• Korean Journal of Poultry Science
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• v.37 no.2
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• pp.125-130
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• 2010

This study was conducted to estimate heritabilities, genectic and phenotypic correlations on economic traits in three strains of Korean Native chickens (KNC) : Black (B), Red Brown (RB) and Yellow Brown (YB). The data used in this study were collected from 2000 to 2007 in the National Institute of Animal Science and a total number was 14,421 birds. The effect of the strains analysis showed that the strain B were greater than the other strains for body weight at 150 days and 270 days. The number of egg production at 270 days of the strain YB was higher than the other strains. The estimated heritabilities age at $1^{st}$ egg, body weight at 150 days, egg weight at $1^{st}$ egg, body weight at 270 days, egg weight at 270 days and number of egg production at 270 days were 0.32, 0.50, 0.31, 0.43, 0.48 and 0.69 for strain B; were 0.42, 0.41, 0.19, 0.48, 0.44 and 0.76 for strain RB; were 0.44, 0.52, 0.24, 0.54, 0.51 and 0.66 for strain YB respectively, The genetic and phenotypic correlations were also estimated.

• Journal of Distribution Science
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• v.11 no.10
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• pp.107-116
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• 2013

Purpose - Eggs are nutritionally complete and one of the most popular natural foods. Moreover, the poultry industry is one of the important food industries. However, early industrialization of the poultry industry on its own did not lead to further development compared to other livestock industries. In this study, we investigate what factors influence consumers' behavior and how consumers' understanding of retail business affects their propensity to consume. This study is different from other studies as it analyzes how the brand names of manufacturers and distribution companies affect the purchasing characteristics or actual purchase behavior of consumers in order to suggest how these manufacturers and distribution companies can increase their competitiveness. Research design, data, methodology - This study conducted a survey of 250 randomly selected egg purchasers in discount stores from January to April 2013. Consumers' purchase tendencies were calculated through frequency analysis. This result was then utilized using cluster analysis to draw a conclusion about which purchase tendency influenced consumers buying three different brands of eggs or whether this tendency really affected consumers. As a result, the outcomes of Hypotheses 2 and 3 were not clear so we drew a conclusion with our analysis of Hypothesis 1. Results - While the outcomes of Hypotheses 2 and 3 did not clearly indicate whether purchasing tendencies affected consumers when buying eggs, our analysis of Hypothesis 1 indicated that consumers were affected by the quality of the eggs rather than exterior factors such as the brand name. Thus, we concluded that it is important to promote the excellence of the quality of the eggs. Usually firms buy eggs from farms and repackage them in order to sell them. In this sense, if consumers were aware of this egg production process, and eggs were fairly distributed to retailers, large retail PB businesses would also be able to enhance their competitiveness. Conclusions - The brand, packaging, retail outlet, and other external features influenced the purchase of eggs to a certain degree, while shelf life, grade of the eggs, cleanliness, and other intrinsic characteristics had more influence. In particular, shelf life was the most important factor influencing purchase. Consumers were influenced not only by intrinsic characteristics of the eggs but also by large-scale producers' brands. Consumers relied upon the brand despite reduced competition because they found it difficult to identify shelf life and/or cleanliness. Small businesses and/or large-scale retailers can remain competitive by maintaining the freshness and cleanliness of the eggs. Further studies need to investigate areas in which consumers' cognition of the product is poor and/or the purchase inclination with regard to less developed industries such as eggs. In this study, the greatest problem was that consumers did not consume in accordance with the current situation as consumers have preferred fresh and clean eggs for a long time compared to purchase decisions based on external brands and/or packaging.

• Korean Journal of Poultry Science
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• v.31 no.3
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• pp.187-191
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• 2004

The experiment was performed to investigate the effect of heating temperature and shaking time on viscosity change of whole egg, yolk, and albumen. Shaking water bath was used at 35, 45, and 50$^{\circ}C$ and the viscosity was measured at 0, 3, 6, 9, and 12 hours. There were no significant differences in viscosity of whole egg between 35$^{\circ}C$ and 45$^{\circ}C$( over-all mean). However, the 50$^{\circ}C$ group showed significantly lower viscosity compared to 35 or 45$^{\circ}C$ groups(P < 0.05). Non-significant differences were noticed in yolk viscosity among temperature treatments, but there were significant differences among shaking times(P < 0.05). Heating temperature and shaking time did not show significant effect on the viscosity of albumen, but the lowest viscosity was shown at 0, 9, and 12 hours at 50$^{\circ}C$. The results suggest that whole egg, yolk, and albumen should be treated for more than 3 hours at 50$^{\circ}C$, more than 3 hours at 35$^{\circ}C$ and 45$^{\circ}C$ and 3～9 hours at 50$^{\circ}C$, and 0, 9, 12 hours at 50$^{\circ}C$, respectively and then can be used in the processing.

