Evaluation of chemical composition of breast duck s muscles from five flocks

Evaluation of chemical composition of breast duck s muscles from five flocks J. WOŁOSZYN 1, J. KSIĄŻKIEWICZ 2, T. SKRABKA- BŁOTNICKA 1, G. HARAF 1, J. BIERNAT 3 and T. KISIEL 2 1 Department of Animal Food Technology, University of Economics, Wroc ław, Poland 2 Department of Genetics and Animal Breeding, National Research Institute of Animal Production, Dworzyska, Poland 3 Department of Food Science and Nutrition, Medical University, Wroc ław, Poland gabriela.haraf@ae.wroc.pl Keywords: duck; muscle; chemical composition; amino acids; fatty acid profile Summary Out of five duck flocks (Miniduck K2, Polish Pekin P33 native, Pekin population typea3, breeding strains A55, P66) 30 seven - week old drakes were used for comparison (i.e. 6 birds from flock). Drakes were fed ad libitum on the same complete feeds. The content of proteins, fat, moisture, essential amino acids, fatty acids and cholesterol in breast muscles were investigated. There were differences in all parameters. The muscles of A55 and P66 comprised more protein and less moisture than P33 and A3 muscles. The P33 muscles comprised the least of lipids (0.8% v/s 1.16-1.32%), however A55 of cholesterol (71.21mg/100g v/s 82.23-111.82 mg/100g).the ILE and VAL were amino acids which limited the biological value of A3, P33 and K2 meat proteins, however TRP for A55 and P66 muscles. The LYS was characterized by the highest value of limiting amino acids index (R=156.4-174.0%) and thereby possessed the highest biological value. The kind of flocks affected on the profile of fatty acids. The highest content of C 18:1 and C 16 were stated. The UFA were predominant for all flocks (50.12-60.64%), the A55 muscles contained the most of UFA. The PUFA amounted to 26.66-30.44%. The highest level of PUFA was established in K2 muscles. The UFA/SFA ratio was 1.19-1.76, the PUFA/SFA ratio was 0.63-0.84 and the n-6/n-3 PUFA ratio was 3.22-5.85. The lipids of A55 were characterized by the best value of n-6/n-3 PUFA ratio (3.22) and the best fatty acid profile among the investigated muscles. Taking into consideration the biological value of proteins, cholesterol content and profile of fatty acids, A55 breast muscles appeared to be the most favourable from the human health point of view. It is evident that muscles from the examined flocks have been characterized by high nutritional value. Introduction In Poland, at present more than ten conservative and genetic reserve flocks of ducks are under the conservation program. Two conservative flocks of Polish origin ducks i.e. Pekin (P33) and Miniduck (K2) have been listed by FAO (World Watch List, 2000) and registered as the protected world genetic resources. The breeding program for the preservation of duck genetic resources, which specifies, among others, the methods of management, evaluation and mating of parental stocks and size of the population is carried out in Poland, in National Research Institute of Animal Production in Kraków. Here the five strains (A44, A55, P66, P77, K11) of meat type ducks have been produced, too. These strains were recognized by the Polish Ministry of Agriculture and Country Development as breeding strains. The populations of P33, K2, A3 belonging to the preservative flocks and A55, P66 ducks have been tested for reproductive and meatness traits so far (Ksi ążkiewicz, 2002). The Polish Pekin (P33), is native of an old indigenous breeding strain subjected to selection