• Korean Journal of Poultry Science
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• v.27 no.2
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• pp.133-153
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• 2000

The egg's interior quality is one of the most important criteria for commercial producers and consumers. Internal quality is complex, including aesthetic factors such as taste, freshness, nutritional and processing values, and the genetic influences upon these upon these factors ranges from none to considerable. The rate of cholesterol synthesis in the hen is very high compared to other animals and humans. Genetic selection, diet drugs and other chemicals can alter cholesterol concentration in the plasma of laying hen, but attempts to manipulate the cholesterol concentration in the egg yolk are generally unsuccessful since the cholesterol can only be changed to a small extent. Factors which may affect the degree of pigmentation of the yolk include the type of xanthophyll and its concentration in the feed, the feed composition, and the health of the hen. Several feed ingredients interact with carotenoid pigment to improve or reduce their deposition rates in yolks. Egg weight is determined by genetics, body size prior to first egg housing density, environmental temperature, lighting program, total feed consumption, calcium, phosphorus, niacin, water, methionine, total sulfur amino acids, energy, linoleic acid, fat and protein levels. Eggs need to be promote levels. Eggs need to be promoted a versatile commodity and new processed egg items need to be developed. Organic eggs are laid by hens which were raised in chemical and drug frdd environments. There are still difficulties in producing these eggs due to the availability of organic poultry feeds and cost of organic grains.

• Korean Journal of Poultry Science
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• v.44 no.4
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• pp.235-243
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• 2017

This experiment was aimed at investigating the effects of dietary supplementation with fermented rice bran (FRB) or fermented broken rice (FBR) on egg-laying performance, egg quality, blood parameters, and cholesterol level in egg yolk of Hy-Line Brown egg-laying hens. Altogether, 144 Hy-Line Brown egg-laying hens (32-week-old) were randomly allocated to one of 4 dietary treatment groups, with 4 replicates per treatment. Of them, 3 treatments diets were prepared by supplementing the basal diet with 0.1% probiotics (PRO), 1% fermented rice bran (FRB), or 1% fermented broken rice (FBR) at the expense of corn. Hen-day egg production was higher (P<0.05) in PRO and FRB treatment groups than in the basal treatment groups. However, feed intake, egg weight, egg mass, and feed conversion ratio did not differ among the treatment groups. Additionally, supplementation with FRB or FBR did not affect eggshell strength, eggshell thickness, egg yolk color, and Haugh unit during the feeding trial. There was no significant difference in leukocyte count. Total cholesterol level was lower (P<0.05) in the FRB treatment group than in the basal treatment groups. Asparate aminotransferase, alanine transferase, glucose, and albumin levels were unaffected by dietary supplementation with FRB or FBR. Egg yolk cholesterol level was lower (P<0.05) in the FRB and FBR treatment groups than in the basal treatment groups. In conclusion, dietary supplementation with FRB or FBR improved egg-laying performance, and reduced the levels of total serum cholesterol and cholesterol in egg yolk of Hy-Line Brown egg-laying hens.

• Animal Bioscience
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• v.36 no.6
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• pp.899-907
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• 2023

Objective: The better understanding of laying pattern of birds is crucial for developing breed-specific proper breeding scheme and management. Methods: Daily egg production until 50 wk of age of six chicken breeds including one layer (White Leghorn, WL), three dual-purpose (Rhode Island Red, RIR; Columbian Plymouth Rock, CR; and Barred Plymouth Rock, BR), one synthetic dwarf (DY), and one indigenous (Beijing-You Chicken, BYC) were used to characterize their clutch traits and egg production. The age at first egg, egg number, average and maximum clutch length, pause length, and number of clutches and pauses were calculated accordingly. Results: The egg number and average clutch length in WL, RIR, CR, and BR were higher than those in DY and BYC (p<0.01). The numbers of clutches and pauses, and pause length in WL, RIR, CR, and BR were lower than those in DY and BYC (p<0.01). The coefficient variations of clutch length in WL, RIR, CR, and BR (57.66%, 66.49%, 64.22%, and 55.35%, respectively) were higher than DY (41.84%) and BYC (36.29%), while the coefficient variations of egg number in WL, RIR, CR, and BR (9.10%, 9.97%, 10.82%, and 9.92%) were lower than DY (15.84%) and BYC (16.85%). The clutch length was positively correlated with egg number (r = 0.51 to 0.66; p<0.01), but not correlated with age at first egg in all breeds. Conclusion: The six breeds showed significant different clutch and egg production traits. Due to the selection history, the high and median productive layer breeds had higher clutch length than those of the less productive indigenous BYC. The clutch length is a proper selection criterion for further progress in egg production. The age at first egg, which is independent of clutch traits, is especially encouraged to be improved by selection in the BYC breed.

