• Food Science of Animal Resources
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• v.36 no.5
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• pp.689-696
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• 2016

This study was conducted to find pork quality to meet the needs of consumers. Thus, the meat quality and fatty acid composition of longissimus muscles from purebred pigs (Landrace, Yorkshire, and Duroc) and three-way crossbred LYD pigs were compared and evaluated. Chemical compositions of longissimus muscles were significant (p<0.05) different among pigs. Duroc contained significant (p<0.05) higher fat contents than other pigs, whereas significant (p<0.05) higher moisture contents were observed in Landrace, Yorkshire, and LYD pigs compared to those of Duroc pigs. The values of pH_{24 h} and pH_{14 d} were the highest in Landrace pigs. Myoglobin contents of LYD pigs were higher (p<0.05) than those of purebred pigs. Regarding meat color, Duroc and Yorkshire pigs had higher redness values than Landrace and LYD pigs, while Landrace pigs had the lowest (p<0.05) color values among all pigs. There was no significant difference in shear force or water holding capacity (WHC). Duroc pigs maintained the lowest drip loss during 14 d of cold storage. In sensory evaluation, the marbling scores of Duroc pigs were higher (p<0.05) than other pigs. Regarding fatty acid compositions, total USFA, poly-, n-3, and n-6 contents were the highest (p<0.05) in LYD pigs, while total SFA contents were the highest (p<0.05) in Duroc pigs. Based on these results, purebred pigs had superior overall meat quality to crossbred pigs.

• Journal of Life Science
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• v.19 no.4
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• pp.467-471
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• 2009

The entire D-loop region of the porcine mitochondrial DNA (mtDNA) was amplified from six pig breeds (Landrace, Duroc, Large White, Korean native pig, Berkshire, and Hampshire) using a primer set designed on the basis of reported porcine mtDNA sequences. From analyses through cloning, DNA sequencing and multiple sequence alignment, an 11-bp (TAAAACACTTA) duplication was observed after known tandem repetition in the D-loop region, which promoted hetroplasmy in mtDNA. Although the existence of the 11-bp duplication has been previously reported in Duroc and Japanese native pigs, there have not been any attempts to know the characteristics of this duplication in other breeds so far. A 150 bp fragment containing the 11-duplication was amplified and typed by polyacrylamide gel electrophoresis (PAGE). All Large Whites had two duplication units and Duroc showed heteromorphic patterns, 11.2% (9/80) of the animals had the 11-bp duplication in total. On the other hand, Landrace, Berkshire, Hampshire and Korean native pigs were non-duplicated. This result showed that the 11-bp duplication could be used as a breed-specific DNA marker for distinguishing pure Landrace and Large White breeds.

• Proceedings of the Korean Society of Life Science Conference
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• 2007.10a
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• pp.51.2-51.2
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• 2007

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• Journal of Embryo Transfer
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• v.31 no.3
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• pp.215-219
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• 2016

Value of excellent breeding animals is important in livestock industry, but their economic life time is limited. And, many countries have been trying procuration of genetic resource in good animals. Therefore, this study was conducted to determine embryo production and to test efficiency of embryo transfer via non-surgical artificial insemination (AI) in different breed of superior sows. A total of 17 sows were used in this experiment (Duroc, n=10; Landrace, n=4; Yorkshire, n=3). The sows were artificially inseminated by semen of same breed boars. After 4 or 5 days following the AI, the embryos were obtained from the sows and then transferred to Landrace and Yorkshire recipients (n=3, respectively) by non-surgical method. The corpora lutea tended to be increased in Yorkshire and Landrace than Duroc(28 and 26 vs. 17, respectively). The recovery of embryo was 78.8% in Landrace, 65.4% in Duroc and 51.4% in Yorkshire. Duroc showed lower morulaes and early blastocyst embryos than 2, 4, 8 and 16 cell. The morula in Yorkshire was higher (P<0.05) than that of Duroc (4.7 vs. 3.4). Similarly, the morulaes and early blastocyst embryos presented greater (P<0.05) in Landrace compared with other breed sows. The recipient sows were pregnant in a Landrace only. This reason may be due to little embryos inserted in the recipients. In addition, pregnancy results were limited because of the little sows. In conclusion, ovulated ovum in sows can be affected by different breed. Also, further study needed pregnant test by using the many embryo in each breed.

