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Effects of linseed and quercetin added to the diet of
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fattening lambs on the fatty acid profile and lipid
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antioxidant status of meat samples
S. Andrésa*, L. Morána, N. Aldaib, M.L. Tejidoa, N. Prietoc, R. Bodasd, F.J.
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Giráldeza
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a
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24346 Grulleros, León (Spain)
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b
Instituto de Ganadería de Montaña (CSIC-Universidad de León). Finca Marzanas, E-
LACTIKER Research Group, Lascaray Research Centre, University of the Basque
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Country (UPV-EHU), Avda. Miguel de Unamuno 3, 01006 Vitoria-Gasteiz (Spain)
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c
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Lacombe Research Centre, 6000 C&E Trail, Lacombe, Alberta, T4L 1W1 (Canada).
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d
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Burgos, km. 119. E-47071 Valladolid (Spain)
Department of Agricultural, Food and Nutritional Science, University of Alberta.
Instituto Tecnológico Agrario, Junta de Castilla y León. Finca Zamadueñas. Ctra.
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RUNNING HEAD:
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*CORRESPONDING AUTHOR: Sonia Andrés, Instituto de Ganadería de Montaña
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(CSIC-ULE) 24346 Grulleros - León, Spain. Tel. +34 987 307 054 Fax +34 987 317
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161. E-mail: sonia.andres@eae.csic.es
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Abstract
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Thirty-two Merino lambs fed barley straw and a concentrate formulated either with
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palm oil (CTRL group) or linseed (+LS group), both alone or supplemented with
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quercetin (+QCT group or +LS+QCT group) were used to assess the effects of these
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dietary supplements on meat quality attributes. After being slaughtered, the longissimus
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thoracis muscles were used to study the fatty acid profile (FA) in detail, whilst
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longissimus lumborum slices were stored under refrigerated conditions to determine the
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lipid stability. Linseed increased the content of highly unsaturated n−3 long-chain fatty
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acid (20:5n−3; 22:5n−3; 22:6n−3). Interestingly, a significant increment of rumenic acid
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content (9c,11t-18:2) was observed when this seed was administered together with
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dietary quercetin. Moreover, the feeding of quercetin resulted in a reduction in the
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proportion of saturated FA and a decrease in lipid peroxidation of meat when the lambs
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were fed linseed. In conclusion, from both a nutritional and a commercial (shelf-life)
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point of view, it may be useful to include a source of quercetin when lambs are fed
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linseed diets.
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Keywords: fatty acids; antioxidants; linseed; quercetin; TBARS; meat.
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1. Introduction
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The scientific evidence establishes that diets that are high in saturated fat are related
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to increased levels of blood total and low density lipoproteins, which are associated
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with an increased risk of cardiovascular disease (Webb & O'Neill, 2008). Consequently,
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consumers from developed countries are interested in fat composition and are currently
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looking for meat products with added health benefits (Scollan, Hocquette, Nuernberg,
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Dannenberger, Richardson, & Moloney, 2006).
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Due to the fact that the fatty acid profile (FA) of lamb is characterised by a low
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polyunsaturated/saturated FA ratio (PUFA/SFA) (Department of Health, 1984; Enser,
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Hallett, Hewett, Fursey, Wood, & Harrington, 1998), numerous studies have attempted
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to increase the proportion of PUFA and conjugated linoleic acid (CLA) in the final
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product, by means of different feeding strategies (Castro, Manso, Mantecón, Guirao, &
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Jimeno, 2005; Bessa et al., 2007). In this regard, the use of linseed is one approach that
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is known to increase levels of n−3 FA in pork, poultry, beef and dairy products and the
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consumption of these enriched products increases erythrocyte n−3 FA levels in humans
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(Legrand et al., 2010). Linseed contains ~40% oil and, of this, ~50–60% is linolenic
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acid (18:3n−3), making linseed one of the richest plant sources of n−3 FA.
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Furthermore, in ruminants, bacterial biohydrogenation of PUFA in the rumen can
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result in the accumulation of other intermediates like trans-MUFA; with this regard
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vaccenic acid (the precursor of rumenic acid) is considered positive for the health of
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consumers. However, other intermediates such as dienes, whose biological effects are
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still unknown, have been barely studied in milk or tissues (Harfoot & Hazlewood,
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1997). While further information about these intermediates is being obtained, they
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should be recognised, identified and quantified correctly using the appropriate
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methodology.
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Other studies have looked for new dietary supplements, such as phenolic compounds
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(Patra & Saxena, 2009), some of which also have the ability to modify rumen
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microbiota and PUFA metabolism (i.e. biohydrogenation) (Lourenco, Ramos-Morales,
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& Wallace, 2010). In this sense, quercetin is a phenolic compound (flavonol) (Nair,
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Kandaswami, Mahajan, Chadha, Chawda, Nair, Kumar, Nair, & Schwartz, 2002) whose
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inclusion in the diet has been shown to modify the rumen population (Oskoueian et al.,
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2013). Consequently, quercetin might have the potential to modify the FA composition
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of lamb.
