• Asian-Australasian Journal of Animal Sciences
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• v.16 no.4
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• pp.481-488
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• 2003

Insulin-like Growth Factors (IGFs) and IGF-binding protein act as intra-ovarian regulators that modulate the proliferation and differentiation of the granulosa and theca cells. Moreover, the IGF system is involved in metabolism by modulating the synthesis and degradation of glycogen and protein in animals. However the effect of the IGF system on egg productivity or body growth in KNOC has not been studied in depth. Therefore, this study was performed to investigate differences of serum IGFs and binding protein expressions between two groups showing high and low egg production or body weight and to elucidate the relationship of IGFs with egg productivity and body growth. KNOCs were divided into high and low groups depending on their egg productivity or body growth, and sera were collected every 10 wk from 20 till 60 wk. Serum IGF-I and -II concentration were measured by RIA using human and mouse antiserum and chicken standards. IGFBP was detected by Western ligand blotting. IGF-I concentrations were significantly greater in the high egg production group compared with those in the low egg production group (30 wk, p<0.01; 20 and 40 wk, p<0.05). Also, differences in IGF-II amounts between the two groups were detected at 60 wk (p<0.05). But IGFBPs in the low egg production group were more intense than that in the high egg production group through the egg laying period. The correlation between IGF-I concentration and number of egg production is significantly positive (20 wk, r=0.2729: p<0.05; 40 wk, r=0.3500: p<0.01), while IGF-II shows no correlation with egg productivity. In male KNOC, IGF-I and -II concentrations in the high body weight group are lower than that in the low body weight group. Body weight also shows a negative correlation with the serum IGF-II concentration in male chickens (20 wk, r=-0.5901: p<0.01). Consequently, we suggest that IGFs and binding protein are (in)directly involved in the egg productivity and body growth in KNOC.

• Korean Journal of Poultry Science
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• v.20 no.4
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• pp.209-216
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• 1993

This study was conducted to classify Korean native chicken(KNC) and imported chicken by phenotypic performances and DNA fingerprinting. Two lines, KNC and White Leghorn(WL) , of chicken were maintained in the laboratory of Yeungnam University. Economic traits (body weight, sexual maturity, hen-day egg production, egg weight) and phenotypic characteristics (body-type, head, feather, shank) were checked. The DNA fingerprinting was analyzed for both breeds. The growth rate of the KNC was similar to WLS and sexual maturity of the KNC came later than WL. Hen-day egg production of the KNC was also slightly lower than the WL. The egg weight was about 10g lighter than WL. There was no difference in body weight of female KNC compared to the WL after 28 weeks. The study confirms difference between KNC and WL in DNA fingerprinting as well as its outlook. Thus, we suggest that these should be tested in nationwide districts about chickens known as the KNC using DNA fingerprinting. Then, the confirmed KNC populations should be maintained and used for the genetic improvement. Finally, only confirmed KNC should be in market which induce consumer to seek the KNC by its favorite.

• Korean Journal of Agricultural Science
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• v.49 no.4
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• pp.1033-1040
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• 2022

The current experiment was conducted to evaluate the effect of diallel crossbreeding on the body weight and laying performance of Korean native chicken from hatch to week 40. A total of 1,000 one-day-old chicks were allotted to 10 cages per crossbreeding treatment with 10 birds per cage on a random basis and then raised until 16 weeks and subsequently moved to layer battery cages and raised until 40 weeks. Ten crossbred treatments (YC, YD, YF, YK, CD, CF, CK, DF, DK, FK) that were obtained from the diallel crossbred of five pure lines were used in the current experiment. The body weight and mortality were measured biweekly from hatching to week 20 and every four weeks from week 20 to week 40. The number of eggs was measured daily. YC and YD crossbreeds showed a higher body weight (p < 0.05) and FK crossbreed showed a lower body weight (p < 0.05) during the whole xperimental period. The week 20 weight range was 1,501 to 1,729 g and the week 40 weight range was from 1,829 to 2,179 g. Earlier onset of egg-laying was noted in the YC and YD groups whereas late onset was observed for the DF and DK groups. YK reached its peak earliest at week 25 with 89.15% while the DK crossbreed attained its peak at week 36 with 89.69%. The YC and YD crossbreeds showed the improved body and egg-laying performance. Conclusively, there are variations in the body weight and laying performance of Korean native chickens with diallel crossing.

