• 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.

• Asian-Australasian Journal of Animal Sciences
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• v.4 no.3
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• pp.275-280
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• 1991

Beta-aminopropionitrile (BAPN)-a Lathyrus toxin was fed to laying chicken to investigate effects on egg weight, production and malformity. Two feeding trials were conducted where the levels of BAPN varied from 0.1 to 0.6 g per kg diet. The responses with regard to egg weight, egg production and the incidence of malformed eggs due to varying concentrations of the toxin were recorded and the results on weekly changes in these important variables were evaluated by plotting graphs. The results showed that there were increasing trends in egg weight and egg shell abnormalities and a decreasing trend in egg production as the dietary level of BAPN was increased indicating that the responses of layers were dose dependent. The effects on egg weight, egg production and egg malformity disappeared following withdrawal of the toxin from the diets.

• Journal of Environmental Science International
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• v.28 no.1
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• pp.159-162
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• 2019

This study aimed to evaluate the effects of dietary microbial-fermented molasses on egg production and egg quality in laying hens.In total, 90 Hy-line Brown laying hens were divided into two treatment groups (control and 1% microbial-fermented molasses)with three replicates of 15 birds each. During the experimental period, supplementation of hen diets with 1% microbial-fermented molassesdid not influence egg weight, hen-day egg production, egg mass, and feed conversion ratio (p > 0.05), except for feed intake. Regarding egg quality, diets containing 1% microbial-fermented molasses significantly affected eggshell thickness, Haugh unit, and albumen height (p < 0.05). However, there were no remarkable differences between control and 1% microbial-fermented molasses in eggshell color and egg yolk color (p > 0.05). These results indicate that supplementing 1% microbial-fermented molasses to the diet of laying hens improved egg quality parameters such as eggshell thickness, Haugh unit, and albumen height rather than egg production.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.6
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• pp.835-840
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• 2005

The main objective of the present study was to determine the effect of dietary $\beta$-cyclodextrin ($\beta$-CD) on egg laying performance and cholesterol content of egg yolk. Feed intake, egg production and egg weight varied slightly, but not significantly, between hens fed either a control diet or a diet containing one of an increasing series of $\beta$-CD concentrations (2%, 4% or 6%). However, feed intake, egg production and egg weight were all lower in the hens fed on 8% $\beta$-CD (p<0.05). No difference in haugh unit values, egg yolk color and egg shell thickness were found between the different treatments. The cholesterol content of egg yolks (mg/g yolk) was significantly decreased by 0.71, 2.98, 4.00 and 4.24 mg in eggs from hens maintained on 2%, 4%, 6% and 8% $\beta$-CD, respectively (p<0.05). These observations indicate that appropriate supplementation of diets with $\beta$-CD can reduce the cholesterol content of eggyolks, thus raising the prospect of the production of a healthier functional food.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.11
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• pp.1611-1616
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• 2012

The aim of the study was to evaluate the effect of sodium nitrate consumption on egg quality and quantity, and some blood parameters of native breeder hens of West Azerbaijan province. One hundred native hens were used from wk 25 to 32 of age. These birds were divided into two groups. One group was fed the control diet (CD) but the other fed the same diet supplemented with 4.2 g/kg sodium nitrate (ND). After 2 wks of adaptation, eggs were collected daily and egg mass and egg production were measured weekly for five weeks. To assess the egg quality parameters, two eggs from each replicate pen were collected for three consecutive days each week. At the end of experimental period (wk 32 of age), blood samples of 5 birds per replicate were collected from the wing vein into anticoagulant tubes. Dietary sodium nitrate didn't affect the egg production, shell stiffness, shell thickness and Haugh unit (p>0.05) but it decreased the both egg production and egg mass during the last three weeks (wks 30, 31 and 32) (p<0.05). Furthermore, a treatment effect was observed for yolk colour (p<0.05). Both the egg production and egg mass were increased over time (p<0.05). No significant treatment${\times}$time interaction was observed for egg weight, egg production and egg mass (p>0.05). No effect of time or treatment${\times}$time were observed for shell stiffness (p>0.05). Over time, shell thickness was decreased while Haugh unit increased (p<0.05). None of the blood TP and TG or the activity of ALT, AST and LDH enzymes were affected by dietary consumption of sodium nitrate at wk 32 of age (p>0.05). Sodium nitrite decreased both the TAC and TC at wk 32 of age (p<0.001). It was concluded that the lower body antioxidant capacity of nitrate fed birds resulted in the lower performance (egg weight, egg production and egg mass).

