https://doi.org/10.52973/rcfcv-e34362

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Revista Científica, FCV-LUZ / Vol. XXXIV, rcfcv-e34362

Received: 05/12/2023 Accepted: 03/02/2024 Published: 19/05/2024

ABSTRACT

The determination of fatty acids composition of glycerolipids and

glycerophospholipids of meat from longissimus thoracis of six

breeds of lamb produced on pasture in Uruguay was undertaken

by gas chromatography. Also some lipids health indices and lipids

metabolism enzymes were determined. The studied lambs were

males aged of 11–12 months of breeds and biotypes Highlander® (H),

Merino Dohne (MD), Corriedale (C), Corriedale Pro® (CPRO), a crossing

between Corriedale × Australian Merino (C×AM) and Romney Marsh

(RM). The animals were reared on pasture in identical conditions

without supplementation. The grazing was rotational based on a

winter annual crops oats (Avena sativa spp.), cocksfoot, (Dactylis

glomerata spp.) and white clover (Trifolium repens spp.). The results

of the study did not show substantial differences between breeds

regarding the fatty acids composition of meat, except for few

relevant fatty acids such as C16:0 (MD>C), C18:3n3 (H<C) and CLA

(H<CPRO, CxAM) for glycerolipids. Also C18:1 (H>CPRO, CxAM), C18:2n6

(H<CxAM) and C18:3n3 (H<C) for glycerophospholipids. Likewise, other

differences were outlined such as the anteiso monomethyl fatty acid

content (MD<RM), the hypocholesterolemic/hypercholesterolemic

ratio (MD<C). For lipids metabolism enzymes indices, MD showed

a lower Δ–9 desaturase enzyme for C16:0 than C, CPRO and CxAM.

Also, H showed a lower Δ–6 desaturase enzyme activity than C, and

both MD and CxAM showed a lower elongase enzyme activity than C.

The results of the present investigation showed that the meat of the

lamb of the different breeds overall present good lipids nutritional

indicators, in comparison with the results of other research in lambs.

That information could help lamb producers in Uruguay to promote

their products based on scientic data.

Key words: Lamb meat; fatty acids; extensive system; pasture

RESUMEN

Se determinó la composición en ácidos grasos de los glicerolípidos

y glicerofosfolípidos del músculo longissimus thoracis de seis razas

de corderos producidos con pasturas en Uruguay, mediante el uso de

cromatografía de gases. También se cuanticaron los ácidos grasos de

cadena ramicada monometiles iso y anteiso, y el contenido de ácidos

grasos impares de la carne. Se determinaron índices lipídicos de salud

y actividades de las enzimas del metabolismo de los ácidos grasos. Los

corderos estudiados fueron machos de 11–12 meses de razas y biotipos

Highlander® (H), Merino Dohne (MD), Corriedale (C), Corriedale Pro®

(CPRO), un cruce entre Corriedale × Australian Merino (C×AM) y Romney

Marsh (RM). Los animales fueron criados sobre pasturas en condiciones

idénticas sin suplementos. El pastoreo fue rotativo basado en una

avena de cultivos anuales de invierno (Avena sativaspp.), cocksfoot

(Dactylis glomerata spp.) y trébol blanco (Trifolium repensspp.). Los

resultados no mostraron diferencias sustanciales entre razas en

la composición en ácidos grasos de la carne, excepto por ácidos

grasos relevantes como C16:0 (MD>C), C18:3n3 (H<C) y CLA (H<CPRO,

C×AM) para glicerolípidos. También C18:1 (H>CPRO y C×AM), C18:2n6

(H<C×AM) y C18:3n3 (H< C) para glicerofosfolípidos. Asimismo, hay otras

diferencias como el contenido de ácidos grasos anteiso (RM>MD) y la

relación del índice hipocolesterolémico/hipercolesterolémico (MD<C).

Para las actividades enzimáticas del metabolismo de los ácidos grasos,

el MD mostró una menor enzima desaturasa Δ–9 para C16:0 que C,

CPRO y CxAM. Además, H mostró una menor actividad de la enzima

Δ–6 desaturasa que C, y tanto MD como CxAM mostraron una menor

actividad de la enzima elongasa que C. Los resultados mostraron

que la carne de cordero de las diferentes razas presenta en general

buenos indicadores nutricionales de lípidos, en comparación con los

resultados de otras investigaciones en corderos. Esa información

podría ayudar a los productores de corderos del Uruguay a promover

sus productos sobre la base de datos cientícos.

Palabras clave: Carne de cordero; ácidos grasos; sistema extensivo;

pastura

Fatty acids composition, lipids health indices and enzyme activities of

longissimus thoracis muscle of six breeds of sheep produced on pasture in

Northern region of Uruguay

Ácidos grasos, índices lipídicos de salud y actividades enzimáticas en el musculo longissimus

thoracis, de seis razas de corderos producidos sobre pasturas en el norte de Uruguay

Maria Helena Guerra

, Maria Cristina Cabrera

2,3

* , Juan Franco

, Oscar Bentancur

, Ali Saadoun

2,3

Universidad de la República, Facultad de Agronomía, Departamento de Producción Animal & Pasturas. EEFAS, Salto, Uruguay.

Universidad de la República, Facultad de Agronomía, Departamento de Producción Animal & Pasturas, Laboratorio Calidad de Alimentos & Productos. Montevideo, Uruguay.

Universidad de la República, Facultad de Ciencias, Fisiología & Nutrición. Montevideo, Uruguay.

Universidad de la República, Facultad de Agronomía, Departamento de Producción Animal & Pasturas. EEMAC, Paysandú, Uruguay.

Universidad de la República, Facultad de Agronomía, Departamento de Biometría, Estadística y Computación. EEMAC, Paysandú, Uruguay.

*Corresponding authors: mcab@fagro.edu.uy; asaadoun@fcien.edu.uy

Fatty acids composition of Longissimus thoracis muscle in sheep / Guerra et al. ______________________________________________________

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INTRODUCTION

Sheep (Ovis aries) meat is since thousands of years, a valuable food

for human nutrition [1] Sheep meat is available in many Countries,

often produced and consumed locally. Approximatively 82% of sheep

breed in the World are local breed well adapted to their particular

biotope, most of them fed local pasture [2]. However, there are also

commercial breeds that are the basis of the international sheep

meat trade, often associated to wool trade. Sheep meat provides to

consumers protein, lipids, minerals (particularly iron and zinc), and

vitamins, all of them necessary to an adequate growth and metabolism

function at all ages. Lipids, through their fatty acids composition, are

particularly relevant since they are associated with some chronic

diseases. Indeed, ruminant meat from sheep or lamb contains

glycerolipids and glycerophospholipids composed by saturated fatty

acids (SAT), monounsaturated fatty acids (MUFA) and polyunsaturated

fatty acids (PUFA). Some of SAT are associated with the occurrence

of cardiovascular pathologies and cancer in human, meanwhile MUFA

seems to have benecial effects on health [3]. For other part, PUFA

such as linoleic acid and α–linolenic acid are essential for human

nutrition and metabolism, which means that they have to be present

in the diet. The latter is precursor for the biosynthesis of EPA (C20:5n3)

and DHA (C22:6n3), two n–3 fatty acids involved in the protection against

cardiovascular diseases and cancer in human.

In Uruguay, sheep production is based on pasture and constitutes a

relevant part for the meat market and the economical scheme of the

Country. Various sheep breeds and crossing are present and producers

have been always interested to improve their knowledge about the

breeds that they produce, mainly in genetically aspects linked to the

wool quality. The main breed present in Uruguay is the Corriedale (42%

of total sheep breeds), because of its dual purpose characteristics to

produce wool and meat. However, in the last few years, the incomes

of sheep producers in Uruguay become depending much more to the

meat, for both domestic and international trade, than wool one. This

is probably due to the relatively better stability of international sheep

meat market, compared to the wool market and the positive future

perspective of sheep meat trade in the region [4]. In consequence,

producers become now interested to known the nutritional quality of

the sheep meat that they produce, to help themselves promote their

products, mainly in the international sheep meat market. Therefore,

the present study has been undertaken to known the fatty acids

composition of meat obtained from six breeds and crossing produced in

Uruguay, including Corriedale, and fed exclusively with pasture. Some of

those breeds have been recently introduced in the country and scarce

or no information, in our knowledge; about the nutritional values of

their meat could be sourced in the scientic literature. Furthermore,

the study will generate information about some lipid health indices for

consumers, and fatty acid metabolism indices related to the enzymes

desaturases, elongases and thioesterases.

MATERIAL AND METHODS

Animals and feeding

The meat studied in the work come from males of six breed

produced in Uruguay on extensive system condition based on pasture.

Highlander

(H, n=15; slaughtered at 54.38 ± 4.45 kg of body weight,

339 ± 6.7 days of age). H is a composite breed (½ Romney, ¼

Texeland ¼ Finnish Landrace) introduced in Uruguay on year 2005.

Merino Dohne (MD, n=11; slaughtered at 55.05 ± 3.72 kg of body

weight, 341 ± 5.8 days of age), a dual purpose breed originated in

South Africa and introduced in Uruguay from Australia on year 2002.

Corriedale (C, n=11; slaughtered at 50.3 ± 5.35 kg of body weight,

339 ± 4.83 days of age), a dual purpose breed obtained by crossing

Merino and Lincoln breeds in Australia and New Zealand around

the years 1874–1880. C was introduced in Uruguay on 1916.

