• Korean Journal of Poultry Science
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• v.40 no.3
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• pp.217-222
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• 2013

This work was carried out to investigate the performance of large-type Korean native ducks at middle laying phase (30 to 50 weeks). A total of one hundred and sixty eight laying ducks were divided into A and B strains (6 replications/strain, 14 birds/replication and fed practical diet, for 20 weeks). There was no significant difference in body weight, daily feed intake and average egg weight. With increasing rearing period, mean body weight tended to be decreased and showed the lowest value (2,649 g) at 42 weeks of age (P<0.05). Similar trend was observed for weekly feed intake and average egg weight which decreased with passing weeks and was lowest (190.5 g and 83.8 g, respectively) at the age of 42~46 weeks (P<0.05). Daily egg production of B strain was higher than that of A strain at the age of 46~50 weeks (P<0.05). Weekly egg production of A and B strains commenced to decrease from the age of 42 weeks, however, B strain recovered at 46~50 weeks of age (P<0.05). At the age of 30~38 weeks, the egg production in B strain was higher than A strain (P<0.05), whereas, there was no significant difference between both the strains during 38~50 week. Feed conversion ratio of A strain was higher than that of B strain at 46~50 weeks of age (P<0.05). Weekly feed conversion was highest at the age of 42~46 weeks (P<0.05). In conclusion, the present results provides the basic information of the performance record of large-type Korean native ducks for the middle laying phase.

• Korean Journal of Agricultural Science
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• v.34 no.1
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• pp.53-60
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• 2007

A layer feeding trial was conducted for 10 weeks to investigate the effects of the addition of corn distillers dried grains with solubles (DDGS) to layer diets on the laying performance, egg qualities, and yolk fatty acid composition. Nine hundred Hyline Brown layers, 24 weeks of age,were randomly allotted to 20 replicate laying cages, 45 birds per replicate. There were four diet treatments (0, 10, 15, and 20% DDGS), and five replicates per treatment. All experimental diets were prepared to contain iso-protein (17%) and iso-calorie (TMEn 2,780 kcal/kg). The use of DDGS up to 20% level in layer diets did not exert any influence on feed intake, laying rate, total egg mass, mean egg weight, and feed conversion ratio. DDGS did not exert any influence in weight of egg, breaking strength, and color of eggshell. The albumen height and Haugh unit was not influenced by DDGS addition. The yolk color was significantly increased by DDGS supplementation. As the DDGS level increased, the oleic acid content decreased, and the linoleic acid increased (P<0.05). The degree of saturation of yolk fatty acids was not affected by dietary DDGS. The inclusion of DDGS up to 20% in layer diets resulted in the decrease of feed cost per kg without any effect in the laying performance. In conclusion, the use of DDGS up to 20% level in layer diets could replace corn and soybean meal without any harmful effect on the laying performances.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.1
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• pp.155-159
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• 2002

Effect of the egg yolky from laying hens intubated, p.o., astaxanthin (designated AEY) on the oxidation of mouse liver microtome was investigated using female ICR mouse (6~7 weeks of age). Mice were adapted in a temperature- and humidity-controlled house for one week and randomly divided into 7 treatment groups (10 mice/cage/treatment). Mice were intubated p.o., AEY (50, 100 and 150 mg) or control egg yolk (CEY, 150 mg) every week for 3 weeks. BHT (5 mg) and e -tocopherol (50 mg) were fed to mice as positive control. At week 4, the liver microsome was prepared from sacrificed mice. Protein content of mouse liver microsome with AEY treatment was relatively higher than that with CEY treatment. AEY treatment remarkably lowered the content of unsaturated fatty acids including oleic acid and linoleic acid, but raised that of the saturated fatty acids including stearic acid. AEY group showed relatively higher antioxidative activity than CEY, when used Asc/F $e^{+2}$ or NADPH/F $e^{+2}$ as oxidant. Antioxidative activity of AEY was more effective than $\alpha$-tocopherol, but less effective than BHT.