• Journal of Animal Science and Technology
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• v.46 no.5
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• pp.735-742
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• 2004

This study was conducted for the identification of pure Landrace, Large White and Duroc breeds which are mainly maintained in Korea using DNA markers. We used known KIT and MC1R mutations, which were related coat color in pigs, and pig mitochondrial DNA variations. The KIT mutation was used to distinguish white and colored animals. Duroc breed could be discriminated from other colored breeds using the MC1R mutation N121D. Discriminating Landrace and Large White was possible using the l l-bp duplication of D-Ioop region and alternative initiation codon of ND2. In conclusion, identification of Landrace, Large White and Duroc breeds was might be possible using the procedure designed in this study.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.9
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• pp.1263-1269
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• 2014

Comprehensive information on genetic diversity and introgression is desirable for the design of rational breed improvement and conservation programs. Despite the concerns regarding the genetic introgression of Western pig breeds into the gene pool of the Korean native pig (KNP), the level of this admixture has not yet been quantified. In the present study, we genotyped 93 animals, representing four Western pig breeds and KNP, using the porcine SNP 60K BeadChip to assess their genetic diversity and to estimate the level of admixture among the breeds. Expected heterozygosity was the lowest in Berkshire (0.31) and highest in Landrace (0.42). Population differentiation ($F_{ST}$) estimates were significantly different (p<0.000), accounting for 27% of the variability among the breeds. The evidence of inbreeding observed in KNP (0.029) and Yorkshire (0.031) may result in deficient heterozygosity. Principal components one (PC1) and two (PC2) explained approximately 35.06% and 25.20% of the variation, respectively, and placed KNP somewhat proximal to the Western pig breeds (Berkshire and Landrace). When K = 2, KNP shared a substantial proportion of ancestry with Western breeds. Similarly, when K = 3, over 86% of the KNP individuals were in the same cluster with Berkshire and Landrace. The linkage disquilbrium (LD) values at $r^2_{0.3}$, the physical distance at which LD decays below a threshold of 0.3, ranged from 72.40 kb in Landrace to 85.86 kb in Yorkshire. Based on our structure analysis, a substantial level of admixture between Western and Korean native pig breeds was observed.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.5
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• pp.669-676
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• 2007

This study was conducted to detect quantitative trait loci (QTL) affecting growth and body composition in an $F_2$ reference population of Korean native pig and Landrace crossbreds. The three-generation mapping population was generated with 411 progeny from 38 $F_2$ full-sib families, and 133 genetic markers were used to produce a sex-average map of the 18 autosomes. The data set was analyzed using least squares Mendelian and parent-of-origin interval-mapping models. Lack-of-fit tests between the models were used to characterize QTL for mode of expressions. A total of 8 (39) QTL were detected at the 5% genome (chromosome)-wise level for the 17 analyzed traits. Of the 47 QTL detected, 21 QTL were classified as Mendelian expressed, 13 QTL as paternally expressed, 6 QTL as maternally expressed, and 7 QTL as partially expressed. Of the detected QTL at 5% genome-wise level, two QTL had Mendelian mode of inheritance on SSC6 and SSC9 for backfat thickness and bone weight, respectively, two QTL were maternally expressed for leather weight and front leg weight on SSC6 and SSC12, respectively, one QTL was paternally expressed for birth weight on SSC4, and three QTL were partially expressed for hot carcass weight and rear leg weight on SSC6, and bone weight on SSC13. Many of the Mendelian QTL had a dominant (complete or overdominant) mode of gene action, and only a few of the QTL were primarily additive, which reflects that heterosis for growth is appreciable in a cross between Korean native pig and Landrace. Our results indicate that alternate breed alleles of growth and body composition QTL are segregating between the two breeds, which could be utilized for genetic improvement of growth via marker-assisted selection.

