• Korean Journal of Poultry Science
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• v.26 no.4
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• pp.247-252
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• 1999

This experiment was carried out to investigate the effects of the laying hens on the immune response against bovine serum albumin(BSA) in egg yolk. Total 45 laying hens were divided into three groups according to breeds (White Leghorn, ISA Brown, Native hen). They were fed the experimental diet for 12 weeks. Immune response were examind in egg yolk from three groups of hens injected with BSA. The results obtained from this work were summaried as follows : 1. The weight of egg yolk and the percentage of hen-day production in the ISA Brown hens are greater than those in the Native hens and the White Leghons. 2. IgY concentrations in eggs from hens immunized with BSA were not different among the breeds laying hens. 3. The anti-BSA antibody activities determined by enzyme linked immunosorbent assay (ELISA) in the egg yolk were similar between the White-Leghorn and ISA Brown hens, but Native hens tended to decrease in 20∼50 days respectively. Therefore, the weight of egg yolk and the percentage of hen-day production in the ISA Brown hens are greater than those in the Native hens and the White Leghons will be as important factors for an efficient production of IgY.

• Korean Journal of Poultry Science
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• v.21 no.4
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• pp.267-275
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• 1994

Three dietary ME levels of 3,200, 2,900 and 2,600 kcal /kg in the same 13% single-stage low protein diet were compared to evaluate the effect of ME levels of grower diets on egg-type pullet growth and subsequent laying performance. As the ME levels of grower diets decreased, cumulative feed and protein consumptions increased(P<0.05), however, the ME intake and body weight at 18 wk of age decreased(P<0.05). Grower feed cost decreased as the dietary ME level was decreased, but no significant difference was found among dietary ME levels of grower diets. During the laying period, sexual maturity, hen-day egg production and average egg weight were not significantly affected by the ME levels of grower diet, however, daily feed intake and feed required per egg decreased as the dietary ME level of grower diet was reduced(P<0.05). Results of this study indicate that pullets can be reared on the low ME diet of 2,600 kcal /kg and it would he economical to utilize the low energy diet during the growing period when they are reared on a 13% single-stage low protein diet.

• Korean Journal of Poultry Science
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• v.14 no.1
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• pp.1-8
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• 1987

Three experiments were conducted to investigate effects of dietary energy and protein levels on performance of laying hens. A total of 360 hens each of 352-day old Manina Brown (Exp.1), 280-day old Brown Warren (Exp.2) or 3174ay old Brown Warren (Exp.3) was divided into 20 pens of 18 birds. Each pen was assigned to one of the four dietary treatments with 5 replications according to a 2${\times}$2 factorial design, consisting of all possible cominations of two levels of metabolizable energy (2,500 and 2,800 kcal/kg of diet) and two levels of crude Protein (13 and 16%). All hens were housed two birds per cage. Exp.1 and 2 were conducted for four weeks and hens were fed experimental diets ad libitum, and Exp.3 lasted two weeks and feed consumption was restricted to 130g/hen/day. In Exp.1 and 2, increasing either energy or protein level in the diet numberically improved egg production. However, in Exp. 3, where feed consumption was restricted, egg Production was affected significantly 〈0.05) by the energy levies and numerically by the protein levels. Neither protein nor energy level influenced egg weight in Exp. 1 and 2, but in Exp. 3 the higher level of energy improved egg weight numerically, In all three experiments increasing either protein or energy level increased egg mass. Higher levels of either protein and energy tended to decrease feed consumption and improve feed conversion rate numerically. It should also be noted that the higher level of energy improved egg mass produced per unit intake of protein and the higher level of Protein improved egg mass produced per unit intake of energy.

• Korean Journal of Poultry Science
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• v.24 no.1
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• pp.39-44
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• 1997

Two experiments were carried out to determine the effects of pelleting layer diets on the laying perforrnance and nutrients utilizability, using either 50-wk-old(Experiment 1) or 80-wk-old (Experiment 2) layers. There was no effect of pelleting layer diets on hen-day egg production and average egg weight but decreased (P<0.05) feed conversion ratio(intake /egg weight) in both experiments. Although both egg specific gravity and eggshell thickness were not influenced by pelleting eggshell breaking strength was improved(P<0.05) only in Experiment 1. Utilizability of dietary fat was improved(P<0.05) by pelleting layer diets with no difference in other nutrients utilizability. There was no difference in the passage rate of mash and pelleted layer diets.

• Korean journal of food and cookery science
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• v.18 no.1
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• pp.94-100
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• 2002

The dietary carbohydrates are mainly digested and adsorbed at small intestine. We developed a new food additive as an egg yolk antibody(1gY) against maltase, sucrase and sodium dependent g1ucose cotransporter(SGLT) for the regulation of blood glucose level and weight control. The maltase, sucrase and SGLT were purified from porcine small intestine which is very similar to that of human in physiological characteristics. The purification step contained an ultracentrifugation, ion exchange chromatography and hydrophobic chromatography. The hens were immunized by purified protein and the IgY activities against immunized antigens were determined. This antibody obtained from the immunized hen's egg yolks directly inhibited the activities of maltase and sucrase in vitro. And the IgY delayed and decreased the increment of blood g1ucose level after administration of maltose, sucrose and glucose in rat about 30 to 60%. The results of this study suggest that the IgY inhibiting the carbohydrate digestion could be used as functional food materials for weight control and regulation of blood glucose level in diabetes.

