• Korean Journal of Poultry Science
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• v.50 no.2
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• pp.91-99
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• 2023

This study aimed to develop a high-productivity breed of Korean native Samgye chicken. We evaluated the production performance of six Korean native chicken combinations (KNC-SCYC, SCYD, SDYC, SDYD, SYYC, SYYD) and GSP-Hanhyup Korean native chickens, with Baeksemi chickens used as a control group. The performance test was conducted from hatching to 7 weeks of age on 756 chickens, and we measured survival rate, body weight, shank length, feed utility, and carcass yield. The overall survival rate was nearly 100% for all strains. However, body weight showed significant differences between strains at all ages (P<0.01), with Baeksemi weighing 863.8±76.9 g, GSP-Hanhyup weighing 804.7±72.5 g, and KNC-combinations weighing 543.0±61.8 g at 5 weeks of age. The duration needed to reach 850 g was estimated to be 34.5 days for Baeksemi, 37.5 days for GSP-Hanhyup, and 45.8-48.8 days for KNC-combinations. Carcass yield percentage was highest for KNC-SYYD combination at 63.3%, followed by Baeksemi at 60.4%, and GSP-Hanhyup at 56.1%. Shank length at 850 g body weight was 7.6 cm for KNC-SYYD combination, 7.8 cm for Baeksemi, and 8.0 cm for GSP-Hanhyup. The feed conversion ratio at 850 g body weight was 1.81 for Baeksemi, 2.17 for GSP-Hanhyup, and 2.27 for KNC-SCYC combination. Our results suggest that the KNC-SYYD combination and GSP-Hanhyup breed have the potential to be used in Samgye production due to their moderate growth performance, higher carcass yield, and shorter shank length, despite their lower growth productivity and feed efficiency when compared to Baeksemi.

• Korean Journal of Poultry Science
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• v.34 no.2
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• pp.85-90
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• 2007

The chicken liver has been involved in various biological functions including detoxification, glycogen storage and plasma protein synthesis. The aim of this study was to investigate differentially expressed genes in chicken liver in four different growing stages. Using 10 arbitrary Annealing Control Primers (ACPs), five differentially expressed genes have been identified. Based on the Basic Local Alignment Search Tool (BLAST) search results, three of them were matched with previously known genes, and the other two were matched with unknown EST sequence and a hypothetical protein, respectively. In order to confirm the expression results, quantitative real-time PCR was also performed. The high similarities between the expression data using arbitrary ACPs and quantitative real-time PCR indicate that the identified genes are the real differentially expressed genes in different growing stages. The genes identified in this study can be used as valuable biomarkers in chicken with further investigation of the functions.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2004.11a
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• pp.16-18
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• 2004

This study was carried out to analyze the amount of telomeres and telomerase activity of several chicken cells. Telomere quantity and telomerase activity were analyzed during organ development, growth and aging in embryonic and adults chicken. Analyzed cells were whole embryos and the cells from brain, heart, liver, kidney, lymphocytes and germinal tissues in Korean Native Chicken. The amount of telomeric DNA was analyzed by quantitative fluorescence in situ hybridization (Q-FISH) techniques using a chicken telomere repeat probe. Telomerase activity was performed by Telomeric Repeat Amplification Protocol (TRAP) assay. In results, telomerase activity was highly detectable in early embryonic cells, germinal cells and kidney cells. Whereas the cells from brain, heart, and liver had gradually down-regulated pattern of telomerase activity. Analyzing the telomere quantities on chicken cells, the amount of telomeric DNA of most chicken cells gradually decreased as growth. From these results, the amount of telomeric DNA was directly affected by telomerase activity. Consequently the telomere quantity and telomerase activity are closely relate to cell differentiation and tissue specificity during developmental and growing stages.

• Korean Journal of Poultry Science
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• v.39 no.1
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• pp.1-8
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• 2012

To evaluate the effects of n-3 and n-9 fatty acid combination on broiler chicks, diets containing the combinations of five different fat sources including flaxseed oil, fish oil, EPA, DHA and olive oil were provided, and all chicks were processed at 4 weeks of growth. Liver, breast and thigh samples were collected and fatty acid composition and/or CIE $L^*$, $a^*$ and $b^*$ measurement were measured. Also, live chick and liver weights were weighed and the ratio was provided as an evidence of fat accumulation in liver. No significant difference was determined in both live and liver weight ratio and liver color. EPA was low in FHO as compared to livers from others. In contrast, DHA was significantly high in FHO. In broiler breasts derived from FDO, AA and n-3 fatty acid content was high, but only numerical differences of EPA and DHA were determined in breasts from FDO. The thighs from FHO showed high in EPA, DHA and n-3 fatty acid content but had low in AA and n-6 to n-3 ratio. Therefore, the results indicate that broiler chicken diets containing either FDO or FHO may be possible combination diets increasing n-3 polyunsaturated fatty acids in broiler chicks.

