Development of Rabbit Meat Products Fortified With n-3 Polyunsaturated Fatty Acids

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1 Nutrients 2009, 1, ; doi: /nu Article OPEN ACCESS nutrients ISSN Development of Rit Met Products Fortified With n-3 Polyunsturted Ftty Acids Mssimilino Petrcci *, Murizio Binchi nd Cludio Cvni Deprtment of Food Science, University of Bologn, Cesen (FC), Itly; E-Mils: (M.B.); (C.C.) * Author to whom correspondence should e ddressed; E-Mil: m.petrcci@unio.it. Received: 25 Septemer 2009 / Accepted: 16 Octoer 2009 / Pulished: 20 Octoer 2009 Astrct: Rit met is highly digestile, tsty, low-clorie food, often recommended y nutritionists over other mets. Currently reserch in the rit sector is interested in developing feeding strtegies iming to further increse the nutritionl vlue of rit met s functionl food y including n-3 polyunsturted ftty cids (n-3 PUFA), conjugted linoleic cid (CLA), vitmins nd ntioxidnts in rit diets nd ssessing their effects on oth rw nd stored/processed met qulity properties. Our recent studies indicte tht the dietry inclusion from 3 to 6% of linseed might e considered s wy to chieve the enrichment of the met with α-linolenic cid nd to gurntee stisfctory product stility during further processing nd storge. Considering tht 6% dietry linseed corresponds to n-3 PUFA content of 8.5% of the totl ftty cids nd lipid content of 4.7 g/100 g of leg met, content of 396 mg n-3 PUFA/100g met cn e estimted, which represents out 19% of the recommended dily llownce (RDA) for n-3 PUFA. Keywords: rit; feeding; linseed; met; n-3 PUFA; α-linolenic cid 1. Introduction Europen rit met production is pproximtely 500 thousnd tons, corresponding to 30% shre of the world production. It is concentrted in the Mediterrnen Region. Itly is y fr Europe s leding producer of rit met, with Spin rnking second, nd Frnce third [1]. Rit met is still considered niche product, especilly ecuse of its time consuming preprtion which requires culinry skills nd ecuse of culturl differences mong Europen consumers. However rit met is

2 Nutrients 2009, often recommended y nutritionists over other mets ecuse it fits well with the current consumer demnd for low-ft met with high degree of ftty cid unsturtion nd low sodium nd cholesterol levels. Moreover, on lst yers, consumer lifestyle chnges in developed countries hve led to met mrket more nd more focused on esy-hndled nd processed products ( convenience foods ). Currently reserch in the rit sector is interested in developing feeding strtegies imed t further incresing the nutritionl vlue of rit met s functionl food y the inclusion in rit diets of n-3 polyunsturted ftty cids (PUFA), conjugted linoleic cid (CLA), vitmins nd ntioxidnts nd ssessing their effects on oth rw nd stored/processed met qulity properties [2,3]. Despite the limited cpcity of metolic conversion of α-linolenic cid (ALA; C18:3 n-3) to longer chin PUFA such s eicospentenoic (EPA; 20:5 n-5) nd docospentenoic (DHA; 22:6 n-3) cids [4], there re mny potentil roles in humn helth for ALA tht could e independent from its conversion to DHA [5]. Linseed (or flxseed) is prticulrly rich in ALA (50-60% of totl ftty cids) nd is commonly used s dietry supplement in humns. Alph-linolenic cid (C18:3 n-3) is n essentil ftty cid in the humn diet nd the mjor dietry source of α-linolenic cid re some vegetle oils such s rpeseed nd soyen, where it ccounts for up to 10% of totl ftty cids [6]. The intrmusculr ftty cid composition of monogstric nimls is reflection of their dietry ftty cids, while in ruminnts iohydrogention in the rumen (i.e., sturtion of the dietry unsturted ftty cids) is responsile for the smller vritions in intrmusculr ftty cid composition [7]. As consequence, the dietry use of linseed in monogstric nimls hs een proposed y mny uthors s plnt-sed wy to rise the content of n-3 PUFA, nd minly α- linolenic cid (C18:3 n-3) in poultry [8-11], pork [12-14] nd rit met [15-19]. Providing incresed mounts of n-3 essentil ftty cids in humn nutrition through the met consumption cn contriute to lnce the n-6/n-3 PUFA rtio of the tody s consumer diet, thus preventing some correlted diseses such s hypercholesterolemi-relted hert ttck nd strokes [4,7,20]. Ftty cids re involved in mny technologicl spects of met qulity. The min prolem ssocited with the modifiction of the nturl ftty cid profile of muscle foods is determined y the ility of unsturted ftty cids, especilly those with more thn two doule ounds, to oxidise nd thus reduce the shelf-life of met products [7]. This prolem could lso e more importnt when the met with high level of PUFA is used for further processing tht involves mincing, long term frozen storge, nd cooking [21]. Moreover, it hs een widely reported tht lipid oxidtion represents keyrole in the development of cooked met flvour. In swine, for exmple, it hs een suggested tht dietry use of linseed could impir the flvour of cooked met when the α-linolenic (C18:3 n-3) cid content of the met is ove 3% of totl ftty cids [14,22]. 2. The Dietry Use of Linseed to Enhnce n-3 PUFA Content of Rit Met Our reserch group crried out some studies in order to investigte the effect of different inclusion levels of whole linseed (up to 9%) in diets for growing rits on ftty cid composition, susceptiility to lipid oxidtion, nd sensory qulity of the met [23,24]. The experimentl diets were formulted to meet the nutritionl requirements of growing rits nd linseed ws dded s sustitute for plm oil. Diets were offered to the rits during the lst phse of growing period (3 4 weeks efore

