Effect of breed on the deposition in beef muscle and adipose tissue of dietary n-3 polyunsaturated fatty acids

Effect of Muscle Fibre Type on the Fatty Acids Profile and Lipid Oxidation of Dry-Cured Venison SM (semimembranosus) Muscle

The aim of the study was to describe the effect of fibre type on the fatty acid profile and lipid oxidation observed in dry-cured ham produced from individual semimembranosus venison (roe-deer, fallow deer, deer and wild boar) muscles. The results indicated that wild boar meat was characterised by the highest percentage of IA fibres and it contained the higher percentage of MUFA, but a low of PUFA and SFA, and was characterised by a(n-6)/(n-3) ratio lower than in the case of deer meat and greater susceptibility to oxidative changes. The highest percentage of SFA, and the lowest of MUFA and PUFA, was recorded in fallow deer meat, which was also characterised by the highest percentage of white fibres. The curing and drying processes increased the percentage share of SFA and the susceptibility of muscle lipids to oxidation, decreased the percentage of PUFA, and caused insignificant changes in the (n-6)/(n-3) ratio of fatty acids. The products were also characterised by a low amount of fat.

Genetic and Environmental Determinants of Beef Quality—A Review

The flavor, quality, and composition of beef changes with the cattle diet regimen. The quality of meat varies, and that variability is determined by both individual and environmental factors: age, breed, live weight, fatness degree, plane of nutrition, and concentrate/roughage ratio. The strategy for the rearing and feeding of cattle for slaughter should therefore aim at reducing the saturated fatty acid content and increasing the polyunsaturated fatty acid and monounsaturated fatty acid levels. Many diseases in humans, like atherosclerosis and cardiovascular diseases, are associated with dietary fat, and their development process could take a year, the results of which can be a shorter life and its lower quality. The objective of this review was to describe the factors affecting the meat quality and fatty acid profile of the intramuscular fat of European cattle fed various diets.

Chemical Characteristics of Limousine Beef Depending on Finishing Diets and Muscle Type of Meat

The goal of this study was to compare the chemical properties of three muscle types of beef cattle fed using different finishing diets compositions. Four finishing feeding models for bulls based on different proportions of concentrates, maise silage, grass silage and hay were evaluated. Muscles chemical composition was evaluated in m. infraspinatus (ISB), m. longissimus thoracis (LTC) and m. longissimus lumborum (LLS). The chemical composition of meat was influenced by muscle type. ISB was characterised by higher moisture, collagen content, lower protein and ash content, and net energy concentration than LTC and LLS. The differences between diets in dry matter and fat content in each of the muscle groups studied were stated. Furthermore, a difference in the collagen content in LLS and protein content in ISB was noted. High correlations (P ≤ 0.05) were found between the concentrate content in the finishing diet and protein content (r = 0.59) in ISB, and dry matter both in LLS (r = 0.69) and LTC (r = 0.58). The lowest fat content of beef was noted for all muscles obtained from animals fed with a diet composed of grass silage, hay, and concentrates (D1).

A Non-Synonymous Single Nucleotide Polymorphism in FASN Gene Alters FASN Enzyme Activity in Subcutaneous and Intramuscular Adipose Tissue in Holstein Friesian Steers