Corriedale Pro

(CPRO, n= 15; slaughtered at 46.54 ± 5.53 kg

of body weight,341 ± 7.57 days of age), CPRO is a composite

crossbreed developed in Uruguay, based on a crossing of

Freisian Milchschaf (25%) with Finnish Landrace (25%) and

C (50%). CPRO has been developed principally to improve the

prolicacy without the loss of double purpose attribute of C.

A crossbreed between Corriedale and Australian Merino breed

(C×AM, n=15; slaughtered at 48.18 ± 7.04 kg of body weight,

334 ± 10.1 days of age). C×AM has been developed in Uruguay

to improve the resistance to the gastrointestinal parasitism.

6. The last breed used in the study was Romney Marsh (RM, n=4;

slaughtered at 48.92 ± 6.82 kg of body weight, 335 ± 2.5 days of

age). RM is a dual purpose breed, developed in England, and

introduced in Uruguay on year 1896. Although only 4 animals RM

were obtained from producers, the results of the experiment

with those animals have been anyway included in the study,

taking into account the long presence of that breed in the

productive scheme of the country and the lack of nutritional

information of RM meat produced in Uruguay.

Animals were maintained in the facilities of the Experimental

Station of the Faculty of Agronomy (Udelar) in Paysandú – Uruguay,

following the regulations of the University's ethics committee. The

investigation has been approved by the Honorary Commission

for Animal Experimentation (CHEA, Universidad de la República,

Udelar, Uruguay), recorded as protocol number 1401. Furthermore,

the investigation has been also approved by the Ethical Commission

for the Use of Animals (CEUA, CENUR, Udelar).

Animals have grazed pasture, without any supplementation, with

a maximum animal density of 6 sheeps by hectare, and rotated

in paddocks of 15 hectares. The animals were reared on pasture,

in groups separated by breed. Pasture (P1) consisted by a winter

annual crops oats (Avena sativa spp.) with the availability of forage of

2,743 kg DM·ha

-1

, that pasture has been used in a rotational grazing.

Furthermore, the lamb grazed another pasture (P2) principally

constituted by cocksfoot, (Dactylis glomerata spp.) and white clover

(Trifolium repens spp.) with an availability of forage of 2,756 kg DM·ha

-1

All groups have been concomitantly transferred between P1 and P2

and inversely, depending of the availability of forage. For the sampling

and the estimation of available forage and botanical composition in the

grazing area, the cutting method "Sample Sward–cutting techniques"

and Botanal was used [5]. The lipids and fatty acid composition of

pasture was presented in TABLE I.

The lambs were slaughtered in a commercial slaughterhouse

(Certied Food Standard, Grade A, Certication Body LSQA S.A. for

exportation by BRC Global Standard). At 72 hours post mortem the

longissimus thoracis muscle (between 9th and 12th vertebrate) was

withdraw, vacuum packaged and stored at -20°C, until analysed.

TABLE I

Lipid content (% of dry matter) and fatty acids composition of glycerolipids and

glycerophospholipids (g·100 g

-1

fatty acids) of pastures grazed by lambs

Pasture P1 Pasture P2

Oat

(Avena sativa)

Legumes

(Trifolium repens)

Gramineae

(Dactylis glomerata)

Undened Pasture

Lipids 3.38 ± 0.03 2.10 ± 0.02 3.65 ± 0.03 3.25 ± 0.03

Glycerolipids fatty acids

C14:0 1.47 ± 0.71 1.26 ± 0.79 0.61 ± 0.06 0.65 ± 0.13

C16:0 16.9 ± 0.69 13.8 ± 0.57 15.00 ± 0.42 18.70 ± 0.63

C16:1 1.49 ± 0.06 1.51 ± 0.06 2.64 ± 0.24 2.49 ± 0.05

C18:0 1.92 ± 0.02 2.07 ± 0.08 1.18 ± 0.11 2.08 ± 0.03

C18:1 2.92 ± 0.10 3.35 ± 0.56 1.79 ± 0.04 2.83 ± 0.09

C18:2n6 8.88 ± 0.36 22.40 ± 0.68 10.3 ± 0.10 13.40 ± 0.16

C18:3n3 49.20 ± 1.41 45.60 ± 1.06 60.5 ± 0.65 50.00 ± 1.18

C20:0 0.58 ± 0.13 1.80 ± 0.10 0.30 ± 0.01 0.95 ± 0.37

C22:0 2.51 ± 0.19 2.47 ± 0.78 0.81 ± 0.03 1.17 ± 0.07

C24:0 3.74 ± 0.20 0.78 ± 0.12 1.29 ± 0.07 0.98 ± 0.07

Unidentied fatty acids 10.40 ± 1.38 4.91 ± 0.66 5.67 ± 1.22 6.68 ± 0.34

Glycerophospholipids fatty acids

C14:0 0.12 ± 0.02 0.17 ± 0.03 0.08 ± 0.01 0.12 ± 0.02

C16:0 16.40 ± 0.48 12.40 ± 1.40 13.20 ± 0.54 17.20 ± 0.55

C16:1 1.97 ± 0.25 1.94 ± 0.14 1.72 ± 0.22 3.18 ± 0.19

C18:0 1.10 ± 0.07 1.48 ± 0.12 0.88 ± 0.05 1.19 ± 0.01

C18:1 2.11 ± 0.04 2.42 ± 0.46 1.33 ± 0.06 2.36 ± 0.09

C18:2n6 7.06 ± 0.34 13.4 ± 1.05 7.28 ± 0.09 12.00 ± 0.04

C18:3n3 51.00 ± 0.80 54.50 ± 4.31 66.70 ± 1.15 54.40 ± 2.18

C20:0 0.48 ±0.05 1.67 ± 0.71 0.31 ± 0.08 1.06 ± 0.45

C22:0 3.52 ± 0.24 4.56 ± 0.76 1.13 ± 0.15 1.59 ± 0.12

C24:0 4.52 ± 0.56 1.52 ± 0.11 1.65 ± 0.32 1.27 ± 0.19

Unidentied fatty acids 11.60 ± 1.41 5.94 ± 0.89 5.61 ± 1.25 5.60 ± 1.89

Data are mean ± SEM of three samples of pasture. Animals have been concomitantly transferred between P1 and P2 and inversely,

depending of the availability of forage

_____________________________________________________________________________Revista Cientifica, FCV-LUZ / Vol. XXXIV, rcfcv-e34362

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Analytical determination

The plant lipids were determined on a dry ground sample, dried at

105°C for 6 hours in a forced air dryer. Lipids of three replicates of

10 g were extracted by Soxhlet method (AOAC Method 945.16), using

hexane (Carlo Erba, France, HPLC grade) as extraction solvent. The

intramuscular lipids were extracted according to Folch et al. [6].

Briey, a sample of 4 grams of meat of longissimus thoracis muscle

(free of dissectible visible fat) was homogenized at 25.000 rpm with

an IKA T25 homogenizer (IKA Brandt, Sweden) during 1 min with

80mL of chloroform: methanol 2:1, (Baker brand HPLC grade, USA).

Afterward, the homogenate was ltered on fritted funnel (Fisher

brand, graduation M, USA), transferred to a separating funnel, mixed

by shaking and inverting for one minute and decanted overnight.

The lower phase (chloroform containing lipids) was recuperated in

a glass balloon (Fisher Brand, USA), evaporated at 45°C with a light

vacuum in a Rotavapor (IKA basic, Sweden). The balloon was dried

in an oven at 35°C for 60 min and cooled at ambient temperature

overnight in a vacuum desiccator protected from light. The balloon

was weighted at 0.0001 g. to determine the percentage of lipids

of each sample. The methylation of fatty acids from glycerolipids

fraction followed the procedure described by Ichihara et al. [7]. That

procedure target the fatty acids from triacylglycerols as well as those

from phospholipids, both associated to a glycerol backbone. For the

selective methylation of fatty acids from glycerophospholipids (polar

glycerolipids), the procedure described by Ichihara et al. [8] has been

used. The determination of fatty acids by gas chromatography followed

a procedure using fused–silica capillary column CPSIL–88 of 100 m

installed in a split/split less chromatograph Clarus 500 (Perkin Elmer

Instruments, USA) with a FID detector. The samples injection was done

using an autosampler from the same manufacturer. Oneµl of each

methylated sample was injected with a split ratio of 50%. Hydrogen

(Brand Linden, Uruguay, purity of 99.9995%) was used as carrier

gas having a ratio air/H

of 350 mL/35 mL. Filtered air was proven

by compressor GAST model 3HBB–11T–M300AX (USA). The thermal

Fatty acids composition of Longissimus thoracis muscle in sheep / Guerra et al. ______________________________________________________

4 of 15

conditions were: Injector/detector temperatures 250°C/250°C,

oven held at 90°C for one minute after the injection of the sample.

The split valve was open 30 seconds after injection. Afterward the

oven temperature was increased to 225°C at 15°C·min

-1

. Fatty acids

methylated esters (FAMEs) were determined comparing the retention

time of authentic standards and the 37 component FAME standard

mixture (Sigma–Aldrich, USA). Individuals FAME were quantied as

a percentage of total detected FAMEs. The integration of signal has

been conducted on Total Chrome software from Perkin Elmer (USA).