• Korean Journal of Poultry Science
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• v.31 no.2
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• pp.79-84
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• 2004

A total of 225 ISA Brown layers, 63-wk-old, were used in a 5-wk feeding trial to measure the effect of dietary canthaxanthin(0, 50, 100, 200, and 300mg/kg feed) on its accumulation in various body parts and the egg yolk. There were three replications per treatment and 15 birds per replication. The redness(a$\^$*/) and yellowness(b$\^$*/) of wing and thigh skin significantly(P＜0.05) increased when canthaxanthin was fed at 2200 and 250mg/kg feed, respectively. However, the color of breast skin was not significantly affected by the canthaxanthin supplementation. Skin lightness(L$\^$*/) was not influenced by the dietary canthaxanthin. The dietary canthaxanthin supplementation did not significantly affect the redness or the yellowness of breast and thigh muscles. However, feeding canthaxanthin at 300mg/kg, compared to the control(0mg/kg feed), significantly(P＜0.05) decreased the lightness of wing and breast muscles. Feeding of canthaxanthin for 1-3d also significantly increased the color of egg yolks. In conclusion, canthaxanthin can be used to improve the color of skin and egg yolks, but it should be used cautiously because too intense egg yolk redness could be rejected by consumers.

• Korean Journal of Organic Agriculture
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• v.17 no.1
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• pp.63-82
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• 2009

This review was conducted to the study on treatment of poultry waste by earthworms, and the effect of feeding earthworms meal on the performance of broilers and laying hens, and safety of meat and egg. 1. The pro-environmental chicken house was building in Daegu National University of Education, Daegu city, chicken wastes will be turn into high quality compost by vermicomposting uses earthworms in the house. 2. The earthworm meal (EWM) has a high proteinic content and a balanced amino acid and fatty acid profile, therefore most feeding applications has been evaluated with mono-gastric animals. 3. The dietary supplementations of 0.2 to 0.4% EWM were effective in improve digestibility of crude protein of diet resulted improved broiler performance in broiler chickens. 4. The supplementing 0.2 to 0.6% of earthworm meal in the laying hens diet, improves the laying performance and egg quality, especially ratio of egg yolk n-6/n-3 fatty acids contents. 5. As, Cd, Cr, Hg and Pb were detected at level of 4.41, 1.23, 1.18, 0.00 and 3.39ppm in earthworm meal, respectively, but those were not detected in the chicken meat and egg. therefore supplementing 0.6% of EWM in the chicken diet, it still did not affect meat and egg safety. 6. These results indicated that vermicompositing uses earthworms good a subject matter in the pro-environmental animal husbandry.

• Korean Journal of Poultry Science
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• v.29 no.2
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• pp.117-124
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• 2002

Betaine functions as an osmoregulators in the cells and its inclusion in diet can spare the choline and carcass fat reduction in chicken. Thus, two hundred eighty eight laying hens were fed with 0, 500, 1,000, 2,000 ppm of betaine from seventy eight to eighty six weeks of age during the environmentally high temperature stress. Com and soybean basal diets contained 2,800 kcal/kg ME and 16% CP. Egg production, feed intake, and feed conversion were examined for eight weeks. Egg quality characters, serum cholesterol, liver betaine, and lower ileal osmolality were measured at the end of experiment. Egg Production rates of hens fed with 500 or 2,000 ppm of betaine were 75.06 and 75.02%, respectively and tended to increase compared to the control. The feed conversion(FCR) of these treatments was significantly(P<0.05) improved compared to that of control although it did not significantly differ in the e99 Production rates between 500 and 2,000 ppm of betain groups. Eggshell breaking strength of hens fed betaine was significantly(P<0.05) higher than those of control. However, betaine supplements did not influence to improving the albumen height and Haugh unit. Liver betaine in hens fed with betaine was linearly increased unto 2,000 ppm. The birds fed with 2,000 ppm betaine showed significantly(P<0.05) higher in the liver betaine than the control birds. Total cholesterol and triglyceride tended to be increased by dietary betaine supplement. The lower ileal osmolality in betaine supplement group tended to be slightly decreased. As a result, dietary betaine supplement tended to improve the egg Production and eggshell Quality in laying hens during heat stress.

