Livestock Research for Rural Development 26 (11) 2014 Guide for preparation of papers LRRD Newsletter

Citation of this paper

Comparison of fatty acid profile of longissimus dorsi muscle in indigenous Lori cattle reared under rural and semi-industrial production system

A Kiani, M H Gharoni1, R Shariati2 and E Fallahi3

Animal Science Group, Lorestan University, Khoramabad, Iran
kiani.a@lu.ac.ir   ;   arkashkia@gmail.com
1Faculty Veterinary, Lorestan University, Khoramabad, Iran
2R&D section, Garrin Dam Simorgh, Khoramabad, Iran
3Nutritional Health Research Center (NHRC), Lorestan University of Medical Sciences, Khoramabad, Iran

Abstract

In this study, the effects of production system and slaughter season on ratio of ω-6:ω-3 fatty acids (FA) and ratio of poly-unsaturated FA to saturated FA (P:S) of meat in indigenous Lori cattle were investigated. In total, 20 Lori bulls (12-15 month) were fed either with 100% forage based diet (rural) or with 60% forage and 40% concentrate (semi-industrial) were slaughtered either during spring or during fall season. Meat samples (100 g) were dissected from longissimus dorsi muscle between rib12th and 13th and were homogenate either without fat (lean meat) or with subcutaneous fat (fat meat). Meat fat was extracted and methylated in one-step method and FA profile was determined.

 

Spring meat compared to fall meat had higher oleic acid (8.1 vs. 5.9%) and less linoleic acid (33.4 vs. 37.8%). Neither production system nor slaughter season showed any significant effects on P:S ratio. Lean meat had higher P:S ratio than fat meat (0.4 vs. 0.1). Ratio of ω-6:ω-3 in lean meat was lower than that in fat meat (6.2 vs. 7.9). Rural meat had lower ratio of ω-6:ω-3 than semi-industrial  (5.2 vs. 8.9). In conclusion, lean meat of Lori cattle had healthy P:S ratio (0.4). Rural meat had lower ratio of ω-6:ω-3 than semi- industrial meat presumably due to higher forage intake in rural production system. Thus Lori beef meat produced in rural system proposes healthier meat for consumers in respect to ω-6:ω-3 ratio.

Keywords: beef, Indigenous Lori cattle, polyunsaturated fatty acids, production system


Introduction

Red meat is a component of a healthy diet with good balance of essential amino acid and important micronutrient (Biesalski  2005; Williams  2007). Red meat is known as source of bioavailable iron and zinc and also contains magnesium, copper, cobalt, phosphorus, chromium, nickel and most importantly selenium. Red meat provides thiamin, riboflavin, pantothenic acid, folate, niacin, B6 and B12 (Williams  2007). However, red meat is blamed for its link with cardiovascular and other chronic diseases mainly because of its high saturated fatty acids (SFA) and low polyunsaturated fatty acids (PUFA) content (McAfee et al 2010). Fatty acid profiles of ruminants products (meat and milk) generally originates from ingested feedstuff. Ruminant diet has usually less than 5% fat per dry matter and α-linolenic acid (C18:3) and linoleic acid (18:2) are the two abundant fatty acids in ruminant feedstuff. However, ruminant products (meat and milk) have high percentage of SFA but low percentage of PUFA due to rumianl biohydrogenation of fatty acids (Jenkins et al 2008). Thus, it is not surprising that the ratio of PUFA to SFA (P:S ratio) in red meat is far from recommended ratio (i.e., >0.4).