Calculus of health indices

The calculus of health indices was performed from the data of fatty

acid composition of glycerolipids. The following indices were calculated:

•

Indice of atherogenicity (AI): Compute the relationship between

the sum of the main saturated fatty acids (pro–atherogenic)

and the unsaturated (anti–atherogenic) fatty acids [9]. It was

calculated as follows:

AI = (4 × C14:0 + C16:0) / [ ∑ MUFA + ∑ (n–6) + ∑(n–3) ]

•

Indices of thrombogenicity (TI): Estimate the potential to form

clots in the blood vessels [9], determined by the relationship

between the pro–thrombogenic and the anti–thrombogenic fatty

acids (Sum of MUFA and PUFA). It was calculated as follows:

IT= (C14:0 + C16:0 + C18:0) / [0.5 × ∑ MUFA + 0.5 × ∑ (n–6) + 3 × ∑

(n–3) + ∑ (n–3) / ∑ (n–6)]

•

Hypocholesterolemic/Hypercholesterolemic ratio (h/H): Compute

the relation between unsaturated fatty acids (MUFA and PUFA)

and the saturated fatty acids 14:0 and 16:0. The h/H ratio was

calculated according to Fernández et al. [10] as follows:

h/H = (C14:1 + C16:1 + C18:1 + C20:1 + C22:1 + C18:2 + C18:3 + C20:3

+ C20:4 + C20:5 + C22:4 + C22:5 + C22:6) / (C14:0 + C16:0)

Enzyme activity indices

The enzyme activity of desaturases, elongase and thioesterase

was estimated by relating the amount of the specic substrate to

the corresponding product of the respective enzyme. The calculus of

those indices was performed from the data of fatty acid composition

of glycerolipids. The calculated ratios were 16:1n–7 to 16:0 and 18:1n9

to 18:0, and their sum, for the activity of stearoyl–CoA desaturase

(Δ–9–desaturase). The Δ–5 desaturase and Δ–6 desaturase were used

as an index for the estimation of catalyzing the formation of long chain

n–6 and n–3 starting from the corresponding precursor C18:2n6 and

C18:3n3, respectively. Also, the ratio 18:0 to 16:0 was calculated to

estimate the elongase activity. The thioesterase was estimated as

the ratio of C16:0 to C14:0.These indices can be used as surrogates

of the measure of the true enzyme activities [11].

Statistical analysis

Data are presented as mean ± SEM. Results were analysed by ANOVA

one way to compare six genotypes, and post hoc Tukey–Kramer Test

(P<0.05), using the NCSS 12 Statistical Software (2018, NCSS, LLC.

Kaysville, Utah, USA, https://www.ncss.com).

In addition, a principal component analysis (PCA) on the

standardized variables at unit scale, associated to human health as

intramuscular fat content (lipids), and C14:0, C16:0, C17:0ai,C18:3n3,

CLA, BCFAai and BCFAi of the total fatty acids were conducted to

evaluate the relative differences of the meat samples in these lipid

prole among breeds.

Another principal component analysis (PCA) on the variables

associated to structure of membrane as C16:0, C16:1, C18:1, C18:2n6,

C18:3n3 C20:4n6, EPA, DPA, DHA in glycerophospholipids fraction to

evaluate if the breeds present differences. Variables were graphed

in a biplot with different colour related their contribution and the

distribution of observations were graphed in a biplot using ellipses

with 95% condence interval. Statistical analysis was conducted

using the PCA functionof the package FactoMineR for the principal

components analysisin the R software version 4.2.2 (R Core Team,

2022). To visualize de PCA results, thefactoextra package in the R

software was used.

RESULTS AND DISCUSSION

Lipids

The intramuscular fats content is perhaps one of the most relevant

parameters, principally thought their fatty acids composition, when

the nutritional quality has to be considered to characterize ruminant

meat. Thus, depending of their specic fatty acids composition,

lipids in meat could affect positively or negatively the health of

consumers. Indeed, they could respond positively to the nutritional

requirement for growth and metabolism at all ages of consumers,

but they could inuence negatively the human health thought the

occurrence of cardiovascular and cancer diseases [3, 12]. However,

for most consumers, the content of lipids expressed as g of total lipids

by 100 g of meat is perceived as a key indicator to classify the meat

products, as well as other foods, in regard to their incidence on health.

In the present work, the comparison between the different breeds

showed lipids contents ranged between 2.39–4.49 g of lipids by 100 g of

meat. Signicant differences have been observed only between C×AM

and H (TABLE II). Limited information was available in the scientic

literature, for comparison, about the fat content of C×AM and H.

However, Jalloul et al. [13] report low lipid content in H lamb ranged

between 1.07–1.18 g of lipids by 100 g of meat from longissimus thoracis.

Nevertheless, lambs were housed in small pens and fed corn, citrus

pulp, rice bran or soybean hulls. Thus, the difference of weight at

slaughtering (30 kg versus 54 kg in our experiment) or the kind of feed

offered to animals, or both, could explain the different fat content of

meat. Regarding the other breeds studied in the present investigation,

for C, lipids content reported in meat obtained in similar conditions in

Uruguay showed levels around 3.65 g of lipids by 100g of meat [14].

In the case of the present experiment, meat was from longissimus

thoracis while in the work of Lucas [14], meat was from longissimus

lumborum. In both experiments, animals were of similar age and

fed pasture in extensive production system. Another experiment

in extensive condition of Uruguay compared C lamb produced on

pasture, but at two different ages. Results showed that there are

difference in lipids content of meat of 3.05 versus 5.92 g by 100 g of

meat from longissimus thoracis, at 3–4 months and 12–13 months,

respectively [15]. The higher content of lipids, compared to the

reported in our experiment, could be explained by the nature of

pasture, probably more than by the difference of ages between the

two works, that is, 12–13 months versus 11–12 months in our work.

However, Diaz et al [15] do not reported, the composition of pastures

offered to the animals.

TABLE II

Lipids content (% of wet tissue) and fatty acids composition (g·100 g

-1

fatty acids) of glycerolipids present

in Longissimus thoracis muscle from lambs of dierent breeds produced on pasture

Breeds

(n=15)

(n=11)

CPR

(n=15)

C×AM

(n=15)

(n=4)

Lipids 2.39

± 0.18 3.21

± 0.44 3.46

± 0.30 4.17

± 0.40 4.25

± 0.33 4.49

± 1.01 0.009

Saturated Fatty acids (SAT)

C14:0 2.52 ± 0.23 3.46 ± 0.36 2.43 ± 0.20 3.04 ± 0.34 3.10 ± 0.28 2.45 ± 0.47 NS

C15:0i 0.12 ± 0.01 0.14 ± 0.01 0.12 ± 0.01 0.13 ± 0.01 0.12 ± 0.01 0.12 ± 0.02 NS

C15:0ai 0.16 ± 0.01 0.17 ± 0.02 0.14 ± 0.01 0.16 ± 0.01 0.15 ± 0.01 0.14 ± 0.03 NS

C15:0 0.51 ± 0.04 0.59 ± 0.04 0.50 ± 0.03 0.55 ± 0.03 0.51 ± 0.04 0.46 ± 0.08 NS

C16:0i 0.16 ± 0.01 0.17 ± 0.01 0.17 ± 0.01 0.16 ± 0.01 0.15 ± 0.01 0.18 ± 0.03 NS

C16:0 24.0

± 1.03 26.10

± 1.43 21.20

± 0.78 23.00

± 0.89 24.40

± 0.92 21.10

±0.62 0.02

C17:0i 0.48 ± 0.04 0.39 ± 0.05 0.49 ± 0.04 0.52 ± 0.03 0.48 ± 0.03 0.55 ± 0.05 NS

C17:0ai 0.47

± 0.03 0.35

± 0.06 0.51

± 0.04 0.50

± 0.03 0.52

± 0.02 0.58

± 0.02 0.01

C17:0 1.50

± 0.06 1.35

± 0.08 1.67

± 0.06 1.59

± 0.04 1.47

± 0.05 1.57

± 0.12 0.03

C18:0 20.4

± 0.72 18.9

± 0.33 21.10

± 0.50 18.90

± 0.62 18.3

± 0.62 20.8

± 0.97 0.01

C20:0 0.10 ± 0.01 0.10 ± 0.01 0.13 ± 0.01 0.13 ± 0.01 0.11 ± 0.01 0.12 ± 0.02 NS

C22:0 0.02 ± 0.01 0.05 ± 0.01 0.05 ± 0.01 0.05 ± 0.01 0.04 ± 0.01 0.05 ± 0.01 NS

Ʃ SAT 49.30 ± 1.08 50.90 ± 1.58 47.30 ± 0.92 47.40 ± 0.77 48.10 ± 1.03 47.10 ± 0.87 NS

Monounsaturated Fatty acids (MUFA)

C16:1 1.77

± 0.11 1.57

± 0.10 1.80

± 0.09 2.04

± 0.07 2.10

± 0.11 1.87

± 0.11 0.004

C17:1 0.83 ± 0.04 0.72 ± 0.04 0.81 ± 0.03 0.80 ± 0.03 0.78 ± 0.03 0.78 ± 0.07 NS

C18:1 40.20 ± 0.62 38.40 ± 0.56 40.00 ± 0.60 39.90 ± 0.49 39.60 ± 0.65 40.00 ± 0.82 NS

Ʃ MUFA 42.80 ± 0.68 40.80 ± 0.63 42.60 ± 0.61 42.80 ± 0.56 42.50 ± 0.70 42.70 ± 0.91 NS

Polyunsaturated fatty acids (PUFA)

C18:2n6 3.14 ± 0.24 3.52 ± 0.42 3.87 ± 0.23 3.62 ± 0.27 3.48 ± 0.18 3.81 ± 0.24 NS

C18:3n3 0.77

± 0.09 0.96

± 0.12 1.21

± 0.12 1.04

± 0.11 1.04

± 0.07 1.14

± 0.11 0.05

CLA 0.61

± 0.12 0.87

± 0.16 0.99

± 0.11 1.15

± 0.13 1.15

± 0.09 1.24

± 0.19 0.008

C20:3n6 0.09

± 0.02 0.14

± 0.03 0.21

± 0.03 0.14

± 0.02 0.17

± 0.02 0.18

± 0.05 0.01

C20:3n3 0.21 ± 0.06 0.37 ± 0.11 0.43 ± 0.07 0.34 ± 0.07 0.32 ± 0.05 0.33 ± 0.08 NS

