Advanced
Comparison of Carcass Characteristics and Meat Quality between Duroc and Crossbred Pigs
Comparison of Carcass Characteristics and Meat Quality between Duroc and Crossbred Pigs
Food Science of Animal Resources. 2014. Apr, 34(2): 238-244
Copyright © 2014, Korean Society for Food Science of Animal Resources
  • Received : February 26, 2014
  • Accepted : April 02, 2014
  • Published : April 30, 2014
Download
PDF
e-PUB
PubReader
PPT
Export by style
Article
Author
Metrics
Cited by
TagCloud
About the Authors
Jung-Seok, Choi
Department of Animal Resources Technology and Swine Science & Technology Center, Gyeongnam National University of Science and Technology, Jinju 660-758, Korea
Hyun-Jin, Lee
Department of Animal Science, Chungbuk National University, Cheongju 361-763, Korea
Sang-Keun, Jin
Department of Animal Resources Technology and Swine Science & Technology Center, Gyeongnam National University of Science and Technology, Jinju 660-758, Korea
Yang-Il, Choi
Department of Animal Science, Chungbuk National University, Cheongju 361-763, Korea
Jae-Joon, Lee
leejj80@chosun. ac.kr

Abstract
This study was conducted to compare the carcass characteristics and meat quality characteristics of Duroc breed and crossbred pigs (Landrace × Yorkshire × Duroc, LYD). Duroc and crossbred pigs did not show differences in carcass characteristics. Crossbred pigs had higher moisture and protein content than Duroc breeds. However, Duroc breeds had a higher fat content than the crossbred pigs. In meat quality characteristics, crossbred pigs showed higher values of drip loss and cooking loss over Duroc breeds, while Duroc breeds showed higher ultimate pH value compared to that of crossbred pigs. However, there were no differences in water holding capacity and shear force value. In myoglobin content, crossbred pigs had higher content compared to that in the Duroc population. In subjective evaluation and sensory characteristics, Duroc breeds showed significantly higher scores in all categories except for tenderness over the crossbred pigs. However, in storage characteristics, Duroc breeds showed reduced tendency relative to crossbred pigs. Crossbred pigs had higher unsaturated fatty acid content than Duroc breeds did. In these results, Duroc breeds showed excellent meat quality characteristics with its higher intramuscular fat content and pH value, lower drip loss and cooking loss and higher juiciness and flavor, compared to the crossbred pigs.
Keywords
Introduction
Pigs have been domesticated as a source of food for intake about 9,000 years ago. There are 30-40 species of domesticated pigs today ( Rothschilds and Ruvinsky, 2010 ). In Korea, consumers prefer high marbled meat. Because marbled meat contains high lipid content, many sensory properties such as flavor and aroma volatiles and essential fatty acids. Tenderness and juiciness of meat are increased by those factors. It is clear that increase of fat in meat has a most significant effect on meat quality, though there are other factor (sex, species, age, feed, and environmental conditions) that affect meat quality. These factors include water holding capacity (WHC), color, pH, shear force, sensory attributes, and storage characteristics in meat. So, quality characteristics in meat have been improved by studies of researchers at livestock research institutes and universities ( Knap , 2001 ; Kolstad , 1996 ; Tizioto , 2012 ).
The pig breeding stock industry is at the top of the pyramid structure of pig farms and plays an important role in providing superior genes to improve the pork industry. Thus, the ability to breed pig stock is the most important factor that influences the success or failure in the pig industry ( Lee, 1996 ; Seo , 2012 ). Currently, consumers prefer meat with excellent quality. Thus, in the threeway crossbreds, Landrace and Yorkshire are highly prolific and have a good mothering ability, and Duroc has good meat quality ( Kim , 2002 ; Kim , 2006a ; Seo , 2011 ). Also, fertility and litter size are inherited through the maternal line, and meat productivity and meat quality are inherited through the paternal ( Kim , 2006b ; Lee , 2011 ). Therefore, the improvement of pig breeding stock is essential. On the other hand, Johnson (2002) stated that average daily gain (ADG) is highest in Duroc. Among Hampshire, Landrace, Yorkshire and Duroc, respectively, ADG values of 0.83±0.13 kg, 0.85±0.15kg, 0.87±0.14 kg, and 0.88±0.13 kg were found during 100-177 d of age. Oh (2005) reported that the EMA (eye muscle area)'s heritability of Landrace, Yorkshire and Duroc were estimated to be 0.33, 0.18 and 0.37, respectively.