The FASN enzyme plays a key role in fatty acids synthesis as the main long-chain fatty acid synthesizer. A non-synonymous SNP (single nucleotide polymorphism) (g.17925A>G) located in the thioesterase domain of this enzyme and an effect in fat deposition has been observed, but has not been evaluated in this breed and, moreover, the reason whereby this occurs remains unclear. The objective of this study was to evaluate the effect of this SNP on the activity of FASN enzyme in subcutaneous and intramuscular adipose tissue from Holstein Friesian steers. To achieve this, 196 animals were sampled in a local abattoir, genotyped for the FASN g.17924A>G SNP and characterized for fatty acid profile. Then a sub-sample of 20 animals per genotype were selected to extract the total protein from subcutaneous and intramuscular adipose tissue to estimate the FASN enzyme activity. The FASN activity for each genotyped animal was assessed indirectly by measuring the decrease in the absorbance of NADPH at 340 nm by spectrophotometry in a 24 well plate in the presence of Acetyl-CoA, Malonyl-CoA, and NADPH. To assess the impact of SNP induced amino acid changes in FASN protein structure, in-silico simulations were performed. Our results indicated that FASN g.17924A>G SNP induces a change in the enzyme activity in subcutaneous adipose tissue, which is higher when the AA genotype is present and lower in the presence of the AG genotype. The in-silico analysis of the amino acid substitution shows that there was a structural change in the dimeric form of the protein between genotypes. Moreover, the global energy between subunits is lower and more favorable when the AA genotype is present and higher and less favorable for the AG genotype. It was also found that the fatty acid profile of subcutaneous adipose tissue was affected when the AG genotype was present, decreasing the C16:0 fatty acid levels and increasing the C18:0 fatty acid levels. The FASN g.17924A>G SNP alters the FASN enzyme structure and activity, leading to a variation in the fatty acid composition of subcutaneous adipose tissue in Holstein Friesian steers. Implications: This SNP could be considered as a tool to improve the fat deposition or marbling and the fatty acid profile in cattle.

Effect of Breed on the Level of the Nutritional and Health-Promoting Quality of Semimembranosus Muscle in Purebred and Crossbred Bulls

Meat from commercial breed cattle are very often used to crossbreed with dairy breeds. The effect of heterosis is most evident when crossbreeds are genetically different from each other. Therefore, the aim of the study was to determine the influence of breed types on the nutritional and pro-health quality of beef. The experiment was conducted on 62 bulls from three breeds: Limousin, Polish Holstein-Friesian, and Polish Holstein-Friesian (PHF) × Limousin. During the fattening period, the animals were fed ad libitum using the same diet. Bulls were slaughtered at 21-23 months of age. The meat of PHF × Limousin hybrids was characterized by the lowest level of SFA and the highest content of n-3 PUFA fatty acids, carnosine, and α-tocopherol compared to the values obtained for the Polish Holstein-Friesian and Limousin breeds. In the case of PHF × Limousin hybrids, there was a 6% increase in n-3 PUFA, 21% in carnosine, and 66% in α-tocopherol compared to the Polish Holstein-Friesian breed. Commodity crossbreeding significantly improved the quality of beef analyzed in this study, resulting in similar or even better results than purebred cattle. This meant that beef from the hybrids with PHF was of the best nutritional and health-promoting quality.

Preferential Partitioning of Rumen-Protected n-3 and n-6 Fatty Acids into Functionally Different Adipose Tissues

Lipids are stored at various sites inside the body as adipose tissue (AT). These include subcutaneous, abdominal, and intermuscular locations. The AT substantially differ in their metabolic function. It is, however, unclear whether AT have specific requirements for individual essential n-3 and n-6 fatty acids (FA). If so, control mechanisms would partition FA from the blood. To investigate the hypothesis of a selective FA incorporation, 18 beef heifers were fed diets supplemented with 60 g/kg diet with lipids from either fish oil (FO) or sunflower oil (SO). The lipids had partially been rumen-protected to ruminal biohydrogenation of n-3 and n-6 FA. The AT analyzed for n-3 and n-6 FA by gas chromatography were obtained from pericardial, longissimus thoracis (LT) intermuscular, perirenal, and subcutaneous sites. The greatest proportions of n-3 and n-6 FA were found in the pericardial AT. Despite generally low abundance, n-3 FA proportions increased with FO compared to SO supplementation in all AT, but to a different extent. No such partitioning was found for the n-6 FA when supplementing SO. Concomitantly, the n-6/n-3 FA ratio was reduced with FO in all AT, except in the pericardial AT. The latter has specific metabolic functions and thus appears to be quite resistant to diet-induced changes in FA profile in order to maintain its function. The present findings showed the special role of specific n-3 and n-6 FA in bovine AT.