• Journal of Life Science
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• v.23 no.7
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• pp.854-862
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• 2013

The number of thoracic and lumbar vertebrae is known to be an unfixed trait among mammals. This study focused on the relationship between numerical variations of cervical (CER), thoracic (THO), and lumbar (LUM) vertebrae and the total number of vertebrae (TNV) and carcass traits in Jejunative black pigs (JBPs), Landrace pigs, and their intercrossed $F_2$ population. There were no numerical variations in CER vertebrae. On the other hand, the numbers of THO and LUM vertebrae and the TNV varied in all three populations. Of the traits investigated in the three populations, only the means${\pm}$SE of the LUM vertebrae did not show statistical significance (p>0.05). The carcass weights (CW), meat color (MC), marbling score (MS), backfat thickness (BFT), carcass length (CLE), THO vertebrae, and TNV all showed statistical significance (p<0.05). The JBP had 14-16 THO vertebrae, 5-6 LUM vertebrae, and 27-29 TNV. The Landrace pigs had 15-16 THO vertebrae, 5-7 LUM vertebrae, and 28-29 TNV. The $F_2$ population had 14-17 THO vertebrae, 5-7 LUM vertebrae, and 27-30 TNV. In the F2 population, increased numbers of THO vertebrae and TNV were associated with a significant increase in the CW, CLE, and BFT (p<0.05). In particular, the increase in the TNV was caused by an increase in the number of THO rather than LUM vertebrae. Although the animals with a greater number of THO and TNV had thicker backfat, they had a longer CLE and a heavier CW. Both these traits are economically more important than the level of backfat when determining the productivity level. These results suggest that genetic selection to increase the number of vertebrae, especially in Landrace pigs, JBPs, and their related populations, may be an excellent strategy for improving productivity.

• Journal of Embryo Transfer
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• v.30 no.2
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• pp.91-97
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• 2015

Amphiregulin (AREG), a glycoprotein that is a member of the epidermal growth factor (EGF) family, is expressed by the porcine conceptus and endometrium. AREG genotypes were determined based on an SNP in the intron 3 of the gene. Contradictory effects of AREG genotypes on reproductive traits in different pig breeds were reported previously. G allele had undesirable effect on reproductive trait in Meishan breed, while it had favorable effects in Polish Landrace and Large White. We determined AREG genotypes of 179 pigs including the Duroc, Landrace, Yorkshire, Korean native pig (KNP), and Meishan breeds. Two new SNPs were identified near the previously reported SNP in the intron 3 of AREG. Frequencies of AREG alleles among the Duroc, Landrace, Yorkshire, and KNP sows were significantly different (p<0.001), indicating association between AREG genotypes and pig breeds. The first parity litter size was significantly affected by the breeds (p=0.014), but not by AREG genotypes (p=0.148). However, there were breed and AREG genotype associated trends in the first parity litter size. The first parity litter size appeared to be higher in Duroc and KNP sows with G allele, while it appeared to be lower in Landrace sows with G allele. Significant variability of AREG alleles among pig breeds, for the first time in Duroc and KNP sows, was identified. AREG genotypes may influence reproductive traits differentially for each breed and thus, AREG genotypes may need to be considered when sows are bred to increase litter size.

• Korean Journal of Animal Reproduction
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• v.12 no.1
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• pp.15-19
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• 1988

This study was carried out to investigate the fertility and farrowing date in post-weaning sows using PG600 and inseminated with frozen semen. A total of 48 sows of Landrace, Large White and Duroc after 7-week lactation were used at the Chungnam Provincial Animal Breeding Station. The results obtained were summarized as follows: 1. Motility had no significant differences between the breeds, but NAR acrosome was highest in Landrace, followed by Duroc and Large White(p<.01). 2. Interval from weaning to estrus and length of estrus were, respectively, 3.7 days and 52.6hours of sows treated with PG600, and 6.5 days and 53.8 hours for control sows. The average interval from weaning to onset of estrus was significantly(p<.01) shorter by 2.8 days in PG600 treated sows compared to control sows. 3. In Landrace, Duroc and Large White, farrowing rate and number of pigs born alive per litter were 55.0%, 10.0; 43.8%, 8.1; and 16.7%, 3.5, respectively. Average pig weight at birth and survival rate at 56 days had no significant differences between the breeds. 4. Farrowing rate, number of pigs born alive per litter, average pig weight at birth and survival rate at 56 days were, respectivey, 45.8%, 101, 1.56kg and 94.5% for sows treated with PG600, and 37.5%, 7.0, 1.66kg and 93.8% for control sows. Sows treated with PG 600 had an average of 3.1 more pigs at farrowing compared to control sows.