 

Red meat is also source of two important groups of long chain fatty acids in healthy diet; ω-3 and ω-6 fatty acids (Williams 2007). The known ω-3 family are α-Linoleic acid (ALA, C18:3), eicosapentaenoic acid (EPA, C20:5), docosapentenoic acid (DPA, C22:5) and docosahexaenoic acid (DHA, C22:6). Linoleic acid (LA, C18:2), gamma-linolenic acid (GLA, C20:3) and arachidonic acid (AA, C20:4) are the main members of ω-6 family. Red meat is the main dietary source of DPA because DPA accumulate in mammals but not in sea animals (Givens et al 2006). Both ω-3 and ω-6 fatty acids are imperative for human nutrition and are critical for body functions (Di Pasquale 2009). The low amount of ω-3 family and extra amount of ω-6 family in most of the foods lead to an unbalanced ratio of omega-6 to omega-3 (ω-6:ω-3 ratio). This ratio in the most of industrial and conventional animal products (meat and milk) has been reported to be 15:1 to 20:1, whereas the recommended ratio of ω-6:ω-3 ratio is  2:1 to 4:1 (Simopoulos 2002). A large number of studies has shown direct links between unbalanced ω-6:ω-3 ratio and many human chronic diseases (Simopoulos 2008). Therefore there is an urgent need to modify or to propose alternative sources of meat with healthier ω-6:ω-3 ratio (Kouba and Mourot 2011).

 

Beef meat in many countries (including Iran) is produced either in rural or semi-industrial production system. Basically, animals in these two production systems are indigenous or cross breeds which fatty acid profile of their product are not yet fully determined. In semi-industrial production system animals are usually fed by 40% concentrate and 60% forages. The forage part of the ration during spring contains green forages whereas agricultural by products (such as different kinds of straw) are main fibrous part of the diet during summer and early autumn Similarly, cattle in rural production system are fed by green forages and grazed in natural ranges during spring but they are fed agricultural by products during summer and autumn. Therefore, the nutritional background of cattle that are sacrificed at two seasons are different though the proportion of forage in daily ration is similar.  The differences in animal nutrition in semi-industrial and rural system at different sacrifice seasons might affect the fatty acid profile of the meat. On the other hand, red meat is consumed either as lean meat (with low fat) or as minced meat (with high fat content) which the differences in their fatty acid are not clearly know. Therefore, in the present study fatty acid profile of red meat of indigenous Lori cattle reared in rural and semi-industrial production system was determined. Furthermore, the effects of production system (rural vs. semi-industrial) and slaughter season on ω-6:ω-3 ratio and P:S ratio of two type of meat in indigenous Lori cattle breed were investigated.


Materials and methods

Animals and meat samples

 

In total, twenty Lori bulls (12 to 15 month age) were slaughtered under commercial processing conditions (Gholshan Abbattoir,  Khoramabad, Lorestan) during spring and autumn season. All calves were reared with their dams until weaning at 5 months of age. Nutritional background of the animals during the last two months prior to slaughter time was recorded. In rural production system, cattle grazed natural ranges (Aleshtar, Lorestan, Iran) during April and May. The predominant plant species of the ranges were ryegrass (Lolium perenne) and clover (Trifolium spp). However, during the summer time calves were fed by agricultural by products mainly wheat and barley straw. In semi-industrial production system, animals were fed a diet with 60% forage and 40% concentrate. During April and May, green red clover and green fresh alfalfa were contributed up to 60 % of the total daily intake. The rest were barley, wheat bran and soyabean meal with 22%, 10% and 5% respectively.  However, during August and September , the forage part of the animals ration were fed by 30 % dried alfalfa, 30% wheat straw .The average slaughter body weight ( SD) was 158 35 and 274 83 kg for animals in rural and semi-industrial production system respectively. Meat samples (about 100 g) were taken from the loin portion of longissimus dorsi (between ribs 12th and 13th) muscles on the left side of the carcass. All meat samples were collected within 3 hours after slaughter and stored at + 4 ̊ C for 24 hours. Samples were divided into two sub-samples; either without subcutaneous fat (lean meat) or with 30 % subcutaneous fat (fat meat). Both group of samples were grounded, in a food processor (35 s), and stored in −80 ̊ C pending analysis.