Effects of Dietary Energy on Growth Performance, Rumen Fermentation and Bacterial Community, and Meat Quality of Holstein-Friesians Bulls Slaughtered at Different Ages

Simple Summary

Beef tenderness, flavour and juiciness are quality characteristics of consumer eating satisfaction. Marbling level of beef could determine quality characteristics by concentrating water soluble flavour molecules and releasing low fat-solubility volatiles faster. Increasing number of Holstein-Friesians bulls are used for beef production, and this breed is considered to have lower meat quality than purebred and crossbred beef cattle. Therefore, in this study we designed different dietary energy levels and slaughter ages to find ways to improve the meat quality of Holstein-Friesians bulls in beef production. We found that Holstein-Friesians bulls fed with 10.90 and 11.68 MJ/kg metabolizable energy diets, compared to a diet with 10.12 MJ/kg of metabolizable energy, had higher average daily gain, dressing percentage, intramuscular fat content and water holding capacity at 23 or 26 months of age. This study provides a basis to use bulls to produce beef by providing indicators of growth performance, rumen fermentation and ruminal bacteria community, and meat quality.

Abstract

The objective of this study was to evaluate the effects of dietary energy levels on growth performance, rumen fermentation and bacterial community, and meat quality of Holstein-Friesians bulls slaughtered at different ages. Thirty-six Holstein-Friesians bulls (17 months of age) were divided into a 3 × 3 factorial experiment with three energy levels (LE, ME and HE; metabolizable energy is 10.12, 10.90 and 11.68 MJ/kg, respectively) of diets, and three slaughter ages (20, 23 and 26 months). Results indicated that bulls fed with ME and HE diets had higher dry matter intake, average daily gain, and dressing percentage at 23 or 26 months of age. The ME and HE diets also reduced bacterial diversity, altered relative abundances of bacteria and produced lower concentrations of acetate, but higher butyrate and valerate concentrations in rumen fluid. Increasing in dietary energy and slaughter age increased the intramuscular fat (IMF) and water holding capacity. In summary, Holstein-Friesians bulls fed with ME and HE diets, slaughtered at 23 and 26 months of age could be a good choice to produce beef with high IMF. Slaughter age may have less influence than dietary energy in altering fermentation by increasing amylolytic bacteria and decreasing cellulolytic bacteria, and thus, further affecting meat quality.

Partitioning of Rumen-Protected n-3 and n-6 Fatty Acids is Organ-Specific in Growing Angus Heifers

Dietary polyunsaturated fatty acids (PUFA), especially n-3 and n-6 fatty acids (FA), play an important role in the regulation of FA metabolism in all mammals. However, FA metabolism differs between different organs, suggesting a distinct partitioning of highly relevant FA. For the present study in cattle, a novel technology was applied to overcome rumen biohydrogenation of dietary unsaturated FA. Angus heifers were fed a straw-based diet supplemented for 8 weeks with 450 g/day of rumen-protected oil, either from fish (FO) or sunflower (SO). The FA composition in blood and five important organs, namely heart, kidney, liver, lung, and spleen, was examined. In blood, proportions of polyunsaturated FA were increased by supplementing FO compared to SO. The largest increase of eicosapentaenoic acid (EPA) proportion was found with FO instead of SO in the kidney, the lowest in the lung. Docosahexaenoic acid (DHA) was increased more in the liver than in kidney, lung, and spleen. The heart incorporated seven times more EPA than DHA, which is more than all other organs and described here for the first time in ruminants. In addition, the heart had the highest proportions of α-linolenic acid (18:3n-3) and linoleic acid (18:2n-6) of all organs. The proportions of polyunsaturated FA in the lung and spleen were exceptionally low compared to heart, liver, and kidney. In conclusion, it was shown that the response to FO in the distribution of dietary n-3 FA was organ-specific while proportions of n-6 FA were quite inert with respect to the type of oil supplemented.