Three way crossbred pigs (Landrace × Yorkshire × Duroc) are mainly utilized for production of commercial pork and have more great production efficiency than pure or two-way crossbreds ( Nelson and Robison, 1976 ). The Duroc breed is used as a terminal sire when commercial pigs are produced. Also, this breed has used for fattening of commercial pigs ( Suzuki , 2003 ). Therefore the objective of this study is to determine the carcass characteristics and meat quality characteristics between Duroc and crossbred pigs and to help pork industry in Korea.
Materials and Methods
- Animals and sampling
A total of 620 pigs used in this study were comprised of 1) 200 purebred Duroc gilts, 2) 420 crossbred pigs in Korea. Duroc pigs were a part of pig improvement network program (Korea Animal Improvement Association, KAIA) at November 2010 to December 2011. Crossbred pigs (Landrace × Yorkshire × Duroc) were provided by Cheongwon Pig Farmers Corporation (CPFC) at March 2008 to February 2009. Pigs were raised by Korean Feeding Standard for Swine (KFSS) in the each farm. The basal diet was formulated to meet nutrient requirements of pigs and made of 51.43% corn, 18.72% wheat and wheat bran, 19.08% soybean meal, and 10.77% other feedstuffs and additives ( Table 1 ). When the mean weight of pigs in a pen reached market weight, pigs were conventionally slaughtered and then chilled overnight. At 24 h postmortem, carcass measurements including backfat thickness, carcass length and carcass grading evaluated by Animal Products Grading Service (2001) were collected. Then, the longissimus muscle from left side between the 5 th and 13 th rib was removed and meat qualities were evaluated at meat science laboratory of Chungbuk National University.
- Carcass characteristics
Carcass grade, carcass weight and backfat thickness were used from the data which was measured based on cold carcass grading system in the Korea institute for animal products quality evaluation (KAPE). Carcass length was measured from the 6 th cervical vertebral to H-bone on the left side.
Formula of basal diets
PPT Slide
Lager Image
1)Supplied per kg diets: Vitamin A, 8,000,000 IU; Vitamin D, 1,500,000 IU; Vitamin E, 40,000 ppm; Vitamin K 1,500 ppm; Thiamin, 1,000 ppm; Riboflavin, 4,000 ppm; Vitamin B12, 20 ppb; Pyridoxine, 2,000 ppm; Niacin 20,000 ppm; Biotin, 30 ppm; Folic acid, 600 ppm 2)Supplied per kg diet: Se, 250 mg; I, 200 mg; Fe, 60,000 mg; Mn, 25,000 mg; Zn, 60,000 mg; Cu, 15,000 mg
- pH
Using a homogenizer (Nihonseiki, Japan), 10 g of samples was homogenized in 100 ml of distilled water for 30 s at 7,000 rpm. The pH levels of the homogenate was determined using a pH meter (Mteeler Delta 340, Mettlertolede, Ltd, UK).
- Meat color
The L*, a* and b* values were determined on the surface of freshly cut meat after 20 min bloom time using a Spectro Colormeter (Model JX-777, Color Techno. System Co., Japan) calibrated to the white plate (L*, 89.39; a*, 0.13; b*, -0.51). L*, a*, b* values described Hunter lab color system (L*=lightness, a*=redness, b*=yellowness) using a white fluorescent light (D65) as light source. Each measurement was performed in 6 replicates, taking the mean value as the assay result.
