• Journal of Animal Science and Technology
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• v.53 no.2
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• pp.133-138
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• 2011

Two experiments were conducted to determine the effects of supplementing different levels of kaolin (Exp. 1) and effects of age of layers and levels of kaolin (Exp. 2) on the performance, egg and shell quality parameters of laying hens. In Exp.1, 64 laying hens of 58 wks age were randomly allotted to 4 treatments of 16 hens in each. Dietary treatments were basal diet supplemented with 0.0, 0.2, 0.4 and 0.6% kaolin. In Exp. 2 96 laying hens were divided into 6 groups of 16 hens each in a 2 ${\times}$ 3 factorial arrangement (two different ages, 30 and 58 wk and three levels of kaolin, 0.0, 0.2 and 0.4%). In both the experiment there were linear decreases in feed intake (P<0.001), improvement in FCR (P<0.05), and egg production (P<0.05), with increasing dietary kolin level. Supplementation of kaolin had no effect on the egg and shell quality parameters in both experiments. Thus, it is concluded that kaolin may improve performance, and 0.2% level showed the best laying performance.

• Korean Journal of Poultry Science
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• v.36 no.3
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• pp.257-264
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• 2009

This work was conducted to investigate the effects of phytase on N and P excretion of laying hens excreta. Three hundred sixty ISA Brown layers were selected to investigate excreta excretion for 65 weeks and to investigate the effect of phytase on total excretion and N and P excretion of layers from 55 weeks. The experimental diets were fed the starter (0~5 wk), grower (5~12 wk), developer (12~16 wk), prelay diets (16 wk~first egg), layer diets for starting period (first egg~32 wk), middle (32~45 wk), finishing diets (45~55 wk, 55 wk~). Thirty ISA Brown layers were selected to investigate the effect of phytase supplementation on total N and P excretion of layers at 55 weeks and assigned randomly to 3 treatments groups (10 birds/treatment) and phytase was added to basal diets at 300 and 600 FTU/kg. Average body weight, feed intake, water intake, and excreta excretion were 1,622, 105.7, 187.2 and 124.7 g/bird/day, respectively. Excreta of birds fed phytase were DM (33.2, 31.2, 30.5 g/day), N (0.46, 0.42, 0.40 g/day) and P (0.51, 0.49, 0.48 g/day) and reduced as dietary phytase increased, Finally, dietary phyase can reduce the N and P excretion, but the amount of excreta was not different depending from the phytase addition in layers. This work investigated the N and P excretion of laying hens excreta and were considered that dietary phytase can reduce the N and P excretion for short period.

• Korean Journal of Poultry Science
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• v.40 no.1
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• pp.49-55
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• 2013

The objective of this study was to compare the principle components and internal quality of eggs by age of laying hens and weight standard. The eggs (2,140 in total) used were from Hy-Line Brown reared from 18 to 63 weeks of ages and all were higher than appearance grade B by animal grading standard of Korea. Eggs were investigated their principle components, internal quality index, and their relationship. The weights of whole egg, shell, yolk, and albumen were increased while albumen height and Haugh unit were decreased by age of laying hens. When the composition of egg was investigated after sorting by ages, the ratio of egg yolk increased while that of albumen decreased. Egg shell composition was not shown significant difference by age. Age of laying hens had positive correlation with the weights of whole egg, shell, yolk, and albumen while albumen height and Haugh unit showed negative correlation. Also, the albumen height and Haugh unit were decreased by increase of weight of whole egg or principle components of egg.

• Korean Journal of Poultry Science
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• v.29 no.3
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• pp.151-156
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• 2002

The objective of this study was to compare the two different eggshell lines of commercial layers on egg traits and egg production rate. Hy-line W-98 (white shell line; WSL) and Hy-line Brown (brown shell line; BSL) were used as experimental stocks. The birds in each line were allocated to three floor pens each containing 25-birds. They were fed a ration containing 15.5% CP and 2,700 ㎉/kg ME, and were supplied 16 h of light per day throughout the experimental Periods. The egg traits and egg Production rate were measured from 53 to 56-wk-old and 20 to 56-wk-old, respectively. The mean egg weight and the mean percentage albumen were significantly heavier and higher (P<0.05) in the BSL than in the WSL, respectively. The mean eggshell thickness and the mean percentage shell were also significantly thicker and higher (P<0.05) in the BSL than those in the WSL, respectively. However, the mean percentage yolk and the yolk to albumen ratio showed a reverse trend as shown in the mean percentage albumen or percentage eggshell. Although the WSL birds started laying 4 d earlier than the BSL ones, the overall mean egg Production rate for BSL during 20 to 56 wk of age was significantly higher (P<0.05) by 6.6% than the WSL. It was concluded that the eggs of brown eggshell line had heavier egg weight and thicker shell, and they had more percentage of albumen, but less percentage of yolk than those of the white eggshell line. These results suggest that the brown eggshell line raised on the floor might be more beneficial than the white eggshell line not only for the preference of the table egg consumers, but also for the efficient production of the eggs.

