Poultry is one of the three major meats in Korea and is a representative source of protein. The annual per capita consumption of chicken has been showing steady growth trends, with an increase of approximately 89% in 2018 compared to that of 2005. In this study, we investigated the domestic chicken production and consumption, and conducted an overall study on the domestic chicken industry. By using consumer panel data, we analyzed the characteristics of consumers buying chicken. Specifically, poultry was categorized into two types: traditional raw chicken and processed chicken, which emphasizes convenience. The purchase of raw chickens has generally been on the decline. From these, however, the proportion of native Korean chicken and chicken cuts is on the rise. Processed chicken, on the other hand, continues to grow, especially online. After examining the consumption characteristics of consumers who buy chicken, it was found that the purchase share increased with increasing age of native Korean chickens, whereas the purchase share increased with decreasing age of processed chicken. Based on these results, we confirmed that it is necessary to establish differentiated marketing and promotion strategies for each consumer target for the growth of chicken market.

The purpose of this study was to determine the effects of mixed or split-sex feeding on growth performance and behavior of Korean native chickens. Three variants of the sex ratio, FO (female only), MO (male only) and MI (mixed) were tested in Korean native chickens (Hanhyop 3) that were between the ages of 7 and 91 days. Body weight gain was the highest (p<0.05) in the MO treatment and the lowest (p<0.05) in the MI treatment. The feed intake (FI) of birds in the MO treatment was higher (p<0.05) than that of birds in the MI treatment during days 14-21, also MO treatment was higher (p<0.05) than that of birds in the MI treatment during days 21-28. However, the FI of birds in the MI group was higher (p<0.05) than that of birds in FO treatment during days 35-42. The behavioral frequency of walking, drinking, and aggressive pecking were not affected by sex ratio treatment. The behavioral frequency of feeding was higher in the FO treatment than that of birds in the other treatments. The comfort time of birds in the MI treatment was longer (p<0.05) than that of birds in the other treatments. The behavioral frequency of pecking was higher in the MO treatment than that of birds in the other treatments. The study suggests that when male and female Korean native chickens are reared together, sex ratio can influence growth performance and behavior frequency.

With emphasis on native genetic resource, Korean native chicken is one of the major native breeds in poultry in Korea. The weight-age data from 216 pullets of Korean native chicken were used to fit the growth curve using Gompertz model. Live weights have been recorded every three weeks for 36 weeks for 5 strains. All available weight data from birth to the 6 specific ages of week were used for the estimation of parameters. The variation in estimates of mature weight (A) decreased with the increase of age 21 through 36 weeks for all 5 strains studied. However, the variation of rate of maturing (k) showed a tendancy increase with the increase of age. These results indicate that the fitting of growth curve is getting more stable for asymptotic value (A) and more flexible for curve shape (k) with the increase of weight-age data range. Correlations among estimates of A and among estimates of k at various ages showed the highest range of 0.93 ~ 0.99 between 30 and 36 weeks except for the maturing rate (k) of red brown strains. The correlations between A and k tended to fluctuate and were not significant statistically at various ages. Thus, the estimates of growth curve parameters, A and k suitable for genetic studies in Korean native chicken can be derived from accumulated weight-age data after 30 weeks of age.

The tyrosinase (TYR) genes have been accepted as major genes involved in the plumage pigmentation of chickens. Tyrosinase (TYR) gene is located on chromosome 1 in chicken and it is composed of five exons and four introns. TYR gene is described as a key enzyme in melanin biosynthesis. Especially, most examples of color patterns in chicken have been due to differential in the tyrosinase gene. This study was conducted to the association of feather color and sequence polymorphism in the Tyrosinase(TYR) gene was investigated using Korean native chickens(red plumage, red-line plumage, Ogol = KNC) and white leghorn(WL). From WL and KNC breed analyses, 232 differential SNPs were detected in 4th exon and 4th intron of TYR gene respectively. The genotype frequencies for 50 SNPs were compared between KCR, KCRD and KCO represented homozygous SNP types in all the analyzed SNP positions while KNC displayed various SNP types. In this study, we conclude that the variation of a wild type sequence in intron 4 of the tyrosinase gene is pigmentation of the original native chickens in korean. This work was supported by a grant from the “Livestock Preservation of Genetic Resources", Rural Development Administration, Republic of Korea.

본 시험은 한국 재래계와 도입계의 육성기(0 ~ 20주령) 성장 능력을 비교분석하기 위하여 수행하였다. 공시계는 가축유전자원 관리기관에서 종란을 인수하여 부화시킨 암수 병아리 180 수를 이용하였으며, 한국 재래계 1 계통(A)과 도입계 2계통(B, C)으로 총 3 계통의 육성률, 육성단계별 체중, 증체량, 사료 요구율, 정강이 길이 등을 조사하였다. 육성 초기(0 ~ 4주) 육성률은, A와 C계통은 98.33%로 높게 나타났으나, B계통은 91.67% 로 낮게 나타났다. 육성기 전 주령(0 ~ 20주)육성률도 C계통이 98.33%로 높게 조사 되었고, B계통이 83.33%로 낮게 조사되었다. 육성기 전 주령의 체중은 A, B계통이 C계통에 비해 높게 조사되었다(p < 0.05). 한국 재래계통인 A계통은 발생 시에는 체중이 가장 낮게 조사되었지만, 20주령에는 1.64 kg으로 가장 무거운 것으로 나타났다(p < 0.05). 계통간 사료 요구율은 0 ~ 8주령에서 C계통이 가장 높았고(p<0.05), 12 ~ 16주령에서는 B계통이 가장 높았으며(p < 0.05), 0 ~ 20주령에서는 유의적 차이가 없었다(p > 0.05). 육성 단계별 정강이 길이를 살펴보면, 0 ~ 12주령까지 B계통에서 가장 높게 나타났고, 16 ~ 20주령에서는 B와 C계통에서 높게 나타났다(p < 0.05). 마지막으로 계통간 정강이 길이 증가량은 0 ~ 8주령까지 B계통에서 가장 높게 나타났고, 8 ~ 16주령까지는 C계통에서 가장 높게 나타났다(p<0.05). 이와 같이 한국 재래계의 육성기 능력이 도입계에 비하여 다소 낮게 조사되었지만, 한국 재래계 고유 특성을 유지하고 있었다. 이러한 한국 재래계의 고유 특성들은 한국 재래계 활용에 있어 기준 자료로 이용될 것으로 사료된다(색인어 : 한국 재래계, 도입계, 육성기, 체중, 정강이 길이).

