Selected functional characteristics of hind leg muscle of nutria (Myocastor coypus Mol.), from an extensive feeding system

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1 Roczniki Naukowe Polskiego Towarzystwa Zootechnicznego, t. 5 (2009), nr 3 Selected functional characteristics of hind leg muscle of nutria (Myocastor coypus Mol.), from an extensive feeding system Robert Głogowski l,marian Czaudernaf, Agnieszka. Rozbicka1.2, Katarzyna A. Krajewska/ lwarsaw University of Life Sciences, Department of Animai Breeding, Fur Animals Unit, Ciszewskiego 8, Warszawa 1'he Kielanowski Institute of Animai Physiology and Nutrition, Polish Academy of Sciences, Instytucka 3, ablonna The eontent of c-, 8- and y-tocopherol; total concentration of cholesterol; levels of Fe, Zn, Ca and Mg with fatty acids profile we re in the muscle of hind leg from eighteen females and twelve males of Greenland nutria. The concentration of total tocopherol and that of «-tocopherol in the muscle of nutria was lg/100 g and lg/100 g, respectively, and was lower than in other farm animals fed with green forage. The total cholesterol eoncentration in the fresh muscle tissue of nutria that was found in our study can be considered high, which can be explained by the high eontent of saturated acids in feeds. The favourable levels of Fe and Zn were found in muscle. Beneficial values of fatty acid biochemical indices and ratios as the result of feeding with fresh green forage should be particularly emphasized. KEY WORDS: nutria mea t / tocopherol / elements / fatty acids Nutritional value of nutria meat can be compared with other slaughtered farm animals. Rheological study results lead to high estimates of nutria meat applicability in meat processing [11, 12]. An extensive feeding of nutria with farm produced feed is common in Poland. Such feeds as fresh grass or clover, rich in valuable nutrients result in raw meat material used for preparation of ham Ol' the production of good quality sausages [12], with at least some of functional characteristics. Moreover, it seems that nutria diet modifications may subsequently improve its value. Functional foods are enriched in bioactive nutrients, which provide confirmed positive health benefits for humans health [13]. They include are vitamins, mineral elements and polyunsaturated fatty acids. 95

2 j Saadoun et al. [15] described some of nutria meat and fat properties from animals fed ad libitum with diet based on soybean and com. In conclusion, meat and fat of nutria origin were suggested for culinary preparations and consumption although values of some biochemical indices raise efficient doubts. In the face of the difficult state of nutria farming it is substantial to point out some valued characteristics of the meat from extensively fed nutria, that eonfirm further necessity of dietary manipulations towards improvement of its biochemical profile as the candidate for functional food. Materiał and methods l The material was obtained on reproduction farm, located in eastern Poland. Nutrias were housed in groups without pools, with separated grill area for defecation. Ali animals were fed the uniform diet (table l). Feed was distributed twice a day. Steamed potatoes were ad libitum fed in the morning. In the afternoon fresh green forage was served. Grass mixture and c\over were fed alternatively (tabies I and 2). Water was constantly available. Table 1 - Tabela 1 Chemical eontent of feeds for nutria Skład chemiczny pasz podawanych nutriom : Specification Wyszczególnienie potatoes ziemniaki Diet - Pasza clover koniczyna green forage zielonka łąkowa Dry matter (g/kg) Sucha masa (g/kg) Crude protein (glkg) Białko surowe (glkg) Crude ash (gikg) Popiół surowy (g/kg) Crude fiber (g/kg) Włókno surowe (g/kg) Metabolizable energy (M/kg) Energia metaboliczna (Ml/kg) Table 2 - Tabela 2 Selected elements' eontent in nutria diets (ug/g) Zawartość niektórych pierwiastków w paszach dla nutrii (ug/g) Wyszczególnienie Fe Zn Ca Mg Specification Potatces Ziemniaki Clover Koniczyna Green forage Zielonka łąkowa 96