• Korean Journal of Poultry Science
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• v.7 no.1
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• pp.1-11
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• 1980

About 6 to 8% of the eggs annually produced are broken or cracked between the hen and the consumer's carton. The majority of this breakage is due to interrelationships between egg shell quality and the many biological, environmental and managerial factors which have been individually identified as affecting breakage. Some of the factors associated with shell damage discussed in this review include age of hens, temperature ana humidity of the laying house, design of the cage systems and of the cage floors, type of material used to manufacture the cages frequency of daily egg collection in the laying house and, Probably most important, the frequency and quality of handling equipment maintenance. Age and genetic constitution of the hens, environmental temperature, and design and quality of equipment maintenance are the major factors that influence shell breakage. There is a curvilinear relationship between shell quality and shell breakage which explains why small changes in shell quality may be associated with large changes in the incidence of breakage. Published data indicate the incidence of breakage may range from as low as 1 to 2% to 35% or more for other egg producers.

• Korean Journal of Poultry Science
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• v.25 no.4
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• pp.161-167
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• 1998

This experiment was carried out to develope the production of specific yolk antibody from laying hens immunized with antigens from Salmonella enteritidis. Antigenic protein isolated from the flagella of Salmonella enteritidis, determined by SDS-PAGE, was pure and has a molecular mass of approximately 54.6 kDa. It was observed that the antibody titers both in egg yolk and serum were performed at 2 weeks after immunization with flagella antigen to the laying hen. And the level was increased gradually to 6 weeks after immunization. At the time of 6 weeks, the antibody titer of yolk showed higher than that of serum. According to the results of specificity test(ELISA), the yolk antibody did not react with different bacterial strains(S. choleraesuis, ETEC Kl2:K99, K88,987P), but reacted only with S. enteritidis strain. The contents of immunoglobulin(IgY) in an egg yolk was 106mg approximately. By the isolation procedure of IgY from the egg yolk, 88.3 percent of IgY content was recovered in this study.

• Korean Journal of Poultry Science
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• v.35 no.3
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• pp.267-274
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• 2008

There are many kinds of anti-oxidant materials in natural plant resources. The Siberian ginseng and Eucommia are well known as anti-oxidant and medicinal plants. To investigate the effect of their anti-oxidant-like activity on telomere quantity and egg quality, diets containing Siberian ginseng leaf and Eucommia leaf at 0.5% and 1% were given Hyline Brown commercial laying hens during two periods of age: 20 to 30 wks and 60 to 70 wks. The amount of telomere in lymphocyte, liver, ovary, heart and lung was analyzed by quantitative fluorescence in situ hybridization using telomeric DNA probe. Egg weight, albumin height, Haugh unit, egg yolk color, egg shell color, egg shell thickness, egg shell weight and egg shell density were measured to analyze egg quality. The chickens consuming diets Siberian ginseng and Eucommia had higher telomeric DNA in lymphocytes than control chickens in younger layers whereas no significant differences were detected in all target cells analyzed from older layers. Egg quality was increased in younger hens with dietary supplementation as determined by egg weight, albumin height and Haugh unit but there were no effects in older hens. These results imply that dietary supplementation of Siberian ginseng and Eucommia in layers improves bio-activity and egg quality at early laying stage.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.7
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• pp.922-928
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• 2001

There exists considerable evidence that steroid hormones are involved in the regulation of ovulation rate and oviductal development in poultry. However, the effect of steroid hormones on egg productivity of Korean Native Ogol Chicken (KNOC) has yet to be studied. Therefore, this study was performed to relate the expression of steroid hormones, especially progesterone ($P_4$) and estradiol ($E_2$), with egg productivity during the laying period. Egg production and egg weight of 70 KNOC were recorded from 20 to 60wk. Blood was taken every 10 wk and serum $P_4$ and $E_2$ were measured by radioimmunoassay. Based on egg productivity and steroid hormones levels up to 60 wk, chickens were divided into two groups, high and low. Compared to the low egg production group, a significantly higher expression of $P_4$ at 30 wk was detected in the high group. Moreover, egg production in the high $P_4$ group significantly differed from that in the low group at 30 wk. On the other hand, a Significant difference (p<0.05) in $E_2$ expression was found between high and low egg weight groups at 30 wk. Although a significant difference in egg weight between two groups by $E_2$ was not detected, the high $E_2$ group showed a higher level of egg weight than the low $E_2$ group except for 25 wk. In the comparison of ovary weight and small yellow follicle number, the group with high egg productivity and steroid concentration showed greater levels than the low group. Taken together, the results indicate that $P_4$ is related to egg productivity whereas expression of $E_2$ is associated with egg weight in KNOC.