Carcass characteristics of grass-fed crossbred bulls and steers slaughtered at two different ages

The aim of this study was to evaluate beef production potential and meat quality in young crossbred bulls and steers raised indoors and fed grass-based diets. One half of 96 bull calves were castrated at 2–3 wk of age. The calves were fed standard diets, and starting at 7 mo of age, they received grass silage supplemented with concentrates. At the end of the fattening period (18 and 21 mo of age), the animals were slaughtered, carcass quality was evaluated, and samples of musculus longissimus thoracis were collected to determine the proximate composition and meat quality. The semi-intensive feeding system contributed to higher daily gains (0.835 kg) in Holstein-Friesian (HF) × Hereford (HH) crosses. In comparison with steers, bulls were characterized by a higher dressing percentage (+1.33%), higher weight of five most valuable primal cuts (+6.7 kg), and higher lean meat content of three-rib cuts (+7.54%). Meat from steer carcasses, which had higher fat content was more tender and had desirable aroma, juiciness, and flavor. In semi-intensive production systems, steers performed better than bulls, and HF × HH crosses were more suitable than HF × Limousin (LM) and HF × Charolais (CH) crosses. Dairy-beef crosses should be slaughtered at 21 mo of age to improve carcass quality.

The use of oxidative stress biomarkers in live animals (in vivo) to predict meat quality deterioration postmortem (in vitro) caused by changes in muscle biochemical components

This study was conducted to determine whether circulating concentrations of blood isoprostanes can be used as an effective biomarker in lambs to predict degradation of color and/or lipid stability in meat. Lambs ( = 84) were fed diets of either lucerne pasture, annual ryegrass pasture, a commercial feedlot pellet, or a combination of annual ryegrass and feedlot pellet for 8 wk, including a 2-wk adaptation period. Blood isoprostane concentration at wk 0, 4, 6 or 8 of feeding was determined. Blood isoprostane concentration for each animal was then correlated with muscle biochemical components that impact color and/or lipid oxidative status during retail display. This included lipid oxidation levels in muscle assessed by thiobarbituric acid reactive substances and meat redness determined by a HunterLab colorimetric spectrometer. Lambs that consumed the commercial feedlot pellet had a lower muscle vitamin E level (< 0.01) and a greater level of -6 PUFA ( < 0.001) compared with lambs finished on annual ryegrass or lucerne. Lipid oxidation levels were greatest for lambs finished on the feedlot ration, lowest in lambs finished on the ryegrass diet, and intermediate for lambs finished on lucerne and ryegrass-feedlot combination ( < 0.01). After 8 wk of feeding, blood isoprostane concentration was positively correlated with lipid oxidation of meat displayed for 72 h in simulated retail conditions ( < 0.01). There was a negative linear relationship between isoprostane concentration and muscle vitamin E concentration ( = 0.07), lipid oxidation and muscle vitamin E concentration ( < 0.01) but a positive linear relationship between isoprostane concentration and muscle -6 PUFA ( < 0.001) or lipid oxidation and muscle -6 PUFA concentration ( < 0.001). Blood isoprostane concentration and lipid oxidation in meat were influenced by muscle vitamin E and -6 PUFA but not by -3 PUFA. There was no significant relationship observed between blood isoprostane concentration at 0, 4, 6 or 8 wk feeding vs. overall meat color (redness of meat) at 0 and 72 h of display, stored under simulated retail conditions. The results indicate that circulating blood isoprostane concentration can be a useful tool to predict the oxidative status of postmortem meat. Future work will examine the impact of this relationship on meat flavor/aroma deterioration post farm.

Effect of breed and diet on total lipid and selected shelf-life parameters in beef muscle

Some studies with beef cattle have shown that breed and diet affect tissue fatty acid composition and meat quality (Choi et al., 2000; Scollan et al., 2001). However, the effects of breed are often confounded with differences in growth rate and body composition. Diet also affects fatty acid composition, however, feed composition studies are often confounded by the use of mixed diets and few have compared all-forage with all-concentrate diets. This study, therefore, was designed to compare Aberdeen Angus and Holstein-Friesian breeds growing at similar rates and fed either all-forage or a high concentrate diet.