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It must also be considered that PUFA are susceptible to oxidation, and lipid
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peroxidation plays a key role in colour changes and undesirable flavour development,
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thus reducing product shelf-life (Elmore, Mottram, Enser, & Wood, 1999). Phenolic
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compounds have shown potent antioxidant effects, such as metal chelation or free-
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radical scavenging activities (Rice-Evans, Miller, & Paganga, 1997). Hence, the
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antioxidant properties of quercetin may protect PUFA from lipid peroxidation.
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Therefore, the aim of the present study was to investigate the FA profile and the lipid
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stability against oxidation processes of lamb meat samples when linseed, quercetin or
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both were included in the diet of light fattening lambs.
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2. Material and methods
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2.1. Animals and diets
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Two weeks before the start of the trial, 32 male Merino lambs were treated with
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Ivermectin (Ivomec, Merial Labs, Barcelona, Spain) and vaccinated against
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enterotoxaemia (Miloxan, Merial Labs, Barcelona, Spain).
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After stratification on the basis of body weight (BW; average of 15.5 ± 2.12 kg), the
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lambs were randomly allocated into 4 different groups (2 replicates per dietary
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treatment, 8 subgroups in total). All of the groups were fed their corresponding total
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mixed ration (TMR) as described below: two replicates comprised the control group
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(CTRL, 4 animals per replicate; 34 g palm oil kg-1 of TMR), two replicates were fed
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ground linseed (+LS, 4 animals per replicate; 85 g linseed kg-1 of TMR), two replicates
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were fed control diet plus quercetin (Shaanxi Sciphar Biotechnology Co., Ltd, Xi'an,
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China) (+QCT, 4 animals per replicate; 34 g palm oil plus 2 g quercetin kg-1 of TMR),
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and two replicates were fed ground linseed plus quercetin extracted form Sophora
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japonica L (+LS+QCT, 4 animals per replicate; 85 g linseed plus 2 g quercetin kg-1 of
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TMR). The four TMRs were formulated to be isoenergetic and isoproteic. The
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ingredients and chemical composition of TMR are shown in Table 1. All handling
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practices followed the recommendations of Directive 2010/63/EU for the protection of
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animals used for scientific purposes and all animals were able to see and hear other
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animals.
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[INSERT TABLE 1 NEAR HERE, PLEASE]
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After 7 days of adaptation to the basal diet, all of the lambs were fed the
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corresponding TMR (CTRL, +LS, +QCT and +LS+QCT) during the experimental
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period (at least 5 weeks, until the animals reached the intended BW, approx. 25 kg). The
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TMR was weighed and supplied ad libitum at 9:00 a.m. every day, and fresh drinking
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water was always available. Samples of feed offered and orts (approximately 20% of
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total offered) were taken daily, weighed, pooled to a composite sample each week,
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oven-dried at 55°C for at least 72 h (to constant weight), ground to pass through a 1-mm
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screen using a Willey mill (Arthur H. Thomas, Philadelphia, PA), and stored until
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analysed.
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2.2. Slaughter procedure, packaging, and storage of meat samples
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The animals were slaughtered on four different days; two lambs per group per day.
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The lambs were selected each day according to their weight (24.8 ± 1.05 kg) and
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slaughtered by stunning and exsanguination from the jugular vein; they were then
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eviscerated and skinned.
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After chilling for 24 hours at 4ºC, the longissimus thoracis (LT) and longissimus
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lumborum (LL) muscles were removed from both carcass sides. The LT samples were
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freeze-dried and ground before chemical analysis (Andrés, Tejido, Bodas, Morán,
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Prieto, Blanco, & Giráldez, 2012), and further FA profile determination. The LL
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samples were cut into 2.5 cm thick slices, placed on impermeable polypropylene trays,
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over-wrapped with an oxygen-permeable polyvinylchloride film (580 ml m-2 h-1) and
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then stored under simulated retail display conditions [12 h daily fluorescent illumination
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(34 W) and 3±1ºC] for 0, 7 and 14 days. Then, the samples were frozen at -30ºC until
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used for TBARS analysis.
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2.3. Fatty acid analysis
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All details regarding lipid extraction and FA determination (GC conditions, peak
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separation and identification using two complementary columns: 100m SP2560 and
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100m SLB-IL111, FAME standards) of lamb meat samples have been previously
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described in Kramer et al. (2008) and Aldai, Lavín, Kramer, Jaroso, & Mantecón
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(2012). For quantification purposes, 1 mL of internal standard (1 mg mL-1 23:0; N-23-
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M, supplied by Nu-Chek Prep Inc., Elysian, MN, USA) was added prior to esterification
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(base methylation). The FA methyl esters (FAME) were expressed as mg 100 g-1 fresh
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meat and a percentage (%) of total FAME.