 

Lipid extraction and methylation

 

Fatty acid methyl esters (FAME) were determined using the procedures described previously by Sukhija and Palmquist (1988) with some modification. About 0.1 g meat sample was weighed by digital scale (KERN, Germany) and then was dried by means of freeze dryer. Freeze-dried sample was placed into culture tube (16*125 ml, Scott glass tube). One ml heptan including internal standard (C13:0) was added and mixed. Then 0.2 ml of sodium methylate (25%) was added and the tube was put in a 50 C water bath for 10 minutes. After that, sample was cooled for about 5 minutes. Then 3 ml of freshly made methanolic HCl 10 % (prepared by adding 20 ml of acetyl chloride to 100 ml of anhydrous methanol) was added and vortexed. The tube was put in a 90 C steam bath for 30 minutes and then the tube sample was cooled. Finally, one ml of heptane and three ml of potassium carbonate 10% was added and mixed for one minute. The sample was centrifuged (Centrifuge 5415 R; Rotofix 32A, Germany) in 5 minutes at 5000 r.p.m. Heptane phase (upper phase) was transferred to the GC vial (1.5 ml) using pastor pipette.

 

Determination of fatty acid composition

 

FAME were analyzed by gas chromatography with flame ionization detection (GC-FID; HP 6890 chromatograph, Hewlett-Packard, Avondale, PA, USA) using a Chrompack CP-Sil 88 TM fused silica capillary column (100 m 0.25 mm i.d., 0.2 mm film thickness; Varian Inc., Walnut Creek, CA, USA). Briefly, the oven temperature was initially 150 C (held for 5 minute), then increased at 5 C min−1 to 180 C (held for 30 minute), then increased at 1 ◦C min−1 to 190 C (held for 5 minute) and finally increased at 1 C min−1 to 200 C (held for 35 minute). Hydrogen was used as the carrier gas at a flow rate of 1.0 ml.min-1. The injector and detector temperatures were maintained at 280 and 300 C respectively. Identification of common fatty acids was accomplished by comparison of sample peak retention times with those of FAME standard mixtures (SupelcoTM 37 component FAME Mix, Supelco-47885-U, Sigma-Aldrich Chemie GmbH, Germany). Quantification of total FAME was done using Tridecanoic acid (13:0) as internal standard (Fluka-91988, Sigma-Aldrich Chemie GmbH, Germany). Results for each fatty acid were expressed as mg per 100 g total fatty acids.

 

Statistical Analysis

 

Data were analyzed using the MIXED procedure of SAS Version 9.2 (SAS Institute, Cary, NC, USA). The model considered the fixed effect of meat sample type (lean meat vs. fat meat), slaughter season (spring vs. fall) and production system (semi-industrial vs. rural) and the interaction effects. Each animal from the sample type was considered as the subject (random effect) and the sample type as repeated measures. Because the interactions effects were not significant, the interactions were excluded (Littell et al 1998).


Results

Fatty acid profiles of Lean- meat vs. fat meat

 

The means of fatty acid composition (%) in beef meat with subcutaneous fat (fat meat) and without fat (lean meat) are shown in Table 1. Sum of SFA in lean meat (44.6 %) and fat meat (47.4 %) were not significantly different (P > 0.05). Lean meat had significantly lower percentage of MUFA (37.7 % vs. 46.9 %) but higher percentage of PUFA (18.9 vs. 4.0 %) than fat meat. The P:S ratio in lean meat was significantly higher than that in fat meat (0.4 vs. 0.1, P < 0.05). The ratio of ω-6:ω-3 in lean meat was significantly lower than that in fat meat (6.2 vs. 7.9, P < 0.05) (Table 1). Total fatty acid (g per 100 g meat) in lean meat and fat meat were 5.3 and 16.6 g (Table 2). As the table 2 shows , lean meat had significantly lower palmitic acid, stearic acid, sum of SFA, oleic acid, sum of MUFA but higher PUFA and  total ω-3 fatty acids than fat meat.

 

Effects of slaughter season on fatty acids profile of beef meat

 

Slaughter season had no significant effect on sum of SFA and sum of PUFA (P > 0.05). Oleic acid and sum of MUFA in spring season were 33.4% and 38.0 % and were significantly lower than those in fall season 37.8 % and 42.6 % respectively. Spring meat had higher linoleic acid and linolenic acid than fall meat (P < 0.05). Neither P:S ratio nor  ω-6:ω-3 ratio had affected by slaughter season in beef meat (P > 0.05). Total fatty acid (g per 100 g meat) was not different between meat from spring and autumn slaughter time with 11.1 and 10.5 g respectively (Table 2). The quantity of fatty acids (mg per 100 g meat) were almost the same in two slaughter time however spring had higher linoleic acid and lower docosahexaenoic acid than fall (table 2).