• Proceedings of the KSAR Conference
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• 2002.06a
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• pp.16-16
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• 2002

The egg productivity of the chick is represented by the number of egg produced, egg weight, and sexual maturity, which are regulated by various endocrine factors. Although there were some reports that insulin-like growth factor-I (IGF-Ⅰ) affected egg production, studies on any correlation between IGFs and egg productivity were not reported in poultry. The objectives of the present study were to examine the IGFs profile and egg productivity in both KNOC and laying hen (Saver) and to investigate the relationship of IGFs with egg productivity. Whole blood was collected every 10 wk until 60 wks. (omitted)

• Korean Journal of Poultry Science
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• v.30 no.4
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• pp.235-244
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• 2003

This study was carried out to estimate the effects of strain and generation on the major production performances of Korean native chicken. The data were collected from 11,583 birds of the 7 generations over the year 1995 through 2001 at National Livestock Research Institute, Korea. Results obtained were summarized as follows: The body weights at 150 and 270 days of age were 1,557.7 and 1880.7, 1,471.7 and 1,738.2, 1,393.5 and 1,694.9, 1,591.2 and 1,910.0, 1,545.6 and 1,763.6g in Red Brown, Yellow Brown, Gray Brown, Black, and White strains, respectively. The Coefficient of Variations (CVs) of the body weights at 150 and 270 days of age were 9.65~13.79% and 13.29~15.16%. The ages at first egg were 150.0, 148.3, 149.5, 152,8 and 147.7 days in Red Brown, Yellow Brown, Gray Brown, Black and White strains, respectively and the CVs were between 9.33 and 10.11%. The egg weights at the first egg and 270 days of age were 33.2 and 50.8, 32.2 and 49.2, 32.2 and 49.1, 33.0 and 50.0, 30.7 and 47.8g respectively. The CVs of the egg weights of the first egg and at 270 days of age were 13.54~15.27% and 6.93~7.36%. The numbers of eggs produced by 270 days of age were 77.0, 79.3, 77.3, 73,7, 75.4, respectively, and observed CVs were between 29.98~36.99%. The significant strain effects were investigated in all the major economic traits in Korean native chicken. The significant strain effects were investigated in all the major economic traits in Korean native chicken. The highest least square (LS) means of the body weights at 150 and 270 days of age were observed in Black strain as 1,594.38 and 1,911.57g. The earliest LS mean of the ages at first egg was 146.88days in White strain. The heaviest LS means of egg weights at the first egg and 270 days of age were observed in Red Brown strain as 32.20 and 50.74g. The LS mean of the largest number of egg production was 79.50 eggs in Yellow Brown strain. Also, The significant generation effects were investigated in all the major economic traits. The highest LS means of the body weights at 150 and 270 days of age were observed in the generation 3 as 1,599.74 and 1,905.01g. The earliest LS mean of the age at first egg was 143.31 days in 4th generation. The heaviest LS means of egg weights at the first egg and 270 days of age were observed in 7th and 5th generation as 35.68 and 50.42g. The LS means of the largest number of egg production was 78.53 eggs in generation 6. In general, light body weight, short time for the age at first egg, heavy egg weight, and large number of egg production were observed as the generation proceeded.

