• Korean Journal of Poultry Science
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• v.32 no.1
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• pp.15-21
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• 2005

This Study was conducted to investigate the effects of microbial phytase in low phosphirus and calcium level diet on the performance and nutrient digestibility in laying hens. One hundred ninety two, 50 wks old, ISA brown commerical layers were used for 12 weeks feeding trial after 7-d adjustment period. Four dietary treatments included CON(control; Co.), P2 ($0.06\%$ Natuphos, BASF) and P3 ($0.06\%$ PHOSMAX, GENOFOCUS). Ca and available P concentrations of P1, P2 and P3 were 90 and $50\%$ of NRC recommecdations to accentuate difference in response to phytase availability. In whole period, egg production was not affected by treatments. At 12 weeks, egg weight was significantly increased in adding phytase treatments (P<0.05). Egg shell thickness was increased in P1, P2 and P3 treatments compared with control (P<0.05) at 9 weeks. Ca concentration of serum tended to decrease in P1 treatment without significant difference (P>0.05). Ca and P concentrations of tibia were higher in layers fed dietary phyrase than those fed control diet without significant difference (P>0.05). Digestibilities of DM, N and ash were improved in P1 treatment compared with P2 and P3 treatments (P<0.05). Ca and P digestibilities were the highest in P2 treatment (P>0.05), but was not significant difference between control and P1 treatments.

• Korean Journal of Poultry Science
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• v.40 no.4
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• pp.291-297
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• 2013

This study was conducted to evaluate the productivity of Korean native chicken (KNC) 2 strains crossbred. The number of chicks analyzed in this study was 300. Crossbreds used in this studywere A) KNC R strains ${\times}$ KNC meat type S strains, B) KNC egg-meat D strains ${\times}$ KNC meat type H strains, C) KNC egg-meat D strains ${\times}$ KNC meat type S strains, D) KNC egg-meat C strains ${\times}$ KNC native Y strains, and E) KNC native Y strains ${\times}$ KNC meat type H strains. The crossbreds C had the highest performance on body weight gains at 7~10 weeks but crossbreds D showed the lowest (p<0.05). The feed conversion ratio of crossbreds D was the highest value at every weeks (p<0.05). But the carcass weight and carcass ratio of crossbreds D was the lowest value at every weeks (p<0.05). For the percentage of cutted meat, the ranges of mean were 30.60~33.75% in breast, 21.48~24.72% in leg, 11.95~14.33% in wing, 21.91~25.83% in back and of 7.38~8.72% in neck. The percentage of cutted meat for leg was the highest value at every weeks (p<0.05). These results suggested that the development of new crossbreds should be necessary for better performance.

• Korean Journal of Poultry Science
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• v.38 no.3
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• pp.165-171
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• 2011

This study was conducted to investigate the effects of dietary supplementation of copper-soy proteinate (Cu-SP) on the performance of laying hens. A total of 1,000 Hy-Line Brown laying hens of 32 wks old were assigned to one of the following 5 dietary treatments: Control, Cu-SP 50, 100, 150, 200 (50, 100, 150, 200 ppm Cu supplementation as Cu-soy proteinate). Each treatment was replicated 4 times with fifty birds per replication, housed in 2 birds cages. Fifty birds units were arranged according to randomized block design. Feeding trial lasted 5 wks under 16L : 8D lighting regimen. There were no significant differences among treatments in hen-day and hen-house egg production, egg weight, broken & soft egg production. Feed intake and feed conversion rate (FCR) were significantly (P<0.01) lower in Cu-SP treated groups than Control. Eggshell thickness was significantly (P<0.01) higher in Control than Cu-SP 100, 150 and 200. Egg yolk color index was significantly (P<0.01) higher in Cu-SP 200 than other treatments. Egg shell color index was significantly (P<0.05) higher in Cu-SP 150 and Cu-SP 200 than Cu-SP 100. Concentration of copper, iron and zinc of the egg yolk were not significantly influenced by treatment. There were no significant differences in the level of leukocytes and erythrocytes in the chicken blood. The result of this experiment showed that dietary supplementation of Cu-SP at the level of 50ppm of Cu can reduce feed intake and FCR.

• Korean Journal of Poultry Science
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• v.28 no.2
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• pp.91-98
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• 2001

