• Korean Journal of Poultry Science
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• v.26 no.1
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• pp.43-50
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• 1999

The features of special brand eggs are growing more and more diverse and it is hard to draw a clear distinction between these and ordinary (no-brand) eggs. Special brand eggs range from those with objectively recognizable characteristics to those given only an unsubstantial product image and price differentials are among them great, too. The relation between product features and prices is unclear. Special brand eggs are the commodity whose characteristics are the vaguest of all livestock products. Farm's brand eggs produce a high profitability to producers is they are directly sold to consumers, by, for example, home-delivery service. But if they are sold to supermarkets, etc., producer's (poultry farmer's) income becomes lower by the amount of distributors' margin, reducing the profitability substantially. Thus how to increase the ration of retailing is important for farmers to secure a high profit. The sales strategies of poultry are the combination of two elements, that is, new product development (product differentiation) and creation of new market. But it is difficult for special brand egg producers to develop products with clear characteristics (use value) distinct form ordinary eggs and so these producers depend on the factors of appearance, such as the color of egg shells and package. Special brand eggs manage to keep their marketable value by the combination of the few product features and product image. Thus NB eggs from feed producers have a great market-ability since they can take advantage of the power of patents and TV commercials. However, market differentiation affects profitability much more than product features and price gaps are very wide between directly sold and wholesaled eggs. The producers of special brand eggs have come to the turning point where they have to decide whether they will content with being the subcontractors for NB and PB eggs or they will continue to keep their independence in production and marketing.

• Korean Journal of Poultry Science
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• v.45 no.2
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• pp.109-118
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• 2018

A great progress in genetic selection, nutrition and management practices has contributed to the improved growth rate of broilers and egg production in laying hens. For the increased productivity of modern poultry, a healthy chicken liver needs to cope with the increased metabolic demands. The liver is the major site of de novo fatty acid synthesis; therefore, hepatic lipogenesis is crucial for producing better quality meat and eggs. When de novo lipogenesis exceeds the capacity of lipid metabolism and secretion, large amounts of lipids accumulate in the liver of broilers, leading to a fatty liver. Upon onset of egg-laying in hens, lipids including free fatty acids, triglycerides, and phospholipids are dramatically increased in blood plasma for the synthesis of yolk precursors in oocytes. Productive hens with fatty liver often have hemorrhagic syndrome and sudden death due to the heavy demands of yolk synthesis, which burdens the liver. Understanding the lipid metabolism and hepatic lipid disorders is a key point in the improvement of the growth and production of chickens. This review focuses on the recent studies on lipid metabolism, the hepatic lipid disorders, and the prevention or reduction of fatty liver in poultry.

• Korean Journal of Poultry Science
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• v.45 no.4
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• pp.245-252
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• 2018

This study investigated the effect of LED light wavelength (color) on reproductive hormones and egg production of brown laying hens raised on floor. Red, blue, green and white colors of LED light were four treatments with four pens per treatment. One hundred forty four Hy-line brown laying hens (47 wks old) were allocated in a floor pen for six weeks trial. Egg production, egg quality, yolk cholesterol and hormones ($17{\beta}$-estradiol, progesterone) concentrations in plasma and oviduct were analyzed. Egg production of red group was higher (P<0.01) than that of green group. Haugh unit of eggs from red group was higher (P<0.01) than that of blue and green groups. Egg weight of green group was heavier (P<0.05) than that of red group. Shell of blue group was stronger (P<0.05) than that of red and white groups. Shell color of white group was browner (P<0.01) than that of blue and green groups. Yolk cholesterol of red group was higher (P<0.01) than that of others. Plasma $17{\beta}$-estradiol of red group was higher (P<0.05) than that of others at $3^{rd}$ week, but that of white group was highest (P<0.05) at $6^{th}$ week. Oviduct progesterone of green group was higher (P<0.01) than that of others. The result showed that the LED colors affect the reproductive hormone concentrations, egg production, egg weight and egg quality. This study suggested that red LED would be the most appropriate color for floor raising brown laying hens to sustain the egg production when it begins to decline with aging.

• Korean Journal of Poultry Science
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• v.29 no.1
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• pp.13-18
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• 2002

This study was conducted to investigate the effects of dietary activated coconut charcoal (ACC) on Performance, e99 quality and Plasma cholesterol level of Plasma in laying hens. One hundred forty four, 47-wk-old, ISA Brown commercial layers were used in a 28-d feeding trial after a 7-d adjustment Period. Four dietary treatments were 0, 0.5, 1.0 and 1.5e% levees of ACC supplemented to a corn-soybean meal basal diet. Egg Production was significantly increased as the levels of ACC increased. However, egg weight was significantly decreased by the addition of ACC in diets. Egg shell breaking strength tended to decrease as the level of ACC increased, however, no significance was found in this respect. As the levels of ACC increased, egg shell thickness decreased significantly. Although not significant, yolk color tended to increase by the addition of ACC. Egg folk index were significantly increased by the addition of ACC In diet. No significant difference was found among four treatments in total cholesterol, HDL cholesterol, and LDL+VLDL cholesterol concentrations in plasma. In conclusion, dietary supplementation of ACC to layer diets could be used to increase egg Production, and yolk index.