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Some nutritionally-interesting indexes were also calculated, according to Ulbricht
and Southgate (1991):
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Saturation index (S/P) = (14:0+16:0+18:0)/(ΣMUFA+ΣPUFA)
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Atherogenic index (AI) = (12:0+4×14:0+16:0)/(ΣMUFA+Σn-6+Σn-3)
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Thrombogenic index (IC) = (14:0+16:0+18:0)/[(0.5×ΣMUFA+0.5×Σn-6+3×Σn-
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3)/(Σn-6)]
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2.4. TBARS analysis
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Thiobarbituric acid reactive substances procedure (TBARS) was performed on pre-
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thawed, raw LL samples displayed for 0, 7 and 14 days under the aforementioned
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refrigerated storage conditions, according to Maraschiello, Sárraga, & García-Regueiro
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(1999). The results were expressed as µg MDA g-1 meat.
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2.5. Statistical analysis
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Fatty acids and TBARS data (n=8 per group) were subjected to a two way analysis of
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variance, using the GLM procedure of SAS (SAS, 1999) according to the following
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model:
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yijk = μ + LSi + QCTj + (LS×QCT)ij + εijk
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where yijk is the dependent variable, μ is the overall mean, LS is the effect of linseed
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addition, QCT is the effect of quercetin addition, LS×QCT is the effect of the
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interaction between quercetin and linseed, and εijk is the residual error. Least square
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means were generated and separated using the PDIFF option of SAS for main or
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interactive effects, with the level of significance being determined at P < 0.05.
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Results
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3.1. Fatty acids composition of intramuscular fat
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In absolute amounts, in general, meat samples obtained from lambs fed linseed (+LS
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and +LS+QCT groups) had a significantly greater content of total FAME per 100 g of
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fresh meat than CTRL and +QCT groups (Table 2). Differences in SFA, MUFA (cis
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and trans) and PUFA were also related to the greater FAME content of the
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aforementioned groups. Regarding trans-MUFA, even though significant differences
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were observed for the total trans-18:1, where +LS+QCT showed the highest content, no
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significant differences were observed for the two major trans isomers (10t- and 11t-18:1
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or vaccenic acid, VA) and their ratio. It was interesting to note that the 11t-/10t- ratio
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was >1, indicating the high content of 11t-18:1 in all treatments. Significant differences
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observed for the total PUFA content between treatments were mainly related to the
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higher content of n−3 FA (18:3n−3, 20:5n−3, 22:5n−3, 22:6n−3) in linseed-fed lamb
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muscles (P<0.001) in comparison to CTRL and +QCT treatments. In relation to n−6 FA,
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there were no significant differences between treatments. Therefore, the n−6/n−3 ratio
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was significantly higher in CTRL and +QCT (average of 4.59) in comparison to +LS
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and +LS+QCT (average 3.18) treatments. No significant differences were found for the
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total CLA content (Table 2), but significant interactions were observed for rumenic acid
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(RA, 9c,11t-18:2; P=0.039) and VA (P=0.024). Most of the total CLA consisted of RA
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and 11t,13c-18:2, which represented over 50% and 30%, respectively. Non-conjugated
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diene (NC-18:2) content was significantly higher in meat from flax-fed lambs.
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[INSERT TABLE 2 NEAR HERE, PLEASE]
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When the results were expressed on a percentage basis (Table 3), meat from lambs
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fed quercetin showed a lower sum of saturated FA (SFA, P=0.015) and, consequently, a
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significant improvement of nutritional indexes such as atherogenic (AI, P=0.029, Table
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2) and saturation (S/P, P=0.022, Table 2). The effect of linseed on SFA did not seem to
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be remarkable, whereas in general terms, branched-chain FA (BCFA) were not
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modified by either LS or QCT.
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[INSERT TABLE 3 NEAR HERE, PLEASE]
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Although significantly higher values (LS effect) were observed for several individual
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cis-MUFA and total trans-18:1, the percentage of total monounsaturated FA (MUFA)
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was not statistically different between dietary treatments (Table 4). The effect of
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quercetin on MUFA did not seem to be remarkable.
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[INSERT TABLE 4 NEAR HERE, PLEASE]
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The total polyunsaturated FA (PUFA) including long-chain PUFA (20-to-22 carbon),
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CLAs, non-conjugated dienes (NC-18:2) and 9c,11t,15c-18:3 (NC-18:3, rumelenic acid)
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percentages are presented in Table 5. The relative abundance of total n−3 PUFA
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(P<0.001), together with α-linolenic acid (ALA, 18:3n−3; P<0.001) and eicosapentanoic
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acid (EPA, 20:5n−3; P=0.019), were greater in the meat of lambs fed linseed. On the
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contrary, the relative abundance of cis-7,10,13,16-docosatetraenoic acid (22:4n−6;
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P=0.006) was significantly decreased in the meat of these animals when compared to
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the CTRL and +QCT lambs. No significant differences were detected for the total n−3
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and n−6 PUFA when quercetin was supplemented in the diet.
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Interestingly, dietary quercetin promoted a significant increment in the relative
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abundance of conjugated FA (Table 5), and significant interactions LS×QCT were
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observed for RA (P=0.016) and total CLA content (P=0.049). Moreover, total NC-18:2
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and rumelenic acid (NC-18:3) percentages were significantly increased and decreased,
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respectively, in the meat when lambs were fed linseed (Table 5).