C20:4n6 0.12 ± 0.04 0.19 ± 0.05 0.26 ± 0.04 0.19 ± 0.04 0.19 ± 0.03 0.22 ± 0.06 NS

EPA 0.02 ± 0.00 0.02 ± 0.00 0.02 ± 0.01 0.02 ± 0.00 0.01 ± 0.00 0.01 ± 0.00 NS

DPA 0.46 ± 0.07 0.33 ± 0.05 0.36 ± 0.04 0.41 ± 0.06 0.29 ± 0.03 0.26 ± 0.04 NS

DHA 0.08 ± 0.05 0.04 ± 0.01 0.06 ± 0.01 0.02 ± 0.01 0.04 ± 0.01 0.11 ± 0.08 NS

Ʃ PUFA 4.89 ± 0.43 5.56 ± 0.74 6.41 ± 0.52 5.76 ± 0.51 5.53 ± 0.35 6.06 ± 0.45 NS

Unidentied Fatty Acids

– 1.26 ± 0.17 0.98 ± 0.19 1.45 ± 0.11 1.63 ± 0.16 1.48 ± 0.19 1.78 ± 0.21 –

Data are mean ± SEM. H=Highlander, MD=Merino Dohne, C=Corriedale, CPRO=Corriedale PRO, C×AM=Corriedale × Australian Merino, RM=Romney

Marsh. For each fatty acid, mean values bearing dierent low case letters are signicantly dierent.

P = Signicance level. NS = non–signicant. i = iso,

ai = anteiso, EPA=C20:5n3, DPA=C22:5n3, DHA=C22:6n3

_____________________________________________________________________________Revista Cientifica, FCV-LUZ / Vol. XXXIV, rcfcv-e34362

5 of 15

Fatty acids of glycerolipids

Regarding the fatty acids composition of glycerolipids, in the case of

SAT there is differences between the breeds for C16:0, C17:0 anteiso,

C17:0 and C18:0 (TABLE II). C16:0 showed a higher content for MD

compared to C. The fatty acid C16:0 (palmitic acid), among all SAT,

is considered an atherogenic fatty acid and promotes inammation

[16]. Thus its consumption is advised to be reduced but not avoided

because of its important physiological role in lipids metabolism,

particularly in neonate and infants [17]. As stated by those authors,

both deciency and excess of palmitic acid in diet are detrimental for

health. Probably this concept could be valid at all age. In the breeds

studied in the present work, the level of C16:0 in meat ranged 21.1–26.1

g·100 g

-1

fatty acids. Those levels are of the same order detected in

Fatty acids composition of Longissimus thoracis muscle in sheep / Guerra et al. ______________________________________________________

6 of 15

meat from longissimus thoracis of lamb from different breeds produced

in other countries. Indeed, Cadavez et al. [18] working on various local

Iberian breeds produced in different rearing systems, that is extensive,

semi–extensive and intensive, showed for C16:0 a level in g·100 g

-1

fatty acids ranged between 19.9–24.7. Diaz et al. [15] compared meat

from longissimus dorsi, in its thoracis part, of different lamb breeds

produced in typical production system of Spain, United Kingdom,

Germany and Uruguay. In that investigation, the composition for C16:0

expressed as g·100 g

-1

fatty acids showed levels ranged 22.5–24.7. In

the same investigation the breed evaluated in Uruguay was C produced

in two systems. One of them, called heavy lamb, consisted in animals

aged of 12–13 months and the other, called light lamb; the animals

were aged of 3–4 months. However, the levels of palmitic acids were

of 24.66% and 24.73% in heavy lamb and light lambs, respectively. This

apparent stability of contents of palmitic acid in meat, is probably due

to the fact that the intake in this fatty acid and the lipogenesis de novo

for the same, act together to maintain a stable level of palmitic acid

in tissues, even when the animals are of different ages as reported by

Diaz et al. [15], for C lamb produced on pasture in Uruguay.

Another fatty acid, the anteiso C17:0ai is present in the meat of the

six breeds (C17:0ai, TABLE II), showed a level, expressed as g/100g

fatty acids of all detected fatty acids, ranged 0.35–0.58. However,

only meat from MD presented a signicant lower level for this fatty

acid, in comparison to the other breeds. This fatty acid is mainly

synthesized during the microbial fermentation processes in the rumen,

and consequently is typical of ruminant milk and meat products. Also,

its amount in meat seems to be inuenced by the level of fattening

of lamb when fed pasture [19]. However, in our work, although there

is difference between the breeds regarding their fattening, there

is not a clear relationship between lipids content in meat and level

of anteiso C17:0 (TABLE II). It could be explained by the differences

in the experimental conditions, that is kind of muscles, breeds and

pastures. There is limited information about the nutritional importance

in human health of anteiso C17:0. However, in the report of Vahmani

et al. [20], the C17ai fails to present anti–carcinogenic properties in

cultured MCF 7 cells, a mammary human cancer established cell line.

In that investigation it is rather the iso C17:0 (C17:0i) which presents a

signicant anti–carcinogenic effect in the same cell line MCF 7. Those

promissory fatty acids, and their potential effects on human health,

warrant future investigations to rene their action against some

diseases [21]. In the same way, the odd fatty acids C17:0 presented

values ranged 1.35–1.67 when expressed as g·100 g

-1

fatty acids

(TABLEII). The breed C showed more C17:0 than MD breed (TABLEI).

These contents were higher than those reported by Diaz et al. [15] using

lambs from C breed produced on pasture in Uruguay, but slaughtered

at different ages. However, the rearing conditions were very close to

those followed in our experiment.

The combined effect on consumer’s health of odd and branched

fatty acids detected in our experiment will be presented in Monomethyl

branched and odd fatty acids point of the present discussion.

Another fatty acid, the C18:0, showed a higher content for C than

C×AM. The level for C18:0 observed in our experiment ranged 18.3–21.1,

being quantitatively the second saturated fatty acid present in meat

of lambs (TABLE II). The value of C18:0 reported in our work are of the

same order of those reported by Lucas et al. [14] and Ramos et al.

[22], even when crossbreed animals were used in those experiments.

However, in the work of Cadavez et al. [18], working on Iberian local

breed of lambs aged around 4–4.5 months and produced in different

typical extensive, semi–extensive and intensive systems of Spain and

Portugal, reported a level expressed in g·100 g

-1

fatty acids ranged

12.3–15.4. This lower level of C18:0 reported in that investigation could

be due to the age of animals. But in another work comparing C lamb

of 3–4 months with others aged of 11–13 months, showed levels of

C18:0, in one part close of those observed in our work, and for other

part no difference has been detected between the animals of the

two ages [15]. Therefore, those differences could be attributable to

the breeds used in those experiments.

In relation to the human health effect when C18:0 is consumed,

it has been dened that these fatty acids have a neutral fatty acid

regarding the cardiovascular diseases. However, there are some

recent reports that point a potential negative effect for human

health. This controversial situation must be clarified in future

investigation [16, 23].

In the case of MUFA, the C16:1 presented a signicant difference

between CPRO and C×AM versus MD. The levels of this fatty acid,

expressed as g·100 g

-1

fatty acids of all detected fatty acids, ranged

1.57–2.10 (TABLE II). Those levels are of the same order as those

reported in the experiment of Diaz et al. [15], Ramos et al. [22],

Lucas et al. [14] and close or slightly lower to the levels observed

by Cadavez et al. [18], even when different productive systems and

breeds were used.

The fatty acid C16:1 has been proposed as lipokine, principally

when it is endogenously synthesized. For other part, the positive

health effect for humans, when foods enriched with C16:1 were

consumed, is not so clearly demonstrated and the information remains

controversial [24].

Regarding the PUFA, the level of C18:3n3 expressed as g·100 g

-1

fatty

acids ranged 0.77–1.21, and the C have more C18:3n3 than H (TABLE II).

In comparison with results from other reports, this fatty acid is present

with levels of the same order than those reported by Ramos et al. [22],

and slightly lower than values reported by Lucas et al. [14]. However, the

levels of C18:3n3 in our work were lower to those reported by Diaz et al.

[15], particularly when C is highlighted. Indeed, in that investigation, C

aged of 3–4 months and others of 11–14 months present levels of C18:3n3

approximately almost three times those detected in the present work.

It could be due to the pasture quality offered to the animals, since the

productive system was extensive in both experiments. As expected, in

the work of Cadavez et al. [18] the animals reared in extensive system

present a higher content of C18:3n3 in comparison to those reared in

a semi–extensive or an intensive system.

The fatty acid C18:3n3 (α–linolenic acid) is an essential fatty acid

precursor of other valuables fatty acids of n–3 family. It is known to

have favourable effect on health of consumers, directly or after its

conversion to C20:5n3 (EPA) and C22:6n3 (DHA). Those three fatty

acids have protective effects against cardiovascular diseases, cancer

and probably some neurodegenerative diseases [16]. Thus, meat

of lamb of our experiment could be considered as a good source

of C18:3n3. Unfortunately, the level of EPA and DHA detected in

meat of the lamb of our experiment is not so high to consider it as

relevant (TABLE II). The cause of the low level of those fatty acids

will be considered in our future investigations.