3 Nutrients 2009, slughtering) nd were supplemented with supr-nutritionl level of 200 mg/kg of feed α-tocopheryl cette (vitmin E) in order to limit lipid oxidtion in met products [16] Ftty Acid Composition The overll met ftty cid composition ws drmticlly influenced y dietry linseed inclusion. With regrd to the min ctegories of ftty cids, the linseed determined lower content of totl sturted ftty cids nd higher content of polyunsturted ftty cids of Longissimus lumorum muscle nd leg met (dt not shown) [23,24]. We lso oserved incresing levels of n-3 PUFA (P < 0.001) from control group (2.21% in L. lumorum nd 2.39% in leg met) towrds groups fed 3% linseed (L3) (4.57% in L. lumorum nd 5.96% in leg met), 6% linseed (L6) (6.77% in L. lumorum nd 8.48% in leg met), nd 9% linseed (L9) (8.85% in L. lumorum nd 10.97% in leg met) [24]. The incresed content of n-3 PUFA ws minly due to the higher content of α-linolenic cid, which represents the min ftty cid of linseed. This result is shown in Figure 1, which reports the reltionship etween the content of whole linseed in the diet nd the content of α-linolenic cid in rit met. Figure 1. Reltionship etween dietry linseed nd α-linolenic cid (ALA) content (men ± sem) in rit met (L. lumorum muscle: y = 0.71x , R 2 = 0.999; Leg met: y = 0.96x , R 2 = 0.989) (n. of smples = 32) (from [24]). 12 L. lumorum muscle Leg met ALA content of the met (%) Dietry linseed content (%) The incresed content of n-3 PUFA ws le to reduce the n-6/n-3 PUFA rtio s evidenced in Figure 2. However the concentrtion of EPA nd DHA found in oth loin nd leg met ws very low (out 0.1%) nd not incresing from control to L9 group evidencing the limited efficiency of α-linolenic cid conversion to the long chin n-3 PUFA in rits. As stressed y Stnley et l. [25], n-6/n-3 PUFA rtio should not used lone s evlution index of the nutritive vlue of met.

4 Nutrients 2009, Figure 2. Reltionship etween dietry linseed content nd n-6/n-3 PUFA rtio (men ± sem) in rit met (L. lumorum muscle: y = 0.09x x , R 2 = 0.995; Leg met: y = 0.12x x , R 2 = 0.993) (n. of smples = 32) (from [24]). 12 L. lumorum muscle Leg met 9 n-6/n-3 PUFA rtio Dietry linseed content (%) The effectiveness of whole linseed to increse the PUFA nd α-linolenic cid contents of the met hs een previously reported y severl studies on oth rit [15-19] nd other species [8-14,26]. It ws lso showed tht dministrtion of n-3 enriched diets during the lst 3-4 weeks of the growing period is sufficient to chieve sustntil ftty cid modifiction in loin nd leg met incresing the n- 3 PUFA content to requested vlues, thus reducing the feed cost in comprison with longer tretment. The recent scientific opinion from the Europen Food Sfety Authority (EFSA) considered n intke for α-linolenic cid of 2 g/d consistent with recommended intkes for individuls in the generl popultion in some Europen countries sed on considertions of crdiovsculr helth [27]. Considering tht 6% dietry linseed determined n-3 PUFA content of 8.5% of the totl ftty cids nd lipid content of 4.7 g/100g of leg met, it cn e estimted content of 396 mg n-3 PUFA/100g met which represents out 19% of recommended dily llownce (RDA) for n-3 PUFA y EFSA [27] (Tle 1). Tle 1. Influence of dietry linseed nd type of muscle on totl n-3 PUFA content of rit met (mg/100g met) nd estimtion of % recommended dily llownce (RDA) for n-3 PUFA sed on serving size of 100 g of met. Loin (L. lumorum muscle) Leg Dietry linseed (%) n-3 PUFA % RDA 1 n-3 PUFA (mg/100g) (mg/100g) % RDA clculted on RDA of 2 g/d of n-3 PUFA s reported from EFSA [27].