3 Table 3 - Tabela 3 Selected isoforms and groups offatty acid eontent in nutria feeds (mglloo g offeed) Zawartość wybranych izomerów oraz grup kwasów tłuszczowych w paszach dla nutrii (mgli 00 g paszy) Specification Wyszczególnienie potatoes Diet - Pasza clover green forage ziemniaki koniczyna zielonka łąkowa LSFA C ł2:0 C 14:0 C 16:0 C 18:2 LMUFA cis9 C 16:1 cisi I C 16:1 cis') C 18:1 LPUFA cis9cisl2 C 18:2 cis9cisl2cisl5 C 18:3 LFA LI After 12 weeks of feeding the constant diet, 30 Greenland nutria (12 males ± 14 months old, average body weight: 4.1 ±0.4 kg and 18 females ± 16 months old, average body weight: 3.9 ±0.3 kg) were randomly selected and slaughtered according to species specific regulations. Left hind leg was cut out from the carcass and the thigh muscle sampies of average weight 80 g were collected, than placed in the eontainer with dry ice until analysis. The eontent of active isoforms of tocopherol and total cholesterol in nutria meat was determined by a high-performance liquid chromatography (HPLC) on Waters chromatograph equipped with spectrophotometer (4]. The volume of injection on the column was 60 ul. The atomie absorption spectrometry (ASA) method was used for assessment of the selected elements levels in biological sampies with flame ionization in: C2H2-air. The following wave lengths (nm) were used: Fe ; Ca ; Mg [3]. Fatty acids separation was performed on gas chromatograph assembled with mass spectrometer. after saponification to methyl esters (FAME), which method is considered highly effective [9). SHIM-POL column was used (120 m x 0.25 mm x 0.25 urn layer thickness). HeIium was used as a carrying gas. The detailed temperature curve was described in the paper of Czauderna et al. (5]. Statistical analyses were conducted using the nonparametric Mann-Whitney U test for comparing independent experimental groups. Statistica ver. 6 was used. ResuIts are presented as means ± standard deviation for individually analyzed muscle. Differences were considered significant at P<0.05, while at P<0.1 differences were indicated as tendencies. 97

4 Results and discussion Table 4 presents the concentrations of tocopherols and total cholesterol in hind leg muscles of extensively fed nutria. The level of total cholesterol in males and in males can be considered rather high. According to Degirolamo et al. [7], the presence of saturated fatty acids (SFA) in diet, as much as oleic (C 18: l) and palmitoleic acid (C 16:1) results in higher level of cholesterol in serum. AIso Temme et al. [17] report, that the diet rich in lauric (C 14:0) and palmitic (C 16:0) acid rises total cholesterol concentrations. In table 3 we report that the eontent of C 16:0 is high in all components of nutria diet. It seems substantial, considering the preference of nutria for consumption of steamed potatoes, where palmitic acid was the most abundant isomer. Therefore, we suggest that the first step to increase the value of extensively reared nutria meat is to remove or significantly reduce the amount of fed potatoes from the diet. At present, when there is no demand from the market on high quality nutria carcasses, the diet form ula is based on the cheapest, easily accessible feeds. As we present later, the significant share of green forage in nutria diet may be of a great importance for nutritional value of the meat. Further studies should be aimed at dietary manipulations with/or the supplementation with vegetable or fish oil, to lower the eontent of cholesterol in meat by means of decreased total SFA amount. Among biologically active forms of tocopherol, a-t form had the highest eontent in nutria muscle. Isoforms 15and y (table 4) were also detected. Indeed, the total concentration of tocopherol in nutria meat was lower than in other farm animals, fed with green forage [8, 10]. I 1 I Table 4 - Tabela 4 The concentration of cholesterol and tocopherols in hind leg muscle of nutria Zawartość cholesterolu i tokoferoli w mięśniach kończyny miednicznej nutrii Sex - Pleć CHOL') Tocopherol (~giloo g'» (mgli 00 s" a_t') o_t') y_t') total - razem Females (n= 18) Samice (n=18) Males (n= 12) Samce (n= 12) 203 ± ± LI ± GI± ± G ± ± LI ± ± ±0.9 ~.. I) _ total cholesterol - cholesterol całkowity 2) _ of fresh tissue - świeżej tkanki 3) _ the most active forms of tocopherol - najbardziej aktywne formy tokoferolu The eontent of Fe and Zn in nutria meat, compared to pork was higher. In pig breeds like Polish Large White, Polish Landrace, Pietrain Ol' Duroc the concentration of Fe was significantly lower than in nutria muscle (respectively 4.97; 4.59; 7.45; 5.50 and ug/g of fresh tissue). The differences in Zn concentration were smaller (respectively 98

