- Email: [email protected]
Comparison of breast muscle meat quality in 2 broiler breeds
Comparison of breast muscle meat quality in 2 broiler breeds G. P. Zhao,*†1 H. X. Cui,*†1 R. R. Liu,*† M. Q. Zheng,*† J. L. Chen,*† and J. Wen*†2 *Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100193, China; and †State Key Laboratory of Animal Nutrition, Beijing 100193, China contents of polyunsaturated fatty acids, unsaturated fatty acids, protein, or amino acids. Breast muscle fiber diameter was significantly smaller (~55.76%) and fiber density was higher (~174.86%) in BJY chickens than in AA chickens (P < 0.05). In this study, breast muscle from 120-d-old BJY chickens was judged to have better quality of phospholipids and essential fatty acid contents and muscle fiber characteristics than breast muscle from 42-d-old AA chickens.
Key words: Beijing-you chicken, Arbor Acres broiler, breast muscle, nutrient component, muscle fiber characteristic 2011 Poultry Science 90:2355–2359 doi:10.3382/ps.2011-01432
INTRODUCTION Chickens used for meat production in China include introduced and genetically improved broiler strains, dual-purpose breeds, and numerous native breeds. Criteria for meat quality vary in different countries and areas and reflect dietary habits. In general, however, chicken meat quality traits consist of 3 categories: appearance (i.e., flesh color), physical (i.e., muscle pH, water-holding capacity, and organizational structure, underlying the texture and tenderness of meat), and chemical [i.e., protein and crude fat contents and their composition (amino acids and fatty acids; Lawrie, 1985)]. Genetics is a major factor influencing meat quality of chickens (Lawrie, 1985; Cisneros et al., 1996), and native Chinese breeds are considered to have superior quality compared with rapidly growing imported broilers (Lu et al., 2007; Zhang et al., 2007; Li et al., 2009). The Beijing-you (BJY) chicken is an indigenous breed in China, 1 of 27 rare breeds listed in Zheng (1988), and has a special appearance and quality in egg and meat products. When compared with the Arbor Acres (AA) broiler, the BJY chicken is highly liked in China because of its taste, rich fragrance, and tenderness.
Previous studies on meat quality of the BJY chicken and other breeds have mainly focused on appearance and physical traits of the carcass, pH values, waterholding capacity, or muscle fiber characteristics. Some studies have examined chemical traits such as intramuscular fat content and fatty acid composition at the same day of age (DeVol et al., 1988; Cherian et al., 2002; Matteo et al., 2007; Zhao et al., 2007; Chen et al., 2008; Jiang et al., 2011). As the living standards of consumers have improved, an increase has occurred in demand for perceived quality in meat products and in consumer preference for indigenous chicken breeds. However, little is known of other nutritional components and muscle fiber characteristics in both BJY chickens and AA broilers at their market ages. The objective of the present study was to compare meat quality traits, including nutrient components and muscle fiber characteristics, between BJY chickens and AA chickens at market ages of each breed. Because breast meat is one of the major high-value cuts, it was examined in the present study.
MATERIALS AND METHODS Birds, Diets, and Sample Collection
©2011 Poultry Science Association Inc. Received February 21, 2011. Accepted June 14, 2011. 1 G. P. Zhao and H. X. Cui contributed equally to this work. 2 Corresponding author: [email protected]
The present study was approved by the Institute of Animal Sciences, Chinese Academy of Agricultural Sciences (Beijing, China) and carried out in accordance with the Guidelines for Experimental Animals estab2355
Downloaded from http://ps.oxfordjournals.org/ at Monash University on June 18, 2015
ABSTRACT On the basis of meat quality traits, muscle fiber characteristics, and nutrient components and contents in chickens at market age, 120-d-old Beijing-you (BJY) chickens (the Chinese local breed) had distinct breast muscle features when compared with 42-d-old Arbor Acres (AA) chickens (the genetically improved broiler line). The phospholipid (P < 0.05) and essential fatty acid (P < 0.05) contents in BJY chickens were significantly higher than those in AA chickens. No differences (P > 0.05) were found between the breeds in the
2356
Zhao et al.
Determination of Phospholipids and Triglycerides A 2.0-g sample of each breast muscle (n = 12) was homogenized and extracted (Folch et al., 1957). Then, triglyceride (TG; Hatch, 1968; Okazaki et al., 1982) and phospholipid (Bergmeyer et al., 1974; Kimura et al., 1996) contents were measured with kits (Beijing
Table 1. Ingredients and calculated chemical composition of starter and grower diets Item (% unless noted) Ingredient Corn (7.8% CP) Soybean meal (43% CP) Corn protein powder (56% CP) Soybean oil Calcium phosphate Limestone Salt l-Lysine hemifumarate dl-Methionine Choline chloride (50%) Mineral premix Multivitamin mix Total Nutrient composition CP Crude fat Calcium Total phosphorus Available phosphorus Lysine Methionine Threonine Tryptophan ME (MJ/kg)
Starter (1–21 d)
Grower (22–120 d)
60.00 32.87 1.92 1.50 1.40 1.36 0.30 0.20 0.20 0.19 0.06 0.02 100
63.54 27.49 3.00 2.03 1.72 1.24 0.32 0.13 0.11 0.20 0.20 0.02 100
20.00 4.00 1.00 0.69 0.45 1.05 0.48 0.74 0.22 12.01
19.00 5.10 0.90 0.63 0.40 1.00 0.43 0.76 0.23 12.55
Deliman Biochemical Technology Co. Ltd., Beijing, China).
Analysis of Compositions of Fatty Acids and Amino Acids Six breast muscle samples (2.0 g) from the total of 12 harvested in each breed were randomly selected, and the composition of fatty acids was determined using gas chromatography according to the method of Sukhija and Palmquist (1988). Breast muscle samples were freeze dried and ground for extraction and methylation of fatty acids before analysis using an HP6890 gas chromatograph (Hewlett-Packard, Palo Alto, CA). Six breast muscle samples (2.0 g) from the total of 12 birds harvested from each breed were randomly selected, and the composition of amino acids was determined on a Beckman 6300 amino acid analyzer (Beckman Instruments Corp., Brea, CA) using ninhydrin for postcolumn derivatization and norleucine as the internal standard. Before analysis, samples were hydrolyzed with 6 N HCl for 24 h at 110°C. Methionine and cysteine were determined as methionine sulfone and cysteic acid after cold perfomic acid oxidation before hydrolysis (method 994.12; AOAC, 1990).