 

Effects of production system on fatty acids profile of beef meat

 

Production system had no significant effect of sum of SFA, sum of MUFA and sum of PUFA in beef meat as percentage (Table 1). Rural meat had significantly higher percentage of palmitic acid (26.8 vs.24.3 %, P < 0.05) but lower percentage of linoleic acid (5.7 vs.8.2 %, P < 0.05) than semi-industrial meat. Sum of ω-6 fatty acids in semi-industrial meat was significantly higher than that in rural meat (P < 0.05). Sum of trans fatty acids in semi-industrial meat was significantly higher than that in rural meat (2.5 vs. 1.75 %, P < 0.05). Ratio of ω-6:ω-3 in rural meat was significantly lower than that in semi-industrial meat (5.2 vs. 8.9, P < 0.05). As the Table 2 shows, Total fatty acids (g per 100 g meat) in semi-industrial and rural production system were 10.5 and 11.3 g respectively with no significant differences (P > 0.05). However, quantity of oleic acid in rural meat was significantly higher than that in semi-industrial meat (4.3 vs. 3.9 g per 100 g meat, P <0.05).

 

Table 1 Effects of slaughter season and production system on fatty acids profile (%) of longissimus dorsi muscle in indigenous Lori cattle

 

Meat type

Slaughter season

Production system

 

SEM

P-values

 

Lean  meat

Fat meat

Spring

Fall

Semi industrial

Rural

Meat type

Slaughter season

Production

 system

Number of animals

10

10

10

10

10

10

 

 

 

 

Louric acid (C12:0)

0.6

0.2

0.3

0.5

0.4

0.3

0.05

<0.001

<0.01

0.10

Myristic acid (C14:0)

2.4

3.4

2.9

3.0

2.7

3.1

0.2

>0.001

0.70

0.13

Palmitic acid (C16:0)

24.2

26.9

24.7

26.4

24.3

26.8

0.8

0.03

0.14

0.04

Margaric acid (C17:0)

1.0

1.1

1.2

1.0

1.0

1.1

0.9

0.66

0.10

0.60

Stearic acid (C18:0)

15.3

15.4

16.0

14.6

15.3

15.4

0.9

0.92

0.24

0.93

Sum of Saturated FA

44.6

47.4

46.0

45.9

44.6

47.4

1.1

0.07

0.95

0.07

Palmitoleic acid (C16:1)

2.4

4.9

3.2

4.1

3.8

3.5

0.4

<0.001

0.07

0.53

Heptadecanoic acid (C17:1)

0.8

0.8

1.0

0.6

0.8

0.7

0.1

0.60

0.02

0.50

Oleic acid (C18:1 ω-9)

30.1

41.1

33.4

37.8

35.1

36.0

0.9

<.001

<0.001

0.44

C24:1

0.4

0.0

0.3

0.1

0.2

0.1

0.05

>0.001

0.06

0.24

Sum of Mono-unsaturated FA

33.7

46.9

38.0

42.6

40.1

40.5

1.0

<0.001

<0.01

0.78

Linoleic acid (C18:2 ω-6)

10.9

3.0

8.1

5.9

8.2

5.7

0.7

<0.001

0.03

0.01

α-Linolenic acid (C18:3 ω-3)

1.0

0.3

0.8

0.4

0.6

0.7

0.1

>0.001

<0.01

0.42

Arashidonic acid (C20:4 ω-6)

4.1

0.4

2.2

2.6

2.6

2.0

0.3

<0.001

0.62

0.12

Ecosopentanoic acid (C20:5 ω-3)

0.8

0.1

0.3

0.5

0.4

0.5

0.1

<0.001

0.12

0.41

Docosapentanoic acid (C22:5 ω-3)