5 Table 5 - Tabela 5 Selected elernents' eontent in hind leg muscle of nutria (ug/g) Zawartość niektórych pierwiastków w mięśniach kończyny miednicznej nutrii (ug/g) Element Females Males P Pierwiastek Samice Samce Fe Zn Ca Mg ; 12.49; 13.74; and ug/g) [14]. The hind leg muscle Fe concentration in nutria females was significantly higher than in males (respectively and ug/g; P=0.02l). Concentration differences in other elements were numerical (tab le 5). Nutria meat colour is lighter than beef [12], but it is considered a red meat. This rheological characteristic is influenced among others by the high concentration of haeme pigments, like metmyoglobin (MetMb) [1,2], what may explain the high eontent of Fe in nutria meat. Table 6 presents fatty ac id profile in hind leg muscle of male and female nutria, expressed in mg/100 g of fresh tissue. The concentration of monounsaturated fatty acids (MUFA) was higher in females than in males (P<0.04). The amount of n-3 PUFA precursor a-linolenic acid (ALA) was levelled (P=0.61), but the level of linoleic acid (LA) was slightly higher in females (P=0.40). This tendency with the higher capacities of desaturation 66- and 65- (respectively P=0.04 and P=O.ll) (table 7) might have an effect in significantly higher concentration of arachidonic acid (AA) in females (P=O.OOl). Higher concentrations of dokozapentaenoic acid (DPA, P=0.025) and docosahexaenoic (DBA, tendency P=0.099) were detected in fernales. One plausible explanation could be that fatty ac id metabolism, including f3-oxidation, is more efficient in male than in female muscle. This explanation stays in generał agreement with our previous statements indicating that the concentrations of LFA as well as PUFA, MUFA and SFA are lower in the male than the female (table 6). Compared to intensively fed nutria [15], fatty acid indices in hind leg of nutria fed with high amount of green forage are more favorable. PUFA/SFA ratio in extensive feeding was 0.59 in females and 0.57 in males with respectively 0.72 and 0.58 for nutria fed intensively. MUFA/SFA in females and males was respectively 1.52 and 1.27 in extensive system with 1.54 and 1.2 in intensive system. The proportion of n-6/n-3 PUFA in the muscle of nutria fed with green forage should be especially ernphasized. Its values of 2.97 for females and 2.61 for males include in highly suggested range 4-1 [16] (tab le 6). 99

6 Table 6 - Tabela 6 Fatty acids profile in nutria muscle (mgli 00 g of fresh tissue) Profil kwasów tłuszczowych w mięśniach nutrii (mglloo g świeżej tkanki) Fatty acids Kwasy tłuszczowe 8:0 e 9:0 e 10:0 e 11:0 e 12:0 e 13:0 e 14:0 c7 e 14:1,9 e 14:1 e 15:0 c7 e 15:1 clo e 15:1 e 16:0 c7 e 16:1 c9 e 16:1 c9cl2 e 16:2 e 17:0,,6 e 17:1 c9 e 17:1 cio e 17:1 e 18:0 /9 e 18:1 tli e 18:1 ('9 e 18:1 ell e 18:1 d2 e 18:1 cl4 e 18:1 /9/12e 18:2 ('9cl2e 18:2 c9,,12d5 e 18:3 (alna) e 20:0 ell e 20:1 e 21:0 cllcl4 e 20:2,,8cllci4 e 20: clld4,,17 e 20:3 n-3 c5,,8cllcl4 e 20:4 (AA) c5c8cllcl4cl7 e 20:5 e 24:0 -is e 24:1 c7cloci3ci6,l9 e 22:5 c4,7cloci3ci6cl9 e 22:6 LSFA LUFA LMUFA LPUFA Females Samice Males Samce l PUFA 11-3 PUFA UFA/S FA MUFA/SFA PUFA/S FA 11-6/ ± ± ± ± ± ± ± ±0.54 Numerous indices were calculated for the activity of metabolic enzymes in fatty acids metabolic chain and for atherogenic fatty acids (A-SFA) and thrombogenic fatty acids (T-SFA) concentrations (tab le 7). Index of desaturase - f"..9 C 14: lic 14:0 (as a result of cis9 C 14:l and C 14:0 isomers ratio) was significantly higher (P=0.049) in females than in males. Similarly, the f"..9-desaturase, i ~ 100 I 1