• Asian-Australasian Journal of Animal Sciences
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• v.8 no.6
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• pp.607-610
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• 1995

An experiment was conducted to study the effects of Ascorbic Acid (AA) supplementations in the layer and broiler diets kept in the natural hot humid tropical climate ($20-35^{\circ}C$). The layers and the broilers were fed on normal commercial diet as control while supplementation of 400 and 600 mg/kg Ascorbic Acid made up the experimental diets. The results showed that AA supplementation in the layers significantly reduced egg weight and increased Haugh unit values of the eggs, but produced no significant effects on feed intake, body weight, egg production, respiratory rate and body temperature. The shell thickness was slightly improved, though not significantly, with AA supplementation. AA supplementation in broilers improved body weight gain and FCR and reduced the effect of heat stress as shown by lower body temperature and respiratory rates.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.02a
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• pp.560-566
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• 2000

• Korean Journal of Poultry Science
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• v.40 no.1
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• pp.67-73
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• 2013

With an increasing concern on laying hen welfare, barn system has appeared as one of the alternatives to replace the conventional cage. This study was conducted to compare the early laying performance and egg quality at the barn system with those at the conventional cage. A total of 288 shaver-579 brown layers were used for 9 weeks ($21^{st}$ to $30^{th}$ weeks of age) feeding study. Feed consumption and egg weight were significantly (P<0.01) higher at barn than at cage. However, there were no significant differences between two housing systems on hen day egg production (HDEP), egg mass, body weight, feed efficiency and livability. In case of egg quality parameters, shell thickness, albumen height and Haugh unit were significantly (P<0.05) different between two systems. Haugh unit and albumen height were significantly higher in eggs produced at cage (88.97 and 8.16 mm) compared than those produced at barn (83.11 and 6.87 mm), whereas shell thickness was thicker in eggs produced at barn than those produced at cage. Shape index, breaking strength, blood spots and yolk index data were not influenced significantly by the types of housing system. To implement welfare bestowing production, this study showed that the barn system can replace the conventional cage without serious sacrifices on starting phase egg production. In addition, this study suggested that the barn system need to be optimized in view of daily feed consumption.

• Food Science of Animal Resources
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• v.38 no.3
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• pp.468-475
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• 2018

The present trial was carried out to study the effect of sea buckthorn seed supplementation on egg quality of laying birds. A total of 160 Rhode Island Red${\times}$Fayoumi layers was divided into four groups of 40 birds each, which was further replicated four times with 10 hens per replicate. Group one was kept as a control, while other three groups were supplemented with sea buckthorn seed powder at a dose rate of 1 (T1), 2 (T2) and 3 (T3) g/kg of feed. The results showed that egg production was significantly (p<0.05) higher in T3 at the end of the study. Egg weight was significantly (p<0.05) high in T2 and T3 during week 39 and 40. Egg yolk weight was significantly (p<0.05) in T3 compared to the control. Significantly (p<0.01) lower egg cholesterol was recorded in T2 and T3. From the results of the present study, we concluded that laying hens supplemented with sea buckthorn at the rate of 2 and 3 g/kg improved the egg quality parameters and egg cholesterol.

• Korean Journal of Poultry Science
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• v.46 no.3
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• pp.193-204
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• 2019

This study aimed to investigate the changes in production performance of five strains of Korean native chickens (KNCs), which have been collected and established at the National Institute of Animal Science, Korea, since 1992. A total of 38,026 KNCs were tested and survival rate, body weight, age at first egg-laying, hen-housed egg production, and egg weight was analyzed. The mean survival rates of KNCs were $87.9{\pm}0.8%$, but no significant difference in survival rate between strains and in the annual survival rates of KNCs was observed. The average body weight of KNCs was $1,609.7{\pm}21.3g$ at 150 d. The average body weight of KNC-Black was the highest, whereas KNC-White had the lowest weight. A gradual increase in the annual weight change has been observed in almost all strains after 2004. The average age at first egg-laying was $146.9{\pm}1.1d$ in KNCs where KNC-White was the earliest and KNC-Black was the latest. The age at first egg-laying has increased after 2003, but has gradually decreased after 2008. The average hen-housed egg production at 270 d was $77.3{\pm}1.7$ in KNCs, wherein KNC-Yellowish brown was the highest and KNC-Black was the lowest. The average egg weight at 270 d was $51.2{\pm}0.3g$ in KNCs, indicating that KNC-Black was the heaviest, whereas KNC-White was the lightest. A significant increase in annual egg weight has been observed since 2008. To conclude, the appearance and feather colors of KNCs have improved uniformly, and the body weight has also improved slightly since 2002.