Shelf life and eating quality of beef from cattle of different breeds given diets differing in n-3 polyunsaturated fatty acid composition

Two experiments were conducted with 32 Charolais cross steers (experiment 1) and 36 Holstein-Friesian and Welsh Black steers (experiment 2) to examine the effects of dietary n-3 polyunsaturated fatty acids (PUFA ) and breed on meat quality. Diets were comprised of grass silage and a concentrate (60 : 40 on a dry-matter basis). Lipid in the concentrate provided 30 g/kg diet dry matter derived from either linseed, fish oil or linseed/fish oil (experiment 1); and linseed or linseed/fish oil (experiment 2). These n-3 PUFA sources were compared with Megalac, a saturated fatty acid control, in both experiments. Diets were offered for 120 days (experiment 1) and 90 days (experiment 2). Measurements of meat quality included fatty acid composition, lipid oxidation and colour during retail display (i.e. shelf life parameters) and eating quality assessed by a trained taste panel. The samples examined were sirloin (longissimus) steaks and minced beef burgers produced from the forequarter muscles infraspinatus, supraspinatus and triceps brachii. The fatty acid results showed that linseed increased the proportion of 18 : 3 n-3 (a -linolenic acid) in neutral lipid of the burgers and approximately doubled it in the phospholipid. Increased synthesis of 20 : 4 n-3 and 20 : 5 n-3 also occurred, raising their levels in the phospholipid. Fish oil doubled the proportions of 20 : 5 n-3 and 22 : 6 n-3, with the linseed/fish oil results intermediate between linseed and fish oil. The Welsh Blacks in experiment 2 had higher proportions of 18 : 3 n-3 in neutral lipid and higher proportions of 18 : 3 n-3, 20 : 5 n-3 and 22 : 5 n-3 in phospholipid. This showed a clear genetic effect on fatty acid composition. The fish oil diet in experiment 1 greatly increased lipid oxidation during retail display in both overwrapped loin steaks and burgers packed in a modified atmosphere. Values for lipid oxidation in the burgers were much higher than in the steaks due to the intimate mixing of phospholipid fatty acids and prooxidants. Lipid oxidation was also greater in the linseed/fish oil samples than controls in both experiments but was similar in linseed and controls. Colour oxidation also proceeded more rapidly in the fish oil samples in experiment 1 and tended to be faster in the linseed/fish oil groups in both experiments. Eating quality was affected by diet in experiment 1 — the fish oil samples eliciting higher scores for ‘fishy’ and ‘rancid’ than controls and having lower ‘overall liking’ scores. Steaks from animals given the linseed diet (with high 18 : 3 n-3 proportions) had the highest ‘overall liking’ scores in experiment 1 but the cattle given linseed for the shorter time in experiment 2 were not different from controls. Despite their different PUFA profile in muscle, Welsh Blacks had similar eating quality scores to Holstein-Friesians which deposited more neutral lipid (marbling fat) in muscle.

Cholesterol and fatty acid composition of longissimus thoracis from water buffalo (Bubalus bubalis) and Brahman-influenced cattle raised under savannah conditions

Male (n=66) water buffalo (Buffalo) and Brahman-influenced cattle (Brahman) were born, raised, weaned, fattened on grazing savannah and harvested at two different ages (19 and 24months) to compare lipid composition of the longissimus thoracis muscle. Half of the animals were castrated at seven months of age (MOA) to examine the castration effects. At 24 MOA Brahman steers showed the highest content of total lipids (P<0.05). No significant variation was detected in cholesterol content for either the main or interaction effects in the age groups. Some individual fatty acids varied with the species (P<0.05), however, interspecific similarities were found in fatty acid ratios. For health-related indices, only atherogenic index (AI) showed lower values in favor of Buffalo meat (P<0.05) at both harvesting ages. Although, meat derived from both bovid groups was leaner and showed lower cholesterol level, AI indicates that Buffalo meat might be beneficial from a human health standpoint.