• 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.34 no.3
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• pp.181-185
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• 2007

This study was conducted to evaluate the effects of dietary delta-aminolevulinic acid (ALA) on egg production and egg quality in laying hens. A total of 114 (30-wk age) ISA brown commercial hens were used in current trial for 28 days. Dietary treatments included 1) CON (basal diet), 2) 0.05 (basal diet + ALA 0.05%), 3) 0.1 (basal diet + ALA 0.1%) and 4) 0.2 (basal diet + ALA 0.2%). There were four dietary treatments with four replication per treatment and twelve laying hens per replication. During the overall period, egg production was quadratically affected (P=0.01) by ALA supplementation compared with control treatment. Egg weight increased (linear effect, P=0.01; quadratic effect, P=0.01) as the level of delta-aminolevulinic acid supplementation increased in the diets. Yolk color was increased quadratically (P=0.03). The difference of hemoglobin concentration was increased (quadratic effect, P=0.01) as the level of delta-aminolevulinic acid supplementation increased in the diets. In conclusion, the results of the experiment suggest that dietary delta-aminolevulinic acid could affect egg weight, yolk color and hemoglobin concentration in laying hens.

• Korean Journal of Poultry Science
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• v.19 no.4
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• pp.197-204
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• 1992

This study was divided into experiment 1(191 g egg-albumen plus 150g sucrose) and experiment 2(222g egg-albumen plus 150g sucrose)which were subdivided into groups treated with 0, 8.71, 17.43 and 26.149 egg yolk. These experiments were incubated in a shaking water bath($50^{\circ}C$ ) with a speed of 92(turnaround) per minute (or a period of times. The pH and specific gravity were measured after 2, 4, 6, 8, 10 and 12 hours incubation. The results obtained were as follows ： 1. The pH and specific gravity were steadily increased by shaking time, but decreased by the amount of egg yolk. 2. In the groups treated with egg-albumen, egg yolk, and sucrose of experiments 1 and 2, PH was increased by shaking time and reached highest value at 10 hours shaking time. However, after 12 hours shaking time pH slightly decreased though not significantly. 3. In the experiment 1 and 2, specific gravity had a higher correlation with pH and the regression equation between specific gravity and pH (X) were Y＝0.1081x+0.272(r＝0.899n) and Y＝0.083X＋0.476(r＝0.825$^{* *}$), respectively.y.

• Korean Journal of Poultry Science
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• v.21 no.1
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• pp.21-34
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• 1994

The objective of this study was to develop a user-friendly computer model for economic analysis on the commercial egg production that could help the egg farmer make managerial diagnosis and rational decision in the changing environment. To raise the adequacy of the model, the program was run for every sample and adjusted to fit the data. The model, programmed with Microsoft QuickBASIC, was a user-friendly computer program in supporting the Korean language. The basic analytical tool used in the study was an engineering-type computerized simulation model which incorporates a cost-benefit analysis of a full-time egg farmer. The computer model developed in this study may be the powerful analytical tool used to evaluate both a managerial decision whether to alter the production system and its impact on production, costs, revenue, and profits. Ultimately, the program is expected to enable the egg farmer to make managerial planning and diagnosis. The program can also calculate the values of economic variables at user-chosen incremental values of market eggs and feed prices. It provides the information on the profit and cost. This may lead the egg farmer, by allowing to establish the best managerial strategy, to increase the profit aor to lessen the cost. The results of this study could be utilized in the evaluation and improvement of the management. It also may be utilized for the researchers and guiding farmers in collecting and analyzing the data on the laying hen. In particular, such a program would be potentially useful to researchers who wish to quickly estimate profits associated with various laying hen treatments. The program could also benefit the egg farmer interested in making managerial decisions based on either current or predicted market conditions. The model would make the egg farmer respond actively to the information-oriented society by promoting to use personal computer.

• Korean Journal of Poultry Science
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• v.39 no.3
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• pp.215-222
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• 2012

This study was conducted to investigate the effects of supplementation diets of powdered mulberry leaves on egg production, egg quality and blood characteristics in laying hens. Laying hens were fed diets for 30 days containing 0% powdered mulberry leaves (Control), 1% powdered mulberry leaves (T1), 2% powdered mulberry leaves (T2), and 5% powdered mulberry leaves (T3). The egg production, yolk weight and albumen weight were no significant difference among treatment groups. The albumen weight was significantly decreased by the supplementation of powdered mulberry leaves in all treatment groups (P<0.05). The albumen high, yolk color score, egg sell thickness and egg shell breaking strength were no significant difference. The total cholesterol and triglyceride concentration of control was higher than T3, and the high density lipoprotein (HDL)-cholesterol concentration and glucose of control were lower than treatment groups (P<0.05). The white blood cell (WBC) was significantly increased by the supplementation of powdered mulberry leaves compared to the control (P<0.05). In conclusion, these data indicate that 5% powdered mulberry leaves supplementation was most effective in decreasing total cholesterol and triglyceride and increasing HDL-cholesterol, glucose and WBC.

• Korean Journal of Poultry Science
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• v.39 no.3
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• pp.207-213
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• 2012

This experiment was conducted to investigate the effects of various levels of dietary protein on laying performance and egg quality in laying quail. A total of six hundred forty 7-week-old laying type Japanese quail were divided into four groups with eight replicates per group (20 birds per replicate) and fed four diets differing in dietary protein levels (18, 20, 22 and 24%) with isocaloric corn-soybean meal-based diets for 8 weeks. The results showed no significant differences in feed intake and egg weight among the groups. With an increase in dietary protein levels, the egg production and daily egg mass were linearly increased (P<0.05). However, there were no significant differences in eggshell thickness and Haugh unit. The dietary protein did not affect the blood levels of GOT, GPT, BUN, albumin, and creatinine. The ammonia concentration of intestinal digesta was not affected by the dietary treatments. The contents of hepatic triacylglycerol in the groups fed diets containing 20% protein or more were significantly reduced as compared with that of 18% CP group (P<0.05). Overall, this study showed that relatively high levels of dietary CP are needed to sustain the higher egg production and daily egg mass and to avoid the hepatic triacylglycerol accumulation in Japanese quail.