7 Table 7 - Tabela 7 Metabolic enzyme indices Indeksy enzymów metabolicznych Specification Females Males P Wyszczególnienie Samice Samce Ildesaturase-t:.9c [4,I/C [4, ± ± Ildesaturaza-t:.9cIUle 14,0 2Idesaturase-t: ± ± Idesaturaza-t:.9 3Idesaturase-t: ± ± Idesaturaza-t:.4 4Idesaturase-t: ± ± Idesaturaza-t:.5 5Idesaturase-t: ± ± Idesaturaza-t:.6 6lelongase ± ±0.OO lelongaza 7IA_SFA 0.584± ± IT_SFA 0.716± ± Ildesaturase-t:.9C14: lic 14,0: desaturase-ćv = c9 C 14:liC 14:0 + c9 C 14:I; c - isomers cis; 2ldesaturase-ó9 = c9 C 14:1 + c9 C 16:1 + e9 C 17:1 + c9 C 18:l/C 14:0 + c9 C 14:1 + C 16:0 + c9 C 16:1 +C 17:0 + c9 C 17:1 + C 18:0 + c9 C 18:1; 3ldesaturase-M = c4c7clorl3cl6cl9 C 22:6/c4c7clOcI3cI6rl9 C 22:6 + c7(ioci3ei6(19 C 22:5; 4ldesaturase-Ó5= c5r8c11 c 14 C 20:4/e8c Ile 14 C 20:3 + c5c8c11 cl4 C 20:4: 5ldesaturase-ó6 = c9cl2 C 18:2I(9cI2 C 18:2 + c11c14c17 C 20:3 n-3: 6lelongase= c9c12c15 C 18:3/c9cl2cI5 C 18:3+ cllc14c17 C 20:3; 7)(C 12:0 + 4 x C 14:0 + C 16:0)/(LMUFA+ LIl-6 + LIl-3) 81(C14:0 + C 16:0 + C 18:0)/(0.5 x LMUFA x LIl x LIl-3 + LIl-3/LIl-6) index deterrnined from cis9 C 14:1, cis9 C 16:1, cis9 C 17:1, cis9 C 18:1, C 14:0, C 16:0, C 17:0 and C 18:0 showed that the capacity of D9-desaturation in females is higher (P<O.O 17) than in males. Interestingly, the ~9-desaturaseC 14:l/C 14:0 index based on nearly completely de nova synthesized cis9 C 14: l is a better criterion for evaluation of the degree of ~9-desaturation compared with the ~9-desaturase index determined fromcis9c 14:1,cis9C 16:1, cis9 C 17:1, cis9c 18:1,C 14:0, C 16:0,C 17:0 and C 18:0. The concentration of cis9 C 14: l in female muscle was consistently significantly higher (P=0.0046) than that in male muscle, whereas the concentration of cis9 C 18: l in the muscle of females was slightly higher than that in males (P<0.30). Indeed, the cis9 C 18: l in muscle also originated from de nova synthesis (e.g. the ~9-desaturation of C 18:0) as well as from the diet (tab le 3). Considering above, we suggest that ~9-desaturation is significantly more efficient in female than in male muscle. Indeed, the consistent concentration of ALA (the precursor of EPA), the similar values of the elongation index (P=0.32) and ~4-desaturase index (P=0.68) in female 101

8 and mai e muscle might explain the lack of statistically significant differences in the concentrations of EPA in female and male muscle (table 7). Atherogenic and thrombogenic index should be possibly low for consumers' preferences and health properties of food [18]. In the meat of nutria fed with large amount of green forage, A-SFA and T-SFA were lower than in rabbit broilers fed with pellets with 44% of soya meal and sunflower seed, supplemented with o.-tocopherol acetate [6]. A-SFA was respectively 0.6 and 0.7 and in T-SFA respectively 0.75 and In conclusion, the results of our experiments may lead to a better understanding of the biochemical effects of an extensive feeding system on the biochemical profile of meat from female and male nutria. In fact, dietary supplementation of minerais and vegetable oils, especially Iinseed oil, can be an effective way of increasing the eoncentrations of human health-prornoting fatty acids in the carcass of farmed nutria. REFERENCES l. BEKHIT A.E.D., FAUSTMAN c., Metmyoglobin reducing activity. Meat Science 71, CALKINS C.R., HODOEN.M., A fresh look at meat tlavor. Meat Science 77, CZAUDERNA M., KOWALCZYK 1., KORNILUK K., Effect of dietary conjugated linoleic acid and selenized yeast on the concentration of fatty acids and minerais in rats. Archives oj Animai Nutritlon 61, CZAUDERNA M., KOWALCZYK 1., NIEDZWIEDZKA K., Simple HPLC analysis of tocopherols and cholesterol from specimens of animai origin. Chemia Analityczna 54, CZAUDERNA M., KOWALCZYK., NIEDZWIEDZKA K. M., KORNILUK K., KASZUBA A., Determination of conjugated linoleic acid isomers using capillary gas chromatography and mass spectrometry. Proceedings of the XXIII International Symposium on the Physico-Chemical Methods of Separation; Toruń, Poland. 6. DAL BOSCO A., CASTELLINI C, BIANCHI L., MUONAI c, Effect of dietary cx-linolenic acid and vitamin E on the fatty acid composition, storage stability and sensory traits of rabbit meat. Meat Science 66, DEGIROLAMO C, SHELNESS O.S., RUDEL L.L., LDL cholesteryl oleate as a predictor for atherosclerosis: evidence from human and ani mai studies on dietary fat. Iournal oj Lipid Research 50, FREDRIKSSON ERIKSSON S., PICKOVA 1., Fatty acids and tocopherol levels in M. Longissimus dorsi of beef cattle in Sweden - A comparison between seasonal diets. Meat Science 76, UAREZ M., POLVILLO O, CONTO M., HCCO A., BALLICO S., FAILLA S., Comparison of four extraction/methylation analytical methods to measure fatty acid composition by gas chromatography in meat. Iournal oj Chromatography A 1190, LEONHARDT M., OEBERT S., WENK C., Vitamin E eontent of different animai products: Influence of animai nutrition. Zeitschrift fiir Emiihrungwissenschaft 36, LESIÓW T., Comparison of changes occurring in functional properties of nutria meat cured by dry method and beef cured without or with the participation of enzymatic preparation. Die Nahrung 37, LESIÓW T., SKRABKA-BŁOTNICKA T., Influence of curing time on rheological properties, colour and display colour stability of nutria harn. Scientifur 18, ~ 102

