterranean clover (Trifolium subterraneum) or white clover (Trifolium repens) pastures. Control birds were maintained at the same site in identical pens but had no access to pasture. The capacity of ingested forage to modulate broiler meat fatty acid profiles and the meat content of total cholesterol, tocopherols, and tocotrienols was investigated in broiler chicks slaughtered at d 56. The results suggested that pasture intake (<5% DM) had a low impact on the fatty acid and vitamin E homologue profiles of meat from free-range broilers. However, breast meat from birds with free access to pasture presented lower levels of the n-6 and n-3 fatty acid precursors linoleic acid (18:2n-6) and alpha-linolenic acid (18:3n-3), respectively. In spring the levels of eicosapentaenoic acid (20:5n-3) in breast meat were significantly greater in birds consuming pastures, which suggests greater conversion of alpha-linolenic acid into eicosapentaenoic acid in these birds. Finally, when compared with meat from slower-growing genotypes obtained under the conventional European free-range production systems with slaughtering at d 81, meat from birds of the Ross genotype raised intensively and slaughtered at d 35 seemed to have greater nutritional quality.

Contents of conjugated linoleic acid isomers in ruminant-derived foods and estimation of their contribution to daily intake in Portugal

The present study provides a detailed overview of the contents of conjugated linoleic acid (CLA) isomers in the most consumed Portuguese CLA-rich foods (milk, butter, yoghurt, cheese, beef and lamb meat), by using silver ion-HPLC. In addition, the contribution of these ruminant-derived foods to the daily intake of CLA isomers was estimated based on Portuguese consumption habits. The total CLA concentration in milk and dairy products ranged from 4·00 mg/g fat in yoghurt to 7·22 mg/g fat in butter, and, regarding meats, from 4·45 mg/g fat in intensively produced beef to 11·29 mg/g fat in lamb meat. The predominant CLA isomers identified in these products were cis-9, trans-11 (59·89–79·21 %) and trans-7, cis-9 (8·04–20·20 %). The average estimated total CLA intake for the Portuguese population was 73·70 mg/d. Milk and cheese are probably the two products with the highest contribution to the final CLA intake, as a result of their high fat content and consumption values. The results also suggested that cis-9, trans-11 and trans-7, cis-9 are the isomers most represented, with, respectively, 76·10 and 12·56 % of the total CLA intake. Being the first detailed report on the contents of total and individual CLA isomers in Portuguese commercial ruminant-derived foods, we further discuss the implication of the results for diet characteristics and human health.

Muscle fiber and fatty acid profiles of Mertolenga-PDO meat

The influence of phenotype and muscle type on intramuscular total lipids (ITL) neutral lipid (NL) and phospholipid (PL) compositions, cholesterol, α-tocopherol and haem iron contents were evaluated in Semitendinosus (St), Longissimus dorsi (Ld) and Supraspinatus (Ss) muscles from 39 Mertolenga young bulls. The results showed that lipid, α-tocopherol, cholesterol and haemic iron contents were not influenced by phenotype. Furthermore, the individual effect of phenotype was not a significant source of variation on ITL, NL and PL fatty acid composition. Muscle histological traits from Unicolor phenotype (n=13) showed that Ss and Ld muscles exhibited higher proportion of type I (P<0.001) and oxidative fibers (P<0.001) and lower percentages of IIB fibers (P<0.001) than St. The Ss muscle, with higher relative area occupied by oxidative fibers (P<0.05-0.001) than Ld and St, had higher ITL (P<0.001), NL (P<0.001), PL (P<0.05-0.01), α-tocopherol (P<0.001), cholesterol (P<0.01) and haem iron (P<0.001) contents than its counterparts. Muscle type notably affected ITL, as a result of its influence on NL rather than in PL composition.

Influence of slaughter season and muscle type on fatty acid composition, conjugated linoleic acid isomeric distribution and nutritional quality of intramuscular fat in Arouquesa-PDO veal

The effects of the slaughter season and muscle type on lipid and conjugated linoleic acid (CLA) contents, fatty acid composition and isomeric profile of CLA in Arouquesa veal, from calves reared according to the specifications of the protected designation of origin (PDO), were assessed. Arouquesa purebred calves (n=31) were raised in a traditional production system, slaughtered in early autumn (October) or late spring (June), and the longissimus dorsi and semitendinosus muscles were sampled for analysis. Arouquesa-PDO veal only showed seasonal differences in the levels of some minor fatty acids (16:1c9, 17:1c9, 18:1t, 18:3n-3, 20:0 and 22:4n-6) and CLA isomers (t12,t14, t9,t11 and c11,t13). Furthermore, significant interactions between the slaughter season and muscle type were obtained for several fatty acids and CLA isomers, total lipids and CLA, and the PUFA/SFA ratio. In both seasons, veal-PDO depicts values of pasture-fed cattle. From a human nutritional perspective, veal-PDO in both slaughter seasons has relatively high CLA contents and percentages of the c9,t11 CLA isomer, which is favourable, while the n-6/n-3 ratios are within the recommended values for the human diet. In conclusion, the results suggest that intramuscular fat in Arouquesa-PDO veal has high nutritional value throughout the year.