Another fatty acid, CLA (Conjugated linoleic acid), showed levels

expressed as g·100 g

-1

of fatty acids ranged 0.61–1.24, and CPRO and

C×AM presented levels higher than H (TABLE II). Those levels in CLA

were of the same order than in the work of Diaz et al. [15] working with

different breeds produced in Europe and Uruguay. In that experiment,

_____________________________________________________________________________Revista Cientifica, FCV-LUZ / Vol. XXXIV, rcfcv-e34362

7 of 15

only lamb from Spain showed a lower content of CLA compared to the

other breeds used in the experiment. The levels of CLA observed in our

work were also in accord with those reported by Ramos et al. [22], even

when the animals were dietary supplemented with different levels of

protein. In other part, the levels of CLA observed in the present work

were also in accord with those reported by Lucas et al. [14].

The CLA was a typical fatty acids present in relevant amount in

ruminant meat and milk. The health effect of intake of CLA in human

has been associated with antitumor action, anti–obesity, and other

benecial effects such as effects against cardiovascular diseases [25].

Fatty acids of glycerophospholipids

For SAT, the fatty acid C17:0 showed levels expressed as g·100 g

-1

fatty acids ranged 0.95–1.31. The breed H presented a higher content

than RM for this fatty acid (TABLE III).

There are no differences for total SAT for the breeds used in our

work (TABLE III). For other part, the comparison of our results to

other reports showed that the level of C16:0 was in the same order

to the results reported by Aurousseau et al. [26] and slightly higher

compared to the results reported by Popova [27], in both experiments

animals were fed pasture. However, our results for this fatty acid

were higher compared to the results reported by Garcia et al. [28]. In

this last work, the use of animals from Merino breed typical for wool

production, could explain that differences. Furthermore, the lambs

were fed shrub grass steppes which could also explain this result.

For the C18:0, the levels expressed as g·100 g

-1

fatty acids reported

by Popova [27] were of the same order that those observed in our

work. However, the level of C18:0 reported by Aurousseau et al. [26]

and Garcia et al. [28] were lower when compared to our own results

for this fatty acid (TABLE III). As expressed before, differences due

to the breed or pasturage, or both, could explain those results.

For MUFA, C17:1 presented level expressed as g·100 g

-1

fatty acids

ranged 0.71–1.30. RM presented a higher level compared to CPRO and

C×AM (TABLE III). There are scarse results for the content of this fatty

acid in lamb meat in the scientic literature. However, Garcia et al.

[28] reported approximately three times more C17:1, expressed in

g·100 g

-1

fatty acids, in comparison to our results.

In the case of C18:1, the levels expressed as g·100 g

-1

fatty acids

ranged 31.7–37.2 and H presented a higher level than CPRO and C×AM

(TABLE III). Those levels are of the same order to those reported by

Aurousseau et al. [26] and Popova [27], by much higher compared

to the results of Garcia et al. [28]. The same explanation proposed

before, to explain the differences between our results and those of

Garcia et al. [28], could be proposed again here. That is, lambs were

Merino, typical breed for wool production, fed shrub grass steppes.

For PUFA, the fatty acid C18:2n6 presented a level expressed as

g·100 g

-1

of fatty acids ranged 8.92–13.5 (TABLE III). The C exhibit

more C18:3n3 than H (TABLE III). This range of levels was of the same

order than the levels reported by Aurousseau et al. [26] and Garcia

et al. [28], but lower than those reported by Popova [27]. In our work

C×AM exhibit more C18:2n6 in comparison to H. This fatty acid is the

most represented in tissue glycerophospholipids, and is the essential

precursor of other fatty acids of the n–6 family, as for example the

C20:4n6 (arachidonic acid). At the same time this last is a prevalent

precursor of many pro–inammatory eicosanoids, leukotrienes,

thromboxanes, among others biomarkers of inammation [16].

In the case of the C18:3n3, the levels observed in our work ranged

2.29–4.71 when expressed as g·100 g

-1

of fatty acids. This range of

levels was of the same order or even slightly higher than the levels

reported in other investigations [26, 27, 28]. Naturally, in those

experiments the animals were fed pasture or shrub grass steppes

[28]. The favourable effect on health of consumers for these fatty

acids has been presented in point “Fatty acids of glycerolipids” above.

Another fatty acid that showed differences between the breeds used

in our work was the 20:3n6 (TABLE III). The same exhibited levels

expressed as g·100 g

-1

of fatty acids ranged 0.36–0.85, and C showed

more 20:3n6 than H (TABLE III). The values detected in our work were

of the same order than those reported by Popova [27] and Garcia et

al. [28] with lamb fed pasture. This fatty acid has been implicated, not

alone but concomitantly with other n–6 fatty acids, in the prevalence

of higher severity of depressive and anxiety symptoms in patients

with depression [3]. Furthermore, other pathologies linked to the

inammatory process could have relation with the metabolism of this

fatty acid [29]. Taking into account the levels of these fatty acids in

lamb meat and its effect on human health, as described above, it could

be interesting and important to consider it as relevant fatty acids to

be considered in future investigations on lamb meat.

Finally, although there is a not difference between the breeds for

glycerophospholipids for C20:4n6, EPA, DPA and DHA, the Authors of

the present work think justied to compare the levels of those fatty

acids obtained in our work, to levels reported elsewhere. Indeed,

taking into account the nutritional importance of these fatty acids for

human health [30, 31], it will be interesting to evaluate the contents

of those fatty acids in meat of lamb produced on pasture in Uruguay.

For C20:4n6 fatty acid, the levels recorded in the work expressed as

g/100 g fatty acids ranged 1.29–3.15 (TABLE III). Those values were

lower than the reported by Aurousseau et al. [26] and Garcia et al.

[28]. In the case of work of Popova [27], the value reported were

substantially more elevated compared to our work and those cited

before, that is 8.23% and 7.21% for muscles longissimus lumborum

and semimembranosus, respectively. Consumption by human of

elevated amount of C20:4n6 is not advised, because this fatty acid

is a precursor of prostanoids of series 2, leukotrienes of series 4,

and many other eicosanoids, all of them promoting inammation and

causing vasodilatation. This fatty acid also could elevate the risk of

hypertension and arteriosclerosis [16, 32].

For EPA, the levels detected in our work ranged 0.22–0.45 g·100 g

-1

(TABLE III), while the values reported by Aurousseau et al. [26] were of

4.1, and 8.23 for Popova [27], both results expressed as g/100 g fatty

acids. However, in the work of Garcia et al. [28] the level of EPA was of

1.60 expressed as g·100 g

-1

fatty acids. For DPA, Aurousseau et al. [26]

and Garcia et al. [28] reported level of 1.10 and 1.35 as g·100 g

-1

of fatty

acids, respectively. In the case of Popova [27], the reported content in

DPA was of 3.28 for longissimus lumborum and 2.76 for semitendinosus,

both expressed as g·100 g

-1

of fatty acids. For the DHA, in the current

work the observed levels were ranged 0.26–0.35 expressed as g·100 g

-1

of fatty acids. In comparison with the report of Popova [27], the levels

were 0.74 and 0.57 as g·100 g

-1

of fatty acids, for longissimus lumborum

and semitendinosus, respectively. In the case of Garcia et al. [28], the

reported levels were 0.56. In the work of Aurousseau et al. [26] the

amount of DHA in meat of lamb was not reported.

The levels of those valuables n–3 PUFA in glycerophospholipids,

that is EPA, DPA and DHA detected in our work clearly present a

lower content in comparison to other reports previously cited. Those

differences could be explained, on one hand, by the environmental

TABLE III

Fatty acids composition (g·100 g

-1

fatty acids) of glycerophospholipids present in Longissimus

thoracis muscle from lambs of dierent breeds produced on pasture

Breeds

(n=15)

(n=11)

CPRO

(n=15)

C×AM

(n=15)

(n=4)

Saturated Fatty Acids (SAT)

C16:0 22.50 ± 1.38 20.10 ± 1.51 18.80 ± 1.45 19.50 ± 1.49 18.60 ± 1.09 17.40 ± 1.61 NS

C17:0 1.31

± 0.08 1.19

± 0.10 0.98

± 0.09 1.08

± 0.09 1.00

± 0.06 0.95

± 0.24 0.05

C18:0 18.80 ± 0.57 17.7 ± 0.76 18.00 ± 0.47 17.60 ± 0.47 17.10 ± 0.43 18.00 ± 2.27 NS

C22:0 0.18 ± 0.04 0.31 ± 0.08 0.33 ± 0.05 0.33 ± 0.06 0.33 ± 0.04 0.40 ± 0.05 NS

Σ SAT 42.80 ± 1.72 39.3 ± 2.09 38.10 ± 1.77 38.60 ± 1.82 37.00 ± 1.46 39.30 ± 2.09 NS

Monounsaturated Fatty Acids (MUFA)

C16:1 1.21 ± 0.06 1.17 ± 0.14 0.82 ± 0.08 1.06 ± 0.14 1.03 ± 0.06 0.87 ± 0.14 NS

C17:1 0.89

± 0.08 0.81

± 0.07 0.74

± 0.06 0.71

± 0.06 0.92

± 0.08 1.30

± 0.20 0.005

C18:1 37.20

± 0.97 34.50

± 1.35 31.70

± 1.19 32.30

± 1.28 32.40

± 0.96 31.90

± 1.30 0.008

Σ MUFA 39.30

± 1.00 36.50

± 1.25 33.30

± 1.25 34.10

± 1.41 34.60

± 0.96 36.50

± 1.26 0.029

Polyunsaturated Fatty Acids (PUFA)