1.1

0.1

0.6

0.5

0.4

0.7

0.1

<0.001

0.52

0.14

Docosahexaenoic (C22:6 ω-3)

0.2

0.0

0.0

0.2

0.1

0.13

0.03

0.003

0.01

0.14

Sum of poly-unsaturated FA

18.9

4.0

13.0

9.9

12.7

10.1

1.2

<0.001

0.08

0.13

Sum of trans FA

2.7

1.6

2.9

1.3

2.5

1.75

0.3

0.003

<0.001

0.05

Sum of ω-6 FA

15.7

3.6

11.0

8.3

11.3

8.0

1.1

<0.001

0.08

0.03

Sum of ω-3 FA

3.0

0.5

1.8

1.6

1.4

2.0

0.3

<0.001

0.55

0.09

PUSA:SFA (P:S) ratio

0.4

0.1

0.3

0.2

0.3

0.2

0.03

<0.001

0.15

0.10

ω-6:ω-3 ratio

6.2

7.9

7.4

6.7

8.9

5.2

0.4

0.01

0.27

<0.001

 

Table 2 Effects of slaughter season and production system on fatty acids profile (mg per 100 g meat ) of longissimus dorsi muscle in indigenous Lori cattle

 

Meat type

Slaughter season

Production System

 

SEM

 

P-values

 

Lean meat

Fat meat

Spring

Fall

Semi industrial

Rural

Meat type

Slaughter season

Production

 system

Number of animals

10

10

10

10

10

 

 

 

 

 

Louric acid (C12:0)

30

30

20

39

35

25

6

0.97

0.04

0.25

Myristic acid (C14:0)

128

570

346

351

324

374

23

<0.001

0.88

0.14

Palmitic acid (C16:0)

1268

4459

2777

2951

2644

3083

133

<0.001

0.40

0.02

Margaric acid (C17:0)

54

183

133

103

111

125

13

<0.001

0.11

0.47

Stearic acid (C18:0)

798

2567

1818

1547

1626

1739

158

<0.001

0.24

0.62

Sum of saturated FA

2338

7874

5180

5032

4798

5414

220

<0.001

0.64

0.06

Palmitoleic acid (C16:1)

121

806

410

517

472

455

50

<0.001

0.14

0.80

Heptadecanoic acid (C17:1)

39

140

115

64

94

85

13

<0.001

0.01

0.62

Oleic acid (C18:1 ω-9)

1586

6746

4067

4265

3983

4349

115

<0.001

0.24

0.03

C24:1

20

2

16

6

13

9

3

<0.01

0.04

0.40

Sum of Mono-unsaturated FA

1773

7715

4631

4856

4575

4912

152

<0.001

0.31

0.13

Linoleic acid (C18:2 ω-6)

580

516

643

454

612

485

59

0.50

0.04

0.15

α-Linolenic acid (C18:3 ω-3)

51

50

69

33

41

60

7

0.94

<0.01

0.09

Arashidonic acid (C20:4 ω-6)

221

69

132

158

171

119

26

<0.001

0.48

0.15

Ecosopentanoic acid (C20:5 ω-3)

41

10

19

32

21

30

6

<0.01

0.17

0.35

Docosapentanoic acid (C22:5 ω-3)

57

15

39

33

28

45

8

<0.01

0.64

0.16

Docosahexaenoic (C22:6 ω-3)

9

3

1

10

4

8

2

0.02

<0.01

0.19

Sum of poly-unsaturated FA

1007

692

969

730

910

789

101

0.03

<0.10

0.39

Sum of trans FA

138

237

291

120

250

161

37

0.02

<0.01

0.11

Sum of ω-6 FA

839

612

830

621

810

641

85

0.08

0.10

0.18

Sum of ω-3 FA

158

79

128

108

95

142

16

<0.01

0.40

0.05

Total fatty acids (g 100 g meat)