A comparison of the aroma volatiles and fatty acid compositions of grilled beef muscle from Aberdeen Angus and Holstein-Friesian steers fed diets based on silage or concentrates

This paper compares the volatile compound and fatty acid compositions of grilled beef from Aberdeen Angus and Holstein-Friesian steers slaughtered at 14 months, each breed fed from 6 months on either cereal-based concentrates or grass silage. Linoleic acid levels were higher in the muscle of concentrates-fed animals, which in the cooked meat resulted in increased levels of several compounds formed from linoleic acid decomposition. Levels of α-linolenic acid, and hence some volatile compounds derived from this fatty acid, were higher in the meat from the silage-fed steers. 1-Octen-3-ol, hexanal, 2-pentylfuran, trimethylamine, cis- and trans-2-octene and 4,5-dimethyl-2-pentyl-3-oxazoline were over 3 times higher in the steaks from the concentrates-fed steers, while grass-derived 1-phytene was present at much higher levels in the beef from the silage-fed steers. Only slight effects of breed were observed.

Effects of fatty acids on meat quality: a review

Interest in meat fatty acid composition stems mainly from the need to find ways to produce healthier meat, i.e. with a higher ratio of polyunsaturated (PUFA) to saturated fatty acids and a more favourable balance between n-6 and n-3 PUFA. In pigs, the drive has been to increase n-3 PUFA in meat and this can be achieved by feeding sources such as linseed in the diet. Only when concentrations of α-linolenic acid (18:3) approach 3% of neutral lipids or phospholipids are there any adverse effects on meat quality, defined in terms of shelf life (lipid and myoglobin oxidation) and flavour. Ruminant meats are a relatively good source of n-3 PUFA due to the presence of 18:3 in grass. Further increases can be achieved with animals fed grain-based diets by including whole linseed or linseed oil, especially if this is "protected" from rumen biohydrogenation. Long-chain (C20-C22) n-3 PUFA are synthesised from 18:3 in the animal although docosahexaenoic acid (DHA, 22:6) is not increased when diets are supplemented with 18:3. DHA can be increased by feeding sources such as fish oil although too-high levels cause adverse flavour and colour changes. Grass-fed beef and lamb have naturally high levels of 18:3 and long chain n-3 PUFA. These impact on flavour to produce a 'grass fed' taste in which other components of grass are also involved. Grazing also provides antioxidants including vitamin E which maintain PUFA levels in meat and prevent quality deterioration during processing and display. In pork, beef and lamb the melting point of lipid and the firmness/hardness of carcass fat is closely related to the concentration of stearic acid (18:0).

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.

Changes in intramuscular fat, fatty acid profile and cholesterol content induced by zeranol implantation strategy in hair lambs

BACKGROUND

The effect of zeranol implantation strategy on intramuscular fat, fatty acid profile and cholesterol content of the longissimus dorsi muscle of hair lambs was studied. Four treatments were tested: C, control group; Z12, 12 mg zeranol; Z24, 24 mg zeranol in a single application; and RZ12, 12 mg zeranol given twice. One-way analysis of variance was employed to estimate the effect of treatments (P < 0.05). To separate the effect of the mean, orthogonal contrasts were tested: C1, C versus Z12 + Z24 + RZ12; C2, Z12 versus Z24 + RZ12; and C3, Z24 versus RZ12.

RESULTS

A decrease (P < 0.05) in intramuscular fat content was observed from implanting (C1 effect) and zeranol reimplantation (C3 effect). Implanted lambs exhibited an increase (P < 0.05) in monounsaturated fatty acids compared with control group (40.60% versus 35.35%). All contrasts were significant for the sum of n-6 and n-3, with values lower (P < 0.05) in the control (n-6: 0.84% and n-3: 1.38%) and higher in the RZ12 treatment (n-6: 7.55% and n-3: 14.9%). Cholesterol decreased by 78% with implantation and increasing the dose.