C18:2n6 8.92

± 0.87 12.20

± 1.35 13.30

± 1.01 12.80

± 1.32 13.30

± 0.78 13.50

± 1.13 0.02

C18:3n3 2.29

± 0.45 3.48

± 0.56 4.71

± 0.59 3.92

± 0.56 4.12

± 0.41 4.46

± 0.66 0.02

C20:3n6 0.36

± 0.07 0.68

± 0.14 0.85

± 0.11 0.74

± 0.11 0.70

± 0.08 0.76

± 0.16 0.01

C20:3n3 1.44 ± 0.41 2.40 ± 0.51 3.11 ± 0.47 2.87 ± 0.51 2.83 ± 0.37 3.17 ± 0.67 NS

C20:4n6 1.29 ± 0.48 1.64 ± 0.41 2.66 ± 0.55 2.34 ± 0.54 2.54 ± 0.46 3.15 ± 0.91 NS

EPA 0.30 ± 0.11 0.22 ± 0.09 0.34 ± 0.10 0.29 ± 0.08 0.35 ± 0.09 0.45 ± 0.20 NS

DPA 0.67 ± 0.21 1.01 ± 0.25 1.57 ± 0.26 1.43 ± 0.26 1.58 ± 0.32 1.64 ± 0.40 NS

DHA 0.31 ± 0.04 0.27 ± 0.04 0.35 ± 0.05 0.26 ± 0.02 0.26 ± 0.02 0.31 ± 0.06 NS

Σ PUFA 15.60 ± 2.48 21.9 ± 3.16 26.90 ± 2.88 24.60 ± 3.20 25.7 ± 2.27 21.90 ± 3.16 NS

Unidentied Fatty Acids

– 2.40 ± 0.26 2.34 ± 0.32 1.78 ± 0.45 2.66 ± 0.33 2.92 ± 0.27 1.66 ± 0.80 –

Data are mean ± SEM. H=Highlander, MD=Merino Dohne, C=Corriedale, CPRO=Corriedale PRO, C×AM = Corriedale × Australian Merino, RM=Romney

Marsh. For each fatty acid, mean values bearing dierent low case letters are signicantly dierent.

P = Signicance level. NS = non–signicant. EPA=

C20:5n3, DPA=C22:5n3, DHA=C22:6n3

Fatty acids composition of Longissimus thoracis muscle in sheep / Guerra et al. ______________________________________________________

8 of 15

condition of the rearing and the global managing of the animals which

include the kind and the quality of offered pastures [33]. On other

part, the breed used in our work could have a reduced capacity to

convert eciently the C18:3n3 to EPA, DPA and DHA as stated by

Sinclair et al. [34]. In this sense, it could be noted that the levels of

C18:3n3, the precursor of EPA, DPA and DHA, present in our work

a clear higher level in meat in comparison to those levels reported

by Aurousseau et al. [26], Popova [27] and Garcia et al. [28]. That

means that, perhaps, there was more storage of this fatty acid in the

muscle rather than being converted into other n–3 fatty acids [34].

This hypothesis needs to be veried in future investigation in lamb.

Monomethyl branched and odd fatty acids

In TABLE IV were grouped the total of monomethyl branched chain

fatty acids (BCFA) detected in our study.

The levels of total BCFA were ranged 1.23–1.57 g·100 g

-1

. There are

not differences between the breeds studied in our work. That range

of values was slightly higher than those reported by Gomez–Cortes

etal. [35] and Pena–Bermudez et al. [36], but slightly lower than those

presented (control group) by Mele et al. [37]. In the three mentioned

experiments the animals were fed concentrate and the expression

of results was as g·100 g

-1

fatty acids. Obviously the differences of

breed, ages, feeding system and the kind of management between

the works probably determined differences of the reported levels in

BCFA. The diversity regarding the levels of BCFA in ovine meat can

be clearly visualized in the review by Vahmani et al. [38]. However,

probably the offered food, that is the composition of concentrate or

the botanical composition of pasture could be the most important

factor which could explain the differences in BCFA in lamb meat. For

example, C in the present experiment presented a level of BCFA of

1.43 g·100 g

-1

fatty acids which included C15:0 iso and anteiso, C16:0

iso and C17:0 iso and anteiso (TABLE II).

In another experiment by our laboratory, using also C, meat

presented a level of BCFA of 0.21 g·100 g

-1

fatty acids and only C15:0

iso and anteiso were detected. No other BCFA were detected above

the threshold of 0.01 g·100 g

-1

fatty acids [14]. In both experiments,

the animals are of the same age (11–12 months), reared extensively

TABLE IV

Branched and odd fatty acids (g·100 g

-1

) of meat from Longissimus thoracis muscle of lambs of dierent breeds produced on pasture

Breeds

(n=15)

(n=11)

CPRO

(n=15)

C×AM

(n=15)

(n=4)

BCFA 1.39 ± 0.07 1.23 ± 0.09 1.43 ± 0.08 1.46 ± 0.06 1.42 ± 0.06 1.57 ± 0.14 NS

BCFA i 0.76 ± 0.05 0.71 ± 0.05 0.78 ± 0.04 0.80 ± 0.03 0.76 ± 0.04 0.85 ± 0.10 NS

BCFA ai 0.63

± 0.03 0.52

± 0.05 0.65

± 0.04 0.66

± 0.03 0.67

± 0.02 0.73

± 0.05 0.03

Odd Fatty Acids 4.23 ± 0.15 3.89 ± 0.18 4.41 ± 0.17 4.39 ± 0.11 4.18 ± 0.13 4.38 ± 0.38 NS

Data are mean ± SEM. H=Highlander, MD=Merino Dohne, C=Corriedale, CPRO=Corriedale PRO, C×AM=Corriedale x Australian Merino, RM=Romney

Marsh. Within lines, mean values bearing dierent low case letters are signicantly dierent.

P = Signicance level. NS = non–signicant. BCFA = sum

of total branched fatty acids, i = iso, ai = anteiso, BCFAi = sum C15:0i + C16:0i + C17:0i, BCFAai = sum C15:0ai + C17:0ai, Odd Fatty acids=C15:0 + C15:0i

+ C15:ai + C17:0 + C17:0i + C17:0ai + C17:1. All calculations were performed on base of results of

TABLE II

_____________________________________________________________________________Revista Cientifica, FCV-LUZ / Vol. XXXIV, rcfcv-e34362

9 of 15

and fed pasture, slaughtered in similar commercial conditions and

all the procedures for extraction and detection of the fatty acids

were identical to those described in the present work. There are

only two differences between the two works. One of them was the

muscle evaluated, longissimus thoracis in the present work versus the

longissimus lumborum in the work of Lucas et al. [14]. The other was

the type of offered pastures regarding their botanical composition,

mainly oat and legumes in the present work (see TABLE I), versus

grasses in the work of Lucas et al. [14].

There are reports that support the concept that the kind and

composition and type of pasture, could inuence the level and type

of fatty acids, including BCFA, in lamb meat [39]. Indeed, in the rumen

the interrelation between the microbial populations [40], the specic

fatty acids synthetases and the composition of pasture regarding fatty

acids and amino acids, will lead to different kind of fatty acids present

in ruminant meat [41, 42]. In the case of amino acids, the content of

leucine, isoleucine and valine in the pasture seems to have a particular

inuence on the kind of nal BCFA present in ruminant meat [41].

This effect of amino acids in the composition of meat regarding the

BCFA, could explain partially the differences observed between the

present experiment and that of Lucas et al. [14] Indeed, the differences

between the two investigations could account for the richness of

legumes and oat in those three amino acids, in comparison to the work

of Lucas et al. [14] where the animal were fed quantitatively mainly

graminae [43, 44]. This interesting point needs more exploration

and investigation to better understand how BCFA, particularly those

linked to positive effect on health, could be incorporated in lamb meat,

thanks to use of different kind of offered pastures.

Regarding the BCFA iso (BCFAi) and anteiso (BCFAai), the level

of the former was ranged 0.71–0.85 expressed as g·100 g

-1

fatty

acids (TABLE IV). No differences between the breeds studied in

this work were detected. The range of BCFAi observed in our work

was of the same order that those reported by Gomez–Cortes et al.

[35] and Mele et al. [37], but higher to the values reported by Pena–

Bermudez et al. [36]. Note that in those three reports the lambs

were fed concentrate. For BCFAai the range observed was between

0.52–0.73 g·100 g

-1

of fatty acids, and RM presented a higher content

than MD (TABLE IV). The range of BCFAai observed here is of the same

order than those reported by Mele et al. [37], but higher than those

reported by Gomez–Cortes et al. [35] and Pena–Bermudez et al. [36].

Certainly, the explanation presented before that in the rumen the

interrelation between the microbial populations, the specic fatty

acids synthetases and the composition of pasture regarding fatty

acids and amino acids leading to the different kind of BCFA in meat

could be introduced newly here. This is particularly true for BCFAi

and BCFAai, regarding the amino acids composition of pasture [41].

In the case of the Odd fatty acids detected in our work, the range

of values was 3.89–4.41. There were not differences between the

breeds studied in our work (TABLE IV). That range was in the same

order of levels reported by Mele et al. [37], slightly higher to values

of Garcia et al. [28], but markedly higher in comparison to values

reported by Gomez–Cortes et al. [35] and Pena–Bermudez et al.

[36]. As indicated before, the lambs used in the works of Mele et al.

[37], Gomez–Cortes et al. [35] and Pena–Bermudez et al. [36] were

fed concentrate, while the lambs in the work of Garcia et al. [28]

were fed shrub grass steppes. As for BCFA, the Odd fatty acids are

inuenced by the rumen metabolism which is, in turn, inuenced by

its microbial population, the primers present for lipogenesis that is

the balance of acetyl–CoA versus propionyl–CoA, and of course the

kind of food consumed by the animals [41]. This could explain the

observed differences between the different studies highlighted here.