- Water holding capacity (WHC)
The centrifugation method described by Laakkonen (1970) was used to measure WHC. Logissimus muscle sample (0.5±0.05 g) from each line were placed in centrifugation tube with filter units, heated for 20 min at 80℃, and then cooled for 10 min. Samples were centrifuged at 2,000 g for 10 min 4℃ and WHC calculated as the difference of sample weight.
- Drip loss
A 2 cm thick slice (weight 100±5 g) cut from logissimus muscle was placed into polypropylene bag and then vacuum pakaged and stored for 24 h at 4℃. Drip loss was calculated by weight difference of samples.
- Proximal analysis
Moisture, protein, lipid and ash were assayed according to the AOAC methods (1995) .
- Cooking loss
A 3 cm thick slice (weight 100±5 g) cut from logissimus muscle was placed into polypropylene bag and then cooked for 40 min at 70℃ in the water-bath and then cooled down to room temperature. Cooking loss was calculated by weight difference of samples.
- Shear force test
A 3 cm thick slice (weight 100±5 g) cut from logissimus muscle was placed into polypropylene bag and then cooked for 40 min at 70℃ in the water-bath and then cooled for 30 min. Samples were cut into 1×2×1 cm (width × length × height) pieces and max weight were measured by a shearing, and cutting test using a Rheo meter (Model Compac-100, SUN SCIENTIFIC Co., Japan) under the following operational conditions: table speed of 110 mm/ min, graph interval of 20 m/sec and load cell (max.) of 10 kg using the R.D.S (Rheology Data System) Ver 2.01.
- Cholesterol
Freeze dried samples of 0.3 g were homogenized with 12 ml of chloroform:methanol (2:1) Folch solution and then placed for 24 h at 4℃. Ten ml of deionized water was added. After well mixed, samples were centrifuged at 3,000×g for 20 min 4℃. Lower phase of centrifuged samples were taken using a syringe and then placed in fume hood for 24 h, after completely evaporation, 1 ml of glacial acetic acid was added to the samples and vortexed for 30 s. Two ml of O-phthaldehyde reagent and 1 ml of H 2 SO 4 were added to 0.1 ml of vortexed samples and then vortexed for 30 s. After 10 min, the absorbance was measured with a spectrophotometer (Optizen-3220UV, Mecasys, Korea) at 530 nm. Standard curve was described through that 10, 20, 30, 40, and 50 ml of cholesterol standard stock solution and 40, 30, 20, 10, 0 ml of glacial acetic acid mixed solution were measured by above procedure, respectively. And regression equation was obtained. Cholesterol content (mg/100g, dry wt.) was calculated following equation: measured amount by standard curve × addition of glacial acetic acid × diluted rate × total lipid weight (mg) / sample weight.
- Sensory characteristics
Well-trained in-house tasting panelists (n=5) evaluated sensory attributes of tenderness, juiciness, flavor and overall acceptability, using on a 5-point scale: 1-very tough, very dry, very mild, very unacceptable, 5-very tender, very juicy, very intense, very acceptable. The sample was evaluated independently by the panelists 3 different times.
- Subjective evaluation
Well-trained in-house tasting panelists (n=5) evaluated subjective characteristics attributes of marbling, texture, meat color and total attribute, using on a 5-point scale: 1- extremely low in intramuscular fat, extremely bed in texture, very pale in meat color, extremely pale soft exudative (PSE), 5-very abundant in intramuscular fat, very good in texture, very dark in meat color, extremely dark firm dry (DFD). The samples were evaluated independently by the panelists 3 different times.
- Myoglobin
Myoglobin content was measured by method of Krzywicki (1982) with modification. Two g of sample was homogenized by polytron (PT 3100, Kinematica AG, USA) with 18 ml of (4℃) 40 mM phosphate buffer (pH 6.8) for 30 s. After centrifuging the slurry at 5,200 rpm for 10 min, the fluid was filtered with Whatman No. 2 ø150 mm. Filtered fluid was measured by spectrophotometer (Optizen-3220UV, Mecasys, Korea) at 700 nm and 525 nm, respectively. The content of myoglobin was calculated using the equation:
Myoglobin = (A 525 −A 700 ) × 2.303 × (18/sample weight)
where A λ = absorbance at λ nm.