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[INSERT TABLE 5 NEAR HERE, PLEASE]
3.2 TBARS analysis
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The evolution of mean TBARS values for each dietary treatment is presented in
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Figure 1. No significant differences were observed in MDA values during the first day
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(day 0) of refrigerated storage. As the refrigerated storage period progressed (day 7), a
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significant effect of linseed was detected (P=0.024), with +LS and +LS+QCT meat
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samples showing greater MDA values than CTRL and +QCT groups. After 14 days of
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refrigerated storage, the effect of linseed still was significant (P=0.038), but also
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corresponded to the dietary quercetin (P<0.001) with +QCT and +LS+QCT meat
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samples showing lower MDA values than CTRL and +LS groups, respectively.
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[INSERT FIGURE 1 NEAR HERE, PLEASE]
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4. Discussion
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4.1. Fatty acid composition of intramuscular fat
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The content and composition of specific FA in meats is an important factor in
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assessing its nutritional quality. Particularly interesting has been the higher fatty acid
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content in the meat of the lambs fed linseed (P=0.025, Table 2), which affected almost
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all of the other individual FA in absolute amounts (per serving size or 100 g of fresh
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meat; De Smet, Raes, & Demeyer, 2004). This is in agreement with the results reported
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by Huang et al. (2008), who explained that feeding n−3 PUFA during a long time may
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stimulate the differentiation of pre-adipocytes into adipocytes, thus enhancing
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intramuscular fat accumulation.
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Also notable in our study is the type of trans-FA present (Aldai et al., 2009; Leheska
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et al., 2008), the content of LC-PUFA (specifically EPA and DHA), the type and
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amount of conjugated FA (especially RA, the major CLA isomer in our meat samples
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which, moreover, has been linked to several health benefits), and the level of SFA.
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Thus, among the trans-FA, both 10t-18:1 and VA were the predominant trans-18:1
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isomers in the meat samples of all groups, with a trend towards significantly higher
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levels in both FA in the meat of linseed-fed lambs when expressed as mg/100 g of meat
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(Table 2), probably as a consequence of the conversion of PUFA to trans-18:1 isomers
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in the rumen of the lambs. However, t10-shift was not observed. Other studies, on the
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contrary, have described an exacerbation of 10t-shift when dairy cows had been
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supplemented with diets high in linoleic (corn) and low in fibre (Griinari et al., 1998) or
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cows fed diets with increased levels of oils or oilseeds rich in linoleic acid such as
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soybean oil (Piperova et al., 2000) and sunflower oil (Roy et al., 2006; Cruz-Hernandez
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et al., 2007). 10t-18:1 has been reported to accumulate in concentrate-fed animals
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(Bessa, Portugal, Méndes, & Santos-Silva, 2005), while rumenic acid (RA, c9,t11-18:2)
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and its precursor vaccenic acid (VA, t11-18:1) have been found to accumulate in forage-
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finished ruminants (Dugan et al., 2007; Aldai et al., 2011, 2012). Regarding other t-18:1
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isomers, increased levels of t12- to t16-18:1 were observed in animals fed linseed
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(around 8.5% of 18:3n−3 in the whole diet, Table 1). This was also described in milk fat
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(Rego et al., 2009), muscle and backfat (Bessa et al., 2007; Nassu et al., 2011) and
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duodenum flow (Shingfield et al., 2011) of ruminants fed with linseed. However, apart
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from the health benefits described for VA (11t-18:1), at this time it is not possible to
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assess the health implication of each of all the individual trans-18:1 isomers.
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Based on levels of intermediates present, biohydrogenation of LNA renders
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9c,11t,15c-18:3 (NC-18:3, rumelenic acid), which is subsequently hydrogenated to the
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non-conjugated diene 11t,15c-18:2 (NC-18:2) by ruminal microorganisms, but does not
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lead to the formation of any CLA isomers (Table 5). For this reason, Jenkins, Wallace,
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Moate, & Mosley (2008) suggested that the eventual goal would be to regulate
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biohydrogenation to the point that any number of desired CLA isomers could be
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delivered to body tissues. In this sense, the interaction LS×QCT observed for total CLA
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content (Table 5) was of interest, thus indicating a positive additive effect of quercetin
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when supplemented together with linseed. This effect was mainly linked to the increase
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of RA (the major CLA isomer) and its precursor, vaccenic acid.
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Also, it must be pointed out that very few studies have analysed 18:3 isomers present
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in the ruminal contents or tissues of ruminants. In the present study, +LS and +LS+QCT
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lambs had significantly higher and lower levels of NC-18:2 and NC-18:3, respectively,
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compared to lambs from the other treatments. As stated beforehand, PUFA are
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subjected to isomerisation and reduction by rumen bacteria producing numerous trans-
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containing metabolites which can be deposited into tissues (Gómez et al., 2009).
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However, the potential health effects of all of these new metabolites require further
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investigation (Dugan, Aldai, Aalhus, Rolland, & Kramer, 2012).
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Currently, the trans issue is of special concern. Most regulatory agencies have
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excluded ruminant meat or dairy products from mandatory labelling of the trans-FA
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content based on the positive effects of VA (11t-18:1) and RA (9c,11t-18:2) (see review
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by Aldai et al. 2013 for more information regarding the regulation of trans fats).