• Korean Journal of Poultry Science
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• v.39 no.3
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• pp.245-252
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• 2012

This study was carried out to investigate the performance of laying period of two-crossbred of Korean native chickens for producing laying hens. A total of four hundred eighty female 2-crossbred chicks that restored strains and were aboriginal at National Institute of Animal Science. There were four crossbreds (4 replications/crossbred, 30 birds/replication) as A) C strain ${\times}$ Y strain, B) C strain ${\times}$ L strain, C) C strain ${\times}$ G strain, and D) C strain ${\times}$ W strain, respectively. There were no significant difference on age at first egg among crossbreds (P>0.05). Egg weight and body weight of B crossbred at first egg was higher than other crossbreds (P<0.05). Body weight of B crossbred was the highest 20 to 72 weeks (P<0.05), and C and D crossbreds were lower compared to A and B crossbreds (P<0.05). Average feed intake of B crossbred was the highest among crossbreds (P<0.05), and that of A crossbred was higher compared to C and D crossbreds (P<0.05). Weekly feed intake of four crossbreds decreased from 50 weeks. Weekly egg weight of B crossbred was the highest and that of D crossbred was the lowest among crossbreds (P<0.05). Feed conversion ratio of A and B crossbreds was lower than that of C and D crossbreds. Hen-house egg production of C crossbred was the highest among crossbreds until 26 weeks old (P<0.05), but there was no significant difference among crossbreds from at the age of 26 weeks (P>0.05). Hen-day egg production decreased after at the age of 38 weeks. Weekly egg production of A and B crossbreds was higher compared to C and D crossbreds at the age of 68~72 weeks (P<0.05). These results suggested the basic data on the record of laying period of 2-crossbreed Korean Native Chickens for producing laying hens.

• Korean Journal of Poultry Science
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• v.30 no.3
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• pp.169-175
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• 2003

This experiment was conducted to study the optimum energy feeding regimens fur broiler breeders peaked in winter season with 400 caged hens of Ross strain. Four energy supply regimens which were different in daily energy allotment during laying period were employed for 40 weeks from 24 to 64 weeks of age. All experimental diets were formulated to contain 2,750 kcal ME/kg with adjustments made in total feed allotment to provide the desired energy levels. Total consumption of the feed would provide 20 g of protein, 4 g of calcium and 0.35 g of available phosphorus. There were no difference in hen-day egg production and average egg weight among the regimens of energy supply. Feed, ME and feed cost required per egg or per kg egg were significantly increased as the level of energy allotment increased(p<0.05). It was concluded that the energy supply regimen, which supplied 280 kcal ME per day at the age of 24 weeks and then increased the energy supply up to 400 kcal ME per day at the peak period of 30∼34 weeks of age, was superior in feed, ME and feed cost required per egg or per kg egg without any adverse effect on eg production and egg weight.

• Korean Journal of Poultry Science
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• v.30 no.1
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• pp.1-10
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• 2003

The objects of this study were to develop a new strain which has resistance to fowl typhoid, high performance in laying, and producing brown shell eggs favored by domestic consumers. Several White Leghorn (WL) breeds known as possessing genetic resistance to fowl typhoid and several brown shell egg breeds such as susceptible to the disease were used to produce the controlled strains with cross mating between the strains within the breeds and the experimental strains with crossbreeding between the breeds. The crossbred strains were Chungnong(CN) 21, 22, 23, 24, 25 and 26. The controlled strains were ISA brown CC, Hyline brown CC and Lohman brown CC. The survival rates were 99.95% for chicks of age 0∼l7 weeks and 91% for adult chickens of age 18∼72 weeks. There was no difference in survival rate between the crossbred and the controlled strains. The means of age of lst egg laying were 147 to 148 days and no difference was observed between the crossbred and the controlled. The egg Production rates of a9e 18∼72 weeks were 83.76% far the crossbred strains and 77.82% for the controlled strains, which is significantly higher in the crossbred than controlled strains by 6%. The numbers of the hen housed egg Production of age 18∼72 weeks were 292.33 eggs for the crossbred strains and 271.31 eggs fur the controlled strains. The difference of 21 eggs more produced by the crossbred than by the controlled was statistically significant. The mean egg weights of age 18∼72 weeks were 64.32g for the crossbred strains and 60.73g for the controlled strains, and the difference of 3.59g was statistically significant. The feed conversion rates during the age of 18 to 72 weeks were 2.297 for the crossbred strains and 2.454 for the controlled strains. The crossbreds were reduced feed consumption by 157g for 1kg of egg Production which was statistically significant. Haugh unit(H$.$u) at the age of 72 weeks were 82.20 for the crossbred strains and 77.82 for the controlled strains. The crossbred strains were superior quality by 4.38 H$.$u. There were no significant differences in the yolk color and the eggshell thickness between the crossbred strains and the controlled strains. The eggshell color of the crossbred strains was light brown which is the medium color of the white eggshell strains and the brown eggshell strains. The body weights at the ages of 8, 12, 18, 42 and 71 weeks were not different between the crossbred strains and the controlled strains.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2003.11a
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• pp.99-100
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• 2003