• Korean Journal of Poultry Science
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• v.44 no.2
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• pp.123-134
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• 2017

This study was conducted to establish new synthetic lines of Korean Native Chicken. We performed $5{\times}5$ diallel crossings with GPS lines of Korean Native Chicken for the selection of parent stock. The production traits including viability, body weight, age at first egg laying, egg weight, hen-day egg production, and hen-housed egg production were measured and analyzed for 25 crosses with 1,157 hens. The heterosis effects of these traits were also estimated. The results showed that the average survival rate during laying periods was 67.7% in the pure lines and 77.1% in the crosses. The 25 cross combinations were shown to be distinctly divided into three groups according to body weight; nine crosses in the high-weight group, 12 crosses in the medium-weight group and four crosses in the light-weight group. The average body weight at 12 weeks of age was $1,873.8{\pm}43.0g$ in the high group, $1,595.4{\pm}56.6g$ in the medium group and $1,152.7{\pm}24.7g$ in the light group, and $1,560.2{\pm}339.3g$ in the pure lines and $1,640.9{\pm}213.7g$ in the crosses. In terms of egg production performance, the age at first egg laying was $139.7{\pm}4.9$ days in the pure lines and $135.8{\pm}5.1$ days in the crosses. The average egg weight was $52.3{\pm}1.6g$ in the pure line and $53.0{\pm}1.6g$ in the crosses. The average hen-housed egg production from 20 to 40 weeks was $58.3{\pm}12.9$ eggs in the pure line and $69.2{\pm}10.4$ eggs in the crosses. The average heterosis effect was 16.9% for survival rate, 5.4% for body weight at 12 weeks, -2.7% for age at first egg laying, 1.3% for egg weight, and 14.3% for hen-day egg production. Generally, the heterosis effect for viability and egg production traits was higher than that for growth trait. On the basis of these results, it is expected that the selection of the HF combination, which had excellent growth performance, is the most desirable as the paternal strain, and the selection of GW and FW combinations, which had excellent laying performance, are preferable as the maternal strain.

• Korean Journal of Agricultural Science
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• v.45 no.2
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• pp.229-237
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• 2018

This study was conducted to investigate the effect of natural mineral complex fed to laying hens during the summer in terms of the egg quality. A total of 480 laying hens (160 leghorns, 160 Korean native chickens and 160 silkies, all 62 weeks old), were used for 4 weeks. The four dietary treatments were as follows: CON) basal diet; MC1) CON + 0.1% natural mineral complex (NMC); NMC3) CON + 0.3% NMC, and NMC5) CON + 0.5% NMC. In terms of egg weight, the NMC3 and NMC5 treatments had significantly higher egg weights than that of the CON (p < 0.001) in all species. Eggshell strength in the NMC3 and NMC5 treatments was significantly higher than that of the CON in the leghorns on 2 week (p < 0.01). In the Korean native chickens, the eggshell strength for the NMC1, NMC3 and NMC5 treatments was significantly higher than that of the CON during all periods. In 4 week, the eggshell strength for the CON and NMC1 treatment was significantly higher in the leghorns (p < 0.001), but the MC treatments had a significantly higher eggshell strength than that of the CON in Korean native chickens. Egg production was significantly improved in all the treatments compared to the NMC3 treatment (p < 0.05), and hatchability was also improved compared to the CON (p < 0.05). In conclusion, supplementation of natural mineral complex in chicken diets influenced the egg quality during the summer season.

• Korean Journal of Poultry Science
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• v.27 no.1
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• pp.51-61
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• 2000