Three experiments were conducted to investigate the Pine Bark Spent Liquor (PBSL) inclusion, prepared by alkaline sulfite-anthraquinone cooking, on Pellet durability index (PDI) of practical diets and performance of broiler chicks and laying hens. Fourteen treatments with four replications were assigned for PDI test in Experiment 1. Control, 10% Wheat(W10), 20% Wheat(W20), 0.25, 0.50, 1.00, 2.00 and 3.00% PBSL, 0.1, 0.2% commercial pellet binder A(CPB A) or B(CPB B), W10 plus 0.1% CPB A or B were used for PDI test. PDI was measured by PDI tester (Oriental Motors, Japan). The control diet was based on corn and soybean meal with no wheat or pellet binders inclusion. The PDI of the PBSL or other commercial pellet binder treatments were significantly higher than control groups(P<0.05). It was shown 95.9, 95.9, 95.8, and 95.7 in W10, 0.5% PBSL, 0.2% CPB A or B treatments, respectively. Thus, those treatments were applied to Experiments 2 and 3. In experiment 2, 200 male broiler chicks (Cobb$\times$Cobb) were allocated to the control, W10, PBSL 0.5%, 0.2% CPB A and B with four replications. Starter diets contained 3,169, 3,149 kcal/kg ME and 21% CP, and finisher diets were fed at the level of 3,192, 3,172 kcal/kg ME and 19W% CP. Weight gain, feed intake, feed conversion ratio (FCR) were weekly measured for 5 wk and the number of intestinal anaerobes were examined at the end of experiment. The weight gain of chicks fed PBSL was not significantly greater than control groups, but was significant different compared to that of W10 or 0.2% CPB A treatments (P<0.05). FCR of chicks treated with PBSL or other pellet binders tended to improve compared to that of control.

• Korean Journal of Poultry Science
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• v.30 no.1
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• pp.29-34
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• 2003

It has been well documented that white egg layers are far more resistant to fowl typhoid than the brown egg layers. In Korea, however, most consumers prefer brown eggs to white ones. Therefore, a study was conducted to Produce fowl typhoid-resistant crossbred layers producing somewhat brown-colored eggs. Several crossbred strains were obtained from crossbreeding white egg lines (W) with brown egg lines (B). These crossbred layers (W${\times}$B) produced eggs with varying degrees of brown-colored shells between the white eggs obtained from W (White) and the brown eggs from B (Brown). Eggs from the peak stage of production were collected and their eggshell color values were measured. The mean eggshell color values of White and Brown were 81.9 and 36.4, respectively. Eggs from the crossbred lines (W${\times}$B) were collected, and their eggshell color values were measured to re-group these eggs according to their color. The mean eggshell color values of Trt-White, Middle, and Trt-Brown were 70, 60, and 50, respectively (Fig. 1). A total of 247 people living in Daejeon area, mainly housewives, took part in this survey. First, they were offered eggs with varying degrees of eggshell color in a paper egg-tray, together with a questionnaire. After they filled out the first questionnaire, they were instructed that the eggshell color has nothing to do with its nutritive value. In the second questionnaire, their preference on both eggshell color and price, i.e., purchasing will, were investigated. In the first questionnaire, the Brown (eggshell color lightness 36.4) were most preferred, and the Trt-white (eggshell color lightness 70) were least preferred. No statistical significance was detected between Brown and Trt-Brown, and White and Trt-White. In the second questionnaire, the trend was the same as in the first. Although no significant difference was found between Trt-Brown and Brown, however, the Trt-Brown were most preferred, surpassing the Brown. In conclusion, regardless of the nutritive values, the Korean consumers prefer brown eggs to white ones, and this trend could be changed gradually through consumer education.

• Korean Journal of Poultry Science
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• v.49 no.2
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• pp.53-60
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• 2022

This study investigated correlations between egg quality indicators to identify external egg quality traits to predict internal egg quality using non-destructive and convenient measurements. Thirteen indicators, including Haugh unit, albumen height, eggshell breaking strength, eggshell thickness, eggshell color (CIE L^*, CIE a^*, CIE b^*), and reflectivity value, egg weight, egg length, egg width, shape index, and yolk color, were investigated. A total of 180 brown eggs were obtained from one 27-week-old flock of Hy-line brown-laying hens raised in a cage system. Correlations were evaluated using Pearson's correlation coefficient (r). The results showed strong correlations between Haugh unit and albumen height, eggshell color CIE L^* and reflectivity, egg weight and width, egg weight and length, eggshell color CIE L^* and CIE a^*, eggshell color CIE a^* and reflectivity, and shape index and egg length (P<0.001). Moderate correlations were observed between eggshell breaking strength and eggshell thickness, eggshell color CIE a^* and CIE b^*, and shape index and egg width (P<0.001). Eggshell color CIE L^* was correlated with eggshell breaking strength (P<0.01), and eggshell color CIE a^* was correlated with Haugh unit, albumen height (P<0.01), and eggshell breaking strength (P<0.001). The present study showed significant correlations between eggshell color and other quality indicators. Thus, this study suggests that eggshell colors based on reflectiveness and the CIE L^*a^*b^* value can be used to estimate the Haugh unit, albumen height, eggshell breaking strength, and thickness.

