• Korean Journal of Poultry Science
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• v.6 no.1
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• pp.31-37
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• 1979

The propose of the present study was to evaluate the relative economic importance of the major Production traits in laying hens. Based on the results of this study, it was showed that feed requirement, average egg weight and hen-housed e99 Production influenced greatly on the income over feed and chick cost.

• KOREAN POULTRY JOURNAL
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• v.25 no.11 s.289
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• pp.136-141
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• 1993

산란계나 종계의 육추, 육성, 성계기에 있어 체중이 낮은 병아리는 계군 전체의 평균체중을 끌어내릴 뿐 아니라 체력이 약하여 육성율, 생존율, 산란율을 저하시키는 주요원인이 되고 있다. 이같은 사실은 육계에서도 같은 결과를 보이고 있어 육계 농장에서의 질병과 관리 및 이에 따른 경제성 개선에 관한 내용을 실예를 들어 살펴보기로 한다.

• The Korean Journal of Malacology
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• v.17 no.2
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• pp.85-94
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• 2001

Spawning, hatching, survival and cannibalism of the octopus, Octopus ocellatus, were investigated at the indoor laboratory. The specimens were collected in the coastal waters of Puan, Korea, from March 2000 to May 2001. Changes in the gonadosomatic index (GSI) during March to May, 2000 were similar to those in 2001. The GSI began to increase in March and reached the maximum in May 2000 and 2001. The mean fecundity of adult individuals in April was larger than those in March and May in 2000 and 2001. In the investigations of survival rates of adults according to the water layers, the mean survival rate in the middle water layer was higher than that in the bottom layer in year 2000 (p = 0.002). The survival rate during 2001 was similar to the result of year 2000 in the water layers (p = 0.018). From the investigations with the purchase dates, the survival (88.8%) in the early spawning period (April 10, 2000) showed larger than those in the mid-spawning (May 11, 2000) and the late spawning (May 23, 2000). For aquaculture, it is suggested that the purchase timing of adults in the early spawning period will have a better result than that of the other spawning periods. In the amount of spawning with water layers, the number of eggs spawned of the adults in the middle layer were larger than those in the bottom layer. In the number of eggs spawned with the purchase dates, the number of eggs spawned in the early spawning period were larger than those in the middle and late spawning periods. The size of eggs spawned were 6.904$\times$2.520 mm. the hatching period required (from spawning to hatched larvae) was 55 days (April 17 to June 7,2000) at water temperatures of 11.2 to 21.1$^{\circ}C$. In case of the hatching rates with water layers, the hatching rate in the middle water layer was larger than that in the bottom one (p = 0.004).

• Korean Journal of Poultry Science
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• v.50 no.3
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• pp.133-141
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• 2023

We conducted a 5 × 5 diallel cross-combination test using 1,060 chickens from pure lines of Korean Rhode-C, -D, Korean Leghorn-F, -K, and Korean Native Yellowish-brown chicken (KNC-Y) to develop a new Korean native chicken layer breeder. The laying performance and combining ability, including livability, body weight, age of first egg-laying, hen-day egg production, and egg weight, were analyzed. The livability from birth to 48 weeks was 72.1±24.0%, with the highest observed in the YC and the lowest in the DK combination (P<0.01). The YC combination exhibited the highest general combining ability (GCA), while the YD combination showed the highest specific combining ability (SCA). Regarding body weight, combinations involving Leghorn showed lighter weights compared to combinations with Rhode and KNC-Y (P<0.01). Additionally, the offspring from the KNC-Y combination reached sexual maturity earlier than those from the Rhode combination. The hen-day egg production was 70.7±12.0%, with the highest seen in the CK combination at 86% (P<0.01). The effects of GCA and SCA on hen-day egg production were similar, with the SCA being highest in the YD combination and the GCA being highest in the Rhode-C. Significant differences in egg weight were observed among the combinations, with the eggs from Rhode and Leghorn combinations being heavier than those from combinations with KNC-Y (P<0.01). In conclusion, the YC and YD combinations, characterized by excellent livability, are highly desirable paternal strains, while the CF and CK combinations, with excellent laying performance and moderate egg weight, are preferred maternal strains for Korean native chicken layer breeders.