and taken from the farm at Borowy Młyn. The Miniduck (K2) was bred from wild mallards (Anas platyrhynchos L.) and Pekin type ducks. The English Pekin population - type A3 (progeny of a commercial stock imported from England in 1977) was included to conservative and genetic reserve flocks of ducks in 1986 too. The meat type A55 sire strain was obtained by crossing A44 (bred from Pekin and Aylesbury and selected over 22 years) with P8 (Pekins of Danish origin) and 17 consecutive years of selection at the Department of Poultry Breeding in Dworzyska. The meat type 159

P66 maternal strain was bred from Pekins of American and English- German origin (Książkiewicz 2002, Mazanowski 2002). There are no adequate data on the chemical composition, amino acid composition of protein and fatty acid profile of lipids from muscles of the above mentioned flocks. This was the reason for undertaking the investigation on this subject. Materials and methods Ducks from the five flocks K2, P33, A3, A55 and P66 maintained by in situ method in the Department of Poultry Breeding in Dworzyska near Poznań were used as experimental material. During the testing period ducks were reared up to the fourth week of age in a poultry house of controlled air temperature, and afterwards they were kept on yards of restricted area, partially shedded and covered with straw. All birds were fed ad libitum on the same complete feeds. This diet was given until the third week of age contained up to19-20% of crude protein and up to11,92-12.13mj metabolizable energy and later up to16-16.5% of crude protein and 11.73-12.34 MJ metabolizable energy per 1 kg of feed. From each flock (comprising K2-50; P33-50; A3-56, A55-60, P66-60 birds) six 7- week-old males of body weight close to the arithmetic mean (K2 1582g, v% = 9.0; P33-2342g, v% = 7.9; A3-2475g,v% = 7.6; A55-2869g v%-6.5: P66-2617g, v%=6.9) for sex within a given group, were taken for analysis. The killing of birds and cutting of breast muscles were made manually. The muscles were held at 2-4 0 C until 24 h after killing and next examined. They were separately minced in a meat grinder (2mm) and mixed in the food processor Büchi Mixer B-400 to obtain a homogeneous mass. Chemical analyses in homogenates were carried out using the following methods: Moisture, protein, and lipids - were determined with standard methods (A.O.A.C., 1990). Cholesterol - using the enzymatic Human test in an extract prepared by Folch et al. (1957) procedure. The saponification was carried out by Rhee et al. (1982) method. Amino acids composition using HPLC Chromatograph MIKROTECHMA Amino Quant AAA T 339 type (Czech Republic). The acid hydrolysis of meat samples was made with 6M HCl in the environment without oxygen in the nitrogen atmosphere at 105 0 C for 24h. Tryptophan was determined from the alkaline hydrolyzate (saturated solution of Ba(OH) 2 at 110 0 C for 48 h). The analysis was carried out in the way described in Operator s Handbook (1986). The limited amino acids index (R%) was established according to formula: R (%) = 100% x A m /A s, (A m - essential amino acid content in the duck meat protein; A s essential amino acid content in the standard FAO). The composition of fatty acids was determined using gas chromatography technique with the AGILENT Tech. 6890N Chromatograph, equipped with a flame ionization detector. The fat from muscles was extracted with the chloroform by Folch et al. (1957) procedure. The methyl esters of fatty acids were obtained by means