• Korean Journal of Poultry Science
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• v.47 no.2
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• pp.95-105
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• 2020

This study presents the production characteristics and physiological characteristics of five Korean native chicken (KNC) breeds consisting of Hwanggalsaek Jaeraejong (HJ), Korean Rhode Island Red (KR), Korean White Leghorn (KL), Korean Brown Cornish (KC), and Korean Ogye (KO). We investigated their production performances, vitalities, and stress responses. We measured the survival rate, body weight, age at first egg-laying, hen-day egg production, egg weight, amount of telomeric DNA, heterophil-lymphocyte ratio (H/L ratio), and heat shock protein (HSP)-70, HSP-90α and HSP-90β gene expression levels for 493 KNCs. The survival rate was highest in KR, and lowest in KO. Body weights were steadily high in the order of KC, KR, HJ, KO and KL. Average hen-day egg production was highest in KL, and lowest in KC. While the amount of telomeric DNA was highest in KR, and lowest in KC. Furthermore, both the H/L ratio and the HSP-90β gene expression level were highest in KC, and lowest in KR. These results indicated that the KR breed was highly resistant to stress, whereas KC was more susceptible to stress. Taken together, it is considered that with improvements the KC breed would be more suited to be used as a Korean broiler breed while KL would be more appropriately used as a Korean layer breed. In addition, it is considered that the KR breed is appropriate to be used as a maternal chicken breeder based on good production capacity and excellent robustness, while the HJ breed is desirable to be improved as a high-quality Korean meat breed based on its excellent meat quality.

• Korean Journal of Poultry Science
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• v.44 no.1
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• pp.19-28
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• 2017

The eggshell is an intricate and highly ordered structure composed of multiple layers and a calcified matrix. The eggshell is formed at the uterine segment of the chicken oviduct. In this study, histological changes in the uterine endometrium and the expression of the eggshell-related genes were investigated according to hen age. We analyzed the expression of eggshell protein-related genes, such as OCX-32, OCX-36, OC-17, OC-116, and eggshell-ion-related genes, such as CABL-1, SPP1, SCNN1G, ATP2A2, CA2, and CALM1. In chicken uterine endometrium, histological deformation, fibrosis, atrophy and elimination of micro-villi were found with increasing hen age. The concentration of blood-ion components did not significantly change with age. The amount of telomeric DNA in uterine endometrial cells decreased with increasing hen age. The expression of most of the eggshell-related genes changed significantly with increasing hen age. The expression of some ovo-proteins, which play a role in eggshell formation, increased with increasing hen age; however, there were no significant correlations among eggshell protein genes. Eggshell ion-related genes, such as ATP2A2, SCNN1G, CA2, and CALM1, were closely related to each other. The OCX-32 and OCX-36 genes were closely related to some of the eggshell ion genes. Eggshell protein-related genes, such as the OCX-32, OCX-36 genes and ion-related genes such as CALB-1, ATP2A2, SCNN1G, CA2, CALM1, affected eggshell formation, mutually or independently. This study shows that, uterine although endometrial cell damage occurs with increasing hen age, normal eggshells can be formed in old hens. This suggests that eggshell protein-and eggshell ion-related genes also control the homeostasis of eggshell formation.

• Korean Journal of Poultry Science
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• v.47 no.3
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• pp.189-197
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• 2020

This study was conducted to compare the production performance and stress response of chickens kept in the conventional cages and floor pens. 491 female White Leghorns were used in this study, and their production characteristics and stress response indicators were analyzed from 34 to 43 weeks of age. The results showed that there was no significant difference in survival rate, hen-day egg production, and body weight between the chickens kept in the conventional cages and those kept in the floor pens. The chickens kept in the conventional cages had a significantly higher egg weight and egg quality compared with those kept in the floor pens (P<0.01). The amount of telomeric DNA in lymphocytes was significantly higher in the chickens kept in floor pens than in those kept in conventional cages (P<0.05). The heterophil-lymphocyte ratio, HSP-90β gene expression level, and DNA damage rate significantly increased in chickens kept in the conventional cages, as compared to the chickens kept in floor pens (P<0.01). In conclusion, there seems to be no difference in the production performance between chickens kept in conventional cages and those kept in floor pens. Furthermore, chickens kept in conventional cages had higher stress response values than those kept in floor pens for all stress response indicators. Therefore, conventional cage types are considered to be a more stressful environment for chickens than floor pens, regardless of the production performance of the chickens.

• Journal of Life Science
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• v.19 no.10
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• pp.1463-1467
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• 2009

Telomeres, comprised of tandem repeats of TTAGGG sequences, are special nucleoprotein structures that protect and stabilize chromosome ends. These structures form the crux of the telomere concept of aging, senescence and genomic instability. The classic terminal restriction fragment (TRF) analysis to quantify the amount of telomeric DNA is disadvantageous in species containing ultra long telomeres like in mice (100Kb). In this study, we used a more sensitive quantitative fluorescence in situ hybridization (Q FISH) technique to quantify telomeric DNA, and used it as a biological aging marker in mice. 12 litters each of Senescence-Resistant (SAMR1) and -Prone (SAMP1) known as senescence accelerated mouse strains were purchased from Central Lab, Animal Inc. We quantified the amount of telomeric DNA using telomere specific DNA probes on the two strains of male mice at 8 weeks, 18 weeks and 26 weeks of age. The amount of telomeric DNA correlated with aging and age associated changes in body and organ weight between SAMR1 and SAMP1 strains of mice. These data suggest the usefulness of the amount of telomeric DNA as a biological aging marker in human aging studies.

• Korean Journal of Poultry Science
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• v.48 no.1
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• pp.1-12
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• 2021

We investigated the effects of breed, laying age, and egg storage period on the vitality of chicks using the Hwanggalsaek Jaeraejong, Korean Rhode Island Red, and Korean White Leghorn chicken breeds. Their eggs were collected during the early laying period (27~29 weeks) and late laying period (50~52 weeks) and were stored for 3 days, 7 days and 14 days. After the eggs hatched, the hatching time, production performance, and organ weight of chicks were investigated. IL-6 gene expression level and relative length of telomeres were analyzed to determine the physiological activity of the chicks. HSP gene expression level and heterophil to lymphocytes ratio were also analyzed to examine the degree of stress response in the chicks. The results showed that breed and laying age influenced the vitality of chicks, but the egg storage period did not. Korean Leghorn chicks were considered the weakest breed in terms of vitality owing to their low survival rate, small heart size, low physiological activity, and high stress response level. Although the survival rate of chicks produced in the early laying period was low, their high physiological activity and low stress response indicated that they had a high vitality than the chicks produced in the late laying period. In conclusion, to obtain chicks with high vitality, it would be desirable to select a high vitality breed and avoid the use of chicks produced in the late laying period.