- Statistical analysis
Statistical analyses were carried out using the Generalized Linear Model (GLM) procedure of the SAS package (Statistical analysis system: The SAS system Release 9.01, 2002 ), Means were compared using the Duncan's multiple range test at a level of significance of p <0.05. And the following model:
- Comparison of Duroc and LYD pigs
y i = μ + τ i + ε
where,
y = observed value of the trait
μ = mean
τ = breeds effect (Duroc and LYD)
ε = random error
Results and Discussion
- Comparison of carcass characteristics between Duroc and crossbred pigs
The results from comparing the carcass characteristics and grades between Duroc and crossbred pig are shown in Table 2 . All carcass characteristics were not significantly different. Carcass weight, carcass length, and backfat thickness of Duroc and crossbred pigs were 87.76, 86.96, 81.10, 80.87, 22.49, and 22.17 respectively. In carcass grade, the incidences of grade 1+ and 1 were higher in the Duroc population than in LYD. In contrast, the incidences of grade A and B were higher in the LYD population. According to Huff-lonergan (2002) , carcass weight was significantly correlated with marbling, juiciness and off-flavor, and backfat thickness was correlated with marbling, firmness, tenderness, flavor and off-flavor. In addition, heavier and leaner carcasses are prone to show less marbling, are less firm, less tender and have reduced characteristics in pork flavor than carcasses that have smaller loin eye and thick backfat. According to the research result of Franco (2014) , crossbreeding improved the growth, carcass yield and percentage of lean meat because of higher ham development in the comparison of pure Celta pig and Celta pig crossed with Duroc. Also, Duroc breed tended to have thicker backfat and fat in muscle compared to Yorkshire breed ( Enfalt 1997 ). Consistent with the results of this study, these results indicate that Duroc breed is good at production of high quality pork and crossbred breed is good at production of better yield.
Comparison of carcass characteristics and carcass grade between Duroc and crossbred pigs (LYD)
PPT Slide
Lager Image
LYD, Landrace × Yorkshire × Duroc, 1)Mean±SE
- Comparison of meat quality characteristics between Duroc and crossbred pigs
The comparison of meat quality characteristics of Duroc and crossbred pig are shown in Table 3 . In chemical composition, moisture and protein contents were higher in crossbred pigs than in the Duroc population ( p <0.05). However, in fat content, the Duroc population showed a higher value than commercial pigs did ( p <0.05). No significant difference was observed in the ash content between the two species. In the comparison of meat quality from Duroc population and crossbred pigs, drip loss and cooking loss of longissimus muscle in the Duroc population were lower than in the crossbred pigs. Also, a higher pH 24h value was detected in Duroc population than in crossbred pigs. However, there were no differences in WHC and shear force value. In Hunter color, the Duroc population showed significantly higher yellowness compared to that in the crossbred pigs which in turn showed a higher value in redness ( p <0.05). In lightness, no significant ( p >0.05) differences were observed between the two species. Total cholesterol content of Duroc and crossbred pigs did not show significant differences. In myoglobin content, crossbred pigs had higher content compared to that in the Duroc population ( p <0.05). Kim (2008) investigated the effects of pig breed on meat quality of the longissimus muscle. LYD showed significantly higher lightness values compared to (Yorkshire × Berkshire) × Berkshire, British Berkshire, Kagoshima Berkshire, and Korean native black pig × wild boars. Lloveras (2008) reported a comparison of meat quality of offspring from sows (50% Landrace, 25% Yorkshire, and 25% Duroc) crossed with Duroc or Yorkshire pure breed boars. The offspring sired by Duroc showed better meat quality in WHC, shear force, tenderness, juiciness, and intramuscular fat content. After slaughter the pH and intramuscular fat content in the muscle is important values to evaluate the meat quality. Pork could be determined to normal or abnormal (pale soft exudative and dark firm dry meat) according to the pH in meat. So, pH is related to meat quality like as drip loss, color, WHC and palatability ( Joo , 1995 ; Kauffman , 1993 ; Warner , 1993 ; Van Laack and Smulders, 1992) . Also, the intramuscular fat has an impact on meat quality including juiciness, tenderness, flavor and shelf-life in meat ( Channon , 2004 ; Garmyn , 2011 ; Ramirez and Cava, 2007 ). Within this context, Duroc in the present study was better in meat quality (intramuscular fat, ultimate pH 24h , drip loss and cooking loss) than crossbred pigs as well.
