• Korean Journal of Poultry Science
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• v.23 no.1
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• pp.27-37
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• 1996

This experiment was carried out to study the effects of feeding split diets for a.m. and p.m. on laying hen performance and feed cost with 480 ISA Brown layers for three periods during 32∼36, 52∼56 and 72∼76 wk of age, respectively. The control group(C) was fed a conventional single diet throughout the day and split diet groups (T$_1$, T$_2$, T$_3$, T$_4$ and T$\_$5/) were offered high energy-high protein-low Ca diets, and low energy-low protein-high Ca diets in a.m. and p.m., respectively. In split diet groups, feed intake, ME and CP consumption, and feed cost were significantly reduced(P<0.05) compared to the C, while the hen-day egg production was significantly improved. However, the average egg weight was not influenced by the feeding system. Due to the reduced daily feed, ME, and CP intakes, and the improved egg production, the conversions of feed, ME, CP, and feed cost required per kg egg mass were also significantly improved (P<0.05) in splits diet groups. Among split diet groups, the T$_2$ group fed the diet devoid of Ca supplement from the conventional laying hen diet in a.m., and the diet containing the Ca supplement 2 times the conventional diet in p.m., was superior in conversion of nutrients and feed cost per kg egg mass to the other split diet groups. It was concluded that daily feed and nutrients cousumption and daily feed cost could be reduced 5∼6％ while hen-day egg production could be improved about 4％, so that about 10％ of the feed and nutrients and feed cost per kg egg mass could be spared by introducing the split diet feeding for a.m. and p.m. based on T$_2$ treatment in laying hens.

• Korean Journal of Poultry Science
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• v.19 no.4
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• pp.177-185
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• 1992

This study was carried out to investigate the relationship between frequency of soft and broken eggs and the economic traits for colored laying hens using the data sampled 7 times in Korea from 1985 to 1991. In addition, the correlation coefficients of frequency of soft and broken eggs on the economic traits for colored laying hens in order to decrease the frequency of soft and broken eggs were studied. The results obtained were summarized as follows ： 1. For colored laying hens, mean of the sexual maturity(SM) was 163.6 days, hen-day egg Production(HDEP) was 79.49％, hen-housed egg Production(HHEP) was 272.9 eggs, egg weight (EW) was 62.69g and the frequency of soft and broken eggs was 1.363％ during 18∼72wks. For white laying hens, SM was 157.2 days, HDEP was 77.87％, HHEP was 265.1 eggs, EW was 60. 26g and the frequency of soft and broken eggs (FSBE) was 1.174％ during 18∼72wks. 2. Statistical significances were observed in laying viability, SM, HDEP, FR, BW and FSBE during 18 ∼72wks and 18 ∼78wks by year for colored laying hens. 3. Sexual maturity was shortened from 168.5 days to 155.9 days. FSBE decreased from 1.4∼l.69％ to 0.94∼o.89％ during 18∼72wks, and HDEP was increased from 74.5∼75.1％ to 77.8∼80.6％, HHEP was increased to 302.0∼304.6 eggs and FSBE was increased from 1.54∼2.02％ to 0.98％ during 18∼78wks in colored laying hens. 4. Estimate of correlation coefficients between FSBE and trait of SM, EW, 72 wks BW were 0.3985, 0.1072, 0.4225, and those of HDEP, HHEP, FR were -0.5662, -2896, -0.245 during 18∼72wks In colored laying hens, respectively. 5. Estimate of correlation coefficients between FSBE and traits of SM, EW, 78wks BW were 0.3791, 0.1171, 0.4609, and those of HDEP, HHEP, FR were -0.5041, -0.2372, -0.2421 during 18∼78wks in colored laying hens, respectively.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2003.11a
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• pp.109-110
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• 2003

본 시험은 스테비아 부산물의 사료적 가치를 구명하기 위하여 산란계 사료에 첨가하여 산란계의 생산성, 난 품질, 계란의 지방산에 미치는 영향을 고찰하였다. 공시계는 78주령 하이라인 360수로 강제환우후 5％ 산란시기에 시행하여 총 20주 동안 사양시험을 시행하였다. 스테비아 부산물을 산란계 사료에 0, 2, 4, 8 ％를 첨가하여 동일한 에너지(2,800 kcal/kg)와 단백질(16 ％) 수준으로 급여하였으며, 처리구당 5반복, 반복당 18수씩 총 360수를 공시하였다. 시험기간 20주 동안, 총 산란율, 난중, 산란량, 사료요구율은 스테비아 부산물 급여구와 대조구 사이에 유의적인 차이는 없었다. 스테비아 부산물의 급여가 계란의 난 품질에 미치는 영향에서 난각강도, 난각두께, 난백고 및 Haugh Unit는 대조구와 차이가 없었지만, 난황색도는 스테비아 부산물의 급여수준이 증가할수록 높은 수치를 보여 스테비아 4 ％와 8 ％ 급여구는 대조구에 비하여 유의적으로 증가하였다. 계란의 당 전이도 시험에서는 스테비아 부산물을 급여하여 생산된 계란과 대조구 사이에 차이가 없었다. 계란의 지방산 함량은 스테비아 부산물 2 ％와 4 % 급여구가 포화지방산은 감소하였고, 단가 불포화지방산은 유의적으로 증가하였다. 이러한 결과 산란계 사료에서 스테비아 부산물은 원료사료로서 8 ％까지 가능하였다.