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.5
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• pp.684-687
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• 2004

A study was conducted to determine the effect of live weight of pheasants on egg production and egg quality characteristics. A total of 48 ring-necked pheasants were divided into control, heavy, middle and light BW groups. Live weights of the control were 1,187 g, 1,352.92 g for heavy group, 1,247.92 g for middle group and 1,003.33 g for light group. Egg production of groups were found as 47.32, 42.82, 45.79 and 46.51% respectively, in 10 weeks of period. There were no statistical differences on egg production among the groups. The effect of live weight on egg weight, shape index, specific gravity, shell weight, shell thickness, Haugh Unit, yolk weight and albumen weight were found statistically significant (p<0.05). The effect of live weight on albumen index, membrane weight and membrane thickness were found not important (p>0.05). On the other hand, other important factors to be effective on the egg quality of pheasants should be investigated. As a result of this study, live weight of pheasant hens is not an important factor to obtain high egg production in pheasants. But, body conformation of breeding materials should be in good conditions.

• Korean Journal of Poultry Science
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• v.25 no.1
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• pp.21-30
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• 1998

The effects of dietary levels and feeding period of Korean hot pepper (Capsicum annum) seed on the performance and egg quality were investigated. Rhode Island Red layers of 84 wk of age were fed the experimental diets containing O.O(Control), 0.5, 1.0, 2.0, and 3.0% of HPS, respectively, in individual cages during 10 wk of the feeding period. The dietary hot pepper seed significantly(P<0.05) improved hen-day egg production and daily egg rnass, but reduced egg weight(P<0.05). During the 10 wk of the feeding period, the egg production and daily egg mass improved after 6 or 7 wk of feeding 0.5, 1.0 or 2.0% hot pepper seed diets. When the layers were fed the 3.0% HPS diet, it only took 1 wk to improve the egg production and daily egg mass. In addition, the birds fed 3.0% hot pepper seed diet showed relatively constant egg weight while those of the Control increased gradually as the feeding period passed. The dietary hot pepper seed significantly improved the eggshell thickness, and redness and whole color of egg yolk. The results indicate that dietary hot pepper seed( $\geq$2.0%) may improve the egg production and egg shell thickness, and increase the redness of egg yolk in layers.

• Korean Journal of Poultry Science
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• v.22 no.2
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• pp.67-75
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• 1995