Comparison of meat quality characteristics of thelongissimusmuscle between Duroc and crossbred pigs (LYD)
PPT Slide
Lager Image
1)L, lightness; a, redness; b, yelloness *LYD, Landrace × Yorkshire × Duroc a,bMeans±SE with different superscription within the same row differ (p<0.05).
- Comparison of subjective evaluation and sensory characteristics of thelongissimusmuscle between Duroc and crossbred pigs
Table 4 shows the comparison of a subjective evaluation and sensory characteristics of longissimus muscle from Duroc and crossbred pigs. All items of the subjective evaluation were significantly higher in the Duroc population ( p <0.05) than in the crossbred pigs. Furthermore, juiciness, flavor and overall acceptability, included in the sensory characteristics, were significantly different except for tenderness ( p <0.05). According to Blanchard (2000) , eating quality (such as juiciness, tenderness, pork flavor, abnormal flavor and overall acceptability) was not affected by intramuscular fat from the loin of hybrid pigs sired by Duroc or Large white boars because other factors (such as proteolysis, sarcomere length and collagen content) may affect the tenderness of meats ( Wheeler , 2000 ).
Comparison of subjective evaluation1)and sensory characteristics2)of thelongissimusmuscle between Duroc and crossbred pigs (LYD)
PPT Slide
Lager Image
LYD, Landrace × Yorkshire × Duroc a,bMeans±SE with different superscription within the same row differ (p<0.05). 1)Marbring: 1, extremely low in intramuscular fat; 5, very abundant in intramuscular fat, Texture: 1, extremely bed in texture; 5, very good in texture, Meat color: 1, very pale in meat color, 5, very dark in meat color, Total attribute: 1, extremely PSE; 5, extremely DFD 2)1: very tough, very dry, very mild, very unacceptable, 5: very tender, very juicy, very intense, very acceptable
Comparison of fatty acid compositions of thelongissimusmuscle between Duroc and crossbred pigs (LYD)
PPT Slide
Lager Image
LYD, Landrace × Yorkshire × Duroc a,bMeans±SE with different superscription within the same row differ (p<0.05).
- Comparison of fatty acid composition between Duroc and crossbred pigs
The comparison of fatty acid composition of longissimus muscle from Duroc and crossbred pigs is shown in Table 5 . Significant differences were found in palmitic acid (C16:0) and eicosenoic acid (C20:1) contents. Palmitic acid (C16:0) content was significantly higher in the Duroc population than in the crossbred pigs. On the other hand, eicosenoic acid content (C20:1) was significantly higher in the crossbred pigs ( p <0.05). Total saturated fatty acids of the Duroc population were higher than those in crossbred pigs. Total unsaturated fatty acids were higher in crossbred pigs ( p <0.05). In addition, the ratio of unsaturated fatty acid to saturated fatty acid (USFA/SFA) showed significantly higher values crossbred pigs than in the Duroc population ( p <0.05). According to Raj (2010) , in a comparison of different breeds (Landrace, Duroc, Hampshire, and Pietrain) of pig, heavier pigs (130 kg body weight) showed higher saturated fatty acid content than did lighter pigs (90 and 110 kg body weight). Also, the content of saturated fatty acids was positively correlated with intramuscular fat and backfat. On the contrary, content of poly unsaturated fatty acid was negatively correlated with the presence of intramuscular fat and backfat. In addition, according to Lo Fiego (2005) , Pascual (2006) , and Bermudez (2012) , fatty acid composition in pigs could change according to nutritional components of the feed. In this study, there was no significant difference in carcass weight between Duroc and crossbred pigs ( p >0.05). Furthermore, Duroc with intramuscular fat content higher than that of crossbred pigs showed a higher saturated fatty acid content.