CONCLUSION

The results indicate that it is possible to induce favorable changes in the fatty acid profile and cholesterol content using a zeranol implantation strategy on hair lambs.

Fatty acid profile of three adipose depots in seven Spanish breeds of suckling kids

Intramuscular, subcutaneous and kidney knob fat depot fatty acid profiles were studied in 104 male suckling kids from seven Spanish breeds: Blanca Andaluza, Blanca Celtibérica, Moncaína, Negra Serrana-Castiza, Pirenaica, Malagueña and Murciano-Granadina. Kids were raised in the traditional production system on mother's milk and slaughtered at around 7kg live weight. Differences were observed between dairy (Malagueña) and meat breeds (Blanca Andaluza, Blanca Celtibérica, Moncaína, Negra Serrana-Castiza, and Pirenaica). Malagueña showed higher monounsaturated and conjugated linoleic fatty acid levels than the other breeds. Highest percentages of saturated fatty acids were observed in meat breeds. For intramuscular fat depot, the range for desirable fatty acids was 66.16-72.27% was. The influence of breed on fatty acid profiles of intramuscular, subcutaneous and kidney knob fat depots studied was evident. Intramuscular fat depot is proposed as a differentiating factor between dairy and meat breed goat kids, but not between meat breed kids.

Association of an ACSL1 gene variant with polyunsaturated fatty acids in bovine skeletal muscle

Background

The intramuscular fat deposition and the fatty acid profiles of beef affect meat quality. High proportions of unsaturated fatty acids are related to beef flavor and are beneficial for the nutritional value of meat. Moreover, a variety of clinical and epidemiologic studies showed that particularly long-chain omega-3 fatty acids from animal sources have a positive impact on human health and disease.

Results

To screen for genetic factors affecting fatty acid profiles in beef, we initially performed a microsatellite-based genome scan in a F₂ Charolais × German Holstein resource population and identified a quantitative trait locus (QTL) for fatty acid composition in a region on bovine chromosome 27 where previously QTL affecting marbling score had been detected in beef cattle populations. The long-chain acyl-CoA synthetase 1 (ACSL1) gene was identified as the most plausible functional and positional candidate gene in the QTL interval due to its direct impact on fatty acid metabolism and its position in the QTL interval. ACSL1 is necessary for synthesis of long-chain acyl-CoA esters, fatty acid degradation and phospholipid remodeling. We validated the genomic annotation of the bovine ACSL1 gene by in silico comparative sequence analysis and experimental verification. Re-sequencing of the complete coding, exon-flanking intronic sequences, 3' untranslated region (3'UTR) and partial promoter region of the ACSL1 gene revealed three synonymous mutations in exons 6, 7, and 20, six noncoding intronic gene variants, six polymorphisms in the promoter region, and four variants in the 3' UTR region. The association analysis identified the gene variant in intron 5 of the ACSL1 gene (c.481-233A>G) to be significantly associated with the relative content of distinct fractions and ratios of fatty acids (e.g., n-3 fatty acids, polyunsaturated, n-3 long-chain polyunsaturated fatty acids, trans vaccenic acid) in skeletal muscle. A tentative association of the ACSL1 gene variant with intramuscular fat content indicated that an indirect effect on fatty acid composition via modulation of total fat content of skeletal muscle cannot be excluded.

Conclusions

The initial QTL analysis suggested the ACSL1 gene as a positional and functional candidate gene for fatty acid composition in bovine skeletal muscle. The findings of subsequent association analyses indicate that ACSL1 or a separate gene in close proximity might play a functional role in mediating the lipid composition of beef.