of esterification of lipid samples according to the Prescha et. al. (2001). The methyl esters of fatty acids were separated on the fused silica CP-Sil 88 (Chrompack, Netherlands) capillary column (100 x 0.25 mm), helium was used as the carrier gas. The separation was conducted at the programmed temperature from 165 to 200 o C by increase rate at 2 o C/min. The identification of fatty acids was accomplished by comparison with external standards. The fatty acids were calculated as % of total fatty acids with the ChemStation v.4.0 Agilent Technologies programme. Statistical analysis was based on arithmetic means (X) and standard deviation (). The effects of flock were analysed by one way analysis of variance (ANOVA) in non-orthogonal scheme. Significant differences between the average values were determined by Duncan s multiple range test. The statistical analysis was conducted with the Software System Statistica, version 6.0 (StatSoft Inc., 2001). Results and discussion Comparing the chemical composition of breast muscles, the significant differences in all investigated parameters were found. The muscles of A55 and P66 comprised more protein and less moisture than P33 and A3 muscles. The P33 breast muscles comprised the least of lipids (0.8% v/s 1.16-1.32%), however A55 of cholesterol (71.21mg/100g v/s 82.23-111.82 mg/100g) (Table 1). Higher percentage of lipids in breast muscles of different Pekin type and their crossbreeds (2.1-2.98%) was found out by, Smith et. al. (1993), Knust 1995, Bons et al. (1998), Mazanowski and Książkiewicz (2004), in 160

comparison with our results. The proportion of moisture in P33 and A3 muscles were higher and in K2, A55, P66 were similar to those reported by Witkiewicz (1998 and 2000) for Pekin meat strains (A44, A55, P66, P77) and for the light strain of Pekin ducks by Knust (1995). The protein content, in the investigated muscles was higher (19.53-21.81%), than that (18.8-19.3%) obtained by: Mazanowski and Książkiewicz (2004) for meat type ducks (7- week old) from two sire strains (A44, A55) and by Górska and Górski (1997) for three and four-breed crosses of Pekin ducks (19.4%). Smith et al. (1993) detected a lower protein content (19.47%) in breast muscles of commercial Pekin ducks, too. The proportion of cholesterol in muscles of investigated flocks ranged from 71.21 to 116.93mg/100g. Lower cholesterol content was reported for: Pekin (Honikel and Arneth 1996-67 to 68.5mg/100g; Smith et al. 1993-99mg100g), Muscovy (Salichon et al. 1993-67mg/100g), force fed Mulard (Wołoszyn 2002-68.6mg/100g). However Baeza et al. (1999) detected the cholesterol content in breast muscles of non force fed Mulard ducks on the level 105-117mg/100g. The ILE and VAL were amino acids which limited the biological value of meat proteins from breast muscles of A3, P33 and K2, however TRP for A55, P66 muscles, because they were characterized by the lower value of index R than the FAO standard (84%). Except of them, the meat proteins contained more essential amino acids than the FAO standard. The LYS was characterized by the highest value of index R (156.4-174.0%) and thereby possessed the highest biological value among essential amino acids (Table 2). Taking into consideration the biological value of proteins, A55 breast muscles appeared to be the most favourable. The amino acids limiting the biological value of meat protein for Mulard ducks were MET+CYS (22-45%) and TRP (70-75%) (Wołoszyn, 2002). The R index for LYS (157.8-174.0%) reached