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However, this assumption may not be valid under some feeding practices when
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ruminants are fed high concentrate diets (Aldai et al., 2009; Aldai, Dugan, Juárez,
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Martínez, & Osoro, 2010; Leheska et al., 2008). In the present study, the presence of
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11t-18:1 was slightly higher in comparison to 10t-18:1. However, if total trans-18:1
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from ruminant fats was to be declared per serving size, it would be between 40.1 and
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70.1 mg for all the dietary treatments (Table 2). Even including VA, the total trans
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would be below the trans regulation limits established in Canada (0.2 g per serving size)
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and in USA (0.5 g per serving size), for example.
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An assessment of both the absolute and relative amounts of the n−6 and n−3 PUFA
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is important for meat evaluation (Gebauer, Harris, Kris-Etherton, & Etherton, 2005).
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The n−3 LC-PUFA are of special interest because of the limited conversion of 18:3n−3
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to 22:6n−3 in humans (Barcelo-Coblijn & Murphy, 2009), and the need to find
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alternative sources of n−3 LC PUFA, other than marine products (Brunner, Jones, Friel,
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& Bartley, 2009). In general, the extensive rumen biohydrogenation promotes a low
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content of n−3 PUFA in ruminants (Scollan et al., 2006). However, the results of this
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study showed that the content of total n−3 PUFA, 18:3n−3 and the n−3 LC-PUFA
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20:5n−3, 22:5n−3 and 22:6n−3 in the meat was significantly higher in lambs fed linseed
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(Table 2). These data suggest a significant conversion rate of 18:3n−3 to n−3 LC-
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PUFA, provided that none of the n−3 LC-PUFA were diet-derived. However, when the
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FA were expressed as percent of total FAME, only the LC-PUFA 20:5n−3 was
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significantly greater in the linseed-fed lambs. Increased levels of neutral rather than
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phospholipids associated with higher levels of fat in meat, and the preferential
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accumulation of LC-PUFA in the phospholipid fraction (De Smet et al., 2004) could
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explain the decreases in the relative proportion of the LC-PUFA in the meat of the
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lambs being fed linseed when expressed on a percentage basis (Table 5). The n−6/n−3
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PUFA and LC-PUFA ratios were generally lower in the meat of +LS and +LS+QCT
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lambs compared to CTRL and +QCT groups (Table 2). Therefore, based on the amount
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of n−3 LC-PUFA and their n−6/n−3 in the meats, feeding linseed to lambs appears to
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provide a meat with a healthier FA profile.
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The feeding of quercetin resulted in a reduction in the proportion of SFA when
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expressed as a percentage of total FAME (Table 3), which makes the meat more
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suitable for human nutrition. Accordingly, quercetin dietary supplementation positively
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affected the atherogenic (AI) and saturation (S/P) indexes of meat, with a decrease of
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these parameters in the +QCT and +LS+QCT groups (Table 2).
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Ovine meat has other minor lipid components such as the BCFA. Higher levels of
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BCFA typically result when readily-fermentable carbohydrate sources are available,
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causing an increase in propionate production (Wood, 1984). However, in the present
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study, excepting anteiso 17:0, no significant differences in the BCFA percentages were
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observed between dietary treatments (Table 3), probably because all of the diets offered
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to the animals showed similar carbohydrate contents and compositions (Table 1).
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4.2 TBARS analysis
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As expected, no differences were observed in the TBARS values between dietary
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treatments on the first day of refrigerated storage. However, TBARS values were
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increased in all groups with advancing refrigerated storage periods as a consequence of
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lipid peroxidation. After 7 days of refrigerated storage, TBARS values were
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significantly greater for the meat of the lambs being fed linseed (P=0.024), probably due
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to the higher content of PUFA (Table 2). This effect was more pronounced after 14 days
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of refrigerated storage (P=0.038, LS effect). In general terms, the results are similar to
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those described by Moloney, Kennedy, Noci, Monahan, & Kerry (2012) in meat from
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lambs fed linseed as oil or seeds.
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However, after 14 days of refrigerated storage, a significant reduction of TBARS
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values was also observed when quercetin was included in the diet of the lambs
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(P<0.001, QCT effect). Several other studies have demonstrated the effectiveness of
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dietary phenolic compounds in order to reduce lipid peroxidation of raw (Morán et al.,
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2012) and cooked meat samples (Nieto et al., 2011). However, to our knowledge, this is
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the first study proving the success of quercetin to reduce the lipid peroxidation of raw
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meat samples during refrigerated storage. These results are in agreement with those
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previously published by the same authors (Andrés, Huerga, Mateo, Tejido, Bodas,
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Morán, Prieto, Rotolo, & Giráldez, 2013), where the usefulness of quercetin to limit the
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lipid peroxidation of cooked meat samples was highlighted. Both results are especially
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important, since it has recently been described that, unlike in monogastric species,
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quercetin aglycone may have a low bioavailability in ruminants after intraruminal (or
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oral) application (Berger et al., 2012).