• Korean Journal of Poultry Science
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• v.50 no.3
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• pp.119-124
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• 2023

This study was conducted to investigate the effect of dietary levels of the metabolic energy (ME) on performance, egg quality, and hatchability of Woorimatdag breeder hens during late laying period. A total of eighty Woorimatdag breeder hens were individually housed in cages from 48 to 64 weeks of age. The hens were assigned to two groups with different dietary ME levels: 2,500 kcal/kg and 2,700 kcal/kg. Each group consisted of four replicates of ten birds. The results indicated that the dietary ME levels did not have a significant effect on the body weight and feed intake of the breeder hens. The egg production was significantly (P<0.05) higher in breeder hens fed 2,500 kcal/kg ME than in those fed 2,700 kcal/kg ME from 48 to 52 weeks of age. However, the egg production was shown to be similar values in both groups from 52 to 64 weeks of age. No significant differences were observed between groups with respect to egg weight, eggshell thickness, and eggshell strength of breeder's eggs. There was no difference in the fertility and hatchability between dietary groups. In conclusion, 2,500 kcal/kg of dietary ME could be considered to meet Woorimatdag breeder hens requirement sufficiently during late laying period.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2003.05a
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• pp.27-35
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• 2003

(시험 1) 육용종계 산란기의 단백질공급수준에 관한 연구: 육용종계 산란기의 적정 단백질공급수중을 구명하기 위하여 강원도 홍천군 북방면소재 홍천종계에서 케이지 사양형태의 아바에이카 육용종계 400수를 공시하여 2001년 2월부터 2001년 12월까지 40주간 (24∼64주령) 1일1수당 단백질 공급량을 18, 20, 22, 24g으로 달리하는 4개처리로 사양시험을 실시한 결과를 요약하면 다음과 같다. 1) 총 산란율과 종란 산란율은 모두 처리간에 유의적인 차이가 있었으며 (P<0.05), 20g 공급구가 가장 높았으나 18∼22g 공급구간에는 유의차가 없어고 24g 공급구는 20g 공급구에 비해 유의적으로 낮았다(P<0.05). 2) 평균난중은 1일 단백질공급수준이 증가할수록 증가하는 경향이었으나 (P<0.05), 20∼24g 공급구간에는 유의차가 없었고 18g 공급구만 24g 공급구와 유의적인 차이가 있었다. 성계생존율은 처리간에 유의적인 차이가 없었다. 3) 계란kg당 또는 계란1개당 사료요구율과 ME요구량은 모두 1일 CP 20g 공급구가 가장 우수했으며(P<0.05), 계란 kg당 사료요구율과 ME요구량에서는 CP 18g 공급구계란1개당 사료요구율과 ME요구량에서는 CP 24g 공급구만 CP 20g공급구오 유의차를 보였다(P<0.05). 4) 계란kg당 또는 계란 1개당 CP요구량은 모두 1일 단백질 공급량이 많아질수록 증가하였으나(P<0.05), 18g과 20g 공급구간에는 유의차가 없었다. 5) 계란kg당 또는 계란 1개당 사료비는 모두 CP 20g 공급구가 가장 우수하였으나(P<0.05), 계란1개당 사료비에서는 18∼20g 공급구간에 유의차가 없었다. (시험 2) 육용종계 하절기 산란피크계의 에너지 공급수준에 관한 연구: 육용종계 산란기의 적정 에너지공급체계를 구명하기 위하여 강원도 홍천군 북방면소재 홍천종계에서 케이지 사양형태의 로스 육용종계 400수를 공시하여 2002년 4월부터 2003년 1월까지 40주간 (24∼64주령) 표2와 같은 4가지 에너지공급체계로 사양시험을 실시한 결과를 요약하면 다음과 같다. 1) 총 산란율, 종란 산란율, 평균난중 및 성계 생존율은 모두 처리간에 유의적인 차이가 인정되지 않았으나, 산란율은 1일 에너지공급량이 많을수록 오히려 저하하는 경향을 보였다. 2) 사료요구율, ME 및 CP요구량과 사료비는 모두 1일 에너지공급량이 많아질수록 증가하는 경향을 보였다(P<0.05).