Conclusion
Duroc pigs are widely used as terminal sires in the pork industry. Therefore, we compared the carcass characteristics and meat quality characteristics between Duroc and crossbred pigs. Duroc and crossbred pigs did not show difference in carcass characteristics. Crossbred pigs had higher moisture and protein content than did Duroc breeds. However, Duroc breeds had a higher fat content than crossbred pigs. In meat quality characteristics, crossbred pigs showed higher values of drip loss and cooking loss than did Duroc breeds while Duroc breeds showed higher ultimate pH value compared to that of crossbred pigs. In a subjective evaluation and sensory characteristics, Duroc breeds showed significantly higher scores in all categories except for tenderness relative to crossbred pigs. However, crossbred pigs had higher USFA content of fatty acid composition than did Duroc breeds. As a result, Duroc breed were desireable in the meat quality characteristics due to higher intramuscular fat content and pH value, lower drip loss and cooking loss, even higher juiciness and flavor compared to crossbred pigs.
Acknowledgements
This study was supported by research funding of Korea Animal Improvement Association. This study was also partially supported by Priority Research Centers Program through the national research foundation of Korea (FRF) funded by the Ministry of Education, Science and Technology.
References
AOAC 1995 Official methods of analysis 13th ed. Association of Official Analytical Chemists Washington, D.C.
Blanchard J. P. , Willis M. B. , Warkup C. C. , Ellis M. 2000 The influence of carcass backfat and intramuscular fat level on pork eating quality J. Sci. Food Agric. 80 145 - 151    DOI : 10.1002/(SICI)1097-0010(20000101)80:1<145::AID-JSFA504>3.0.CO;2-M
Bermudez R. , Franco I. , Franco D. , Carballo J. , Lorenzo J. M. 2012 Influence of inclusion of chestnut in the finishing diet on fatty acid profile of dry-cured ham from Celta pig breed Meat Sci 92 394 - 399    DOI : 10.1016/j.meatsci.2012.05.001
Channon H. A. , Kerr M. G. , Walker P. J. 2004 Effect of Duroc content, sex and ageing period on meat and eating quality attributes of pork loin Meat Sci 66 881 - 888    DOI : 10.1016/j.meatsci.2003.08.010
Franco D. , Vazquez J. A. , Lorenzo J. M. 2014 Growth performance, carcass and meat quality of the Celta pig crossbred with Duroc and Landrance genotypes Meat Sci 96 195 - 202    DOI : 10.1016/j.meatsci.2013.06.024
Enfalt A. C. , Lundstrom K. , Hannson I. , Lundeheim N. , Nystrom P. E. 1997 Effects of outdoor rearing and sire breed (Duroc or Yorkshire) on carcass composition and sensory and technological meat quality Meat Sci. 45 1 - 15    DOI : 10.1016/S0309-1740(96)00101-5
Garmyn A. J. , Hilton G. G. , Mateescu R. G. , Morgan J. B. , Reecy J. M. , Tait, Jr. R. G. , Beitz D. C. , Duan Q. , Schoonmaker J. P. , Mayes M. S. , Drewnoski M. E. , Liu Q. , VanOverbeke D. L. 2011 Estimation of relationships between mineral concentration and fatty acid composition of longissimus muscle and beef palatability traits J. Anim. Sci. 89 2849 - 2858    DOI : 10.2527/jas.2010-3497
Huff-Lonergan E. , Baas T. J. , Malek M. , Dekkers J. C. M. , Prusa K. , Rothschild M. F. 2002 Correlations among selected pork quality traits J. Anim. Sci. 80 617 - 627
Johnson Z. B. , Chewning J. J. , Nugent R. A. 2002 Maternal effects on traits measured during postweaning performance test of swine from four breeds J. Anim. Sci. 80 1470 - 1477
Joo S. T. , Kauffman R. G. , Kim B. C. , Kim C. J. 1995 The relationship between color and water-holding capacity in post-rigor porcine longissimus Muscle J. Muscle Foods 6 211 - 226    DOI : 10.1111/j.1745-4573.1995.tb00568.x