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5. Conclusions
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According to the results of the present study, even though the total fatty acid content
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is increased significantly with dietary linseed, the total n−3 fatty acid content would
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contribute to making a healthier meat product. Regarding quercetin, the inclusion of this
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flavonoid in the diets of lambs being fed linseed may offer some interesting aspects
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given the numerous positive effects that CLA is believed to have on human health.
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Also, the feeding of quercetin seems to reduce the concentration of SFA and improve
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the nutritional profile of the meat. Finally, quercetin may reduce the lipid peroxidation
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of the meat when the lambs are fed linseed, thus extending the shelf life of this product.
341
Consequently, according to the results of the present study, the addition of a source of
342
quercetin to the diet of the lambs when these animals are being fed linseed seems to be
343
interesting from different perspectives.
344
Acknowledgements
345
Financial support received from ‘Consejería de Educación de la Junta de Castilla y
346
León’ (Project CSI185B11-2) is gratefully acknowledged. María Luisa Tejido, Raúl
347
Bodas, and Nuria Prieto had a JAE-Doc contract and Lara Morán was supported by a
348
JAE-Predoc grant under the programme ‘Junta para la Ampliación de Estudios’ (CSIC-
349
European Social Fund). Noelia Aldai thanks the Spanish Ministry of Science and
350
Innovation and the University of the Basque Country (UPV-EHU) for the contract
351
through the ‘Ramón y Cajal (RYC-2011-08593)’ program.
352
References
353
Aldai, N., Dugan, M. E. R., Juárez, M., Martínez, A., & Osoro, K. (2010). Double-
354
muscling character influences the trans-18:1 and conjugated linoleic acid profiles in
355
concentrate-fed yearling bulls. Meat Science, 85, 59–65.
15
356
Aldai, N., Dugan, M. E. R., Rolland, D. C., & Kramer, J. K. G. (2009). Survey of the
357
fatty acid composition of Canadian beef: Backfat and longissimus lumborum
358
muscle. Canadian Journal of Animal Science, 89, 315–329.
359
Aldai, N., Lavín, P., Kramer, J. K. G., Jaroso, R., & Mantecón, A. R. (2012). Breed
360
effect on quality veal production in mountain areas: emphasis on meat fatty acid
361
composition. Meat Science, 92, 687–696.
362
Aldai, N., de Renobales, M., Barron, L.J.R., Kramer, J.K.G. (2013). Review: The
363
dilema of trans fatty acids in ruminant products. European Journal of Lipid Science
364
and Technology (under review).
365
Andrés, S., Tejido, M. L., Bodas, R., Morán, L., Prieto, N., Blanco, C., & Giráldez, F. J.
366
(2013). Quercetin dietary supplementation of fattening lambs at 0.2% rates reduces
367
both discolouration and microbial growth in meat during refrigerated storage. Meat
368
Science, 93, 207–212.
369
Andrés, S., Huerga, L., Mateo, J., Tejido, M. L., Bodas, R., Morán, L., Prieto, N.,
370
Rotolo, L., Giráldez, F. J. (2013). The effect of quercetin dietary supplementation
371
on meat oxidation processes and texture of fattening lambs. Meat Science (In
372
press).
373
Barceló-Coblijn, G., & Murphy, E. J. (2009). Alpha-linolenic acid and its conversion to
374
longer chain n−3 fatty acids: Benefits for human health and a role in maintaining
375
tissue n−3 fatty acid levels. Progress in Lipid Research, 48, 355–374.
376
Bauchart, D., Roy, A., Lorenz, S., Chardigny, J. M., Ferlay, A., Gruffat, D., Sébédio, J.
377
L., Chilliard, Y., & Durand, D. (2007). Butters varying in trans 18:1 and cis-9,
378
trans-11
379
hypercholesterolemic rabbit. Lipids, 42(2), 123–133.
conjugated
linoleic
acid
16
modify
plasma
lipoproteins
in
the
380
Berger, L. M., Wein, S., Blank, R., Metges, C. C., & Wolffram, S. (2012).
381
Bioavailability of the flavonol quercetin in cows after intraruminal application of
382
quercetin aglycone and rutin. Jounal of Dairy Science 95, 5047–5055.
383
Bessa, R. J. B., Portugal, P., Méndes, I., & Santos-Silva, J. (2005). Effect of lipid
384
supplementation on growth performance, carcass and meat quality and fatty acid
385
composition of intramuscular lipids of lambs fed dehydrated lucerne or concentrate.
386
Livestock Production Science, 96(2-3), 185–194.
387
Brunner, E. J., Jones, P. J. S., Friel, S., & Bartley, M. (2009). Fish, human health and
388
marine ecosystem health: Policies in collision. International Journal of
389
Epidemiology, 38, 93–100.
390
Castro, T., Manso, T., Mantecón, A., Guirao, J., & Jimeno, V. (2005). Fatty acid
391
composition and carcass characteristics of growing lambs fed diets containing palm
392
oil supplements. Meat Science, 69(4), 757–764.