• Korean Journal of Poultry Science
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• v.42 no.2
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• pp.157-167
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• 2015

We compared the degrees of stress response of 12 domestic purebred chicken strains that have been bred at National Institute of Animal Science, RDA, Korea since 1980. As a physiological marker of stress response, the expression levels of heat shock protein (HSP)-70, HSP-$90{\alpha}$, HSP-$90{\beta}$, hydroxyl-3-methyl-glutaryl coenzyme A reductase (HMGCR) genes and telomere length were measured by quantitative real-time polymerase chain reaction using the lymphocytes of 1,101 chickens. There was significant difference in HSP-70, HSP-$90{\alpha}$, HMGCR expression and telomere length among the strains. There was also significant difference in HSP-$90{\alpha}$, HSP-$90{\beta}$, and HMGCR expression between male and female chickens. Different age groups of chicken exhibited different expression levels of HSP-70, HSP-$90{\alpha}$ and telomere length. The results of the HSPs expression level suggested that, the strains of R, L and Y were highly resistant to stress, whereas the strains of S, O and W were susceptible to stress. Although the statistical differences in some of HSPs gene expression existed between genders, the HSP expression results varied in different strains that some opposed to the others, and there might be interaction between strains and genders, which conclude that there was no difference in stress response between male and female chickens. Moreover, despite of significant difference in some of HSPs expression level, it was considered that there was no difference in stress response between ages due to the inconsistent trends among HSP markers.

• The Korean Journal of Applied Statistics
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• v.26 no.3
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• pp.401-411
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• 2013

This study investigates the controversial chickens-eggs dilemma and empirically performs statistical tests to examine if there exists a causality between them. Granger and Hsiao tests are applied to both level and stationary variables to identify the lead-lag relationships. Each of these test is found to have the robust result where the causality runs from eggs to chickens; in addition, the explanatory power of one variable in variations of the other appears to remain time invariant. The outcome is proved to be valid as the hypothesis test for no structural change in their relationship fails to be rejected.

• Korean Journal of Food Science and Technology
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• v.32 no.3
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• pp.674-680
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• 2000

This study was conducted to investigate the effect of soaking and blanching of chicken- head on the quality of chicken-head broth. The longer soaking time, the lower the contents of free amino acids and nucleotide and its derivatives in chicken-head broth. Sensory panel showed that increased soaking time led to decreases in the degree of darkness, yellowness, turbidity and the intensity of bloody flavor and organ meat-like flavor. Optimal soaking time was determined to be 30 min according to the result of sensory evaluation. While the broth using unblanched chicken-head contained more free amino acids, nucleotide and its derivatives than the broth using blanched one, sensory test revealed no significant difference between two broths. Therefore, blanching was found to be unnecessary process for the preparation of chicken-head broth.

• Feed Journal
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• v.2 no.8
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• pp.114-117
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• 2004

뉴캐슬병은 국제동물보건기구인 국제수역사무국(OIE)에서 고병원성 조류인플루엔자, 구제역, 돼지콜레라 등과 같이 세계적인 악성 가축전염병 (15종)인 A등급으로 분류하여 관리할 정도로 피해가 심각한 질병으로서 국가간의 축산물 교역과 방역에 이TDj 특별히 취급하도록 권장하고 있고, 예방접종을 하지 않은 계군에 감염되면 거의 100%의 폐사를 일으킬 정도로 무서운 닭의 전염병이다.(중략)

• Korean Journal of Poultry Science
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• v.4 no.1
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• pp.16-27
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• 1977

우리나라 양계산업은 과거 수연간에 있어서 계란과 닭고기의 수요가 급증함에 따라 닭의 사료수수에 있어서나 사양규모에 있어서 크게 발전하여 사업 또는 기업화경영으로 안정되어 가고 있다. 앞으로 양계산업이 지향하여야 할 바는 양적 증가보다는 질적 향상을 꾀하여 생산효율을 높이는 경영방식이 바람직하다. (중략)

• KOREAN POULTRY JOURNAL
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• v.23 no.8 s.262
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• pp.124-126
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• 1991

영양소로서의 물의 중요성에 대해서는 앞에서 이미 충분히 강조한 바 있다. 물은 동물체의 주성분일 뿐아니라 며칠간 사료의 급여를 중단했을 때 가축이 받는 스트레스 보다 물의 급여를 중단했을 때 받는 스트레스가 훨씬 크다는 사실로 보더라도 물을 제외한 모든 영양소를 합한 것보다 물이 더 중요하다는 사실을 말해준다. 오늘은 물의 물리적 및 화학적 성질을 고찰하고 닭의 체내에서 물의 생리적 기능 및 물의 체내 대사에 대해서 알아보기로 한다.