• Korean Journal of Poultry Science
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• v.50 no.4
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• pp.203-212
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• 2023

This study conducted a diallel-crossbreeding test using four Korean native chicken parent stock lines (YC, YD, CK, and CF) to develop a native commercial layer with high egg-laying performance. A total of 312 chickens in six combinations were examined for various traits, including livability, body weight, age at first egg-laying, hen-day, and hen-housed egg production, egg weight, and egg quality, from hatching to 60 weeks of age. The results showed that the average survival rate was 77.1±18.8% with the YDYC combination having the highest survival rate along with excellent specific combining ability. The YDYC combination exhibited significantly higher body weight compared to the other combinations (P<0.01). The average age at first egg-laying was 121.3±2.5 days, with no significant difference between the combinations. The average hen-day egg production was 74.0±6.4%, and the hen-housed egg production was 181.4±33.8 eggs with the YDCF and YCCK combinations demonstrating the highest laying performance, while the YDYC and CKCF combinations had the lowest (P<0.05). Laying performance was more influenced by specific combining ability than general combining ability. The eggs from the YDYC combination were significantly lighter and had the darkest shell color (P<0.01), whereas the YDCF combination exhibited the thickest eggshells. There was no difference in internal egg quality among combinations, except the YDCF combination had the darkest yolk color. Overall, we concluded that the YCCK combination, characterized by high laying performance and livability, and the YDCF combination with high laying performance and good egg quality are the most desirable combinations for Korean native commercial layers.

• Korean Journal of Poultry Science
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• v.13 no.1
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• pp.1-14
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• 1986

The subject of this study was to obtain some genetic information for developing superior layer chickens. Heterosis and combining ability effects were estimated with 5,759 progenies of full diallel crosses of 6 strains in White Leghorn. Fertility, hatchability, brooder-house viability, rearing- house viability, laying-house viability, age at 1st egg laying, body weight at 1st egg laying, average egg weight, hen-day egg production, hen-housed egg production, and feed conversion were investigated and analyzed into heterosis effect, general combining ability, specific combining ability and reciprocal effect by Grilling's model I. The results obtained were summarized as follows; 1. The general performance of each traits was 94.76% in fertility, 74.05% in hatchability, 97.47% in brooder-house viability, 99.72% in rearing-house viability, 93.81% in laying-house viability, 150 day in the age at 1st egg laying, 1,505g in the body weight at 1st egg laying, 60.08g in average egg weight, 77.11% in hen-day egg production, 269.8 eggs in hen-housed egg Production, and 2.44 in feed conversion. 2. The heterosis effects were estimated to -0.66%, 9.58%, 0.26%, 1.83%, -3.87%, 3.63%, 0.96%, 4.23%, 6.4%, and -0.8%, in fertility, hatchability, brooder-house viability, laying-house viability, the age at 1st egg laying, the body weight at 1st egg laying, average egg weight, hen-day egg Production, hen-housed egg production and feed conversion, respectively. 3. The results obtained from analysis of combining ability were as follows ; 1) Estimates of general combining ability, specific combining ability and reciprocal effects were not high in fertility. It was considered that fertility was mainly affected by environmental factors. In the hatchability, the general combining ability was more important than specific combining ability and reciprocal effects, and the superior strains were K and V which the additive genetic effects were very high. 2) In the brooder-house viability and laying-house viability, specific combining ability and reciprocal effects appeared to be important and the combinations of K${\times}$A and A${\times}$K were very superior. 3) In the feed conversion and average egg weight, general combining ability was more important compared with specific combining ability and reciprocal effects. On the basis of combining ability the superior strains were F, K and B in feed conversion, F and B in the average egg weight. 4) General combining ability, specific combining ability and reciprocal effects were important in the age at 1st egg laying and the combination of V ${\times}$F, F${\times}$K and B${\times}$F were very useful on the basis of these effects. In the body weight at 1st egg laying, general combining ability was more important than specific combining ability and reciprocal effects, relatively. The K, F and E strains were recommended to develop the light strain in the body weight at 1st egg laying. 5) General combining ability, specific combining ability and reciprocal effects were important in the hen-day egg production and hen-housed egg production. The combinations of F${\times}$K, A${\times}$K, and K${\times}$A were proper for developing these traits. 4. In general, high general combining ability effects were estimated for hatchability, body weight at 1st egg laying, average egg weight, hen-day egg production, hen-housed egg production, and feed conversion and high specific combining ability effects for brooder-house viability, laying house viability, age at 1st egg laying, hen-day egg production and hen-housed egg production, and high reciprocal effects for the age at 1st egg laying.