This experiment was conducted to investigate the effect of restricted feeding to pullet on growth and laying Performance, e99 qualify and endocrine profile in brown layers. 1,080 brown-layer chicks divided to three diet treatments, conventional diet and two restricted diets, for 70 weeks. Conventional diets(C) was formulated by NRC recommendation, and one of restricted diet started from seven to seventeen week of age(T1), and the other started from twelve to seventeen(T2). Overall egg Production was the highest in T1 (P＜0.05) and there were not difference in C and T2. Average egg weight also showed similar to the tendency of egg production. Feed intake was higher in T1 during maximum production(P＜0.05), but there were not difference in all treatments after the peak. Overall feed conversion ratio improved in T1 compared to C and T1(p＜0.05). Egg shell thickness and egg shell strength tended to weak in aging, but there were not significant difference by treatments. Haugh unit also tended to similar to egg shell quality. Concentration of IGF-1 was influenced by feed intake. That of T1 maintained in low concentration compared to C during restriction period. The concentration of IGF-1 was decreased dramatically after the first egg. Estradiol concentration increased slightly at twelve week, and surged greatly near the first egg. Those of profile showed similar tendency of the first egg during laying period.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2003.11a
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• pp.97-98
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• 2003

This experiment was conducted to investigate the effect of restricted feeding to pullet on growth and laying Performance, egg qualify and endocrine Profile in brown layers. 1,080 brown-layer chicks divided to three diet treatments, conventional diet and two restricted diets, for 70 weeks. Conventional diets(C) was formulated by NRC recommendation, and one of restricted diet started from seven to seventeen week of age(T1), and another started from twelve to seventeen(T2) with adjusted eighty percentage amount of conventional diet. Body weight decreased with starting restriction of feeding comparing to the C(P＜0.05), but reached to similar weight in all treatments at twenty week regardless restriction. All of birds started to lay egg around 1,400 to 1,450gram of body weight though the age was in order of C, T2 and T1. Overall e99 Production was the highest in T1 (P＜0.05) and there were not difference in C and T2. Average egg weight also showed similar to the tendency of egg production. Feed intake was higher in T1 during maximum production(P＜0.05), but there were not difference in all treatments after the peak. Overall feed conversion ratio improved in T1 compared to C and T1(p＜0.05). Restriction feeding in rearing period could be beneficial to improve egg productivity and to decrease feed cost.

• Korean Journal of Poultry Science
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• v.39 no.2
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• pp.133-141
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• 2012

This study was carried out to investigate the performance of laying period of two-way crossbred of Korean native chickens. A total of four hundred eighty female 2-crossbred chicks that restored strains and were aboriginal at National Institute of Animal Science. Treatments were four crossbreds (4 replications/crossbred, 30 birds/replication) as A) C strain ${\times}$ S strain, B) C strain ${\times}$ H strain, C) R strain ${\times}$ S strain, and D) L strain ${\times}$ H strain, respectively. There were no significant difference on age, egg weight, and body weight at first egg among crossbreds (P>0.05). Body weight of D crossbred was lower compared to other crossbreds at the age of 24, 32, 40 and 60 week (P<0.05). Feed intake of A crossbred was highest among crossbreds (P<0.05). Weekly egg weight of A crossbred was the highest among crossbreds all laying period except 48~52 and 60~64 weeks. Hen-house egg production of A and B crossbreds was higher than that of C and D crossbreds (P<0.05). Hen-day egg production decreased after at the age of 36 weeks. Weekly egg production of A and B crossbreds was higher compared to C and D crossbreds (P<0.05). These results suggested the basic data on the record of laying period of 2-crossbreed Korean Native Chickens.