• Korean Journal of Poultry Science
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• v.24 no.4
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• pp.199-206
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• 1997

In this experiment, three kinds of autoclaved poultry by-product meals, P1 (head+feet+viscera), P2(P1+blood), and P3(P2+feathers), mixed as to the yielding ratios, and three kinds of autoclaved hatchery by-products meals, H1 (male d-old chicks of egg strain), H2(dead embryos ＆ infertile eggs), and H3(H1+H2, 2:1) were formulated into the layer diets each at 5％ level, respectively, and compared with the control diets(C) containing fishmeal on laying performances and egg qualifies. The egg production, average egg weight, feed intake and feed conversion were not significantly affected by the poultry or hatchery by-product meals. The egg shell qualities, such as the egg specific gravity, egg breaking strength and shell thickness, were not different among treatments. The egg yolk colour was improved by the feeding of hatchery by-products meals (P<0.05). In conclusion, pultry and hatchery by-product meals could be used in layer diets without any adverse effects on laying performances to substitute for fishmeal at about 5％ level.

• Korean Journal of Poultry Science
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• v.48 no.4
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• pp.161-168
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• 2021

The present study investigated production traits, including body weight, egg production, egg weight, and egg quality in Korean indigenous parent stocks. Parent stocks produced from a nine-combination association from five pure line strains (C, D, F, K, and Y) were used. The body weight analyses results showed that the CY combination had the highest body weight (1,604.9 g) and the DK combination had the lowest (1,424.4 g). The average age at first egg of the nine combinations was 118.6 days; however, that of the YD combination was 111.6 days, making it the fastest growing combination, whereas the DK combination was the slowest, at 126 days. Hen-day egg production was 74% or more for the CF, CK, and DK combinations. The DK combination hens showed excellent persistence in egg laying. Hen-housed egg production exhibited results similar to those of hen-day egg production. Egg weight was significantly higher in the DK combination than in the other combinations and was observed to increase from 20 (43.9 g) to 40 (58.1 g) weeks. The egg quality analyses results showed that the combinations based on the F and K strains had a bright eggshell color, with relatively high egg weights. Eggshell strength and thickness were the highest in the DK combination (3.8 kg/cm², 0.38 mm). In summary, the CF and DK combinations showed excellent egg production ability and egg quality, while the YC, YD, and YK combinations with the Y strain as the paternal strain exhibited poor performance.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.3
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• pp.417-423
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• 2017

Objective: This experiment investigated the effects of dietary supplementation with conjugated linoleic acid (CLA) on the serum components, laying hen productivity, lipid composition of egg yolk, egg flavor and egg quality. Methods: Healthy 28-week-old Hy-Line white laying hens (n = 480) were divided randomly into 4 groups, 6 replicates/group, 20 birds/replicate. The 30-day experimental diets included 0% (control), 0.4%, 0.8%, and 1.6% CLA. Some serum indices of the birds, and egg production, quality, fatty acid composition, egg quality were measured. Results: The dietary supplementation with 0.4%, 0.8%, and 1.6% CLA did not significantly affect the laying rate and feed intake, as well as calcium ion and phosphorus ion concentration in serum (p>0.05). However, the CLA had significantly increased the strength of eggshell, decreased the odor, flavor, and taste of egg yolk, deepened the color of egg yolk, increased saturated fatty acids and polyunsaturated fatty acids, and reduced the monounsaturated fatty acids (p<0.05). On the other hand, the dietary supplementation with 1.6% CLA had significant effects on feed/gain, and improved serum hormones. Dietary supplementation with 0.4% and 0.8% CLA can significantly enhance the activity of alkaline phosphates. Conclusion: CLA has no effect on production performance, but does enhance the lipid content of the egg yolk and the strength of the eggshell.