5 Nutrients 2009, The consumption of loin gurntees lower intke of n-3 PUFA ecuse of the lower totl lipid content. This shows tht enrichment of rit met hs the potentil to provide useful contriution intke of n-3 PUFA helping to lnce n-6/n-3 PUFA rtio in rit met products Susceptiility to Lipid Oxidtion With regrd to the lipid susceptiility to oxidtion, we did not oserve ny differences in L. lumorum muscle, wheres the leg met exhiited higher susceptiility of group fed 9% linseed (L9) in respect with the other groups, ut only t the end of oxidtion induction time (dt not shown) [24]. Despite to these results, when hmurger-type product ws considered, the susceptiility to lipid oxidtion ws higher for L6 nd L9 in comprison with L3 nd control group which did not differ ech other (Figure 3). Overll these results gree with the findings of n our previous study [23] which tested met from rits fed on diets contining 0 or 8% linseed nd indicte tht lipid oxidtion of the n-3 PUFA enriched met ecomes very criticl especilly when met is further processed (i.e., mincing with high oxygen exposure of the met). Figure 3. Influence of dietry linseed content on lipid susceptiility to oxidtion (induced TBARS) of rit met hmurgers (, = P<0.05) (n. of smples = 32) (modified from [24]). nmol MDA/mg protein ns Control group (C) 3% linseed (L3) 6% linseed (L6) 9% linseed (L9) ns * Incution time (min) * * * 2.3. Sensory Properties Sensory nlyses were crried out on hmurgers nd indicted tht the diet does not determine significnt differences in the cceptility of the products produced with frozen met tter stored for three or six months [24]. In the previous study [23], we oserved no differences in the sensory chrcteristics of hmurgers produced with met tters otined from rits fed diets contining 0 or 8% linseed nd frozen for three months of storge. However, t six months, differences in the sensory properties of the met were detected.

6 Nutrients 2009, Conclusions Our studies on rit met indicte tht the dietry inclusion of linseed from 3 to 6% might e considered s wy oth to chieve the enrichment of α-linolenic cid of the met nd gurntee stisfctory product stility. This α-linolenic cid enrichment hs the potentil to provide useful contriution intke of n-3 PUFA helping to lnce n-6/n-3 PUFA rtio in rit met products, even if it ws confirmed limited efficiency of its conversion to the long chin n-3 PUFA (EPA nd DHA). Higher levels of dietry linseed inclusion cn e profitly used in products sold s whole crcss or cut-up which re less prone to undergo lipid oxidtion compred to processed products. Prticulr ttention should e given when met with high level of PUFA is used for further processing tht involves mincing, cooking nd long term frozen storge. Moreover, considering the overll results, the product qulity concerning lipid oxidtion nd sensory properties cn e considered quite good, despite the high level of unsturtion determined y the use of linseed. This might e lso relted to the positive effect exerted y α-tocopheryl-cette (200 mg/kg feed). Acknowledgments This reserches ws supported y PRIN 2003 prot _003 nd PRIN 2005 prot _002. References nd Notes 1. Food nd Agriculture Orgniztion of the United Ntions. FAOSTAT. Aville online: (ccessed Septemer 2009). 2. Hernàndez, P.; Gondret, F. Rit met qulity. In Recent Advnces in Rit Sciences; Mertens, L., Coudert, P., Eds.; Plot-it-vPulisher: Mreleke, Belgium, 2006; pp Cvni, C.; Petrcci, M.; Trocino, A.; Xiccto, G. Advnces in reserch on poultry nd rit met qulity. Itl. J. Anim. Sci. 2009, 8, Givens, D.I. Animl nutrition nd lipids in niml products nd their contriution to humn intke nd helth. Nutrients 2009, 1, Plourde, M.; Cunnne, S.C. Extremely limited synthesis of long chin polyunsturtes in dults: implictions for their dietry essentility nd use s supplements. Appl. Physiol. Nutr. Met. 2008, 33, Burdge, G.C.; Clder, P.C. Dietry α-linolenic cid nd helth relted outcomes: metolic perspective. Nutr. Res. Rev. 2006, 19, Wood, J.D.; Enser, M.; Fisher, A.V.; Nute, G.R.; Sherd, P.R.; Richrdson, R.I.; Hughes, S.I.; Whittington, F.M. Ft deposition, ftty cid composition nd met qulity: A review. Met Sci. 2008, 78, Ajuyh, A.O.; Fenton, T.W.; Hrdin, R.T.; Sim, J.S. Effect of dietry full flxseed with nd without ntioxidnt on the ftty cid composition of mjor lipid clsses of chicken mets. Poult. Sci. 1993, 72,