• Korean Journal of Poultry Science
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• v.43 no.3
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• pp.177-189
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• 2016

This study was conducted to verify the relationships between the expression values of stress-related markers and their production performances in 25 strains of Korean domestic chicken breeds. For stress response markers, the amount of telomeric DNA; expression levels of heat shock protein (HSP)-70, $HSP-90{\alpha}$, and $HSP-90{\beta}$; and comet scores were analyzed. Production performances were measured by the survival rate, body weights, days at first egg laying, egg weight and hen housed egg production. The results showed that the production traits and values of stress-related markers showed significant differences between strains. In general, the stress response of pure bred chickens with heavy weights was relatively high, while that of hybrid chickens with light weights was relatively low. The correlation coefficients between telomere contents and body weights showed that there were weak negative relationships. However, the correlations of telomere content with the survival rate and egg production were weakly positive after 20 weeks old. The expression levels of HSP genes and DNA damage rate (comet scores) were positively correlated to body weight, but were negatively correlated to the survival rate and egg production. The results implied that increasing body weight was associated with increasing HSPs expression and the DNA damage rate was associated with decreasing telomere content. In addition, increasing HSPs expression and the DNA damage rate decreased the survival rate and egg production, but the relationships with the telomere content was the reverse. Correlations among the stress-related markers showed that there were significant correlation coefficients between all of the marker values. HSPs expression was negatively correlated to the telomere content, while it was positively correlated to the DNA damage rate. There was a highly negative correlation between the telomere content and DNA damage rate. In conclusion, increasing the HSP values and DNA damage rate can promote telomere reduction, which led to a decrease in disease resistance and robustness of the chicken. Thus, increasing the stress response was verified to adversely affect the laying performance and viability of chickens.

• KOREAN POULTRY JOURNAL
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• v.13 s.146
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• pp.108-116
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• 1981

제15회 산란계 경제능력검정에는 총 13개 계군이 출품되었으며 능력검정 결과를 요약하면 다음과 같다. 1. 육추율, 육성율, 성계생존율 이번회 검정계의 육추율은 13개 계군 평균 97.72$\%$로서 14회 99.7$\%$와 비슷하다. 특히 이번 검정에서 육추기간 중 한마리의 폐사도 없는 구는 3구였으며 9구 만이 79.64$\%$로 육추율이 가장 낮았는데 그 원인은 1개 검정소에서 육추기간 중 백혈병으로 인한 폐사수가 많았기 때문으로 보인다. 육성율 평균은 99.07$\%$로서 14회 99.0$\%$와 같았고 한마리의 폐사도 없는 구는 11구로서 최고 육성율을 보였다. 성계 생존율은 평균이 90.14$\%$로서 14회의 92.6$\%$에 비슷 하였으며 13구는 97.98$\%$로서 상당히 좋은 성적을 보였으며 6구, 7구 9구, 10구 및 11구는 90$\%$이하로 성계생존율은 5회 점검 이후 점차 높아 졌는데 이유는 MD백신이 개발되어 이의 접종으로 인한 마렉병의 발생을 예방 할 수 있었던 것으로 생각된다. 2. 성 성숙일령 15회 검정에서 13개 계군의 평균 성 성숙 일령은 163일에서 14회 161일과는 비슷하였는데 성 성숙 일령은 육성기의 사료 급여와 사양관리에 따라서 영향을 많이 받는 형질이므로 더 이상의 고찰이 필요하지 않다. 성 성숙이 제일 빠른구는 5구의 154일이었고 늦은 구는 9구의 168일 이었는데 그 차는 14일이였다. 3. 산란율 및 산란지수 이번 검정계군의 평균 산란율은 70.14$\%$로서 14회에 73.8$\%$와 약 3.6$\%$가 낮았다. 한편 최고 산란율을 나타낸 구는 5구의 73.86$\%$였으며 산란율이 제일 낮은 구는 11구의 65.95$\%$였다. 산란지수의 평균은 232.02로서 14회의 246.5보다는 14.5개가 적었는데 이는 산란율에서와 같은 경향치 였다. 최고 산란 지수를 보인 구는 5구의 250.69였고 2구와 3구, 8구, 13구도 240이상으로서 상당이 좋은 성적을 보였으며 9구는 204.82로서 산란지수가 최하위 였고 최상위와 최하위와의 산란지수의 차이는 무려 45.87이었다. 4. 사료 요구율 13개 계군의 평균사료 요구율은 2.67로서 14회 2.68과 비슷하였다. 사료 요구율이 제일 낮았던구는 3구의 2.56이였고 사료 요구율이 제일 높았던 구는 9구의 2.78이였다. 5. 난중 13개 계군의 평균난중은 60.72g으로서 14회 59.08g보다는 약간 무거웠는데 난중은 다른 형질에 비하여 유전력이 높은 형질인 것을 감안할 때 사양관리 면에서의 영향이 아니고 출품계군의 구성에 의한 영향인 것으로 생각된다. 8회 검정 성적 중 난중이 제일 무거운 구는 4구의 63.32g이었고 제일 가벼운 구는 5구의 58.08g이었다. 6. 체중 300일령 평균체중은 1,966.33.g으로 14회 1,986.7g보다는 가벼웠는데 체중 역시 유전력이 높은 형질로서 이 차이는 검정계군의 구성에 따른 차이로 생각 된다. 500일령 체중의 평균은 1,985.68g으로 14회의 1,994.9g보다는 약간 가벼웠으나 500일령 체중에 있어서와 같이 검정계군의 구성에 따른 차이로 생각 된다. 7. 사료 섭취량 육추기간 중의 1일 1수당 평균사료 섭취량은 32.97g으로 14회 34.82g보다 적었는데 이것 역시 출품계군의 구성에 있어 겸용종 내지 유색종의 비율이 낮았던 데에 기인한 것으로 생각된다. 육성기의 1일 1수당 사료섭취량은 70.06g으로서 14회의 70.91g과 같았고 산란기간 중의 1일 1수당 사료섭취량은 평균이 113,54g으로서 14회 115.81g과 비교할 때 큰 차가 없었으며 특히 11구는 118.61g으로 가장 사료를 많이 섭취 했는데 산란기 수당 사료 섭취량은 해가 거듭될수록 적어지는 경향이었다. 8. 경제성 13개 검정계군이 총 수입은 45,405원으로 계란 판매 수입은 86.4$\%$였고 폐계 판매수입은 13.59$\%$였으며 총 지출은 33,657원으로 사료비의 지출비율이 95.5$\%$였고 초생추대가 4.5$\%$였다.