Kim J. H. , Park B. Y. , Yoo Y. M. , Cho S. H. , Hwang I. H. , Seong P. N. , Hah K. H. , Lee J. M. 2006 Characteristics of Carcass and Meat Quality for Landrace, Yorkshire, Duroc and their Crossbreeds Journal of Animal Science and Technology 48 (1) 101 - 106    DOI : 10.5187/JAST.2006.48.1.101
Kim I. S. , Jin S. K. , Song Y. M. , Park K. H. , Kang S. M. , Ha J. H. , Kim I. J. , Park Y. S. , Kim J. H. 2006 Quality Characteristics of Pork by Sex on Crossbred Pigs The Journal of the Korean Society of International Agriculture 18 (1) 34 - 39
Kim J. H. , Park B. Y. , Yoo Y. M. , Cho S. H. , Kim Y. K. , Lee J. M. , Yun H. J. , Kim K. N. 2002 Characteristics of carcass and meat yield of fattening pigs by production step J. Anim. Sci. Technol. 44 793 - 800    DOI : 10.5187/JAST.2002.44.6.793
Kim I. S. , Jin S. K. , Kim C. W. , Song Y. M. , Cho K. K. , Chung K. H. 2008 The effect of pig breeds on proximate, physicochemical, cholesterol, amino acid and sensory properties of loins J. Anim. Technol. 50 121 - 132    DOI : 10.5187/JAST.2008.50.1.121
Knap P. W. , van der Steen H. A. M. , Plastow G. S. 2001 Developments in pig breeding and the role of research Livest. Prod. Sci. 72 43 - 48    DOI : 10.1016/S0301-6226(01)00265-2
Kolstad K. , Vangen O. 1996 Breed differences in maintenance requirements of growing pigs when accounting for changes in body composition Livest. Prod. Sci. 47 23 - 32    DOI : 10.1016/S0301-6226(96)01007-X
Kauffman R. G. , Sybesma W. , Smulders F. J. M. , Eikelenboom G. , Engeld B. , van Laack R. L. J. M. , Hoving-Bolink A. H. , Sterrenburg P. , Nordheim E. V. , Walstra P. , van der Wal P. G. 1993 The effectiveness of examining early post-mortem musculature to predict ultimate pork quality Meat Sci 34 283 - 300    DOI : 10.1016/0309-1740(93)90078-V
Krzywicki K. 1982 The determination of haem pigments in meat Meat Sci 7 29 - 36    DOI : 10.1016/0309-1740(82)90095-X
Laakkonen. E. , Wellington G. H. , Skerbon J. W. 1970 Low temperature longtime heating of bovine. I. Changes in tenderness, water binding capacity, pH and amount of watersoluble component J. Food. Sci. 35 175 - 177    DOI : 10.1111/j.1365-2621.1970.tb12131.x
Lee Y. H. , Kwon S. G. , Park D. H. , Kwon E. J. , Cho E. S. , Bang W. Y. , Park H. C. , Park B. Y. , Choi J. S. , Kim C.W. 2011 Development of High Meat Quality Using Microsatellite Markers in Berkshire Pigs Journal of Animal Science and Technology 53 (2) 89 - 97    DOI : 10.5187/JAST.2011.53.2.89
Lee W. 1996 Problems and countermeasures of pig husbandry industry in Korea Livest. Technol. Ind. 4 1016 - 1028
Lloveras M. R. , Goenaga P. R. , Irurueta M. , Carduza F. , Grigioni G. , Garcýa P. T. , Amendola A. 2008 Meat quality traits of commercial hybrid pigs in Argentina Meat Sci 79 458 - 462    DOI : 10.1016/j.meatsci.2007.10.033
Lo Fiego D. P. , Macchioni P. , Santoro P. , Pastorelli G. , Corino C. 2005 Effect of dietary conjugated linoleic acid (CLA) supplementation on CLA isomers content and fatty acid composition of dry-cured parma ham Meat Sci 70 285 - 291    DOI : 10.1016/j.meatsci.2005.01.014
Nelson R. E. , Robison O. W. 1976 Comparisons of specific two- and three-way crosses of swine J. Anim. Sci. 42 1150 - 1157
Ngapo T. M. , Riendeau L. , Laberge C. , Fortin J. 2012 Marbling and ageing - Part 2. Consumer perception of sensory quality Res. Intl. 51 985 - 991
Ngapo T. M. , Riendeau L. , Laberge C. , Fortin J. 2012 Marbling and ageing - Part I. Sensory quality of pork Food Res. Intl. 49 396 - 405    DOI : 10.1016/j.foodres.2012.07.039
Oh H. S. 2005 Estimation of genetic trend for economic traits of the integrated swine group led by kaya GGP in Gyeongsangnamdo, Korea, Doctorate Thesis.