Analysis of Muscle Structure Samples (~2 cm3) of 6 randomly selected birds were removed from consistent locations on the breast muscle from 12 birds harvested from each breed. The samples were oriented for transverse fiber sectioning and mounted on cork disks using the OCT Tissue-Tek (Sakura Finetechnical Co., Tokyo, Japan). Serial cryostat sections (10-μm; −20°C) were cut and stained with hematoxylin and eosin (Cumming et al., 1994). For each bird, muscle fiber size was estimated by measuring the minimum fiber diameter of 100 fibers using image analysis software, and the density of muscle fibers (fibers/mm2) was estimated by point-counting stereology using 500 points.
Statistical Analyses Data were subjected to 1-way ANOVA using SAS version 8.2 (SAS Institute, Cary, NC). Statistical significance was accepted at P < 0.05.
RESULTS AND DISCUSSION Nutritional Components of Breast Muscle The content of TG was slightly, but not significantly, higher in BJY than in AA chickens. The content of phospholipids and its relative ratio to TG in BJY chickens were both more than twice (P < 0.05) the values in AA chickens (Table 2). Phospholipids, important components of cell membranes, are made up of glycerol,
Downloaded from http://ps.oxfordjournals.org/ at Monash University on June 18, 2015
lished by the Ministry of Science and Technology (Beijing, China). One-day-old female hatchlings, 48 each of AA (Dadongliu Broiler Company, Beijing, China) and BJY (Institute of Animal Science, Chinese Academy of Agricultural Sciences), were used. Individuals within each breed had the same genetic background. All birds entered the experiment at the same time and were randomly distributed into 4 replicate groups for each breed; each group comprised 12 BJY birds and 12 AA birds. Birds were raised in an environmentally controlled room with 8 floor pens. Feed and water were provided ad libitum during the experiment. Diets for the starter (1–21 d) and grower (≥22 d) phases were formulated (Table1) to be intermediate between recommendations for the 2 breeds (NRC, 1994; Ministry of Agriculture of P. R. China, 2004). Birds were slaughtered at typical market ages: AA broilers at 42 d old and BJY chickens at 120 d old. Following a 12-h overnight fast, 3 birds of similar weight from each replicate were electrically stunned and killed by exsanguination. The breast muscle (pectoralis major) from one side was frozen at −20°C for further chemical evaluation.
2357
MEAT QUALITY AND BROILER BREEDS Table 2. Phospholipid (PL) and triglyceride (TG) contents in breast muscle of Beijing-you (BJY) and Arbor Acres (AA) chickens1 Breed BJY AA BJY/AA ratio
PL (g/kg)
TG (g/kg)
PL/TG (%)
5.77 ± 0.30a 2.14 ± 0.26b 2.70
9.25 ± 0.51 8.81 ± 0.72 1.05
62.38a 24.29b 2.57
a,bMeans within a column with different superscripts differ significantly (P < 0.05). 1Data are means ± SD (wet weight, n = 12).
Muscle Fiber Size and Density Previous studies demonstrated the close relationship between the muscle fiber characteristics (including muscle fiber density and diameter) and tenderness of meat:
Table 3. Fatty acid composition of lipids in breast muscle of Beijing-you (BJY) and Arbor Acres (AA) chickens1 Fatty acid2 (%) C14:0 C16:0 C18:0 C20:0 C24:0 C16:1 C18:1 n-9 C18:1 n-7 C18:2 C18:3 n-6 C18:3 n-3 C20:1 C20:2 C20:4 n-6 C20:5 C22:4 n-6 C22:5 C22:6 C24:1 SFA UFA PUFA EFA Major components
BJY 0.58 23.41 10.37 0.26 0.21 1.73 21.67 1.92 21.89 0.08 0.73 0.23 0.45 10.42 0.32 2.38 1.57 1.52 0.25 34.83 65.14 37.19 33.11 89.68
± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ±
0.02 0.55 0.12 0.03 0.02b 0.08 0.89 0.11 1.02 0.01b 0.05 0.02 0.04 0.88a 0.06 0.97a 0.32 0.33 0.05 1.33 1.79 0.98 0.72a 0.57
AA 0.49 24.14 9.66 0.13 1.18 2.30 25.68 2.99 20.31 0.20 0.88 0.29 0.80 6.48 0.42 1.63 1.15 0.93 0.31 35.60 64.36 37.86 27.87 89.26
± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ±
0.03 0.39 0.10 0.04 0.08a 0.10 0.72 0.12 0.72 0.01a 0.10 0.09 0.02 1.19b 0.04 0.66b 0.29 0.37 0.01 1.07 1.12 1.01 0.86b 0.71
a,bMeans within a row with different superscripts differ significantly (P < 0.05). 1Data are means ± SD (n = 6). 2SFA = saturated fatty acids; UFA = unsaturated fatty acids; PUFA = polyunsaturated fatty acids; EFA = essential fatty acids (including linoleic acid, linolenic acid, and arachidonic acid). Major components included C16:0, C18:0, C18:1, C18:2, and C20:4.