7 Nutrients 2009, Rymer, C.; Givens, D.I. N-3 ftty cid enrichment of edile tissue of poultry: review. Lipids 2005, 40, Rymer, C.; Givens, D.I. Effect of species nd genotype on the efficiency of enrichment of poultry met with n-3 polyunsturted ftty cids. Lipids 2006, 41, Zuidhof, M.J.; Betti, M.; Korver, D.R.; Hernndez, F.I.L.; Schneider, B.L.; Crney, V.L.; Renem, R.A. Omeg-3-enriched roiler met: 1. Optimiztion of production system. Poult. Sci. 2009, 88, Mtthews, K.R.; Homer, D.B.; Thies, F.; Clder, P.C. Effect of whole linseed Linum usittissimum in the diet of finishing pigs on growth performnce nd on the qulity nd ftty cid composition of vrious tissues. Br. J. Nutr. 2000, 83, Rey, A.I.; Kerry, J.P.; Lynch, P.B.; Lopez-Bote, C.J.; Buckley, D.J.; Morrissey, P.A. Effect of dietry oils nd lph-tocopheryl cette supplementtion on lipid TBARS nd cholesterol oxidtion in cooked pork. J. Anim. Sci. 2001, 79, Wood, J.D.; Richrdson, R.I.; Nute, G.R.; Fisher, A.V.; Cmpo, M.M.; Kspidou, E.; Sherd, P.R.; Enser, M. Effects of ftty cids on met qulity: review. Met Sci. 2004, 66, Bernrdini, M.; Dl Bosco, A.; Cstellini, C. Effect of dietry n-3/n-6 rtio on ftty cid composition of liver, met nd perirenl ft in rits. Anim. Sci. 1999, 68, Dl Bosco, A.; Cstellini, C.; Binchi, L.; Mugni, C. Effect of dietry α-linolenic cid nd vitmin E on the ftty cid composition, storge stility nd sensory trits of rit met. Met Sci. 2004, 66, Comes, S.; Cuquil, L. Une limenttion riche en luzerne permet d enrichir l vinde des lpin en omég 3. Vindes Prod. Crnés 2006, 25, Kou, M.; Bentmne, F.; Blochet, J.E.; Mourot, J. Effect of linseed diet on lipid oxidtion, ftty cid composition of muscle, perirenl ft, nd rw nd cooked rit met. Met Sci. 2008, 80, Mertens, L.; Huygheert, G.; Delezie, E Ftty cid composition of rit met when fed linseed sed diet during different periods fter wening. In Proceedings of the 9th World Rit Congress, Veron, Itly, June 2008; pp Simopoulos, A.P. Humn requirement for n-3 polyunsturted ftty cids. Poult. Sci. 2000, 79, Lee, S.; Fustmn, C.; Djordjevic, D.; Frji, H.; Decker, E.A. Effect of ntioxidnts on stiliztion of met products fortified with n-3 ftty cids. Met Sci. 2006, 72, Cmpo, M.M.; Nute, G.R.; Wood, J.D.; Elmore, S.J.; Mottrm, D.S.; Enser, M. Modelling the effect of ftty cids in odour development of cooked met in vitro: prt I sensory perception. Met Sci. 2003, 3, Binchi, M.; Petrcci, M.; Cvni, C. Effects of dehydrted lucerne nd whole linseed on rit met qulity. World Rit Sci. 2006, 14, Binchi, M.; Petrcci, M.; Cvni, C. The influence of linseed on rit met qulity. World Rit Sci. 2009, 17,

8 Nutrients 2009, Stnley, J.C.; Elsom, R.L.; Clder, P.C.; Griffin, B.A.; Hrris, W.S.; Je, S.A.; Lovegrove, J.A.; Moore, C.S.; Riemersm, R.A.; Snders, T.A.B. UK Food Stndrds Agency Workshop Report: the effects of the dietry n-6:n-3 ftty cid rtio on crdiovsculr helth. Brit. J. Nutr. 2007, 98, Riley, P.A.; Enser, M.; Nute, G.R.; Wood, J.D. Effects of dietry linseed on nutritionl vlue nd other qulity spects of pig muscle nd dipose tissue. Anim. Sci. 2000, 71, EFSA. Lelling reference intke vlues for n-3 nd n-6 polyunsturted ftty cids. The EFSA J. 2009, 1176, y the uthors; licensee Moleculr Diversity Preservtion Interntionl, Bsel, Switzerlnd. This rticle is n open-ccess rticle distriuted under the terms nd conditions of the Cretive Commons Attriution license (