For reconstituting genetic resource(Korean Native Chicken: KNC) with grem-line chimeric chicken made with cryopreserved biastdermal cells, the experiments were carried out to optimize cryopreservating conditions. Stage X biastdemal cells were collected from KNC embryos and dissociated. Cells were susupended in medium containing cyopretectant and fetal bovine serum(FBS), and distributed into plastic ampules. Cell susupensions were seeded to induce ice formation at — 7℃ to — 35℃ at in the experiments, the effect of modification of dissociation way, concentration of FBS and cell density on the vaibility of frezen-thawed cells were investigated by trypan blue exclusion. Then change the way of cell dissociation from pipetting to short time vortexing, viability of frozen- thawed cell tended to be increaced from 29 % to 52 %. Increase concentraition of FBS in frozen medium from 20 % to 80 % made viability of thawed cell from 28 % to 35 %. The viability of thawed cells were 33.9% frozen at 2 embryos/ 0.5 ml, and 43.6 % frozen at 20embryos/0.5 ml. Furthermore, combination of three modifications make big improvement. The viability of frozen-thawed cell was 60 % for combinated method, and 41 % for general method. This result means the advance to practical cryoreservation of blastdermal cell of the KNC(Ogolgye breed).

For reconstituting genetic resource(Korean Native Chicken: KNC) with grem-line chimeric chicken made with cryopreserved biastdermal cells, the experiments were carried out to optimize cryopreservating conditions. Stage X biastdemal cells were collected from KNC embryos and dissociated. Cells were susupended in medium containing cyopretectant and fetal bovine serum(FBS), and distributed into plastic ampules. Cell susupensions were seeded to induce ice formation at —7 ℃ to —35 ℃ at in the experiments, the effect of modification of dissociation way, concentration of FBS and cell density on the vaibility of frezen-thawed cells were investigated by trypan blue exclusion. Then change the way of cell dissociation from pipetting to short time vortexing, viability of frozen-thawed cell tended to be increaced from 29 % to 52 %. Increase concentraition of FBS in frozen medium from 20 % to 80 % made viability of thawed cell from 28 % to 35 %. The viability of thawed cells were 33.9% frozen at 2 embryos/ 0.5ml, and 43.6 % frozen at 20 embryos/0.5 ml. Furthermore, combination of three modifications make big improvement. The viability of frozen-thawed cell was 60 % for combinated method, and 41 % for general method. This result means the advance to practical cryoreservation of blastdermal cell of the KNC(Ogolgye breed).

This study was carried out to investigate the effects of semen on reproductive ability in crossbred Korean native chicken (KNC, 58-wk old). The body weight, volume of semen and concentration of spermatozoa, were 2.96 g, 0.40 ml, 36.58×108/ml, respectively, in KNC. The fertility and hatchability were 94.8% and 78.8% respectively in crossbred KNC. KNC(Y) was high compared to other strains in fertility. The other strains were not significantly different among 6 strains. The results of this experiment indicated that hatchability of (G) was high compared to other strains. The result of this study could be available to genetic improvement of reproductive traits as a basic reference in KNC strains. To achieve the more effective improvement of reproductive traits, addition research such as genetic parameter evaluation should be performed.

This study aimed to investigate the effects of dietary supplementation of mixed probiotics on growth performance and fatty acid profiles of Korean native chicken and to provide information regarding producers. Ninety six Korean native chicken (48 males and 48 females, Hanhyup-3-ho) were allocated to 16 wire cages with 4 treatments, 4 replicates and 6 chicks (3 males and 3 females) per wire cage and fed one of four diets containing 0, 0.5, 1 and 1.5% mixed probiotics for 6 weeks. There were no differences among treatments in growth performance of Korean native chicken. For fatty acid profiles, no statistically differences in each fatty acid, total saturated fatty acid and unsaturated fatty acids were observed in all treatments. In the present study, irrespective of statistically differences, inclusion of mixed probiotics tended to improve growth performance, reduce saturated fatty acid and increase unsaturated fatty acids in breast muscles from Korean native chicken compared to controls.

The characteristics of the components related to the meat taste of the commercial broiler (CB) and the Korean native chicken (KNC) were compared. The breast meat from CB showed higher amounts of C16:1 and C18:2 but lower amounts of C16:0 and C22:6. The thigh meat from CB showed a higher amount of C18:1 but lower amounts of C16:0, C18:0, C20:4, and C22:6. The flavor- and taste-contributing amino acids, including aspartic acid, threonine, serine, glycine, alanine, tyrosine, lysine, histidine, and arginine, were significantly higher in the KNC breast meat, but the level of amino acids in the thigh meat were not different between the two breeds. The measurement of the volatile compounds revealed that CB contains much higher volatile compounds compared to KNC in their fresh breast and thigh meat. Both in the breast and thigh meat, however, the amount of flavor compounds increased significantly after cooking; as such, KNC turned out to have more flavor compounds than CB.