Downloaded from http://ps.oxfordjournals.org/ at Monash University on June 18, 2015
fatty acid, phosphoric acid, choline, or cholamine and can be divided into lecithin and cephalin. Phospholipids play an important role in nervous system development and animal development. Phospholipids contain most of the polyunsaturated fatty acids, such as linolenic acid and arachidonic acid, in animal tissues; these constitute the essential fatty acids (EFA) in human diets. Degradation products of the phospholipids from oxidative changes postmortem influence the composition of the volatile flavor components and consequently change the flavor of meat (Gandemer, 1997). In this study, the phospholipids content in breast muscle of BJY chickens was 2.70 times that of AA chickens (P < 0.05); this higher phospholipids content can improve the nutritional value of breast muscle in BJY chickens. Fatty acid compositions of the total lipids in breast muscle are shown in Table 3. The major components, accounting for 89.68% (BJY) and 89.26% (AA), were C16:0 (palmitic acid), C18:0 (stearic acid), C18:1 (oleic acid), C18:2 (linoleic acid), and C20:4 (arachidonic acid). The contents of EFA and, most notably, of C20:4, in BJY chickens were significantly higher than in AA chickens (P < 0.05). The content of total unsaturated fatty acid of BJY chickens was marginally (P > 0.05) higher than that of AA chickens, whereas the percentages of total polyunsaturated fatty acids and saturated fatty acid in BJY chickens were slightly (P > 0.05) lower than those of AA chickens. A notable difference was found in the content of C20:4 (arachidonic acid), which was about 50% greater in BJY chickens than in AA chickens. Differences of this magnitude might underlie flavor characteristics of the 2 breeds and indicate that the content of dietary EFA would be greater from BJY meat. Essential fatty acids have an important role biologically. Arachidonic acid is an important intracellular second messenger that directly participates in intracellular signal transduction and affects other signaling pathways to control biological activity of cells (Bell et al., 1996; Byung et al., 1997). These results indicate that the breast muscles of BJY chickens have more nutritional value to humans than those of AA chickens. The method used allowed accurate measurement of 17 amino acids; however, glutamine, asparagines, and tryptophan could not be determined reliably. The total content of the 17 amino acids (protein and free) in breast muscle did not differ (P > 0.05) between BJY
(214.65 g/kg) and AA (223.15 g/kg) chickens. Similarly, no significant differences were found in contents of individual amino acids (Table 4). With few exceptions (threonine, cystine, and histidine), contents of most amino acids, the essential amino acids, and those related to flavor were slightly lower in BJY chickens; lysine content was significantly lower in BJY chickens. Muscle tissue mainly consists of muscle fiber, containing a large amount of protein, and is an important food source for humans (Lawrie, 1991; Warriss, 2000). In addition, amino acid is one of the main precursors of meat smell (Farmer, 1999), and the content of protein in meat affects different flavor substances (Chevance and Farmer, 1999). Analysis of amino acid composition (protein and free in breast muscle) showed no great difference between BJY chickens and AA chickens. Although the content of lysine was lower in BJY, the totals (21.47 and 22.32% by weight) were within the optimal range for quality meat. This may indicate that protein would not contribute to the difference of nutrition and flavor in breast muscle between BJY chickens and AA chickens at market age.
2358
Zhao et al.
Table 4. Amino acid composition and total content in breast muscle of Beijing-you (BJY) and Arbor Acres (AA) chickens1 Amino acid2 (g/kg)
21.28 8.42 7.48 38.33 8.73 12.65 1.32 12.80 5.87 11.76 22.14 3.24 9.51 15.99 11.05 16.41 7.69 106.41 121.63 214.65
± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ±
0.59 0.23 0.23 0.58 0.30 0.35 0.10 0.40 0.17 0.69 0.92 0.07 0.13 0.68b 0.50 0.79 0.22 1.90 2.09 1.99
AA 22.02 8.40 7.63 39.44 9.48 13.15 1.25 13.00 5.99 11.92 22.38 3.43 9.87 19.79 10.49 16.88 8.03 110.25 126.74 223.15
± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ±
0.76 0.27 0.22 0.64 0.32 0.36 0.09 0.43 0.11 0.56 0.89 0.10 0.12 0.78a 0.34 0.85 0.18 1.88 1.74 2.23
a,bMeans within a row with different superscripts differ significantly (P < 0.05). 1Data are means ± SD (wet weight, n = 6). 2EAA = essential amino acid (including threonine, valine, methionine, isoleucine, leucine, phenylalanine, lysine, histidine, arginine, and proline); FRAA = flavor-related amino acids (including cystine, glycine, aspartic acid, arginine, proline, alanine, and glutamic acid).
thinner muscle, more density, better tenderness (Sifre et al., 2005). Tenderness has been noted as the most important quality attribute in determining consumers’ ultimate satisfaction with a whole poultry muscle cut. The results from this study showed that the diameters of breast muscle fibers in 120-d-old BJY chickens (Table 5; Figure 1) were markedly smaller (~55.76% those of AA) and densities of fibers were accordingly greater (~174.86%) than those of 42-d-old AA chickens; both variables differed significantly (P < 0.05) between the breeds. Thus, it is reasonable to deduce that the tenderness of BJY chicken breast at the typical market age might be better than that of AA chicken. Moreover, the difference in fiber density probably accounts for the breed difference in phospholipids content of the muscle
Breed
Muscle fiber diameter (μm)
Muscle fiber density (fibers/mm2)
BJY AA BJY/AA ratio (%)
23.7 ± 1.6a 42.5 ± 1.2b 55.76
780.4 ± 42.9a 446.3 ± 57.9b 174.86
a,bMeans within a column with different superscripts differ significantly (P < 0.05). 1Data are means ± SD (n = 6).
because the quantity of sarcolemma must be greater in the BJY. Although extensive research has focused on the influence of age and speed of growth on muscle fiber characteristics or muscle tenderness (Staun, 1972; Swatland, 1990; Dransfield and Sosnicki, 1999; Koohmaraie et al., 2002; Baryshnikova et al., 2007), this study first characterizes the muscle fiber characteristics of both BJY chickens and AA chickens at market ages and contributes to the establishment of systematic evaluation methods for meat quality in broilers.
Conclusions The results from this study demonstrated differences between BJY chickens and AA chickens in several indices related to breast meat quality. At the typical market age, the breast muscle from 120-d-old BJY chickens was judged to have better quality with regard to muscle fiber characteristics, contents of EFA (especially C20:4), and phospholipids compared with breast muscle from 42-d-old AA chickens.
ACKNOWLEDGMENTS The authors acknowledge W. Bruce Currie for making suggestions on the manuscript. The research was supported by the China Agriculture Research System (CARS-42) and the National Nonprofit Institute Research Grant (China; 2010jc-1).
Figure 1. Typical transverse sections (stained with hematoxylin and eosin) of breast muscle in (A) Beijing-you and (B) Arbor Acres chickens. Photomicrographs are shown at 40× magnification. Color version available in online PDF.