• 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.

• Korean Aquaculture
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• v.14 no.2
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• pp.52-65
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• 2002

비단가리비의 인공 종묘 생산을 목적으로 전라남도 신안군 대흑산도 주변에 서식하는 비단가리비를 대상으로 인공 종묘 생산을 위한 산란 유발, 수정란의 발생 과정, 유생 사육, 채묘 및 중간 육성 등 양식 생물학적 연구를 실시하였다. 어미의 각종 산란 유발 자극에 대한 반응은 Serotonin 주사, 온도 자극, 혼합 자극에서 반응율이 가장 높았으며, 자외선 조사 해수 자극은 수컷만 반응을 하였고 간출 자극은 반응이 없어 실효성이 없는 것으로 나타났다. 수정란의 크기는 $69.5{\mu}m$이었고, 수정 후 약 2시간에 2 세포기, 8시간 후에 8 세포기, 20시간 후에는 담륜자 유생으로 부화하였으며 40시간 후에는 D상 유생으로 되었다. 수온별 비단가리비 유생의 성장은 수온 $20^{\circ}C$에서 각장 $178.9{\mu}m$로 가장 좋았으며, 이 때의 생존율은 15.5%이었다. 그러나 수온 $15^{\circ}C$에서는 낮은 성장을 보여 각장 $135.9{\mu}m$로 성장하였으며, 생존율도 9.8%로 저조하였다. 수용 밀도별 사육 시험에서 $1m{\ell}$당 1개체와 5개체에서 성장 및 생존율이 양호하여 성장 및 생존율을 볼 때 적정 사육 밀도는 $1m{\ell}$당 5개체 이하로 나타났다. 먹이 생물 종류에 따른 유생의 성장을 알기 위하여 I, gal-baba, C, calcitrans, N, oculata를 단독 또는 혼합으로 공급하였을 때 실험 종료후 각장의 성장은 I, galbana+C. calcitrans+N. oculata구가 $194.2{\mu}$로 가장 좋았고 N. oculata구는 $162.2{\mu}m$로 가장 낮은 성장을 보였다. 생존율에서는 I. galbana+C. calcitransoculata구는 9.4%로 가장 낮은 생존율을 보였다. 채묘기별 유생의 부착률은 염화비닐판을 수평으로 놓은 것과 패각이 각각 3.43%와 3.17%로 가장 양호하였으나, 양파망과 염화비닐판을 수직으로 놓은 것은 각각 1.52%와 1.61%로 비교적 저조하였다. 수정 후 40일째부터 90일째까지 측정한 부착치패의 경과 일수에 따른 각장의 성장은 $SL=184.44e^{0.0335X}(r^2=0.9861)$의 회귀직선식으로서 나타났다. 중간육성 시험에서 수심별 성장을 분석한 결과, 비단가리비 치패는 저층보다 표층이 각장 5.92mm, 전중량 6.07g 정도 더 빨리 성장하였다.