5.3

16.6

11.1

10.8

10.5

11.3

0.4

<0.001

0.56

0.15


Discussion

In the present study, total fatty acids in fat meat (meat + 30% subcutaneous fat) was three times higher than that in lean meat. On the other hand, mixing subcutaneous fat with longissimus dorsi muscle increased MUFA and decreased PUFA content of minced beef meat. Thus, it was clearly shown that lean meat without subcutaneous fat was healthier than fat meat due to its higher P:S ratio (0.4 vs. 0.1). Lean meat contains approximately four times more PUFA in comparison to the fat meat. Arashidonic acid (C20:4), EPA (C20:5), DPA (C22:5) were about 10 times more in lean meat compared to fat meat. It could be partly explained by low storage of long chain fatty acids in adipose tissue in ruminant (Wood et al 2008). Another reason is that, fat meat in comparison to lean meat has less phospholipids and more triglycerides. In general, phospholipids have 10 times more linoleic acids (C18:2) and 8 times more linoleic acid (C18:3) than triglycerides. In contrary, triglycerides have higher amounts of plamitic acid (C16:0), setearic acid (C18:0) and oleic acid (C18:1) than phospholipids (Scollan et al 2006; Wood et al 2008). In ruminants, generally P:S ratio is very low (approximately 0.15) because unsaturated fatty acid mostly are converted to saturated fatty acid in the rumen. Dietary lipid goes through bacteria lipolysis and biohydrogenation process in the rumen (Jenkins et al 2008). Most of the lipids are broken down to glycerol and fatty acid by microbial enzymes and a large extent of unsaturated fatty acid are saturated. Finding of this study showed that lean meat of Lori breed had acceptable P:S ratio (0.4), however fat meat should be consumed with cautions.

 

In the present study, ω-6: ω-3 ratio of Lori beef lean meat was healthier than fat meat. Both quantity and ratio between ω-6 and ω-3 fatty acids in human nutrition are imperative and essential for human health (Williams  2007). The recommended ratio of ω-6: ω-3 is 2:1 to 4:1 (Simopoulos 2002). In recent decades, human consumption of w-6 fatty acids had increased by 250 % whereas consumption of ω-3 fatty acids had decreased by 30 % leading to unbalanced ratio between ω-6 and ω-3 fatty acid (Kouba and Mourot 2011; McAfee et al 2010). Unbalanced ratio of ω-6:ω-3 is related to cardiovascular disease, cancer, insulin resistance, depression, early aging, diabetes and obesity (Adkins and Kelley 2010; Bourre 2004; Simopoulos 2002; Simopoulos 2006). According to the world health organization recommendation, the best ratio of ω-6: ω-3 should be less than  4:1. In the present study, the ratio of ω-6: ω-3 was 6.2 and 7.9 for lean meat and fat meat. These values were substantially less than the reported values; however present values yet were far from acceptable ratio.

 

This study revealed that beef meat produced in rural production system had lower and thus healthier ratio of ω-6: ω-3 than semi-industrial meat. The composition of animal diet is the main and key determinate of fatty acid profile in red meat (Daley et al 2010). In semi-industrial production system ratio of concentrate to forage in animal ration was high aiming to get higher daily gain. Relative high percentage of concentrate leaded to an increase in SFA and in ω-6 fatty acid (Daley et al 2010; Leheska et al 2008). Contrarily, in rural production system, animals had freely access to the green forages thus consume less concentrate. Basically, green plants have about 20 to 50 mg per kg dry matter fatty acids. Linolenic acid (7 to 37 g), linolleic acid (2 to 10 g) and palmitic acid (3 to 8 g) contribute to the 90 % of fatty acids in forages and only have a small amount of other SFA and MUFA (Clapham et al 2005). Dietary (forage) fatty acids mostly are hydrogenated in the rumen consequently the amount of linolenic acid is decreased and SFA and MUFA are increased (Fincham et al 2009). Because the legumes compared to the grasses have more fatty acids, thus more fatty acids escaped from ruminal biohydration in legume based compared to the grass based diet. Most likely, secondary metabolites (such as saponins, terpens and flavenoides) in legumes also may affect fatty acid metabolism in ruminant. For instance, polyphenol oxidase activity in red clover reduced ruminal lypolysis and biohydrogenation leaded to higher storage of linolenic acids in ruminant tissues (Fincham et al 2009; Van Ranst et al 2011). When green forage were included in ruminant diet, the amount of ecosopentanoic acid (c20:5) and linoleic acid (c18:3) in red meat were increased (Fincham et al 2009; Nuernberg et al 2005). The meat of cattle grazed on pasture had higher amount of linolenic acid (C18:3) and lower linolenic acid (C18:2) compared to meat from concentrate based fed cattle (Daley et al 2010). The muscle of beef cattle on pasture had higher amount of ω-3 fatty acids, consequently better ratio of ω-6: ω-3 compared to concentrate fed beef cattle (French et al 2000).