Downloaded from http://ps.oxfordjournals.org/ at Monash University on June 18, 2015
Aspartic acid Threonine Serine Glutamic acid Glycine Alanine Cystine Valine Methionine Isoleucine Leucine Tyrosine Phenylalanine Lysine Histidine Arginine Proline EAA FRAA Total
BJY
Table 5. Muscle fiber diameter and density of breast muscle in Beijing-you (BJY) and Arbor Acres (AA) chickens1
MEAT QUALITY AND BROILER BREEDS
REFERENCES
performance, carcass characteristics and meat quality in three genotypes of chicken. J. Anim. Physiol. Anim. Nutr. (Berl.) 95:137–145. Kimura, S., S. Iyama, Y. Yamaguchi, S. Hayashi, and R. Fushimi. 1996. New enzymatic assay for calcium in serum. Clin. Chem. 42:1202–1205. Koohmaraie, M., K. Matthew, and D. Steven. 2002. Meat tenderness and muscle growth: Is there any relationship? Meat Sci. 62:345–352. Lawrie, R. A. 1985. Meat Science. 4th ed. Pergamon Press, Oxford, UK. Lawrie, R. A. 1991. Meat Science. 5th ed. Pergamon Press, Oxford, UK. Li, W. J., G. P. Zhao, J. L. Chen, M. Q. Zheng, and J. Wen. 2009. Influence of dietary vitamin E supplementation on carcass and meat quality traits and gene expression related to lipid metabolism in chicken. Br. Poult. Sci. 50:188–198. Lu, Q., J. Wen, and H. Zhang. 2007. Effect of chronic heat exposure on fat deposition and meat quality in two genetic types of chicken. Poult. Sci. 86:1059–1064. Matteo, B., F. C. Maria, T. Maria, E. Rodriguez, and L. Giovanni. 2007. Effect of feeding fat sources on the quality and composition of lipids of precooked ready-to-eat fried chicken patties. Food Chem. 101:1327–1337. Ministry of Agriculture of P. R. China. 2004. Nutrient requirements of yellow-feathered broiler. In Feeding Standard of Chickens, ICS 65.020.30, B 43, NY/T 33-2004. China Agricultural Press, Beijing, China. NRC. 1994. Nutrient Requirements of Poultry. Natl. Acad. Press, Washington, DC. Okazaki, M., N. Hagiwara, and I. Hara. 1982. Heterogeneity of human serum high density lipoproteins on high performance liquid chromatography. J. Biochem. 92:517–524. Sifre, L., P. Berge, E. Engel, J. F. Martin, and J. Culioli. 2005. Influence of the spatial organization of the perimysium on beef tenderness. J. Agric. Food Chem. 53:8390–8399. Staun, H. 1972. The nutritional and genetic influence on number and size of muscle fibres and their response to carcass quality in pigs. World Rev. Anim. Prod. 3:18–26. Sukhija, P. S., and D. L. Palmquist. 1988. Rapid method for determination of total fatty acid content and composition of the feedstuffs and feces. J. Agric. Food Chem. 36:1202–1206. Swatland, H. J. 1990. A fibre-optic probe for muscle composition in poultry. Can. Inst. Food. Sci. Technol. J. 23:239–241. Warriss, P. D. 2000. Meat Science: An Introductory Text. CABI Publishing, New York, NY. Zhang, G. M., J. Wen, J. L. Chen, G. P. Zhao, and M. Q. Zheng. 2007. Effect of conjugated linoleic acid on growth performances, carcase composition, plasma lipoprotein lipase activity and meat traits of chickens. Br. Poult. Sci. 48:217–223. Zhao, G. P., J. L. Chen, M. Q. Zheng, J. Wen, and Y. Zhang. 2007. Correlated responses to selection for increased intramuscular fat in a Chinese quality chicken line. Poult. Sci. 86:2309–2314. Zheng, P. 1988. Breeds of Domesticated Animal and Poultry in China. Shanghai Scientific and Technical Publishers, Shanghai, China.
Downloaded from http://ps.oxfordjournals.org/ at Monash University on June 18, 2015
AOAC. 1990. Official Methods of Analysis. 16th ed. Assoc. Offic. Anal. Chem., Arlington, VA. Baryshnikova, L. M., S. A. Croes, and C. S. von Bartheld. 2007. Classification and development of myofiber types in the superior oblique extraocular muscle of chicken. Anat. Rec. (Hoboken) 290:1526–1541. Bell, J. G., I. Ashton, C. J. Secombes, B. R. Weitzel, and J. R. Sargent. 1996. Dietary lipid affects phospholipid fatty acid compositions, eicosanoid production and immune function in Atlantic salmon (Salmo salar). Prostaglandins Leukot. Essent. Fatty Acids 54:173–182. Bergmeyer, U., J. Bergmeyer, and M. Grassl. 1974. Methods of Enzymatic Analysis. Vol. 2. Sample, Regents, Assessment of Results. Academic Press Inc., New York, NY. Kim, B. C., C. J. Lim, and J. H. Kim. 1997. Arachidonic acid, a principal product of Rac-activated phospholipase A2, stimulates c-fos serum response element via Rho-dependent mechanism. FEBS Lett. 415:325–328. Chen, J. L., G. P. Zhao, M. Q. Zheng, J. Wen, and N. Yang. 2008. Estimation of genetic parameters for contents of intramuscular fat and inosine-5′-monophosphate and carcass traits in Chinese Beijing-You chickens. Poult. Sci. 87:1098–1104. Cherian, G., R. K. Selvaraj, M. P. Goeger, and P. A. Stitt. 2002. Muscle fatty acid composition and thiobarbituric acid-reactive substances of broilers fed different cultivars of sorghum. Poult. Sci. 81:1415–1420. Chevance, F. F., and L. J. Farmer. 1999. Release of volatile odor compounds from full-fat and reduced-fat frankfurters. J. Agric. Food Chem. 47:5161–5168. Cisneros, F., M. Ellis, F. K. McKeith, J. McCaw, and R. L. Fernando. 1996. Influence of slaughter weight on growth and carcass characteristics, commercial cutting and curing yields, and meat quality of barrows and gilts from two genotypes. J. Anim. Sci. 74:925–933. Cumming, W. J. K., J. Fulthorpe, P. Hudgson, and M. Mahon. 1994. Colour Atlas of Muscle Pathology. Mosby-Wolfe, London, UK. DeVol, D. L., F. K. Mckeith, P. J. Bechtel, J. Novakofski, R. D. Shanks, and T. R. Carr. 1988. Variation in composition and palatability traits and relationships between muscle characteristics and palatability in a random sample of pork carcasses. J. Anim. Sci. 66:385–395. Dransfield, E., and A. A. Sosnicki. 1999. Relationship between muscle growth and poultry meat quality. Poult. Sci. 78:743–746. Farmer, L. J. 1999. Poultry meat flavor. Pages 127–158 in Poultry Meat Science. R. I. Richardson and G. C. Mead, ed. CABI Publishing, New York, NY. Folch, J., M. Lees, and G. H. Sloane Stanley. 1957. A simple method for the isolation and purification of total lipids from animal tissues. J. Biol. Chem. 226:497–509. Gandemer, G. 1997. Muscle lipid and meat quality: Phospholipids and flavor. Lipides 4:19–25. Hatch, F. T. 1968. Practical methods for plasma lipoprotein analysis. Adv. Lipid Res. 6:1–68. Jiang, R. R., G. P. Zhao, J. L. Chen, M. Q. Zheng, and J. Wen. 2011. Effect of dietary supplemental nicotinic acid on growth
2359
Key words: Beijing-you chicken, Arbor Acres broiler, breast muscle, nutrient component, muscle fiber characteristic 2011 Poultry Science 90:2355–2359 doi:10.3382/ps.2011-01432
INTRODUCTION Chickens used for meat production in China include introduced and genetically improved broiler strains, dual-purpose breeds, and numerous native breeds. Criteria for meat quality vary in different countries and areas and reflect dietary habits. In general, however, chicken meat quality traits consist of 3 categories: appearance (i.e., flesh color), physical (i.e., muscle pH, water-holding capacity, and organizational structure, underlying the texture and tenderness of meat), and chemical [i.e., protein and crude fat contents and their composition (amino acids and fatty acids; Lawrie, 1985)]. Genetics is a major factor influencing meat quality of chickens (Lawrie, 1985; Cisneros et al., 1996), and native Chinese breeds are considered to have superior quality compared with rapidly growing imported broilers (Lu et al., 2007; Zhang et al., 2007; Li et al., 2009). The Beijing-you (BJY) chicken is an indigenous breed in China, 1 of 27 rare breeds listed in Zheng (1988), and has a special appearance and quality in egg and meat products. When compared with the Arbor Acres (AA) broiler, the BJY chicken is highly liked in China because of its taste, rich fragrance, and tenderness.