Effect of whole linseed addition on meat production and quality of Italian Simmental and Holstein young bulls

The effect of long term dietary linseed addition on performance, carcass characteristics and meat quality of Italian Simmental (IS) and Italian Holstein (HI) young bulls was investigated. Thirty-two animals were assigned to 4 groups following a factorial design: 2 breeds - IS and IH - ×2 diets - containing whole ground linseed (5-8% of DM) and control. IS had greater in vivo performance and carcass characteristics than IH. IS muscle had lower C14:0, C16:0, SFA, higher C18:2n-6 cis, PUFAn-6, PUFA and PUFA/SFA proportion than IH in phospholipids (PL) fraction. Linseed inclusion did not affect animal's performance and carcass characteristics. In muscle PL, linseed increased C20:0, C22:0, C23:0, C20:5n-3 and decreased C20:4n-6, PUFAn-6/n-3, PUFAn-6 concentration. Linseed decreased C14:0, C16:0 proportion in neutral lipids (NL) and increased total PUFAn-3, C18:3n-3 proportions both in NL and PL fraction. However, these differences were relatively low from a quantitative point of view.

Alpha-linolenic acid and its conversion to longer chain n-3 fatty acids: benefits for human health and a role in maintaining tissue n-3 fatty acid levels

There is little doubt regarding the essential nature of alpha-linolenic acid (ALA), yet the capacity of dietary ALA to maintain adequate tissue levels of long chain n-3 fatty acids remains quite controversial. This simple point remains highly debated despite evidence that removal of dietary ALA promotes n-3 fatty acid inadequacy, including that of docosahexaenoic acid (DHA), and that many experiments demonstrate that dietary inclusion of ALA raises n-3 tissue fatty acid content, including DHA. Herein we propose, based upon our previous work and that of others, that ALA is elongated and desaturated in a tissue-dependent manner. One important concept is to recognize that ALA, like many other fatty acids, rapidly undergoes beta-oxidation and that the carbons are conserved and reused for synthesis of other products including cholesterol and fatty acids. This process and the differences between utilization of dietary DHA or liver-derived DHA as compared to ALA have led to the dogma that ALA is not a useful fatty acid for maintaining tissue long chain n-3 fatty acids, including DHA. Herein, we propose that indeed dietary ALA is a crucial dietary source of n-3 fatty acids and its dietary inclusion is critical for maintaining tissue long chain n-3 levels.

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).

Beef lipids in relation to animal breed and nutrition in Argentina

Fatty acid (FA) composition of intramuscular fat (IMF) in M. Longissimus dorsi (LD) was measured in 72 steers from Angus (A), Charolais×Angus (CHA×A) and Holstein Argentine (HA) breeds. The steers were allotted to four dietary treatments of six animals each: T1, steers grazed on pasture; T2, steers supplemented with cracked corn grain (0.7% of live-weight) daily and free access to pasture; T3, steers supplemented with cracked corn grain (1% of live-weight) daily and free access to pasture; and T4, feedlot (concentrate based on corn, alfalfa hay and soybean meal without access to pasture). At slaughter weight, samples of LD at the 11th rib were used for intramuscular lipid analysis. The diet was shown to be more important than breed in determining FA composition. Pasture beef had higher percentages of saturated fatty acids (SFA), n-3 polyunsaturated fatty acids (PUFA) and conjugated linoleic acid (CLA) and lower percentages of IMF, monounsaturated fatty acids (MUFA), n-6 PUFA and n-6/n-3 ratios than feedlot beef. HA beef presented lower percentages of SFA and more MUFA with a higher n-6/n-3 ratio than A and CHA×A. Comparing grass and feedlot beef the amounts of FA in muscle (mg/100g) were, respectively 18:3 n-3 (44 vs. 11mg), CLA (20 vs. 12mg), 20:5 n-3 (20 vs. 11mg), 22:5 n-5 (20 vs. 11mg), 22:6 n-3 (12 vs. 6mg) and n-3 PUFA (84 vs. 32mg). Feedlot beef has more SFA (1372 vs. 1081mg), MUFA (1574 vs. 1078mg), PUFA (350 vs. 227mg) and n-6 PUFA (318 vs.143mg).