In the same direction, Lucas et al. [14] reported level of Odd fatty

acids of 2.40 g·100 g

-1

fatty acids for C, a lower level in comparison to

the value observed in the present work (4.41 g·100 g

-1

fatty acids) for

the same breed C (TABLE IV). As stated before, the main difference

between the two studies was the botanical type of pasture offered

to the lamb, if the muscle difference that is longissimus thoracis here

versus longissimus lumborum in Lucas et al. [14], is ruled–out as main

factor, to explain the differences.

As stated before in the text for individual BCFA and Odd fatty acids,

it seems to have some benecial effect on health of consumers

related to those fatty particular acids [21]. More investigation must

be undertaken in the future to improve the knowledge about the

effect on human health of this kind of component present in meat

and milk of ruminants.

Lipids health indices

In TABLE V were grouped some indices that help to known the

nutritional characteristics associated to the health of consumers of

this kind of lamb meat. The sum of n–6 fatty acids presented a range

between 3.35–4.34 g·100 g

-1

of fatty acids.

These levels are of the same order that those reported by Lucas et

al. [14] working on C and Ramos et al. [22] using crossing between C

and MD, both investigations were conducted in condition of Uruguay.

However, another investigation using also C [15], reported a slightly

TABLE V

Lipids health indices, of meat from Longissimus thoracis muscle of lambs of dierent breeds produced on pasture

Breeds

(n=15)

(n=11)

CPRO

(n=15)

C×AM

(n=15)

(n=4)

Ʃn–6 3.35 ± 0.29 3.85 ± 0.49 4.34 ± 0.29 3.94 ± 0.32 3.83 ± 0.23 4.21 ± 0.27 NS

Ʃn–3 1.53 ± 0.14 1.72 ± 0.25 2.08 ± 0.23 1.82 ± 0.19 1.70 ± 0.13 1.85 ± 0.19 NS

n–6/n–3 2.25 ± 0.12 2.32 ± 0.08 2.24 ± 0.14 2.25 ± 0.09 2.31 ± 0.06 2.31 ± 0.13 NS

P/S 0.10 ± 0.01 0.11 ± 0.02 0.14 ± 0.01 0.12 ± 0.01 0.12 ± 0.01 0.13 ± 0.01 NS

AI 0.73 ± 0.06 0.89 ± 0.09 0.64 ± 0.04 0.73 ± 0.06 0.78 ± 0.05 0.63 ± 0.05 NS

TI 1.70 ± 0.08 1.80 ± 0.14 1.51 ± 0.07 1.55 ± 0.07 1.62 ± 0.07 1.51 ± 0.05 NS

h/H 1.87

± 0.11 1.64

± 0.13 2.12

± 0.11 1.93

± 0.09 1.80

± 0.09 2.08

± 0.09 0.05

Data are mean ± SEM. H=Highlander, MD=Merino Dohne, C=Corriedale, CPRO=Corriedale PRO, C×AM = Corriedale × Australian Merino, RM=Romney

Marsh. Within lines, mean values bearing dierent low case letters are signicantly dierent.

P = Signicance level. NS = non–signicant. Ʃn–6 =

total n–6 fatty acids, Ʃn–3 = total n–3 fatty acids, EPA = C20:5n3, DHA = C22:6n3, P/S = PUFA/SAT ratio, AI = atherogenic indices, TI=thrombogenic

indices, h/H=hypocholesterolemiant indices, BCFA = total branched fatty acids, i = iso, ai = anteiso, Odd FA = odd fatty acids

Fatty acids composition of Longissimus thoracis muscle in sheep / Guerra et al. ______________________________________________________

10 of 15

higher values in n–6 fatty acids, that is 5.14 versus 4.34 g·100 g

-1

fatty

acids / 100 g, as reported in this work (TABLE V). Note that in those

experiments, the animals were of similar age, reared extensively and

fed pasture. Outside of Uruguay, using local breed reared extensively

on pasture, Ela et al. [45], reported 3.59 g of n–6 / 100 g of fatty

acids. A value within the range observed in our work. However, other

trials using other breeds fed pastures showed higher levels of n–6

fatty acid, such as in the work of Faria et al. [46] and Garcia et al.

[28], 10.56 and 9.23 g·100 g

-1

fatty acids, respectively. This last work

used Merino lamb fed shrub grass steppes.

Regarding the n–3 fatty acids, the same pattern as reported for the n–6

has been noted. Indeed, the works of Lucas et al. [14], Ramos et al. [22]

and Ela et al. [45] reported values within the range observed in the

present work, while the reports of Diaz et al. [15], Garcia et al. [28] and

Faria et al. [46] reported a much higher level of n–3 fatty acids in meat.

In the case of the n–6:n–3 ratio, the range observed in our work

were between 2,24–2.31. These values were in the same order that

those reported by, Cadavez et al. [18], Ramos et al. [22], Garcia et al.

[28] and Ela et al. [45]. In contrast, the values observed in our

work were slightly lower compared to the report of Faria et al. [46],

or clearly lower particularly for C, when reared in similar productive

conditions in Uruguay [15]. In practice, the content of n–6, n–3 and

their ratio in meat of the animals evaluated in the current work,

seems to have values in accord with other results reported in lamb.

Albeit there are not specic advices about the adequate intake of

n–6 and n–3 fatty acids regarding human health, the ratio between

those two classes of fatty acids has been recommended to be near

of 4–5 [47], or even between 1:1 and 2:1 [48]. The meat of the animals

evaluated in the present work, present all a ratio n–6:n–3 in accord to

the recommendation of 2:1. However, nowadays that ratio becomes

open to question about its usefulness regarding the human health

[49]. Future investigation should improve the knowledge to establish

better parameters related to the human consumption of lipids and

their fatty acids present in lamb meat.

Another index established as parameters related to the human

health, was the ratio between PUFA and SAT (P/S). In our experiment,

the P/S ratio observed varied between 0.10 and 0.14 (TABLE V). Those

values were of the same order that those reported by Ramos et al.

[22], but largely below to those reported by Diaz et al. [15], Cadavez

et al. [18], Garcia et al. [28], and Faria et al. [46]. The recommended

levels of P/S in different kind of meat to ensure an adequate health

in human in regard to the cardiovascular diseases must be between

0.4 and 1 [50]. Thus, meat of the animals used in our work is below

that recommended level, as reported in TABLE V. Therefore, this point

justies a particular attention in the future investigations.

The other indices used in our work to assess the potential protection

against cardiovascular disease were AI, TI and h/H [51]. For AI, the

value observed in our work ranged 0.63–0.89 (TABLE V). The advised

level of AI must be as low as possible. The range observed was of the

same order or slightly higher than those reported by Cadavez et al.

[18], Belhadj et al. [52] and the compilation work by Procisur–IICA

[53]. For TI, the values observed in our work ranged 1.51–1.80 (TABLE

V). Those levels are higher than the reported by Cadavez et al. [18],

Belhadj et al. [52] and the compilation of Procisur–IICA [53]. The

recommended value of TI in meat must be as low as possible, to

reduce the thrombogenic effects in human [54].

In the case of h/H indices, the values observed in the current work

ranged 1.64–2.12 and the C showed a higher indice than MD (TABLE

V). For that index, the recommended value in meat must be as high

as possible to minimize the risk of hypercholesterolemia leading to

cardiovascular diseases [55]. The range of levels observed in our

work was of the same order or slightly lower than those reported

by Belhadj et al. [52] working with four local breeds fed pasture in

Morocco, and Murariu et al. [56] in Romania using Karakul lamb fed

pasture and supplemented with hay and cereals in winter season.

Some of the presented indices such as P/S and TI were not within

the recommended value, thereby more investigation must be

undertaken to try to improve those parameters. This could be done

through the modication of feeding system of the animals using

different kind of pasture. This point is an important challenge for

the ovine production in Uruguay, as a way to help farmers to promote

their products in base to the health of consumers.

Enzyme activity indices

Enzyme indices for desaturases Δ–9, Δ–5 and Δ–6, elongase, and

thioesterase have been calculated in an attempt to detect differences

TABLE VI

Enzymes indexes of fatty acid metabolism estimated on the basis of fatty acid composition of

Longissims thoracis muscle of lambs of dierent breeds produced on pasture

Breed

(n=15)

(n=11)

C×AM

(n=15)

(n=4)

Δ–9 – C16 6.98

± 0.46 5.88

± 0.56 7.91

± 0.44 7.97

± 0.40 8.11

± 0.47 0.02

Δ–9 – C18 66.40 ± 0.89 67.00 ± 0.48 65.50 ± 0.77 68.50 ± 0.90 65.80 ± 1.38 NS

Δ–9 – C16+C18 48.60 ± 0.87 47.10 ± 1.02 49.70 ± 0.75 49.40 ± 0.86 50.00 ± 1.00 NS

Δ–5 45.00 ± 5.10 49.70 ± 6.60 51.60 ± 3.92 50.40 ± 2.98 53.50 ± 5.03 NS

Δ–6 2.51

± 0.35 3.49

± 0.47 4.83

± 0.51 4.33

± 0.42 4.62

± 1.05 0.005

Elongase 0.88

± 0.06 0.75

± 0.05 1.01

± 0.05 0.77

± 0.04 0.99

± 0.07 0.008

Thioesterase 10.10 ± 0.55 7.99 ± 0.51 9.08 ± 0.47 8.46 ± 0.52 9.38 ± 1.35 NS

Data are mean ± SEM. H=Highlander, MD=Merino Dohne, C=Corriedale, CPRO=Corriedale PRO, C×AM=Corriedale x Australian Merino, RM=

Romney Marsh. Within lines, mean values bearing dierent low case letters are signicantly dierent.