the highest value in our investigation. This is in agreement with our own previous results obtained for meat protein from Mulard ducks (Wołoszyn et al. 1998). The kind of flocks affected on profile of fatty acids (Table 3). The presence of such fatty acids C 18:2, C 18:3, C 20:4, C 20:5, C 22:6, which are the essential polyunsaturated fatty acids (PUFA) is very important. The highest contents of C 18:1 (22.07-29.42%) and C 16:0 (21.86-24.31%) among the identified fatty acids was stated. Lipids of P66 comprised more C 18:1 (29.41% v/s 22.07-27.41%) than remaining muscles and less C 18 (10.33% v/s 12.74-13.78%) than P33 and K2 ones. However lipids of P33 comprised more C 16 (24.31% v/s 21.86-22.58%) as compared to the remaining muscles. The highest content of C 20:4 (10.17% v/s 7.03-8.56%) was detected in the K2 muscles. The unsaturated fatty acids (UFA) were predominant in fatty acids composition for all flocks (50.12-60.64%) (Table 3). The monounsaturated fatty acids (MUFA) amounted to 23.46-31.97% and the PUFA to 26.66-30.44% of the global content of fatty acids. The lipids of P66 comprised the most of UFA (60.64%) especially MUFA (31.97%), however P33 muscles contained the most of SFA (42.04%). The highest content of PUFA was established in K2 muscles (30.44%). The UFA/SFA ratio was more favourable for P66 and A55 muscles than for remaining breast muscles. The PUFA/SFA ratios ranged to 0.63-0.84 and were on the higher level for all muscles than recommended (0.4). The n-6/n-3 PUFA ratios were 3.22-5.85 and they were close to recommended (4-5). The lipids of A55 muscles were characterized by the best value of n-6/n-3 PUFA ratio and also the best fatty acid profile among the investigated muscles. The data relative to the UFA and the MUFA contents in A3, P33, K2, A55 breast muscles were lower than data previously published by Salichon et al. (1993) for Muscovy ducks (~61% and 32.07% respectively), however for P66 were similar to those results. Leskanich and Noble (1997) reported more of the SFA (50.3%) and less of the UFA (49.5%,) in breast muscles of Pekin in comparison with our results. However, the muscles from the investigated ducks were characterized by significantly higher PUFA content in comparison with data published by Smith et. al (1993), Leskanich and Noble (1997) and Chartrin et al (2003) (~17.03%, 16.5, 18.3% respectively). The UFA/SFA ratios for investigated muscles were lower than for Muscovy (Romboli et al. 1997-UFA/SFA ~ 1.7) and Mulard (Wołoszyn 2001, Chartrin et al. 2003- UFA/SFA ~ 1.9, 1.7 respectively) ducks. The PUFA/SFA and the n-6/n-3 PUFA ratios were significantly more favourable for investigated muscles than results obtained by Smith et al. (1993) for Pekin ducks (PUFA/SFA ~0.37, n-6/n-3 PUFA ~10.0), Salichon et.al. (1993), Romboli et al. (1997) for Muscovy ducks (PUFA/SFA ~ 0.37-0.42,n-6/n-3 PUFA ~ 11.0-11.7). This is very important, because preference in human diets is given to the high level of the n-3 PUFA, which is the most valuable acid in the UFA group from the nutritional and physiological points of view. However, comparing all investigated traits it should be mentioned that Pekin and Muscovy originate from two species genetically very distinct from each other. 161