Previous studies on meat quality of the BJY chicken and other breeds have mainly focused on appearance and physical traits of the carcass, pH values, waterholding capacity, or muscle fiber characteristics. Some studies have examined chemical traits such as intramuscular fat content and fatty acid composition at the same day of age (DeVol et al., 1988; Cherian et al., 2002; Matteo et al., 2007; Zhao et al., 2007; Chen et al., 2008; Jiang et al., 2011). As the living standards of consumers have improved, an increase has occurred in demand for perceived quality in meat products and in consumer preference for indigenous chicken breeds. However, little is known of other nutritional components and muscle fiber characteristics in both BJY chickens and AA broilers at their market ages. The objective of the present study was to compare meat quality traits, including nutrient components and muscle fiber characteristics, between BJY chickens and AA chickens at market ages of each breed. Because breast meat is one of the major high-value cuts, it was examined in the present study.
MATERIALS AND METHODS Birds, Diets, and Sample Collection
©2011 Poultry Science Association Inc. Received February 21, 2011. Accepted June 14, 2011. 1 G. P. Zhao and H. X. Cui contributed equally to this work. 2 Corresponding author: [email protected]
The present study was approved by the Institute of Animal Sciences, Chinese Academy of Agricultural Sciences (Beijing, China) and carried out in accordance with the Guidelines for Experimental Animals estab2355
Downloaded from http://ps.oxfordjournals.org/ at Monash University on June 18, 2015
ABSTRACT On the basis of meat quality traits, muscle fiber characteristics, and nutrient components and contents in chickens at market age, 120-d-old Beijing-you (BJY) chickens (the Chinese local breed) had distinct breast muscle features when compared with 42-d-old Arbor Acres (AA) chickens (the genetically improved broiler line). The phospholipid (P < 0.05) and essential fatty acid (P < 0.05) contents in BJY chickens were significantly higher than those in AA chickens. No differences (P > 0.05) were found between the breeds in the
2356
Zhao et al.
Determination of Phospholipids and Triglycerides A 2.0-g sample of each breast muscle (n = 12) was homogenized and extracted (Folch et al., 1957). Then, triglyceride (TG; Hatch, 1968; Okazaki et al., 1982) and phospholipid (Bergmeyer et al., 1974; Kimura et al., 1996) contents were measured with kits (Beijing
Table 1. Ingredients and calculated chemical composition of starter and grower diets Item (% unless noted) Ingredient Corn (7.8% CP) Soybean meal (43% CP) Corn protein powder (56% CP) Soybean oil Calcium phosphate Limestone Salt l-Lysine hemifumarate dl-Methionine Choline chloride (50%) Mineral premix Multivitamin mix Total Nutrient composition CP Crude fat Calcium Total phosphorus Available phosphorus Lysine Methionine Threonine Tryptophan ME (MJ/kg)
Starter (1–21 d)
Grower (22–120 d)
60.00 32.87 1.92 1.50 1.40 1.36 0.30 0.20 0.20 0.19 0.06 0.02 100
63.54 27.49 3.00 2.03 1.72 1.24 0.32 0.13 0.11 0.20 0.20 0.02 100
20.00 4.00 1.00 0.69 0.45 1.05 0.48 0.74 0.22 12.01
19.00 5.10 0.90 0.63 0.40 1.00 0.43 0.76 0.23 12.55
Deliman Biochemical Technology Co. Ltd., Beijing, China).
Analysis of Compositions of Fatty Acids and Amino Acids Six breast muscle samples (2.0 g) from the total of 12 harvested in each breed were randomly selected, and the composition of fatty acids was determined using gas chromatography according to the method of Sukhija and Palmquist (1988). Breast muscle samples were freeze dried and ground for extraction and methylation of fatty acids before analysis using an HP6890 gas chromatograph (Hewlett-Packard, Palo Alto, CA). Six breast muscle samples (2.0 g) from the total of 12 birds harvested from each breed were randomly selected, and the composition of amino acids was determined on a Beckman 6300 amino acid analyzer (Beckman Instruments Corp., Brea, CA) using ninhydrin for postcolumn derivatization and norleucine as the internal standard. Before analysis, samples were hydrolyzed with 6 N HCl for 24 h at 110°C. Methionine and cysteine were determined as methionine sulfone and cysteic acid after cold perfomic acid oxidation before hydrolysis (method 994.12; AOAC, 1990).
Analysis of Muscle Structure Samples (~2 cm3) of 6 randomly selected birds were removed from consistent locations on the breast muscle from 12 birds harvested from each breed. The samples were oriented for transverse fiber sectioning and mounted on cork disks using the OCT Tissue-Tek (Sakura Finetechnical Co., Tokyo, Japan). Serial cryostat sections (10-μm; −20°C) were cut and stained with hematoxylin and eosin (Cumming et al., 1994). For each bird, muscle fiber size was estimated by measuring the minimum fiber diameter of 100 fibers using image analysis software, and the density of muscle fibers (fibers/mm2) was estimated by point-counting stereology using 500 points.
