• Proceedings of the Korea Society of Poultry Science Conference
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• 2003.11a
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• pp.125-126
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• 2003

The observed genetic gains per generation in Korean native chicken on the basis of the 7 generation data collected from 11,583 birds from 1995 to 2001 at National Livestock Research Institute, Korea. Results obtained were summarized as follows : The body weight at 150 days, -5.292 ∼ 3.682 g ； for the body weight at 270 days, -6.184 ∼ 4.591 g ； for the age at first egg, -0.399 ∼ -0.102 ； for the egg weight at the first egg, -0.026 ∼ 0.016 ； for the e99 weight at 270 days, -0.039 ∼ 0.068 g ； for the egg production at 270 days, 0.222 ∼ 0.587, respectively.

• Korean Journal of Poultry Science
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• v.45 no.3
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• pp.155-165
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• 2018

Chicken feathers could be classified into early-feathering (EF) and late-feathering (LF) depending on the development and patterns of the wing and tail feathers. Currently, feather-sexing is a widely used chick sexing method in the industry. This study was carried out to suggest the method of classifying of EF and LF chicks to establish auto-sexing Korean native chicken (KNC) strains. The development and morphology of wing feathers and tail feathers in 856 KNCs from hatching to 55-days old were analyzed to classify EF and LF chicks. We also performed PCR analysis using K-specific gene primers to confirm the agreement between the phenotypes and genotypes of EF and LF chickens. In the results, the EF chicks had long primaries and coverts, and there was a significant difference in length between primaries and coverts. The LF chicks had shorter primaries and coverts than the EF chicks, and showed little difference in the length between primaries and coverts. LF chicks could be classified into four groups: LF-Less, LF-Scant, LF-Equal and LF-Reverse according to their wing feather patterns. EF chicks had 1.5 times longer primaries than LF chicks until they were 15-days old, but the lengths were almost the same at 50-days old. The tail feathers of the EF chicks were apparent at 5-days old, but those of the LF chicks were short and indefinite at that time. When EF and LF chicks were classified by the length of primaries being more or less than 9 mm, the classification accuracies for EF and LF chicks were 96.2% and 85.4%, respectively, compared to the PCR results. In conclusion, juvenile EF and LF KNC showed distinct differences in feather development and morphology, and could be easily distinguished at one day-old.

• Korean Journal of Poultry Science
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• v.41 no.2
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• pp.115-125
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• 2014

With Single Comb White Leghorn (WL) and Korean Native Chicken (KNC) breeds, we compared the stress response with chicken breeds that were subjected to a high stocking density. Stress response was analyzed by the quantity of telomeric DNA, the rate of DNA damage and the expression levels of heat shock proteins (HSPs) and hydroxyl-3-methyl-glutaryl coenzyme A reductase (HMGCR) genes on tissues and blood. The telomere length and telomere shortening rates were analyzed by quantitative fluorescence in situ hybridization on the nuclei of lymphocytes and tissues. The DNA damage rate of lymphocytes was quantified by the comet assay. The expression levels of HSP70, HSP90-${\alpha}$, HSP90-${\beta}$ and HMGCR genes were measured by quantitative real-time polymerase chain reaction in lymphocytes. There was no significant difference between KNC and WL in body weight, weight gain, telomere shortening rate and DNA damage rate. However, the growth rate significantly decreased in chickens raised under high stocking density conditions, as compared to the control group. The telomere-shortening rate, DNA damage and HSPs expression of the lymphocytes were significantly higher in the high stocking density group than the control. The stress condition and breeds had a significant effect on the expressions of HSP70, HSP90-${\alpha}$ and HSP90-${\beta}$ in lymphocytes, except HMGCR. The stress response of WL was higher than that of KNC, as analyzed to the expression of HSP70 and HSP90-${\alpha}$. Therefore, we concluded that the chickens which were exposed to a high stocking density had increased the individual physiological stress response regardless of breeds, and White Leghorns are more susceptible to stress condition than Korean Native Chickens.