Conclusion Comparing the basic chemical composition, amino acid composition and profile of fatty acids of lipids, we can say, that the A55 breast muscles were the most favourable from the nutritional point of view. Admittedly, they were characterized by the highest content of lipids, however taking into consideration the biological value of proteins, the fatty acids profile and cholesterol content, the A55 breast muscles appeared to be the most suitable. It is evident too, that muscles from all the examined flocks have been characterized by high nutritional value. References A.O. A.C., (1990) OFFICIAL METHODS ANALYSIS. 15 th ed. Association of Official Analytical Chemists. Washington, D.C. BAEZA E., M. R. SALICHON, G. MARCHE, N. WACRENIER, B. DOMINGUEZ and J. CULIOLI, (1999) age and sex effects on the technological and chemical characteristics of mule duck meat. Proceedings of 1 st World Waterfowl Conference, Taiwan, 531-537. BONS A., R. TIMLER and H. JEROCH, (1998) Changes in body composition and content of fat and protein in carcass of male and female Pekin ducks during growth. Zesz. Nauk. Prz. Hod., 36, 165-175. CHARTRIN P., J. MOUROT, M. BERNADET, G. GUY, M. J. DUCLOS, and E. BAEZA, (2003) Effect of genotype and force- feeding on the intramuscular fat deposition in duck. Proceedings of 16 th Europ. Symp. on the Quality of Poultry Meat. Saint - Brieuc Ploufragan, 224-230. CRAWFORD R. D., (1993) Gene resources: global view of inventory and conservation Proceedings of 10 th Int. Symp. Nitra, Slovakia, 131-136. GÓRSKA A. and J. GÓRSKI, (1997) The change of the total protein, collagen and fat content in Pekin duck crossbreds at the end of rearing period. Proceedings of 13 th Europ. Symp. on the Quality of Poultry Meat, Poznań, 334-337. FOLCH J., M. LESS and STANLEY G. H. SLOANE, (1957) A simple method for the isolation and purification of total lipides from animal tissues. J. Biol. Chem., 226, 437-439. HONIKEL K.O. and W. ARNETH, (1996) Cholesterol in meat and eggs. Cholesteringehalt in Fleisch and Eiren. Fleischwirtschaft, 12, 1244, 1246-1248, 1253, 1329 KNUST U., (1995) Untersuchungen zur Charakterisierung der Wirkung von prä - and postmortalen Faktoren auf die Schlachtkörperzusammensetzung, die Muskel- faserzusammensetzung und die Fleischqualität von Enten. Diss., Universität Halle. KSIĄŻKIEWICZ J., (2002) Reproductive and meat characteristics of Polish ducks threatened with extinction. Czech J. Anim. Sci., 47, 401-410. LESKANICH C.O. and R. C. NOBLE, (1997) Manipulation of the n-3 PUFA composition of avian Eggs and meat. World s Poultry Sci. J., 53, 156-183. MAZANOWSKI A., (2002) Rody zarodowe kaczek mięsnych i ich mieszańce. Wyd. Inst. Zootechniki, Balice k. Krakowa, B-3/2002 MAZANOWSKI A. and J. KSIĄŻKIEWICZ, (2004) Comprehensive evaluation of meat traits of ducks from two sire strains. J. of Anim. And Feed Sci., 13, 175-184. OPERATORS HANDBOOK - MIKROTECHMA Amino Quant AAA T 339, 1986. PRESCHA A., A. ŚWIĘDRYCH, J. BIERNAT and J. SZOPA, (2001) Increase in lipid content in potato tubers modified by 14-3-3 gene over expression. J. Agric. Food Chem., 49, 3638-3643. RHEE K.S., T. R. DUTSON, G. C. SMITH, R. L. HOSTELLER and R. REISEL, (1982) cholesterol content of raw and cooked beef Longissimus Muscles with different degrees of marbling. J. Food Sci., 47, 716. ROMBOLI I., C. RUSSO and S. ZANOBINI, (1997) Effect of dietary vitamin E on chemical composition and meat colour in heat stressed muscovy duck. Proceedings of 13 th Europ. Symp. on the Quality of Poultry Meat, Poznań, 205-211. SALICHON R. M., B. LECLERCQ, G. REMIGNON, G. MARCHE and I. C. BLUM, (1993) Composition biochimique des filets de canard de barbarie. Proceedings of 11 -th Europ. Symp.on the Quality of Poultry Meat, Tours, 368-371. STATSOFT. INC.2001. STATISTICA-Data analysis software system, version 6.0, Tulsa OK, USA. SMITH D.P., D. L. FLETCHER, J. R. BUHR and D. S. BEYER, 1993: Pekin duckling and broiler Pectoralis Muscle structure and composition. Poultry Sci., 72, 202-208. 162