393
Cruz-Hernandez, C., Kramer, J. K. G., Kennelly, J. J., Glimm, D. R., Sorensen, B. M.,
394
Okine, E., Goonewardene, L. A., & Weselake, R. J. (2007). Evaluating the
395
conjugated linoleic acid and trans 18:1 isomers in milk fat of dairy cows fed
396
increasing amounts of sunflower oil and a constant level of fish oil. Journal of
397
Dairy Science, 90, 3786–3801.
398
399
De Smet, S., Raes, K., & Demeyer, D. (2004). Meat fatty acid composition as affected
by fatness and genetic factors: A review. Animal Research, 53, 81–98.
400
Department of Health (2003). Regulations amending the food and drug regulations
401
(nutritional labelling, nutrient content claims and health claims), Canada Gazette,
402
part II (Ottawa, Canada) 137, no 1, 2–499.
17
403
Department of Health and Human Services, U.S. Food and Drug Administration (2003).
404
Food labelling; trans fatty acids in nutrition labelling; nutrient content claims, and
405
health claims; final rule, July 11, 2003. Federal Register 68 (no. 133) (pp. 41434–
406
41506).
407
Department of Health (1984). Report on health and social subjects No. 28. Diet and
408
cardiovascular disease. London: HMSO, Department of Health and Social Security.
409
Dugan, M. E. R., Aldai, N., Aalhus, J. L., Rolland, D. C., & Kramer, J. K. G. (2012).
410
Trans-forming beef to provide healthier fatty acid profiles. Canadian Journal of
411
Animal Science, 91, 545–556.
412
Dugan, M. E. R., Kramer, J. K. G., Robertson, W. M., Meadus, W. J., Aldai, N., &
413
Rolland, D. C. (2007). Comparing subcutaneous adipose tissue in beef and muskox
414
with emphasis on trans 18:1 and conjugated linoleic acids. Lipids, 42(6), 509-518.
415
Elmore, J. S., Mottram, D. S., Enser, M., & Wood, J. D. (1999). Effect of the
416
polyunsaturated fatty acid composition of beef muscle on the profile of aroma
417
volatiles. Journal of Agricultural and Food Chemistry, 47(4), 1619–1625.
418
Enser, M., Hallett, K. G., Hewett, B., Fursey, G. A. J., Wood, J. D., & Harrington, G.
419
(1998). Fatty acid content and composition of UK beef and lamb muscle in relation
420
to production system and implications for human nutrition. Meat Science, 49(3),
421
329–341.
422
423
Field, C. J., Blewett, H. H., Proctor, S., & Vine, D. (2009). Human health benefits of
vaccenic acid. Applied Physiology, Nutrition, and Metabolism, 34, 979–991.
424
Fritsche, S., Rumsey, T. S., Yurawecz, M. P., Ku, Y., & Fritsche, J. (2001). Influence of
425
growth promoting implants on fatty acid composition including conjugated linoleic
426
acid isomers in beef fat. European Food Research and Technology, 212, 621–629.
18
427
428
Gebauer, S. K., Psota, T. L., & Kris-Etherton, P. M. (2007). The diversity of health
effects of individual trans fatty acid isomers. Lipids, 42, 787–799.
429
Gebauer, S., Harris, W. S., Kris-Etherton, P.M., & Etherton, T. D. (2005). Dietary
430
n−6:n−3 fatty acid ratio and health. In C. C. Akoh, & O. -M. Lai (Eds.), Healthful
431
lipids (pp. 221–248). Champaign, IL: AOCS Press.
432
Griinari, J. M., Dwyer, D. A., McGuire, M. A., Bauman, D. E., Palmquist, D. L., &
433
Nurmela, K. V. V. (1998). Trans-octadecenoic acids and milk fat depression in
434
lactating dairy cows. Journal of Dairy Science, 81, 1251–1261.
435
Gómez-Cortés, P., Tyburczy, C., Thomas Brenna, J., Juárez, M., & de la Fuente, M. A.
436
2009. Characterization of cis-9 trans-11 trans-15 C18:3 in milk fat by GC and
437
covalent adduct chemical ionization tandem MS. Journal of Lipid Research, 50,
438
2412-2420.
439
Harfoot, C. G., & Hazlewood, G. P. (1997). Lipid metabolism in the rumen. In P. N.
440
Hobson, & C. S. Stewart (Eds.), The rumen microbial ecosystem (pp. 382–426).
441
London, UK: Chapman & Hall.
442
Health Canada (2006). Food and nutrition. TRANSforming the food supply. Report of
443
the trans fat task force submitted to the minister of health [Online] Available:
444
http://www.hcsc.gc.ca/fn-an/alt_formats/hpfb-dgpsa/pdf/nutrition/tf-gt_reprap-
445
eng.pdf
446
Huang, F. R., Zhan, Z. P., Luo, J., Liu, Z. X., & Peng, J. (2008). Duration of dietary
447
linseed feeding affects the intramuscular fat, muscle mass and fatty acid
448
composition in pig muscle. Livestock Science, 118, 132–139.
19
449
Jenkins, T. C., Wallace, R. J., Moate, P. J., & Mosley, E. E. (2008). Recent advances in
450
biohydrogenation of unsaturated fatty acids within the rumen microbial ecosystem.
451
Journal of Animal Science, 86(2), 397–412.