 

In conclusion, lean meat of Lori cattle had healthy P:S ratio (0.4). Ratio of ω-6:ω-3 in lean meat (6.2) was lower than that in fat meat (7.9), however these values were yet higher that recommended ratio (i.e., <4). The ratio of ω-6:ω-3 was not affected by slaughter season. Rural meat (5.2) had lower ratio of ω-6:ω-3 than semi- industrial meat (8.9) presumably due to higher forage intake in rural production system.


Acknowledgment

The authors wish to thank the Lorestan University of Medical Sciences for its financial support.


References

Adkins Y and Kelley D S 2010 Mechanisms underlying the cardioprotective effects of omega-3 polyunsaturated fatty acids. The Journal of Nutrition Biochemistry, 21 (9): 781-792. Available at: http://www.sciencedirect.com/science/article/pii/S0955286310000136

Biesalski H K 2005 Meat as a component of a healthy diet -are there any risks or benefits if meat is avoided in the diet? Meat Science, 70 (3): 509-524. Available at:  http://www.sciencedirect.com/science/article/pii/S0309174005000422

Bourre J M 2004 Roles of unsaturated fatty acids (especially omega-3 fatty acids) in the brain at various ages and during ageing. The Journal of Nutrition Health and Aging, 8 (3): 163-174. Available at: http://www.bourre.fr/pdf/publications_scientifiques/251.pdf

Clapham W M, Foster J G, Neel J P S and Fedders J M 2005 Fatty acid composition of traditional and novel forages. Journal of  Agricultral and Food Chemistry., 53 10068-10073. Available at: http://pubs.acs.org/doi/abs/10.1021/jf0517039

Daley C A, Abbott A, Doyle P S, Nader G A and Larson S 2010  A review of fatty acid profiles and antioxidant content in grass-fed and grain-fed beef. Nutriton Journal, 9: 10. Available at: http://www.nutritionj.com/content/9/1/10

Di Pasquale M G 2009 The Essentials of Essential Fatty Acids. Journal of Dietary Supplements. 6 (2): 143-161. Available at: http://informahealthcare.com/doi/abs/10.1080/19390210902861841?journalCode=jds

Fincham J R, Fontenot J P, Swecker W S, Herbein J H, Neel J P S, Scaglia G, Clapham W M and Notter D R 2009 Fatty acid metabolism and deposition in subcutaneous adipose tissue of pasture- and feedlot-finished cattle. Journal of Animal  Science, 87 (10): 3259-3277. Available at: http://www.journalofanimalscience.org/content/87/10/3259.full.

French P, Stanton C, Lawless F, O'Riordan E G, Monahan F J, Caffrey P J and Moloney A P 2000 Fatty acid composition, including conjugated linoleic acid, of intramuscular fat from steers offered grazed grass, grass silage, or concentrate-based diets. Journal of Animal Science., 78 (11): 2849-2855. Available at: http://www.journalofanimalscience.org/content/78/11/2849.abstract

Givens D I, Kliem K E and Gibbs R A 2006 The role of meat as a source of n-3 polyunsaturated fatty acids in the human diet. Meat Science, 74 (1): 209-218. Available at: http://linkinghub.elsevier.com/retrieve/pii/S0309-1740%2806%2900110-0