P = Signicance level, NS = non–signicant,

C16= palmitic acid, C18= stearic acid. Δ–9= Δ–9–desaturase, Δ–5= Δ–5–desaturase, Δ–6= Δ–6–desaturase, indexes of Δ–9, Δ–5 and Δ–6 desaturases,

and elongase (ratio C18:0/C16:6) and thioesterase (ratio C16:0/C14:0) indexes were calculated according to del Puerto

et al. [11]

_____________________________________________________________________________Revista Cientifica, FCV-LUZ / Vol. XXXIV, rcfcv-e34362

11 of 15

in the lipids metabolism between the breeds studied in the present

work. These indices are generally used as surrogates the measure

of the true enzyme activities. This procedure has been used also in

medical eld as simple way to evaluate the activities of enzymes

such as desaturases, elongases and thioesterases in some human’s

pathologies [57]. The enzyme activities were presented in

TABLE VI and it can see that C, CPRO and C×AM have a much

more active Δ–9–C16 than MD. This result could maybe explain the

differences for C16:1 content, reported for glycerolipids in TABLE II,

for CPRO and CxAM, but not for C.

In the case of the enzyme Δ–9–C18, as well as the sum of the

activities of both enzymes Δ–9–C16+C18, there are no differences

between the animals studied in the present work (TABLE VI). Δ–9

enzyme introduce a cis– double bond in the D9 position between

carbons 9 and 10, and the preferred substrates are palmitoyl–CoA for

Δ–9–C16 and stearoyl–CoA for Δ–9–C18, which lead to their conversion

into palmitoleoyl–CoA and oleoyl–CoA, respectively [58]. MUFA, and

particularly C18:1, are of great importance for membrane structure

and function based on phosphoglycerides [59]. However, globally

there is not a clear difference between the breeds regarding the de

novo synthesis and the deposition of MUFA, in glycerolipids as well

as in glycerophoapholipids, in longissimus thoracis muscle. Probably

the fact that the animals have been reared in identical conditions,

that is fed same pasture and management, could have minimised

the possible enzymes expression differences between the breeds.

The enzyme indices for Δ–5 do not show either differences between

the animals, while for Δ–6, C have a higher activity than H (TABLE

VI). This result probably explains the higher content in C18:3n3 for C

compared to H, as well as for glycerolipids than for glycerophospholipids

(TABLES II and III). Indeed, Δ–5 and Δ–6 desaturases are crucial for the

synthesis of PUFA [46, 57].

In the case of the elongase activities, C showed higher activity

compared to MD (TABLE VI). The enzymes elongase add two carbon

atoms to the fatty acid C16:0 obtaining the fatty acid C18:0, but also

elongate other fatty acids from the two essential fatty acids C18:2n6

and C18:3n3 [60, 61]. However, the comparison between C and MD

regarding the content of C18:0 and PUFA; do not show differences

neither for glycerolipids nor for glycerophospholipids (TABLES II and

III). Probably, the differential activity observed for elongases between

C and MD was too small to affect signicantly the content of C18:0

and PUFA in meat of both breeds. As stated before for desaturases,

the fact that the animals have been reared in identical conditions,

fed same pasture and conducted within a same extensively system,

possibly could have minimised the differences between breeds for

elongase activities.

For the thioesterase indice, there is not differences between the six

breeds studied here (TABLE VI). The thioesterase is part of the fatty

acid synthase enzyme complex encoded by the FASN gene in mammals,

and regulating principally the formation of C16:0 as nal product and

C14:0 as a minor one [62]. Taking into account, as reported above,

the implication of C16:0 in cardiovascular diseases in human, hence

it could be interesting to investigate how the thioesterase activity in

lamb meat can be modulated. That focus could help to improve the

nutritional and health quality of meat regarding the content of C16:0

in meat. Future research could open the way in that direction.

Interrelations among fatty acids of glycerolipids and

glycerophospholipids

A principal component analysis carried out on total lipids and selected

fatty acids of glycerolipids of lambs meat (FIG. 1a), shows that the two

rst principal components accounted for 66.7% of the data variability.

The rst component (43.2%) was positively correlated with C17:0ai

(r=0.870), 18:3n3 (r=0.769), CLA (r = 0.798) and BCFAai (r= 0.771), and

associated negatively to C14:0 (r=0.544) and to C16:0 (r=0.820).

The second component that explains 23.5% of the data variability was

positively associated mainly to intramuscular fat content (r=0.562), C14:0

(r=0.731) and BCFAi (r=0.648). The principal component analysis shows

that lamb meat with a higher content of linolenic acid tend to have lower

content of saturated fatty acids, C14:0 and C16:0. When the individual

observations for glycerolipids are projected in the two dimensional

space (FIG. 1b), there is an evidence that H and MD genotypes are

differentiated from others by CLA, BCFAai, C17:0ai, and 18:n3.

By other side the variability of RM is associated to component two,

BCFAi, intramuscular fat content and C14:0. In terms of lipid attributes

a b

A B

FIGURE 1. a) Variables factor map of compositional lipid metabolism of glycerolipids related to human health of lamb meat from six breeds. Liptot= total lipids; C14:0=

myristic acid; C16:0= palmitic acid; C17:0ai=margaric acid anteiso ; BCFAai= anteiso branched chain fatty acid; BCFAi=iso branched chain fatty acid; C18:3n–3=linolenic

acid; CLA= conjugated linoleic acid ; DHA= C22:6n3. b) Individuals factor map of compositional lipid metabolism of glycerolipids in lamb meat grouped by breed, with

ellipses superimposed at

α = 0.95. C=Corriedale; CPRO=Corriedale Pro; C×AM=Corriedale x Australian Merino; H=Highlander; MD=Merino Dohne; RM= Romney Marsh

FIGURE 2. A) Variables factor map of compositional lipid metabolism of glycerophospholipids fraction related to membrane structure of lamb meat from six breeds.

C16:0= palmitic acid; C16:1= palmitoleic acid; C18:1= oleic acid; C18:2n6= linoleic acid; C18:3n–3=linolenic acid; C20:4n6= arachidonic acid; EPA= C20:5n3; DPA=C22:5n3;

DHA= C22:6n3. B) Individuals factor map of compositional lipid metabolism associated to glycerophospholipids fraction of lamb meat grouped by breed, with ellipses

superimposed at

α = 0.95. C=Corriedale; CPRO=Corriedale Pro; CxAM=Corriedale x Australian Merino; H=Highlander; MD=Merino Dohne; RM= Romney Marsh

PCA - Individuals glycerophospholipids

PCA - Individuals glycerolipids

Fatty acids composition of Longissimus thoracis muscle in sheep / Guerra et al. ______________________________________________________

12 of 15

selected, lamb meat of C, CPRO, and C×AM overlap in quality attributes,

associated with higher CLA and 18:3n3 and H with the lower content

and also lower content of lipids. RM shows higher level of BCFAai

possibly associated to intramuscular fat content. When a principal

component analysis was carried out for glycerophospholipids, a

clearer patron of association among variables is observed (FIGS. 2A

and 2B). Two components explain the 77.9% of the total variability.

First component that explains the 66.2% of the variability is positively

and hardly associated with C18:2n6 (r=0.922), C18:3n3 (r=0.951), C20:4n6

(r=0.903) and DPA (r=0.922) and negatively with C16:0 (r=0.948) and C18:1

_____________________________________________________________________________Revista Cientifica, FCV-LUZ / Vol. XXXIV, rcfcv-e34362

13 of 15

(r=0.913). The component two that explains 11.7% of the variability is

mainly associated positively to DHA (r=0.882). Concerning individual

observations for glycerophospholipids only CPRO is associated with the

variables of the rst component, while for individuals of C, a relation is

evidenced for the variables that affect the component two, the DHA.

CONCLUSIONS

The results of the study show overlapping among breeds related of

compositional lipid metabolism, except for few relevant fatty acids

such as C16:0, C18:3n3 and CLA for glycerolipids, and C18:1, C18:2n6

and C18:3n3 for glycerophospholipids. Likewise, other differences

were outlined such as for BCFAai, h/H and enzymes activity of Δ–9–C16,

Δ–6 and elongase. But actually the differences are just between two

or three breeds of the six studied in the present investigation, and

not for all those relevant fatty acids.

Thus, it can be said that overall the studied breeds present good

lipid nutritional indicators in comparison with the results of other

research in lambs, except for EPA and DHA fatty acids, as those

breeds present a relatively low content in comparison to the values

indicated in some reports from the scientic literature. This last point

will be taken into account in our future studies, in order to improve

the nal composition of meat of those breeds, with the most relevant

n–3 fatty acids regarding the health of consumers.

As mentioned throughout the text, the animals were fed and

managed in identical conditions. This could explain why there are

not more substantial differences between the breeds, regarding

the fatty acid composition of meat. Maybe other conditions, such

as the ages of the animals, different kind of pasture with or without

supplementation, could well affect differently each of the breeds used

here. This hypothesis should be considered in future experiments.

Anyway, the results of the present investigation established indicators,

based on typical productive conditions of Uruguay, about the lipids

and fatty acids content of lamb meat for the breeds studied here.

Those lipids parameters, not determined before, could be used as a

baseline for future study directed to the nutritional quality of lamb

meat produced on pasture in Uruguay.

Conict of interest

The Authors declare that there is no conict of interest.

This research did not receive any specic grant from funding

agencies in the public, commercial, or not–for–prot sectors.

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