• Korean Journal of Poultry Science
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• v.47 no.3
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• pp.189-197
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• 2020

This study was conducted to compare the production performance and stress response of chickens kept in the conventional cages and floor pens. 491 female White Leghorns were used in this study, and their production characteristics and stress response indicators were analyzed from 34 to 43 weeks of age. The results showed that there was no significant difference in survival rate, hen-day egg production, and body weight between the chickens kept in the conventional cages and those kept in the floor pens. The chickens kept in the conventional cages had a significantly higher egg weight and egg quality compared with those kept in the floor pens (P<0.01). The amount of telomeric DNA in lymphocytes was significantly higher in the chickens kept in floor pens than in those kept in conventional cages (P<0.05). The heterophil-lymphocyte ratio, HSP-90β gene expression level, and DNA damage rate significantly increased in chickens kept in the conventional cages, as compared to the chickens kept in floor pens (P<0.01). In conclusion, there seems to be no difference in the production performance between chickens kept in conventional cages and those kept in floor pens. Furthermore, chickens kept in conventional cages had higher stress response values than those kept in floor pens for all stress response indicators. Therefore, conventional cage types are considered to be a more stressful environment for chickens than floor pens, regardless of the production performance of the chickens.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.7
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• pp.841-846
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• 2008

In this study, the effects of feeding citrus byproducts on nutritional properties of Korean native chicken eggs were investigated. Two samples of Korean native chicken eggs were used for this study: T0 (Eggs of chickens that were not fed with citrus byproducts until they became 30 weeks old) and T1 (Eggs of chickens that were fed with 4% citrus byproducts when they were between 17 and 30 weeks old). There was nostatistically meaningful difference between T0 and T1 in terms of various properties, such as general components of egg albumen and yolk, total structural amino acid, and total free amino acid. Also, no significant difference was noticed between T0 and T1 in terms of various components of egg yolk, such as amount of mineral, vitamin, and xanthophyll, which showed that those components are not affected by citrus byproducts. However, the amount of cholesterol of egg yolk for T1 was 1,168 mg/100 g, which was significantly lower than that for T0 which was 1,207 mg/100 g (p<0.05). The amount of L-glutamic acid, one of the free amino acids, of the egg albumen was 39.22 and 58.54 ppm for T0 and T1, respectively. The results of this study show that citrus byproducts can be used for the feed for Korean native chicken by adding them to general feed.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2002.11a
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• pp.120-121
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• 2002

Two experiments were conducted to investigate the effect of feeding Monascus Purpures(MP) on the growth performance of broiler chicks and egg qualify in laying hens. In Expt 1, MP were supplemented with 0. 0.5, 1.0, 2.0, 4.0% in basal diets. Weight gain, feed intake, feed conversion were examined for five weeks and blood cholesterol, protein were measured at the end of experiment. In Expt 2, diets supplemented with 0, 0.5, 1.0, 2.0, 3.0% MP were fed for two weeks. Egg qualify and yolk cholesterol were weekly measured. In Expt 1, Basal diets containing CP 21.5, 19%, ME 3,100, 3,200 kcal/kg were fed ad libitum for starting and finsihing period, repectively. In Expt 2, hens diet contained CP 16%, ME 2,800 kca1/kg and fed for two weeks. In Expt 1, weight gain of birds fed 2.0% MP was maximized at five weeks of age. Feed efficiency was not statistically different, but tended to improve in 1.0, 2.0% MP supplemental groups compared with control. Total serum cholesterol tended to be lower in 2.0% MP supplemental group but was not statistically different. In Expt 2, albumen height and Haugh unit of birds fed 1.0 and 2.0% MP were higher than other treatments, but was not statistically different. Yolk cholesterol of hens fed MP diets showed no significance.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2004.11a
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• pp.69-79
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• 2004

A feeding trial was conducted to determine whether dietary vitamin C (200 mg/kg) and vitamin E (250 mg/kg) prevent any drops in egg shell quality under heat stress in broiler breeder hens. One hundred and sixty molted Ross broiler breeders were housed randomly in an individual cage at 83 weeks of age. Four dietary treatments with forty hens and four replications per treatment were control (no additional vitamins). vitamin C-. or vitamin E-supplemented. and combined supplementation of the two vitamins. After a ten-day-adaptation period at 25 $^{\circ}C$. the ambient temperature was kept at 32 $^{\circ}C$ for a three-week-testing period. Egg production dropped dramatically over week but it did not show a significant change among treatments (P<0.05). However. egg weight. SG. shell thickness. SWUSA. puncture force and shell breaking strength of the birds fed the diet with the combined vitamins C and E were significantly improved than those fed the basal diet during the heat stress period (P<0.05). The hens fed the vitamin C supplemented diet showed a tibia breaking strength of 37.16 kg statistically higher than those of the basal and the vitamin E supplemented groups (P<0.05). The hens fed the basal diet showed higher serum corticosterone levels. a mean of 5.97 ng/ml. than those of the rest of treatments (P<0.05). The heat stress elevated heterophils but decreased lymphocytes in serum. and it changed H/L ratios of all the treatments. The increases in H/L ratios were alleviated in the bird by feeding vitamin C and/or vitamin E supplemented diets. but they did not differ significantly (P<0.05). In conclusion. vitamins C (200 mg/kg) and/or E (250 mg/kg) supplementation to diets could prevent drops in egg shell quality and tibia bone strength by alleviating stressful effects from high temperature in broiler breeder hens.