• Korean Journal of Poultry Science
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• v.30 no.4
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• pp.259-267
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• 2003

Two experiments were conducted to investigate the effect of betaine on egg production, lipid metabolism, and osmoregulation in 18-to 42-week-old ISA Brown laying hens. In experiment 1, three hundred and sixty one hens were fed a com-soy basal diet contailing 16% crude protein (CP), 2800 kcal/kg metabolizable energy (ME), 0.33% methionine, and 0, 300, 600, or 1200 mg betaine per kg diet. Egg production, egg weight, feed consumption, feed conversion, and egg quality were measured every eight weeks. Betaine concentration in live and egg were determined along with serum cholesterol, abdominal fat, total serum protein and albumin levels. In experiment 2, twenty thirty-three-week-old laying hens were fed the same diets as those used in experiment 1 in individual cages and the amount of feed and water consumption were measured for two weeks. At the end of experiment 2, all birds were killed to determine blood plasma and ileal osmopressure, arginine vasotocin (AVT), and liver moisture content. In experiment 1, egg production between the treatments during the first eight weeks were not different, whereas the significant increment of egg production were noticed in the birds fed more than 600 ppm betaine after reaching the peak egg production stage (p<0.05). The egg weight was reduced significantly by the betaine supplementation for the first 8 weeks (p<0.05). Feed conversion tended to improve by betaine supplement. Egg quality was not enhanced by betaine supplementation. Liver betaine level increased with betaine feeding compared to the control but betaine concentration in eggs decreased with betaine supplementation. Betaine supplementation elevated the level of serum total cholesterol and triglyeerides compared to the control. Abdominal fat content was increased by betaine supplementation, whereas liver fat content decreased. In experiment 2, water consumption significantly increased in hens fed diets containing 300 and 600 mg betaine/kg (p<0.05) and osmotic pressure of ileal digesta increased with betaine supplement. Liver moisture content was not affected by betaine, but AVT increased in hens fed betaine. The overal results suggested the possibility of using betaine as a feed additives in the laying hens beacuse of its positive contribution to improving egg production and other metabolic parameters related to lipid metabolism.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2003.05a
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• pp.73-82
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• 2003

본 연구에서는 국내 종계의 생산성 저하요인들을 평가·분석하였으며, 국내사육 종계의 실질적인 생산성을 극대화 시킬 수 있는 방안을 제시하고자 시험을 수행하여 다음과 같은 결론을 얻었다. 1. 혈청검색에 의한 품종별 종게군 질병 모니터링을 실시 한 결과, SE, MS 등 2종의 난계대성 세균성 질병과 REV, APV, CAV, ORT, REO 등 5종의 만성소모성 질병을 유발하는 질병이 종계군의 산란기에 감염되어 이들이 단독 또는 중복감염되어 나타나는 피해가 예상되었으며, 이들의 감염을 효과적으로 예방 할 수 있는 백신의 개발 및 도입의 필요성이 대두되었다. 2. 집중관리 모니터링 대상농장에 대한 ND, IB, IBD 등 3종의 생독백신에 대한 접종효능을 평가해 본 결과 산란종계, 육용종계를 막론하고 전반적으로 니플급수기를 이용한 음수접종법 적용시 5주령 이하 계군에 2내지 3회의 음수접종을 실시하였음에도 불구하고 항체가 거의 형성되지 못하거나 매우 불균일한 면역반응이 나타나는 것으로 조사되어 국내 야외농장에 대한 분무접종 유도 등 기존의 백신접종법에 대한 시급한 개선대책 마련이 요구되었다. 3. 육성기 및 산란기 종계 질병·위생관리 프로그램 확립을 위하여 ND, IB, IBD에 대한 개선된 백신접종 프로그램을 모델계군에 적용한 후, 주령별로 생독백신 접종효능을 조사한 결과 백신접종 후 ND, IB, IBD에 대한 평균 항체가와 항체의 균일도 (%CV)가 표준 목표치 이상 상승하여 개선의 효과를 볼 수 있었다. 4. 산란기 종계 질병·위생관리 프로그램 확립을 위하여 실시된 변이형 IB에 대한 방어능 시험결과 정기적인 Mass type IB 생독백신의 분무접종은 국내 유행 호흡기형 IBV 유전형 VI에 대한 방어효과는 다소 떨어지는 것으로 조사되어 국내분리주를 이용한 IB 생독백신의 개발이 요구되었다. 5. 종계장 살모넬라 및 마이코플라즈마 조기 검출을 위하여 실시한 종계장 살모넬라 및 마이코플라즈마 환경 모니터링 실시 결과 기존의 평판응집반응이나 ELISA에 의한 혈청검색법에 비하여 검출효율이 매우 높은 것으로 조사되어 향후 국내 종게군에 대한 살모넬라 및 마이코플라즈마 조기검출과 방제연구에 큰 도움이 될 것으로 사료되었다.