Statistical Analyses Data were subjected to 1-way ANOVA using SAS version 8.2 (SAS Institute, Cary, NC). Statistical significance was accepted at P < 0.05.
RESULTS AND DISCUSSION Nutritional Components of Breast Muscle The content of TG was slightly, but not significantly, higher in BJY than in AA chickens. The content of phospholipids and its relative ratio to TG in BJY chickens were both more than twice (P < 0.05) the values in AA chickens (Table 2). Phospholipids, important components of cell membranes, are made up of glycerol,
Downloaded from http://ps.oxfordjournals.org/ at Monash University on June 18, 2015
lished by the Ministry of Science and Technology (Beijing, China). One-day-old female hatchlings, 48 each of AA (Dadongliu Broiler Company, Beijing, China) and BJY (Institute of Animal Science, Chinese Academy of Agricultural Sciences), were used. Individuals within each breed had the same genetic background. All birds entered the experiment at the same time and were randomly distributed into 4 replicate groups for each breed; each group comprised 12 BJY birds and 12 AA birds. Birds were raised in an environmentally controlled room with 8 floor pens. Feed and water were provided ad libitum during the experiment. Diets for the starter (1–21 d) and grower (≥22 d) phases were formulated (Table1) to be intermediate between recommendations for the 2 breeds (NRC, 1994; Ministry of Agriculture of P. R. China, 2004). Birds were slaughtered at typical market ages: AA broilers at 42 d old and BJY chickens at 120 d old. Following a 12-h overnight fast, 3 birds of similar weight from each replicate were electrically stunned and killed by exsanguination. The breast muscle (pectoralis major) from one side was frozen at −20°C for further chemical evaluation.
2357
MEAT QUALITY AND BROILER BREEDS Table 2. Phospholipid (PL) and triglyceride (TG) contents in breast muscle of Beijing-you (BJY) and Arbor Acres (AA) chickens1 Breed BJY AA BJY/AA ratio
PL (g/kg)
TG (g/kg)
PL/TG (%)
5.77 ± 0.30a 2.14 ± 0.26b 2.70
9.25 ± 0.51 8.81 ± 0.72 1.05
62.38a 24.29b 2.57
a,bMeans within a column with different superscripts differ significantly (P < 0.05). 1Data are means ± SD (wet weight, n = 12).
Muscle Fiber Size and Density Previous studies demonstrated the close relationship between the muscle fiber characteristics (including muscle fiber density and diameter) and tenderness of meat:
Table 3. Fatty acid composition of lipids in breast muscle of Beijing-you (BJY) and Arbor Acres (AA) chickens1 Fatty acid2 (%) C14:0 C16:0 C18:0 C20:0 C24:0 C16:1 C18:1 n-9 C18:1 n-7 C18:2 C18:3 n-6 C18:3 n-3 C20:1 C20:2 C20:4 n-6 C20:5 C22:4 n-6 C22:5 C22:6 C24:1 SFA UFA PUFA EFA Major components
BJY 0.58 23.41 10.37 0.26 0.21 1.73 21.67 1.92 21.89 0.08 0.73 0.23 0.45 10.42 0.32 2.38 1.57 1.52 0.25 34.83 65.14 37.19 33.11 89.68
± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ±
0.02 0.55 0.12 0.03 0.02b 0.08 0.89 0.11 1.02 0.01b 0.05 0.02 0.04 0.88a 0.06 0.97a 0.32 0.33 0.05 1.33 1.79 0.98 0.72a 0.57
AA 0.49 24.14 9.66 0.13 1.18 2.30 25.68 2.99 20.31 0.20 0.88 0.29 0.80 6.48 0.42 1.63 1.15 0.93 0.31 35.60 64.36 37.86 27.87 89.26
± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ±
0.03 0.39 0.10 0.04 0.08a 0.10 0.72 0.12 0.72 0.01a 0.10 0.09 0.02 1.19b 0.04 0.66b 0.29 0.37 0.01 1.07 1.12 1.01 0.86b 0.71
a,bMeans within a row with different superscripts differ significantly (P < 0.05). 1Data are means ± SD (n = 6). 2SFA = saturated fatty acids; UFA = unsaturated fatty acids; PUFA = polyunsaturated fatty acids; EFA = essential fatty acids (including linoleic acid, linolenic acid, and arachidonic acid). Major components included C16:0, C18:0, C18:1, C18:2, and C20:4.
Downloaded from http://ps.oxfordjournals.org/ at Monash University on June 18, 2015
fatty acid, phosphoric acid, choline, or cholamine and can be divided into lecithin and cephalin. Phospholipids play an important role in nervous system development and animal development. Phospholipids contain most of the polyunsaturated fatty acids, such as linolenic acid and arachidonic acid, in animal tissues; these constitute the essential fatty acids (EFA) in human diets. Degradation products of the phospholipids from oxidative changes postmortem influence the composition of the volatile flavor components and consequently change the flavor of meat (Gandemer, 1997). In this study, the phospholipids content in breast muscle of BJY chickens was 2.70 times that of AA chickens (P < 0.05); this higher phospholipids content can improve the nutritional value of breast muscle in BJY chickens. Fatty acid compositions of the total lipids in breast muscle are shown in Table 3. The major components, accounting for 89.68% (BJY) and 89.26% (AA), were C16:0 (palmitic acid), C18:0 (stearic acid), C18:1 (oleic acid), C18:2 (linoleic acid), and C20:4 (arachidonic acid). The contents of EFA and, most notably, of C20:4, in BJY chickens were significantly higher than in AA chickens (P < 0.05). The content of total unsaturated fatty acid of BJY chickens was marginally (P > 0.05) higher than that of AA chickens, whereas the percentages of total polyunsaturated fatty acids and saturated fatty acid in BJY chickens were slightly (P > 0.05) lower than those of AA chickens. A notable difference was found in the content of C20:4 (arachidonic acid), which was about 50% greater in BJY chickens than in AA chickens. Differences of this magnitude might underlie flavor characteristics of the 2 breeds and indicate that the content of dietary EFA would be greater from BJY meat. Essential fatty acids have an important role biologically. Arachidonic acid is an important intracellular second messenger that directly participates in intracellular signal transduction and affects other signaling pathways to control biological activity of cells (Bell et al., 1996; Byung et al., 1997). These results indicate that the breast muscles of BJY chickens have more nutritional value to humans than those of AA chickens. The method used allowed accurate measurement of 17 amino acids; however, glutamine, asparagines, and tryptophan could not be determined reliably. The total content of the 17 amino acids (protein and free) in breast muscle did not differ (P > 0.05) between BJY
(214.65 g/kg) and AA (223.15 g/kg) chickens. Similarly, no significant differences were found in contents of individual amino acids (Table 4). With few exceptions (threonine, cystine, and histidine), contents of most amino acids, the essential amino acids, and those related to flavor were slightly lower in BJY chickens; lysine content was significantly lower in BJY chickens. Muscle tissue mainly consists of muscle fiber, containing a large amount of protein, and is an important food source for humans (Lawrie, 1991; Warriss, 2000). In addition, amino acid is one of the main precursors of meat smell (Farmer, 1999), and the content of protein in meat affects different flavor substances (Chevance and Farmer, 1999). Analysis of amino acid composition (protein and free in breast muscle) showed no great difference between BJY chickens and AA chickens. Although the content of lysine was lower in BJY, the totals (21.47 and 22.32% by weight) were within the optimal range for quality meat. This may indicate that protein would not contribute to the difference of nutrition and flavor in breast muscle between BJY chickens and AA chickens at market age.