WITKIEWICZ K., (1998) Comparison of ducks from two breeding strains with regard to some selected live and slaughter traits (in Polish). Rocz. AR Poza ń, 302, 243-251. WITKIEWICZ K., (2000) Zoometric measurements, slaughter value and chemical composition of the breast muscle in two strains of ducks of Pekin type (in Polish). Rocz. AR Pozna ń, 330, 231-240. WOŁOSZYN J., SKRABKA- BŁOTNICKA T. and PRZYSIĘŻNA E., (1998) The chemical composition of Mullard duck muscles. 10 -th European Poultry Conference. Jerusalem, Abstracts, 110. WOŁOSZYN J., (2001) The fatty acid profile of lipids from Mulard duck muscles. Proceedings of 47 th Intern. Congress of Meat Sci. and Technol., Kraków, 232-233. WOŁOSZYN J., (2002) The physicochemical and technological characteristic of muscles from force fed ducks (in Polish). Wyd. AE Wrocław, 145. World Watch List for Domestic Animal Diversity, (2000) 3 rd edition FAO, Roma. 163

Table 1 Basic chemical composition of breast (BM) muscles (X - average values from 6 tests; - standard deviation; a,b,c,d - values with different letters at the same level are significantly different; n.s. = not significant; = p<0.05; = p<0.01. PARAMETER P33 K2 A3 A55 P66 Effect of flock X X X X X Protein [%] 20.25a 0.277 20.91a 0.246 19.53a 0.189 21.37a 0.277 21.81a 0.516 Lipids [%] 0.80a 7 1.16b 0.111 1.28b 0.101 1.32b 3 1.32b 8 Moisture [%] 77.70a 0.523 76.67b 0.535 77.53a 0.543 75,86b 0.533 76,10b 0.537 Cholesterol [mg/100g] 95.17a 7.98 111.82b 9.67 106.05b 10.91 71,21c 7.06 82,23d 7.57 Table 2 Limited amino acids index (R%). Amino acid P33 K2 A3 A55 P66 PHE + TYR 99.0 105.0 106.5 134.6 130.5 ILE 81.7 81.0 81.0 157.2 151.5 LEU 108.3 112.6 111.1 122.5 117.8 LYS 159.2 157.8 156.4 174.0 161.8 MET + CYS 92.0 90.0 89.1 89.0 92.2 THR 101.5 103.8 111.2 103.2 130.5 TRP 113.0 115.0 125.0 78.0 70.0 VAL 72.6 74.8 73.4 140.2 138.6 164

Table 3 Fatty acids composition of lipids from breast muscles (BM). Fatty acid (%) P33 K2 A3 A55 P66 C14 C16 X X C16:1 X 0.82a 24.31a 0.48 1.12a 0.65b 22.58b 0.51 1.21a 0.11 C18 X 12.74a 0.41 13.78a 0.71 C18:1 X 22.07a 22.31a 0.52 1.27 C18:1 X 2.76 3.02 Σ isom. 0.42 0.30 C18:2 X 14.28a 14.69a 0.81 0.94 C18:3 X 1.62a 0.83b 0.21 0.08 C20:1 X 0.41 0.03 0.04 C21 X 0.60a 0.38b 0.12 0.20 C20:4 X 7.03a 10.17b 0.42 0.51 C20:5 X 0.59a 0.44a 0.12 0.11 C22:4 X 0.80 1.01 C22:6 X 1.97a 2.98b 0.21 0.41 For description, see Table 1. 0.74a 0.08 22.32b 0.47 1.55a 0.14 10.69b 0.35 25.07b 1.08 3.71 12.52b 1.43 1.00b 0.07 0.41 0.02 0.85a 0.15 8.56c 0.61 0.49a 0.10 0.82 0.05 3.38b 0.41 0.65b 21.86b 0.65 2.45b 0.17 10.49b 0.375 27.41c 0.79 3.76 14.20a 0.151 1.10b 0.06 0.021 0.71a 0,17 7.11a 0.59 1.12b 0,10 0.74ac 0.07 3.42b 0.35 0.64b 22.30b 0.57 2.08b 0.18 10.33b 0.103 29.41d 0.99 2.77 0.42 14.13a 0.162 1.03b 0.025 0.61a 0.18 7.49a 0.57 0.91b 0.13 0.80bc 0.08 3.40b 0.24 Effect of flock n.s. n.s. n.s. Table 4 Balance sheet of fatty acids composition in breast muscles (BM). P33 K2 A3 A55 P66 SFA 42.04 38.84 38.16 34.17 34.53 MUFA 23.46 24.01 27.15 29.96 31.97 PUFA 26.66 30.44 27.62 28.92 28.67 UFA 50.12 54.45 54.77 58.88 60.64 n-6 21.31 24.85 21.08 21.31 21.62 n-3 4.18 4.25 5.45 6.62 6.02 UFA/ SFA 1.19 1.40 1.43 1.72 1.76 PUFA/SFA 0.63 0.78 0.72 0.84 0.83 n-6/n-3 5.09 5.85 3.85 3.27 3.59 165