9 13. MARCINIAK-ŁUKASIAK K., KRYGIER K., Charakterystyka kwasów omega 3 i ich zastosowanie w żywności funkcjonalnej. Przemysł Spożywczy 12, MIEŃKOWSKA-STĘPNIEWSKA K., KULISIEWICZ., BATORSKA M., REKIEL A., WIĘCEK L, Mineral composition of loin meat in the Polish maternal and patemal breeds of pigs. Annais oj Warsaw University oj Life Sciences - SGGW, Animai Science 44, SAADOUN A., CABRERA M.C., CASTELLUCIO P., Fatty acids, cholesterol and protein eontent of nutria tmyocastor coypus) meat from an intensive production system in Uruguay. Meat Science 72, SIMOPOULOS A.P., The importance of the ratio of omega-6/omega-3 essential fatty acids. Biomedicine & Pharmacotherapy 56, TEMME E.H., MENSINK R.P., HOR STRA G., Comparison of the effects of diets enriched in lauric, palmitic, or oleic acids on serum lipids and lipoproteins in healthy women and men. American Iournal oj Clinical Nutrition 63, ULBRICHT T.L., SOUTHGATE D.A., Coronary heart disease: seven dietary factors. Lancet 338, Robert Głogowski, Marian Czauderna, Agnieszka. Rozbicka, Katarzyna A. Krajewska Wybrane cechy funkcjonalne mięsa kończyny miednicznej nutrii (Myocastor coypus Mol.) utrzymywanych W systemie ekstensywnym Streszczenie W mięśniach kończyny miednicznej 30 nutrii (18 samic i 12 samców) odmiany grenlandzkiej oznaczono: zawartość a-, 0- oraz v-tokoferolu: poziom cholesterolu całkowitego; zawartość Fe, Zn, Ca i Mg oraz określono profil kwasów tłuszczowych. Zawartość tokoferoli była znacznie niższa w porównaniu do wyników uzyskiwanych u innych zwierząt gospodarskich, żywionych zielonkami. Wysoki poziom nasyconych kwasów tłuszczowych (szczególnie C 16:0) w paszach podawanych ekstensywnie utrzymywanym nutriom, w połączeniu z preferencjami pokarmowymi zwierząt, miało wpływ na wysoki poziom cholesterolu w mięsie nutrii. Z punktu widzenia dążenia do poprawy cech użytkowych oraz podniesienia wartości odżywczej mięsa ekstensywnie utrzymywanych nutrii wydaje się konieczne zmodyfikowanie składu dawki w kierunku zaniechania stosowania niektórych pasz, takich jak parowane ziemniaki, i podawanie innych o bardziej korzystnym składzie chemicznym. Zanotowano wysoki, korzystny poziom Fe i Zn w tkance mięśniowej. Na podkreślenie wydają się zasługiwać korzystne wartości indeksów zawartości poszczególnych grup kwasów tłuszczowych i ich wzajemnych proporcji w efekcie znaczącego udziału w dawce świeżej zielonki łąkowej, w tym wartości współczynnika proporcji n-6/n-3 PUFA, mieszczących się w zalecanym przedziale. 103