• Korean Journal of Poultry Science
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• v.42 no.4
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• pp.335-345
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• 2015

This study was conducted to compare carcass yield and meat quality among four lines of Korean native chickens (Yeonsan Ogye, Hyunin Black, Hoengseong Yakdak and Hwangbong) and White Leghorn as control. Chickens (N=23, male) were grown under same conditions and slaughtered at 56 weeks old to observe the physicochemical differences in breast and leg meats. The live and carcass weights of Hwangbong were significantly higher than other chickens (p<0.05). Four lines of Korean native chickens, regardless of the part, had higher shear force value than White Leghorn (p<0.05). In addition, the breast meat of Korean native chickens had higher cooking loss and lower water holding capacity than that of White Leghorn. The cooked meat of Hwangbong particularly were more chewy, gummy and cohesive with lower tenderness than other chickens (p<0.05). Oleic acid content which is related to meat flavor was significantly higher in the breast meat of Hoengseong Yakdak (39.6%). The meat of Korean native chickens had lower n6/n3 ratio, in which the breast and leg meat of Hoengseong Yakdak contained the lowest ratio (p<0.05). The meat of Hwangbong and Hoengseong Yakdak were more acceptable than the others according to sensory test (p<0.05).

• Korean Journal of Poultry Science
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• v.42 no.4
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• pp.315-325
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• 2015

Recently, livestock breeding is more focused on the meat quality rather than meat quantity, mainly due to the improvement of consumers' income. Among the meat quality traits, meat color is one of very important traits because meat color is the first selection criterion from the consumers in the market. Most of the economically important traits have continuous variations and these are called quantitative traits. the genomic locations affecting these traits are called quantitative trait locus (QTL), which is mostly controlled by many genes having small effects. In this study, the recent QTL and candidate gene studies were reviewed in order to meet the consumers' demand for the future market. In the chicken QTL database, three traits are related with meat colors, namely breast color (Bco), meat color (Mco), drip loss (DL) and pH. The identified number of QTLs is 33 from 13 chromosomal regions. In these QTL regions, 14 candidate genes were identified; Eight for meat color (APP, BCMO1, COL1A2, FTO, KPNA2, PSMD12, G0S2, FTSJ3), two for drip loss (AGRP, FTO) and four for pH (GALNT1, PCDH19, DIAPH1, SPP2). These QTLs and candidate genes need to be confirmed and fine mapping is ultimately needed for identification of causative variations. The recently developed chicken resource population using Korean native chicken can be used for the improvement of meat quality traits, which increase the value that needed in the chicken industry.

• Korean Journal of Poultry Science
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• v.41 no.4
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• pp.305-311
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• 2014

Copy number variation (CNV) is a form of structural variation that shows various numbers of copies in segments of the DNA. It has been shown to account for phenotypic variations in human diseases and agricultural production traits. Currently, most of chicken breeds in the poultry industry are based on European-origin breeds that have been mostly provided from several international breeding companies. Therefore, National Institute of Animal Science, RDA has been trying to restore and improve Korean native chicken breeds (12 lines of 5 breeds) for about 20 years. Thanks to the recent advance of sequencing technologies, genome-wide CNV can be accessed in the higher resolution throughout the genome of species of interest. However, there is no systematic study available to dissect the CNV in the native chicken breed in Korea. Here, we report genome-wide copy number variations identified from a genome of Korean native chicken (Line L) by comparing between the chicken reference sequence assembly (Gallus gallus) and a de novo sequencing assembly of the Korean native chicken (Line L). Throughout all twenty eight chicken autosomes, we identified a total of 501 CNVs; defined as gain and loss of duplication and deletion respectively. Furthermore, we performed gene ontology (GO) analysis for the putative CNVs using DAVID, leading to 68 GO terms clustered independently. Of the clustered GO terms, genes related to transcription and gene regulation were mainly detected. This study provides useful genomic resource to investigate potential biological implications of CNVs with traits of interest in the Korean native chicken.

• Korean Journal of Poultry Science
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• v.37 no.2
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• pp.125-130
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• 2010

This study was conducted to estimate heritabilities, genectic and phenotypic correlations on economic traits in three strains of Korean Native chickens (KNC) : Black (B), Red Brown (RB) and Yellow Brown (YB). The data used in this study were collected from 2000 to 2007 in the National Institute of Animal Science and a total number was 14,421 birds. The effect of the strains analysis showed that the strain B were greater than the other strains for body weight at 150 days and 270 days. The number of egg production at 270 days of the strain YB was higher than the other strains. The estimated heritabilities age at $1^{st}$ egg, body weight at 150 days, egg weight at $1^{st}$ egg, body weight at 270 days, egg weight at 270 days and number of egg production at 270 days were 0.32, 0.50, 0.31, 0.43, 0.48 and 0.69 for strain B; were 0.42, 0.41, 0.19, 0.48, 0.44 and 0.76 for strain RB; were 0.44, 0.52, 0.24, 0.54, 0.51 and 0.66 for strain YB respectively, The genetic and phenotypic correlations were also estimated.