• Korean Journal of Poultry Science
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• v.30 no.2
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• pp.101-106
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• 2003

In order to study the optimum daily protein allowance for broiler breeders of 24 to 64 weeks of age on a control-fed basis, an experiment was carried out with 400 hens of Arbor Acres strain. Four levels of protein allowances were used to supply 18 to 24g of protein per day in 2g increments. As the age of hens increased, a same stepwise increase and decrease in daily energy allotment was used in all treatments. Same amount of calcium, phosphorus, methionine and lysine were supplied in all treatments and throughout laying period. Hen-day egg production was highest in hens receiving 20g protein per day(p<0.05), but there was no significant difference among those fed daily protein ranging 18 to 22g, and increasing the daily protein allotment up to 24g resulted in a significant decrease(p<0.05). Average egg weight showed a trend to increase as the daily protein allowance increase(p<0.05), but no significant difference was found among the hens fed daily protein 20 to 24g. Feed and ME conversion was superior in hens receiving 20g daily protein(p<0.05). CP conversion was increased as the daily protein allowance increase(p<0.05), but there was no significant difference between hens receiving 18 and 20g daily protein. Feed cost required per egg or per kg egg was lowest in hens fed 20g daily protein. It could be concluded that the optimum daily protein allowance was 20g in all performances.

• Korean Journal of Poultry Science
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• v.20 no.4
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• pp.217-231
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• 1993

Due to the increased awareness on the relationship between high cholesterol intake and cardiovascular disease, the development of low cholesterol eggs and egg products are necessary at the present time. Largely, two approaches are possible to develop low cholesterol eggs. The first approach is the production of low cholesterol eggs by altering feeds of layers, by administering drugs, by genetic selection of strains and breeds, and by management of laying cycle, age and egg size. The second approach is to manufacture low cholesterol eggs technically treated with adsorbant, solvent, enzyme, edible oil and supercritical fluid. Both approaches have their own pros and cons, respectively, as far as the cholesterol removal rates, the easeness of process, and the economic reasons are concerned. The low cholesterol egg production is quite labor-intensive and has relatively low cholesterol removal rate(30∼50％ ) compared to that of chemically treated eggs. On the other hand, the low cholesterol eggs treated with chemicals have a very high cholesterol removal rate (80∼90％) but some of the methods are not completely safe as food processing purposes due to the residual chemicals and the sensory quality is not as good as the low cholesterol eggs without chemical treatment. Therefore, further studies must be conducted to improve the sensory quality of low cholesterol eggs and to eliminate fear about the harmfulness using low cholesterol eggs.

• Korean Journal of Poultry Science
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• v.47 no.4
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• pp.237-245
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• 2020

This study investigated the effects of breed, laying age, and egg storage period on hatching performance. Eggs were collected from early laying period (27 to 29 weeks old) and late laying period (50 to 52 weeks old) in Hwanggalsaek Jaeraejong, Korean Rhode Island Red, and Korean White Leghorn chicken breeds. Eggs laid for each period were stored for 3, 7 and 14 days and then hatched. Fertility, hatchability, and embryonic mortality were observed to determine the hatching performance. The results showed that hatching performance was affected by breed, laying age, and egg storage period with independently or interactively. The Korean Rhode Island Red breed had the lowest hatching performance. Hatchability and early embryonic mortality rate increased in early laying period eggs compared to the late laying period, but the late embryonic mortality rate increased in late laying period eggs. Additionally, hatching performance decreased as the egg storage period increased. Using breed-specific hatching management techniques, avoiding late laying period eggs, and shortening the egg storage period to seven days after laying may improve the hatching performance.

• 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.