• Korean Journal of Poultry Science
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• v.47 no.1
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• pp.39-48
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• 2020

The present study intended to analyze and detect any possible shortcomings in the current egg distribution system in Korea through a questionnaire. The institutional system and cases of operation thereof in advanced countries such as the USA, Japan, and Germany for the development of the egg distribution industry in Korea. The results revealed the following issues: absent pricing system, ineffective egg distribution, and difficulty in balancing supply and demand. Suggestions for addressing these issues and the subsequent improvement were based on cases found in the instated systems of advanced countries, and were given as follows: (i) The existing GP Center needs to be separated from the farms of laying hens, and the current institutional system and its operations need to be improved and should be approved by the government. Parallel to the institutional improvement, establishing a distribution system centered on the GP Center would be desirable. (ii) Egg pricing regulations are needed as a standard to determine the price of eggs. (iii) The reinforcing control standards and securing means for egg preservation are pertinent to each stage of egg distribution and should take into account environmental factors such as egg preservation temperature to guarantee high hygiene standards and egg safety.

• Korean Journal of Agricultural Science
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• v.39 no.1
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• pp.53-60
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• 2012

This work was conducted to evaluate the laying performance of Korean Native Ducks (KND) Pure-Line (PL). A total of 400 female pullets were hatched from PL to keep in National Institute of Animal Science, Korea. Twenty weeks old PL female ducks were divided into 4 groups (5 replications/group, 20 head/replications). Four groups were compared in a $2{\times}2$ factorial arrangement with strain (White strains, WW; Celadon strains, CC) and house type (flat house, cage house). On first egg laying day, CC strain laid eggs earlier compared to WW strain (P<0.01), but there was no significant difference between flat and cage house. Egg weight (EW) and body weight (BW) at first egg laying day have no difference among strains and houses. BW of CC strain was higher than WW strain at the age of 30 week (P<0.01). Weekly feed intake (FI) have no difference between flat and cage house, but FI of WW strain was high compared to CC strain during 20~30 weeks. There was no significant difference on EW between CC and WW strains, but EW was low at flat house compared to cage house (P<0.05). Weekly egg productions of WW strain and flat house were lower than CC strain and cage house, respectively (P<0.01). Finally, These results can provide the information that needed to introducing new strains.

• Korean Journal of Poultry Science
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• v.22 no.1
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• pp.7-13
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• 1995

To investigate the response of egg production to the artificial light to induce early egg laying. and the changes of egg weight and egg shape during the egg laying cycle, 30 Korean ring-necked pullets and their 1,284 eggs layed under artificial light control were used in this study. The first egg was ohserved at the age of 31 wk, after 4 wk of stimulating light(16 hour light: 8 hour dark). Egg production rate during seven 2-wk periods from the begining of the first egg was 43.7% and a clear peak egg production(61.7%) was shown at the 4th 2-wk period. The effects of egg production period and pullet on the egg weight, egg length, egg width and egg shape index(width/length) were significant(P<0.01). In the egg production cycle. egg weight, egg length and egg width increased steadly with time. but the value of egg shape index increased up to the 3rd 2-wk period and then decreased. Repeatabilities from intraclass correlation for the egg weight, egg length. egg width and egg shape index were 0.61. 0.53, 0.49 and 0.48, respectively.

• Korean Journal of Poultry Science
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• v.43 no.2
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• pp.89-96
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• 2016

This study aimed to determine the effect of different dietary level of rice bran extract (RBO) on the laying performance, egg quality, blood parameter, cholesterol, and fatty acids in yolk of Hy-Line Laying hens. In all, 144 Hy-Line Brown laying hens (29 weeks old) were randomly allocated to one of 4 dietary treatments, with 4 replicates per treatment. A commercial basal diet was used and three additional diets were prepared by supplementing 2.5, 5.0 or 10.0 g/kg of RBO to the basal diet. The experimental diets were fed on an ad libitum basis to the bird during 8 weeks. Hen-day egg production increased (quadratic, p<0.05) with inclusion level of RBO, but feed intake, egg weight, and egg mass were not influenced by inclusion of level of RBO in diet. However, the supplementation of RBO did not have an effect on eggshell strength, eggshell thickness, egg yolk color, and HU during the feeding trial. There were no significant differences in the level of leukocyte. However, heterophil and lymphocytes decreased (quadratic, p<0.01) with inclusion level of RBO. H:L ratio tended to decrease (linear p=0.08) with inclusion level of RBO. As expected, increasing inclusion level of RBO in diets decreased (linear, p<0.01) the concentrations of total cholesterol in plasma. AST, ALT, glucose, and albumin were not affected by inclusion of RBO in diets. Egg yolk cholesterol increased (linear and quadratic, p<0.05) with inclusion level of RBO in diet. The results of this study indicate that dietary supplementation of RBO improves laying performance and decreased total cholesterol and egg yolk cholesterol levels in laying hens. Therefore, dietary RBO is considered a valuable functional ingredient to improve the performance of birds.