• Korean Journal of Poultry Science
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• v.46 no.2
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• pp.65-75
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• 2019

A number of Korean native chicken(KNC) populations were registered in FAO (Food and Agriculture Organization) DAD-IS (Domestic Animal Diversity Information Systems, http://www.fao.org/dad-is). But there is a lack of scientific basis to prove that they are unique population of Korea. For this reason, this study was conducted to prove KNC's uniqueness using 25 Microsatellite markers. A total of 548 chickens from 11 KNC populations (KNG, KNB, KNR, KNW, KNY, KNO, HIC, HYD, HBC, JJC, LTC) and 7 introduced populations (ARA: Araucana, RRC and RRD: Rhode Island Red C and D, LGF and LGK: White Leghorn F and K, COS and COH: Cornish brown and Cornish black) were used. Allele size per locus was decided using GeneMapper Software (v 5.0). A total of 195 alleles were observed and the range was 3 to 14 per locus. The MNA, $H_{\exp}$, $H_{obs}$, PIC value within population were the highest in KNY (4.60, 0.627, 0.648, 0.563 respectively) and the lowest in HYD (1.84, 0.297, 0.286, 0.236 respectively). The results of genetic uniformity analysis suggested 15 cluster (${\Delta}K=66.22$). Excluding JJC, the others were grouped in certain cluster with high genetic uniformity. JJC was not grouped in certain cluster but grouped in cluster 2 (44.3%), cluster 3 (17.7%) and cluster8 (19.1%). As a results of this study, we can secure a scientific basis about KNC's uniqueness and these results can be use to basic data for the genetic evaluation and management of KNC breeds.

• KOREAN POULTRY JOURNAL
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• v.48 no.10
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• pp.192-195
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• 2016

본고는 양계와 한평생을 함께 한 오봉국 교수(서울대 명예 교수)가 그 동안의 인생여정을 정리하여 출간한 '축산의 비전을 심으며 살아온 나의 인생여정' 자서전 내용 중 '양계와 함께 걸어온 나의 회고' 내용을 발췌, 게재한 것이다. 오봉국 교수는 1925년 평안남도 진남포에서 태어나 1956년 서울대학교 축산과에서 농학석사과정을 거친 후 미국 미네소타대학과 호주 시드니 대학에서 석, 박사과정을 마친후 서울대학교에서 후학양성은 물론 양계산업 발전을 위해 많은 공을 세웠다. 1969년에는 (사)한국가금협회장(대한양계협회 전신)을 역임하고 현재까지 대한양계협회 고문으로 활동하고 있다. 1991년에는 국민훈장 모란장을 수여한 바 있으며, 현대 가금학 등 16편의 주옥같은 저서를 남겼다.

• Korean Journal of Poultry Science
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• v.24 no.3
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• pp.117-126
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• 1997

This study was conducted to estimate the hatching and growing performance, and heterosis of Korean Native Chicken(KNC), Rhode Island Red(RIR) and KNC XRIR crossbred. A total of 1,274 female pullets were produced from KNC, RIR and KNC x RIR crossbred kept in National Live-stock Research Institute, Korea. The experiment was conducted for 20 weeks from Sep. 2, 1995 to Jan. 20,1996. Hatchabilities of KNC dark brown strain x RlR(DR), KNC light brown strain x RlR (LR) and KNC dark black strain x RlR(BR) were 77.3%, 73.6% and 72.5%, respectively. Viabilities up to 20 weeks of age were not significantly (P>0.05) different among purebreds and crossbred. Body weights of DR, LR and BR were 1,890 g, 1,849 g and 1,967 g, respectively, at 20 weeks of age. The feed conversion ratio(feed /gain) of DR, LR, and BR were 5.88, 6.07 and 5.87, respectively, up to 20 weeks of age. Average shank lengths of DR, LR and BR were 97.1 mm, 98.9 mm and 99.4 mm, respectively, at 20 weeks of age. The heterosis effects were estimated to be -0. 48%, and 12.58%, respectively, in fertility and hatchability. Up to 20 weeks of age, the heterosis effects were estimated to be 0.07%, 13.49%, -5.77%, and 3.52% in viability, body weight, feed conversion ratio, and shank length, respectively.