Pascual J. V. , Rafecas M. , Canela M. A. , Boatella J. , Bou R. , Baucells M. D. , Codony R. 2006 Effect of increasing amounts of a linoleic-rich dietary fat on the fat composition of four pig breeds. Part I: backfat fatty acid evolution Food Chem 96 538 - 548    DOI : 10.1016/j.foodchem.2005.02.042
Ramirez R. , Cava R. 2007 Carcass composition and meat quality of three different Iberian × Duroc genotype pigs Meat Sci 75 388 - 396    DOI : 10.1016/j.meatsci.2006.08.003
Raj St. , Skiba G. , Weremko D. , Fandrejewski H. , Migdal W. , Borowiec F. , Polawska E. 2010 The relationship between the chemical composition of the carcass and the fatty acid composition of intramuscular fat and backfat of several pig breeds slaughtered at different weights Meat Sci 86 324 - 330    DOI : 10.1016/j.meatsci.2010.04.037
Rothschild M. F. , Ruvinsky A. 2010 The genetics of pigs CABI Cambridge, MA
SAS 2002 The SAS System Release 9.1 SAS Institute Inc. Cary, NC
Seo J. H. , Shin J. S. , Noh J. K. , Song C. E. , Do C. H. 2011 The Situation of Genetic Exchange in Duroc Breed and Impacts on Genetic Evaluation Journal of Animal Science and Technology 53 (5) 397 - 408    DOI : 10.5187/JAST.2011.53.5.397
Seo K. S. 2012 Activation of the system of the domestic pig husbandry business network and export competitiveness suggestions for pig husbandry Pig & Pork 173 - 177
Suzuki K. , Shibata T. , Kadowaki H. , Abe H. , Toyoshima T. 2003 Meat quality comparison of Berkshire, Duroc and crossbred pigs sired by Berkshire and Duroc Meat Sci 64 35 - 42    DOI : 10.1016/S0309-1740(02)00134-1
Tizioto P. C. , Meirelles S. L. , Veneroni G. B. , Tullio R. R. , Rosa A. N. , Alencar M. M. , Medeiros S. R. , Siqueira F. , Feijo G. L. , Silva L. O. , Jr. Torres R. A. , Regitano L. C. 2012 A SNP in ASAP1 gene is associated with meat quality and production traits in Nelore breed Meat Sci 92 855 - 857    DOI : 10.1016/j.meatsci.2012.05.018
Van Laack R. L. J. M. , Smulders F. J. M. 1992 On the assessment of water-holding capacity of hot- vs cold-boned pork Meat Sci 32 139 - 147    DOI : 10.1016/0309-1740(92)90101-9
Warner R. D. , Kauffman R. G. , Russel R. L. 1993 Quality attributes of major porcine muscles: A comparison with the longissimus lumborum Meat Sci 33 359 - 372    DOI : 10.1016/0309-1740(93)90007-5
Wheeler T. L. , Shackelford S. D. , Koohmaraie M. 2000 Variation in proteolysis, sarcomere length, collagen content, and tenderness among major pork muscles J. Anim. Sci. 78 958 - 965