This study was conducted to estimate the general production performance, heritabilities, and genetic phenotypic correlations on several economic traits by multiple trait animal model in Korean native chicken. The data were collected from the records of 5,192 pullets produced from 2,029 dams and 250 sires in Daejon Branch, National Livestock Research Institute from April 10. 1994 to February 10. 1997. Body weights of Red Brown (RB), Yellow Brown (YB), Grey Brown (GB) and Black (B) strains were 1,649.9, 1,439.6, 1,455.6 and 1,575.3g at age of 150 days and 1,923.5, 1,689.6, 1,812.4 and 1,924.0g at age of 270 days, respectively. The ranges of coefficient of variation for body weight were 11.52 to 14.02 at age of 150 days and 12.82 to 14.59% at age of 270 days, respectively. The first eggs of RB, YB, GB and B strains were produced at 147.4, 146.5, 151.1 and 152.1 days, respectively and the coefficients of variation were 7.80 to 8.41%. Egg weight at 270 days were 49.7, 47.6, 48.8 and 48.7 g for RB, YB, GB nd B strains, and coefficients of variation were 6.99 to 7.94% . The number of eggs at age of 270days were 75.8, 78.0, 76.7 and 68.8 for RB, YB, GB and B strains, respectively, and coefficient of variations were 23.87 to 29.89%. On heritability estimates in RB, YB, GB and strains body weight were 0.40, 0.10, 0.09 and 0.57 for RB, YB, GB and B strains at age of 150 days, and 0.23, 0.09, 0.38 and 0.24 at age of 270 days were 0.39, 0.47, 0.60 and 0.62, and egg weights at 270 days and age at 1st egg were 0.36, 0.12, 0.38 and 0.26, number of egg production at 270 days were 0.44, 0.36, 0.58 and 0.49, respectively. The genetic correlation coefficients of body weight with the age of first egg, egg weight and number of egg production at 270days were -0.07∼0.67, -0.24∼0.70 and 0.12∼0.41, respectively ; age of first egg with number of egg production at 270days and egg weight were -0.75∼0.91 and 0.34∼0.97 ; and egg weight with number of egg production at 270days were 0.18∼0.68. The phenotypic correlation coefficients of body weight with at age of first egg, egg weight and number of egg production at 270days were -0.01∼0.74, -0.04∼0.72 and 0.25∼0.57 ; age of first egg with number of egg production at 270days and egg weight were 0.26∼0.52 and 0.52∼0.92, respectively ; and egg weight with number of egg production at 270days were 0.34∼0.91.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2004.11a
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• pp.97-98
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• 2004

The observed means and standard divisions of the major laying traits per generation in korean native chickens were as follow. The age at first egg, the egg weight at the first egg, the weight at 270days and the egg production to 270days were 147.1$\pm$1.9 days. 32.3$\pm$0.9 g, 49.4$\pm$0.7 g and 76.2$\pm$1.7 eggs. The regression coefficients were -0.75$\pm$0.01 days, 0.33$\pm$0.08 g, 0.19$\pm$0.05 g and 0.47$\pm$0.3 eggs respectively.

• Korean Journal of Poultry Science
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• v.44 no.3
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• pp.189-198
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• 2017

This study was conducted to develop a new synthetic breed of Korean native chicken. The combining ability and reciprocal effects for production traits were estimated on 1,157 hens from a $5{\times}5$ diallel cross-mating design using grand parent stock (GPS) lines of Korean native chicken. Body weight, viability, age at first egg laying, egg weight, and hen-day egg production were measured and analyzed. The results showed that the general combining ability (GCA) of the survival rate during laying periods was -9.6 to 11.1, with the highest value obtained in the W strain. Additionally, the GCA of the body weight at 12 weeks was -209.7 to 162.2, with the highest value obtained in the F strain. The GCA for age at fist egg laying was estimated to be -2.8 to 3.7, while the GCA of egg weight was -0.91 to 0.96, and the GCA of hen-day egg production was -4.9 to 6.0. In the estimation of specific combining ability, the YW combination showed the highest survival rate, FW showed the highest body weight at 12 weeks, and GW showed the highest hen-day egg production. The reciprocal effects were significantly different among crosses for almost all productivity traits. In identical breeding combinations, differences in ability were observed when the maternal or paternal breeds were switched. The mean value based on combining ability was higher in WY, WF, and GW combinations for survival rate; GF, HG, and HF combinations for body weight at 12 weeks; and GW, YW, and FW combinations for hen-day egg production. It is concluded that the GF and HF combinations, which have excellent growth performance and moderate survival rate, are the most desirable paternal parent stock (PS) strains, and the GW and FW combinations, which have great laying performance and moderate body weight, are the most desirable maternal PS strains.