2358
Zhao et al.
Table 4. Amino acid composition and total content in breast muscle of Beijing-you (BJY) and Arbor Acres (AA) chickens1 Amino acid2 (g/kg)
21.28 8.42 7.48 38.33 8.73 12.65 1.32 12.80 5.87 11.76 22.14 3.24 9.51 15.99 11.05 16.41 7.69 106.41 121.63 214.65
± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ±
0.59 0.23 0.23 0.58 0.30 0.35 0.10 0.40 0.17 0.69 0.92 0.07 0.13 0.68b 0.50 0.79 0.22 1.90 2.09 1.99
AA 22.02 8.40 7.63 39.44 9.48 13.15 1.25 13.00 5.99 11.92 22.38 3.43 9.87 19.79 10.49 16.88 8.03 110.25 126.74 223.15
± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ±
0.76 0.27 0.22 0.64 0.32 0.36 0.09 0.43 0.11 0.56 0.89 0.10 0.12 0.78a 0.34 0.85 0.18 1.88 1.74 2.23
a,bMeans within a row with different superscripts differ significantly (P < 0.05). 1Data are means ± SD (wet weight, n = 6). 2EAA = essential amino acid (including threonine, valine, methionine, isoleucine, leucine, phenylalanine, lysine, histidine, arginine, and proline); FRAA = flavor-related amino acids (including cystine, glycine, aspartic acid, arginine, proline, alanine, and glutamic acid).
thinner muscle, more density, better tenderness (Sifre et al., 2005). Tenderness has been noted as the most important quality attribute in determining consumers’ ultimate satisfaction with a whole poultry muscle cut. The results from this study showed that the diameters of breast muscle fibers in 120-d-old BJY chickens (Table 5; Figure 1) were markedly smaller (~55.76% those of AA) and densities of fibers were accordingly greater (~174.86%) than those of 42-d-old AA chickens; both variables differed significantly (P < 0.05) between the breeds. Thus, it is reasonable to deduce that the tenderness of BJY chicken breast at the typical market age might be better than that of AA chicken. Moreover, the difference in fiber density probably accounts for the breed difference in phospholipids content of the muscle
Breed
Muscle fiber diameter (μm)
Muscle fiber density (fibers/mm2)
BJY AA BJY/AA ratio (%)
23.7 ± 1.6a 42.5 ± 1.2b 55.76
780.4 ± 42.9a 446.3 ± 57.9b 174.86
a,bMeans within a column with different superscripts differ significantly (P < 0.05). 1Data are means ± SD (n = 6).
because the quantity of sarcolemma must be greater in the BJY. Although extensive research has focused on the influence of age and speed of growth on muscle fiber characteristics or muscle tenderness (Staun, 1972; Swatland, 1990; Dransfield and Sosnicki, 1999; Koohmaraie et al., 2002; Baryshnikova et al., 2007), this study first characterizes the muscle fiber characteristics of both BJY chickens and AA chickens at market ages and contributes to the establishment of systematic evaluation methods for meat quality in broilers.
Conclusions The results from this study demonstrated differences between BJY chickens and AA chickens in several indices related to breast meat quality. At the typical market age, the breast muscle from 120-d-old BJY chickens was judged to have better quality with regard to muscle fiber characteristics, contents of EFA (especially C20:4), and phospholipids compared with breast muscle from 42-d-old AA chickens.
ACKNOWLEDGMENTS The authors acknowledge W. Bruce Currie for making suggestions on the manuscript. The research was supported by the China Agriculture Research System (CARS-42) and the National Nonprofit Institute Research Grant (China; 2010jc-1).
Figure 1. Typical transverse sections (stained with hematoxylin and eosin) of breast muscle in (A) Beijing-you and (B) Arbor Acres chickens. Photomicrographs are shown at 40× magnification. Color version available in online PDF.