• Journal of Animal Science and Technology
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• v.48 no.1
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• pp.59-68
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• 2006

This experiment was conducted to investigate the effects of dietary supplementation of activated charcoal (AC) mixed with wood vinegar on performance and egg quality in laying hens. A total of one hundred ninety two, 56-wk-old Lohmann brown laying hens were divided into four groups, consisting four replicates of 12 birds each and fed one of the four experimental diets containing AC 0%, AC 0.5%, AC 1%, AC 2% for 5 wks. The blood profiles and contents of total lipid and cholesterol, fatty acid profiles in egg yolk were determined. There were no significant differences in laying performance, feed intake and vitelline membrane strength among the treatments. The eggshell breaking strength and Haugh unit were significantly increased in 2% AC group compared to the other groups (P<0.05). Egg yolk index in 2% AC group was significantly higher (P<0.05) than those of the control and 0.5% AC group and yolk color was significantly improved by the dietary AC (P<0.05). The levels of serum total cholesterol, HDL-cholesterol and enzyme activities were not influenced by feeding AC. Total lipid of egg yolk in 1 % and 2% AC groups was significantly decreased (P<0.05) compared to that of the control, although there was no significant difference in yolk cholesterol. In conclusion, the addition of activated charcoal with wood vinegar in layer diet resulted in improving egg quality by means of enhancing eggshell breaking strength, Haugh unit, yolk index and yolk color.

• Korean Journal of Poultry Science
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• v.45 no.3
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• pp.201-207
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• 2018

An experiment was conducted to investigate the effect of fermented garlic solution (FGS) on the performance, egg quality and blood profiles of laying hens in the finishing period. In total, 432 Lohmann Brown hens aged 79 weeks were equally distributed into four dietary treatments with six replicate. Hens were fed the basal diet containing 2,750 kcal/kg of ME and 16% of CP, which was supplemented with either 0% (control), 0.05%, 0.10% and 0.20% FGS from 79 to 83 weeks old. Laying performance, egg quality, yolk fatty acids and serum characteristics were analyzed at the end of experiment. Egg production and feed conversion was numerically improved in FGS supplementation treatments compared to those in the control, but were not statistically different. The albumen height and Haugh unit showed significant increase (P<0.05) in the FGS supplementation groups. The concentration of saturated fatty acid decreased in the yolks of birds fed FGS (P<0.01), whereas the unsaturated fatty acid (UFA) and mono-UFA contents were significantly higher (P<0.01) in those treatments than in the control. Significantly lower natural fat and cholesterol in serum were observed in birds fed the 0.20% FGS supplementation diet (P<0.01). However, the high-density lipoprotein (HDL) cholesterol increased in both the 0.10% and 0.20% FGS supplementation groups. In addition, interleukin-2 mRNA and CD4+/CD8+ level in serum which were cellular immunity indicators showed statistical differences (P<0.01) among treatments and a higher concentration in the 0.10% and 0.20% FGS groups than in the control. Thus, it can be concluded that dietary supplementation of FGS improved egg quality and stimulated immune response in mature laying hens.

• Korean Journal of Poultry Science
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• v.36 no.1
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• pp.47-55
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• 2009

This study was carried out to investigate the effects of spider-derived protease [Arazyme (AZ)] supplementation on egg production, egg quality, cecal microflora and viscosity of intestinal contents in laying hens at the late production. A total of two hundred, 59-wks-old, Hy-Line Brown layers were divided into four groups, placed into 5 replicates per group (50 birds per group) and fed one of four diets containing 0.05, 0.075 or 0.1% AZ or control for 5 wks. The results showed that egg weight in group fed the diet containing 0.05% AZ was significantly higher than those of other groups (P<0.05). There were no significant differences in egg interior and eggshell qualities among the groups. The serum parameters such as total cholesterol, the levels of GOT and GPT were not influenced by AZ feeding. There were no significant differences in the cecal number of total microbes, Coliforms and lactic acid bacteria among the groups. The viscosity and ammonia concentration of intestinal contents in the groups fed AZ were significantly reduced compared to those of the control (P<0.05). In conclusion, laying hens fed AZ supplemented diet improved egg weight as compared with that of control. In addition, the AZ supplemented diet reduced the viscosity and ammonia concentration of intestinal contents, reflecting a significant feed enzyme effect.