The present study was conducted to estimate production performances, heritabilities, and genetic and phenotypic correlations on several economic traits in Korean native chicken. Data analyzed were the records of 1,096 pullets produced from 180 dams and 26 sires of Korean native chicken from April 19,1994 to February 26, 1995. Results obtained are surnmarized as follows: 1. The body weights(X${\pm}$SD) at 2, 8, 14 and 20 weeks of age were 114${\pm}$13, 690${\pm}$114, 1,163${\pm}$238, and 1,687${\pm}$349g, respectively. The age at first egg was 165.95${\pm}$14.54 days, and the number of eggs produced by 300 days of age were 70.78i23.47. The egg weights of the first egg and at 300 days of age were 37.88${\pm}$3.73 and 50.97${\pm}$3.69 g, respectively. 2. The heritability estimates of body weight based on the variance of sires, dams and combined components were 0.149, 0.298, and 0.224 at 8 weeks of age: 0.162, 0.220, and 0.192 at 20 weeks of age, respectively. 3. The heritability estimates of egg production traits based on the variance of sires, dams, and combined components were 0.232, 0.504, and 0.368 for age at first egg; 0.113, 0.172, and 0.143 for number of egg production by 300 days of age: 0.174, 0.352, and 0.236 for egg weight at 300 days of age, respectively. 4. The genetic correlation coefficients of some economic traits were as follows: between body weight and age at first egg, -0.354~-0.048; between body weight and number of egg production, -0.279~ -0.002; between body weight and egg weight, 0.338~0.977; between age at first egg and number of egg production, -0.791; between age at first egg and egg weight, 0.009~0.178; between number of egg production and egg weight, -0.572~ -0.256, respectively. 5. The phenotypic correlation coefficients of some economic traits were as follows: between body weight and age at first egg, -0.179~-0.006 between body weight and number of egg production, -0.045~0.074: between body weight and egg weight, 0.229~0.404: between age at first egg and number of egg production, -0.588: between age at first egg and egg weight, -0.029~0.597: between number of egg production and egg weight, -0.376~0. 019, respectively.

• Journal of the korean society of oceanography
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• v.32 no.2
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• pp.85-92
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• 1997

Seasonality in abundance and egg production was investigated for Calanus sinicus in Asan Bay, Korea, and feeding effort was measured in the laboratory condition. Although abundances of this species in this bay showed only one Peak in spring, egg Production showed two peaks, spring and fall, in this bay. Potential of year-round egg Production was also found. Food availability judged by the particulate organic carbon (POC) concentration was usually more than enough in this bay. High egg Production in fall resulted in spring Peak in abundance. But high egg Production in spring did not result in summer or fall Peak in abundance. Low abundances in summer and fall were believed to be the result of long range horizontal migration out to the central Part of the Yellow Sea. The highest average egg Production by the Population of this species was 16.3 eggs female-'day-'. Maximum e99 Production by an individual was 39.0 e99s female$^{-1}$ day$^{-1}$, which yielded 30.7% of specific egg Production rate in terms of body carbon content with the carbon contents of 44.44$^{\mu}$gC and 0.35 $^{\mu}$gC for individual adult female and egg, respectively. Clearance rate (F) measured in the laboratory condition decreased exponentially with the increase of food concentrations, as expected. The asymptote of F was 3.17 ml copepod$^{-1}$ h$^{-1}$. When this value and the minimum concentration of POC measured in the field were applied under the assumption of continuous feeding in the nature, the calculated gross efficient of egg production was 41.6% in case of average egg production of the population. Violation of the assumption of diurnal feeding rhythm and application of the minimum concentration of POC may offset the influence on calculation each other.

• Proceedings of the KSAR Conference
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• 2003.06a
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• pp.20-20
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• 2003

Phenotypic characteristics and genetic markers in livestock have been utilized for improvement of the economic traits including egg productivity. Korean Native Ogol Chicken (KNOC) has low egg productivity compared to White Leghorn. Therefore, in this study, serum IGF-I concentration and number of egg production were used as selection markers to improve egg productivity. KNOCs were divided into three groups showing high IGF-I concentration (IGF-I high), high egg production (EP high), and IGF-I/EP high groups. Blood was collected every 10 weeks, and serum concentrations of IGF-I, estradiol (E2), and progesterone (P4) were measured by radioimmunoassay. In comparison of three groups in each generation, the highest increment of egg production was detected in the IGF-I/EP high group from 20 weeks till 40 weeks, and the IGF-I high group also showed the significant increment of egg production after 50 weeks. Interestingly, there were the increase of egg production and decrease of periods in sexual maturity in the second and third generation selected by serum IGF-I concentration, while egg weight and body weight decreased during experimental period. In conclusion, the present study suggest the possibility of IGF-I as a selection marker to improve the egg productivity of KNOC.