Jenkins T C, Wallace R J, Moate P J and Mosley E E 2008 Recent advances in biohydrogenation of unsaturated fatty acids within the rumen microbial ecosystem. Journal of  Animal Science, 86 (2): 397-412. Available at: http://www.journalofanimalscience.org/content/86/2/397.long

Kouba M and Mourot J 2011 A review of nutritional effects on fat composition of animal products with special emphasis on n-3 polyunsaturated fatty acids. Biochimie, 93 (1): 13-17. Available at:  http://www.sciencedirect.com/science/article/pii/S030090841000088X

Leheska J M, Thompson L D, Howe J C, Hentges E, Boyce J, Brooks J C, Shriver B, Hoover L and Miller M F 2008 Effects of conventional and grass-feeding systems on the nutrient composition of beef. Journal of Animal Science, 86 (12): 3575-3585. Available at: http://journalofanimalscience.org/content/86/12/3575.full

Littell R C, Henry P R and Ammerman C B 1998 Statistical analysis of repeated measures data using SAS procedures. Journal of Animal Science, 76 (4): 1216-1231. Available at: http://www.journalofanimalscience.org/content/76/4/1216.full.pdf

McAfee A J, McSorley E M, Cuskelly G J, Moss B W, Wallace J M W, Bonham M P and Fearon A M 2010 Red meat consumption: An overview of the risks and benefits. Meat Science, 84 (1): 1-13. Available at: http://www.sciencedirect.com/science/article/pii/S0309174009002514

Nuernberg K, Dannenberger D, Nuernberg G, Ender K, Voigt J, Scollan N D, Wood J D, Nute G R and Richardson R I 2005 Effect of a grass-based and a concentrate feeding system on meat quality characteristics and fatty acid composition of longissimus muscle in different cattle breeds. Livestock Prodution Science, 94 (1-2): 137-147. Available at: http://www.sciencedirect.com/science/article/pii/S0301622604002738

Scollan N, Hocquette J F, Nuernberg K, Dannenberger D, Richardson I and Moloney A 2006 Innovations in beef production systems that enhance the nutritional and health value of beef lipids and their relationship with meat quality. Meat Science, 74 (1): 17-33. Available at: http://www.sciencedirect.com/science/article/pii/S0309174006001409

Simopoulos A P 2002 The importance of the ratio of omega-6/omega-3 essential fatty acids. Biomedicine and Pharmacotheraphy., 56 (8): 365-379. Available at: http://www.sciencedirect.com/science/article/pii/S0753332202002536

Simopoulos A P 2006 Evolutionary aspects of diet, the omega-6/omega-3 ratio and genetic variation: nutritional implications for chronic diseases. Biomedicine and Pharmacotheraphy, 60 (9): 502-507. Available at: http://www.sciencedirect.com/science/article/pii/S0753332206002435

Simopoulos A P 2008 The importance of the omega-6/omega-3 fatty acid ratio in cardiovascular disease and other chronic diseases. Exprimental Biology and Medicine, 233 (6): 674-688. Available at: http://ebm.sagepub.com/content/233/6/674.long

Sukhija P S and Palmquist D L 1988 Rapid method for determination of total fatty acid content and composition of feedstuffs and feces. Journal  of Agricultural and  Food Chemistry, 36 (6): 1202-1206. Available at: http://pubs.acs.org/doi/abs/10.1021/jf00084a019

Van Ranst G, Lee M R F and Fievez V 2011 Red clover polyphenol oxidase and lipid metabolism. Aniaml, 5 (4): 512-521. Available at: http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=8130177&fileId=S1751731110002028

Williams P 2007 Nutritional composition of red meat. Nutrition and Dietetics, 64 (Suppl (4)): S111-S119.

Wood J D, Enser M, Fisher AV, Nute G R, Sheard P R, Richardson R I, Hughes S I and Whittington F M 2008 Fat deposition, fatty acid composition and meat quality: A review. Meat Science, 78 (4): 343-358. Available at: http://www.sciencedirect.com/science/article/pii/S0309174007002525


Received 25 June 2014; Accepted 19 October 2014; Published 3 November 2014

Go to top