• Korean Journal of Poultry Science
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• v.29 no.4
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• pp.243-247
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• 2002

A study was conducted to investigate the effect of induced molting on the relative weight and hormone levels of thyroid, ovary, and adrenal glands in spent laying hens. Three hundred sixty 77-wk-old, Babcock White hens were divided into 36 experimental units of 10 hens each and induced to molt for seven weeks. A diet containing 16% CP and 2,800 kcal ME/kg was fed ad libitum from 84 to 126 weeks of age. Thirty-six birds were randomly selected for blood collection and slaughtered at Pre-molt, 5% egg Production, Peak, and end Phase of the egg Production. Weights of the thyroid, ovary, adrenal glands, and plasma T3, T4, cortisol, and estradiol contents were measured at each stage. Weight of the thyroid reached its highest level at 5% e99 Production stage. The ovary weight was greatly reduced during molting, but started to increase after induced molting until the end of the egg Production Phase (P<0.05). Plasma T3,T4 and cortisol were found to be the highest at the start of the Post-molt Production stage, but reached their minimum at the end Phase of e99 Production. Plasma estradiol was the lowest at the 5% egg Production stage. The Present study demonstrated that molting is a complex Process that require the involvement of endocrine glands to trigger their specific hormones, which play a key role in molt induction.

• Korean Journal of Poultry Science
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• v.30 no.3
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• pp.161-167
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• 2003

A study was conducted to investigate the effect of supplementing earthworm meal (EWM) on the performance of laying hens and fatty acid composition in egg yolks. A total of 360 laying hens at 55 weeks of age were fed the experimental diets containing 0.0% (Control), 0.1% and 0.2% of EWM for 5 weeks. Eggs were collected and weighted every day and egg production and feed conversion were recorded every weeks during the experimental period. However fatty acid composition of egg yolk were measured at last week of experimental period. Amount of feed intake tended to increase by supplemental EMW, but feed conversion ratio of birds fed EWM was not different among three groups. Average egg production seemed to increase and significantly improved (P<0.05) when fed a 0.1% EWM and 0.2% EWM, respectively. Average egg weight was prone to decrease when fed a 0.1% EWM compared to that fed a 0% (control) or 0.2% EWM. Average daily egg mass tended to improve by the addition of EWM. It was more increased in 0.2% EWM treatment than 0.1% EWM. The ratio of egg yolk n-6/ n-3 fatty acids contents was 5:1 fed a 0.1% and 0.2% EWM. But these ratio was 10:1 in control group. It is concluded that 0.2% earthworm meal supplementation in the 55 weeks old laying hens diet, improves the laying performance and ratio of egg yolk n-6/ n-3 fatty acids contents (P<0.05).

• Korean Journal of Poultry Science
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• v.33 no.3
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• pp.225-231
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• 2006

To investigate the effect of feeding rare earth (RE) on the performance of breeder hens a feeding trial with sixteen thousands of 158 day old Ross broiler breeder hens was conducted for thirty weeks. A mixture of RE- chlorides containing mainly La, Ce, and Pr was mixed into corn-soy based diet at two levels, 300 and 600 mg/kg, All the hens were housed in flat layer houses and the ratio of male to female was maintained at one to ten. Dietary supplementation of the of RE at a level of 300 mg/kg made the hens reach egg production peak higher by about 6% and earlier by about two weeks. As a result, it made higher hatchable egg production by 3.5%. It also reduced dramatically the mortality of both male and female breeders(P<0.05). Egg weight was slightly increased but egg qualify was not much influenced by dietary supplementation of RE. Egg albumin hight and Haugh unit were significantly improved while egg shell thickness, egg breaking strength and yolk color were similar to those of the control. Experimental results appeared to show a good possibility that egg fertility and hatchability were improved by feeding RE. Dietary supplementation of RE at a level of 300 mg/kg should be acceptable but not the 600 mg/kg level for breeder hens. Further studies on the effect of RE on egg fertility and hatchability appears to be necessary.