452
Legrand, P., Schmitt, B., Mourot, J., Catheline, D., Chesneau, G., Mireaux, M.,
453
Kerhoas, N., & Weill, P. (2010). The consumption of food products from linseed-
454
fed animals maintains erythrocyte omega-3 fatty acids in obese humans. Lipids,
455
45(1), 11–19.
456
Leheska, J. M., Thompson, L. D., Howe, J. C., Hentges, E., Boyce, J., Brooks, J. C.,
457
Shriver, B., Hoover, L., & Miller, M. F. (2008). Effects of conventional and grass
458
feeding systems on the nutrient composition of beef. Journal of Animal Science, 88,
459
3575–3585.
460
Lourenco, M., Ramos-Morales, E., & Wallace, R. (2010). The role of microbes in
461
rumen lipolysis and biohydrogenation and their manipulation. Animal, 4(7), 1008–
462
1023.
463
Maraschiello, C., Sárraga, C., García-Regueiro, J.A. (1999). Glutathione peroxidase
464
activity, TBARS, and α-tocopherol in meat from chickens fed different diets.
465
Journal of Agricultural and Food Chemistry, 47, 867-872.
466
Mensink, R. P., Zock, P. L., Kester, A. D. M., & Katan, M. B. (2003). Effects of dietary
467
fatty acids and carbohydrates on the ratio of serum total to HDL cholesterol and on
468
serum lipids and apolipoproteins: A meta-analysis of 60 controlled trials. American
469
Journal of Clinical Nutrition, 77, 1146–1155.
470
Moloney, A.P., Kennedy, C., Noci, F., Monahan, F.J., & Kerry, J.P. (2012). Lipid and
471
colour stability of M. longissimus muscle from lambs fed camelina or linseed as oil
472
or seeds. Meat Science, 92, 1–7.
20
473
Morán, L., Andrés, S., Bodas, R., Prieto, N., & Giráldez, F. J. (2012). Meat texture and
474
antioxidant status are improved when carnosic acid is included in the diet of
475
fattening lambs. Meat Science, 91(4), 430–434.
476
Nair, M.P.N., Kandaswami, C., Mahajan, S., Chadha, K.C., Chawda, R., Nair, H.,
477
Kumar, N., Nair, R.E., & Schwartz, S.A. (2002). The flavonoid, quercetin,
478
differentially regulates Th-1 (IFNγ) and Th-2 (IL4) cytokine gene expression by
479
normal peripheral blood mononuclear cells. Biochimica et Biophysica Acta-
480
Molecular Cell Research, 1593, 29-36.
481
Nassu, R. T., Dugan, M. E. R., He, M. L., McAllister, T. A., Aalhus, J. L., Aldai, N., &
482
Kramer, J. K. G. (2011). The effects of feeding flaxseed to beef cows given forage
483
based diets on fatty acids of longissimus thoracis muscle and backfat. Meat
484
Science, 89, 469–477.
485
Nieto, G., Bañón, S., & Garrido, M. D. (2011). Effect of supplementing ewes’ diet with
486
thyme (Thymus zygis ssp. gracilis) leaves on the lipid oxidation of cooked lamb
487
meat. Food Chemistry, 125(4), 1147–1152.
488
Oskoueian, E., Abdullah, N., & Oskoueian, A. 2013. Effects of flavonoids on rumen
489
fermentation activity, methane production, and microbial population. Biomed
490
Research International, Article ID 349129.
491
492
Park, Y. (2009). Conjugated linoleic acid (CLA): Good or bad trans fat? Journal of
Food Composition and Analysis, 22, S4–S12.
493
Patra, A. K., & Saxena, J. (2009). Dietary phytochemicals as rumen modifiers: a review
494
of the effects on microbial populations. Antonie van Leeuwenhoek, 96(4), 363–375.
21
495
496
497
498
499
500
Rice-Evans, C., Miller, N. J., & Paganga, G. (1997). Antioxidant properties of phenolic
compounds. Trends in Plant Science, 2, 152–159.
SAS (1999). 1999 SAS, SAS/STAT(R) User's guide (version 8). Cary, NC, USA: SAS
Publishing.
Schmid, A., Collomb, M., Sieber, R., & Bee, G. (2006). Conjugated linoleic acid in
meat and meat products: A review. Meat Science, 73(1), 29–41.
501
Scollan, N., Hocquette, J. F., Nuernberg, K., Dannenberger, D., Richardson, I., &
502
Moloney, A. (2006). Innovations in beef production systems that enhance the
503
nutritional and health value of beef lipids and their relationship with meat quality.
504
Meat Science, 74(1), 17–33.
505
506
507
508
Ulbricht, T., & Southgate, D. (1991). Coronary heart disease: seven dietary factors. The
Lancet, 338(8773), 985-992.
Webb, E. C., & O'Neill, H. A. (2008). The animal fat paradox and meat quality. Meat
Science, 80, 28–36.
509
Wood, J. D. (1984). Fat deposition and the quality of fat tissues in meat animals. In J.
510
Wiseman (Ed.), Fats in animal nutrition (pp. 407–436). Toronto, ON:
511
Butterworths.
512
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