Downloaded from http://ps.oxfordjournals.org/ at Monash University on June 18, 2015
Aspartic acid Threonine Serine Glutamic acid Glycine Alanine Cystine Valine Methionine Isoleucine Leucine Tyrosine Phenylalanine Lysine Histidine Arginine Proline EAA FRAA Total
BJY
Table 5. Muscle fiber diameter and density of breast muscle in Beijing-you (BJY) and Arbor Acres (AA) chickens1
MEAT QUALITY AND BROILER BREEDS
REFERENCES
performance, carcass characteristics and meat quality in three genotypes of chicken. J. Anim. Physiol. Anim. Nutr. (Berl.) 95:137–145. Kimura, S., S. Iyama, Y. Yamaguchi, S. Hayashi, and R. Fushimi. 1996. New enzymatic assay for calcium in serum. Clin. Chem. 42:1202–1205. Koohmaraie, M., K. Matthew, and D. Steven. 2002. Meat tenderness and muscle growth: Is there any relationship? Meat Sci. 62:345–352. Lawrie, R. A. 1985. Meat Science. 4th ed. Pergamon Press, Oxford, UK. Lawrie, R. A. 1991. Meat Science. 5th ed. Pergamon Press, Oxford, UK. Li, W. J., G. P. Zhao, J. L. Chen, M. Q. Zheng, and J. Wen. 2009. Influence of dietary vitamin E supplementation on carcass and meat quality traits and gene expression related to lipid metabolism in chicken. Br. Poult. Sci. 50:188–198. Lu, Q., J. Wen, and H. Zhang. 2007. Effect of chronic heat exposure on fat deposition and meat quality in two genetic types of chicken. Poult. Sci. 86:1059–1064. Matteo, B., F. C. Maria, T. Maria, E. Rodriguez, and L. Giovanni. 2007. Effect of feeding fat sources on the quality and composition of lipids of precooked ready-to-eat fried chicken patties. Food Chem. 101:1327–1337. Ministry of Agriculture of P. R. China. 2004. Nutrient requirements of yellow-feathered broiler. In Feeding Standard of Chickens, ICS 65.020.30, B 43, NY/T 33-2004. China Agricultural Press, Beijing, China. NRC. 1994. Nutrient Requirements of Poultry. Natl. Acad. Press, Washington, DC. Okazaki, M., N. Hagiwara, and I. Hara. 1982. Heterogeneity of human serum high density lipoproteins on high performance liquid chromatography. J. Biochem. 92:517–524. Sifre, L., P. Berge, E. Engel, J. F. Martin, and J. Culioli. 2005. Influence of the spatial organization of the perimysium on beef tenderness. J. Agric. Food Chem. 53:8390–8399. Staun, H. 1972. The nutritional and genetic influence on number and size of muscle fibres and their response to carcass quality in pigs. World Rev. Anim. Prod. 3:18–26. Sukhija, P. S., and D. L. Palmquist. 1988. Rapid method for determination of total fatty acid content and composition of the feedstuffs and feces. J. Agric. Food Chem. 36:1202–1206. Swatland, H. J. 1990. A fibre-optic probe for muscle composition in poultry. Can. Inst. Food. Sci. Technol. J. 23:239–241. Warriss, P. D. 2000. Meat Science: An Introductory Text. CABI Publishing, New York, NY. Zhang, G. M., J. Wen, J. L. Chen, G. P. Zhao, and M. Q. Zheng. 2007. Effect of conjugated linoleic acid on growth performances, carcase composition, plasma lipoprotein lipase activity and meat traits of chickens. Br. Poult. Sci. 48:217–223. Zhao, G. P., J. L. Chen, M. Q. Zheng, J. Wen, and Y. Zhang. 2007. Correlated responses to selection for increased intramuscular fat in a Chinese quality chicken line. Poult. Sci. 86:2309–2314. Zheng, P. 1988. Breeds of Domesticated Animal and Poultry in China. Shanghai Scientific and Technical Publishers, Shanghai, China.
Downloaded from http://ps.oxfordjournals.org/ at Monash University on June 18, 2015
AOAC. 1990. Official Methods of Analysis. 16th ed. Assoc. Offic. Anal. Chem., Arlington, VA. Baryshnikova, L. M., S. A. Croes, and C. S. von Bartheld. 2007. Classification and development of myofiber types in the superior oblique extraocular muscle of chicken. Anat. Rec. (Hoboken) 290:1526–1541. Bell, J. G., I. Ashton, C. J. Secombes, B. R. Weitzel, and J. R. Sargent. 1996. Dietary lipid affects phospholipid fatty acid compositions, eicosanoid production and immune function in Atlantic salmon (Salmo salar). Prostaglandins Leukot. Essent. Fatty Acids 54:173–182. Bergmeyer, U., J. Bergmeyer, and M. Grassl. 1974. Methods of Enzymatic Analysis. Vol. 2. Sample, Regents, Assessment of Results. Academic Press Inc., New York, NY. Kim, B. C., C. J. Lim, and J. H. Kim. 1997. Arachidonic acid, a principal product of Rac-activated phospholipase A2, stimulates c-fos serum response element via Rho-dependent mechanism. FEBS Lett. 415:325–328. Chen, J. L., G. P. Zhao, M. Q. Zheng, J. Wen, and N. Yang. 2008. Estimation of genetic parameters for contents of intramuscular fat and inosine-5′-monophosphate and carcass traits in Chinese Beijing-You chickens. Poult. Sci. 87:1098–1104. Cherian, G., R. K. Selvaraj, M. P. Goeger, and P. A. Stitt. 2002. Muscle fatty acid composition and thiobarbituric acid-reactive substances of broilers fed different cultivars of sorghum. Poult. Sci. 81:1415–1420. Chevance, F. F., and L. J. Farmer. 1999. Release of volatile odor compounds from full-fat and reduced-fat frankfurters. J. Agric. Food Chem. 47:5161–5168. Cisneros, F., M. Ellis, F. K. McKeith, J. McCaw, and R. L. Fernando. 1996. Influence of slaughter weight on growth and carcass characteristics, commercial cutting and curing yields, and meat quality of barrows and gilts from two genotypes. J. Anim. Sci. 74:925–933. Cumming, W. J. K., J. Fulthorpe, P. Hudgson, and M. Mahon. 1994. Colour Atlas of Muscle Pathology. Mosby-Wolfe, London, UK. DeVol, D. L., F. K. Mckeith, P. J. Bechtel, J. Novakofski, R. D. Shanks, and T. R. Carr. 1988. Variation in composition and palatability traits and relationships between muscle characteristics and palatability in a random sample of pork carcasses. J. Anim. Sci. 66:385–395. Dransfield, E., and A. A. Sosnicki. 1999. Relationship between muscle growth and poultry meat quality. Poult. Sci. 78:743–746. Farmer, L. J. 1999. Poultry meat flavor. Pages 127–158 in Poultry Meat Science. R. I. Richardson and G. C. Mead, ed. CABI Publishing, New York, NY. Folch, J., M. Lees, and G. H. Sloane Stanley. 1957. A simple method for the isolation and purification of total lipids from animal tissues. J. Biol. Chem. 226:497–509. Gandemer, G. 1997. Muscle lipid and meat quality: Phospholipids and flavor. Lipides 4:19–25. Hatch, F. T. 1968. Practical methods for plasma lipoprotein analysis. Adv. Lipid Res. 6:1–68. Jiang, R. R., G. P. Zhao, J. L. Chen, M. Q. Zheng, and J. Wen. 2011. Effect of dietary supplemental nicotinic acid on growth
2359