• Korean Journal of Poultry Science
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• v.24 no.1
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• pp.29-37
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• 1997

An experiment was conducted for 20 days( from July 21 to August 10, 1996) to investigate the differences in thickness of eggshell and eggshell membrane in Korean native chicken. All the eggs were purchased from a farm located in Chinju area. All eggs were categorized into Treatment I (34.89~51.39 g), H (53.32~60.70 g), and III (34.89~60.70 g) according to their weights. Eleven items were measured in all three treatments, i.e., egg weight, egg length, egg width, breaking strength, eggshell thickness of large end(STLE), eggshell membrane thickness of large end(SMTL), eggshell thickness of small end (STSE), eggshell membrane thickness of small end(SMTS), eggshell thickness of middle part(STMP), and eggshell membrane thickness of middle part(SMTM). Correlation coefficients between egg weight and eggshell weight, among eggshell thickness of large end, small end and middle end and eggshell weight were significant (P<0.01). Correlation coefficients between egg weight and large eggshell membrane were nega-tively significant(P<0.01). Breaking strengths were higher in Treatment I than in Treatment H. Correlation coefficients among thickness of eggshell and eggshell membrane at each point at 3 parts of large end, small end and middle end were not significant.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.7
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• pp.993-998
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• 2015

Possibilities of predicting eggshell ultrastructure from direct non-destructive and destructive measurements were examined using 120 Fayoumi eggs collected from the flock at 45 weeks of age. The non-destructive measurements included weight, length and width of the egg. The destructive measurements were breaking strength and shell thickness. The eggshell ultrastructure traits involved the total thickness of eggshell layer, thickness of palisade layer, cone layer and total score. Prediction of total thickness of eggshell layer based on non-destructive measurements individually or simultaneously was not possible ($R^2=0.01$ to 0.16). The destructive measurements were far more accurate than the non-destructive in predicting total thickness of eggshell layer. Prediction based on breaking strength alone was more accurate ($R^2=0.85$) than that based on shell thickness alone ($R^2=0.72$). Adding shell thickness to breaking strength (the best predictor) increased the accuracy of prediction by 5%. The results obtained indicated that both non-destructive and destructive measurements were not useful in predicting the cone layer ($R^2$ not exceeded 18%). The maximum accuracy of prediction of total score ($R^2=0.48$) was obtained from prediction based on breaking strength alone. Combining shell thicknesses and breaking strength into one equation was no help in improving the accuracy of prediction.

• Asian-Australasian Journal of Animal Sciences
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• v.9 no.6
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• pp.723-726
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• 1996

A water loaded pressure device using water as the breaking force was developed to evaluate eggshell strength and compared with a dropping ball techniques. Further, relationships of shell thickness and weight of eggs to shell strength were also studied. Values for both of the shell strength measuring methods showed a highly significant correlation (p < 0.001) with shell thickness. The water loaded pressure method had a much higher simple correlation coefficient for shell thickness (r = + 0.786) than the dropping ball method (r = + 0.577). The shell strength measured by the water loaded pressure method appeared not to be correlated to egg weight. On the other hand, the negative sign of the standard partial regression coefficient and the partial regression coefficient of egg weight in the estimated multiple regression equation implied that for a given shell thickness a larger egg tended to have less shell strength than a smaller egg.

• Journal of Environmental Science International
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• v.26 no.7
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• pp.869-874
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• 2017

This study was conducted to investigate the effects of dietary supplementation of various types of fermented red ginseng marc with red koji to laying hens on eggshell and egg yolk quality characteristics. A total of 240 Hy-line Brown laying hens (40 wk of age) were randomly allotted to 24 pens (6 replicates per treatment and 10 laying hens per replicate). Experimental diets consisted of 4 treatments containing basal diet (control), 1% fermented red ginseng marc powder with red koji, 1% fermented red ginseng marc pelleted with red koji and 1% fermented red ginseng marc coated with red koji. During the 8-wk feeding trial, there were no significant differences in eggshell strength, eggshell thickness and eggshell color among the treatments, except for eggshell strength at 4 and 8 wk and eggshell thickness at 0 wk. In addition, no differences in egg yolk color and egg yolk index were found for all treatments throughout the 8-wk feeding period, except for egg yolk color at 0 wk. Thus, using various types of fermented red ginseng marc with red koji to laying hens did not improve eggshell and egg yolk quality characteristics.

• Journal of Environmental Science International
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• v.29 no.10
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• pp.1011-1014
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• 2020

The purpose of this study was to investigate the egg freshness and eggshell characteristics of old laying hens by adding sea urchin shell powder to the feed of such hens to achieve the objectives continuously pursued by environmental management, such as business profitability and waste resource utilization. A total of 90 Hy-Line Brown layers (66 weeks of age) were randomly divided into 2 treatments with 3 replicates, each of which consisted of 15 older layers, for 4 weeks. These treatments included a control (i.e., 0%) and 2% sea urchin shell powder. The 2% supplementation of sea urchin shell powder increased the Haugh unit (HU) at 2 and 4 weeks and eggshell strength at 4 wks compared to the controls (p<0.05). The HU at 0 weeks, eggshell thickness from 0 through 3 weeks, and eggshell strength at 0 and 2 weeks were not different between treatments (p>0.05). These results suggest that the addition of 2% sea urchin powder to the feed of laying hens improves egg freshness and eggshell strength in old laying hens.

• Asian-Australasian Journal of Animal Sciences
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• v.5 no.2
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• pp.217-224
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• 1992

The study was undertaken to determine the effect of dietary magnesium on the eggshell quality and other performance in laying Tsaiya ducks and Leghorn hens. Twenty-five Tsaiya ducks and 25 Leghorn hens were raised in individual cages. The basal diet was mainly consisted of corn starch and isolated soybean protein. At the beginning of the experiments, birds were fed for 10 days with the basal diet supplemented with 500 mg/kg Mg (1070 mg/kg in total by analysis) in order to allow the birds adapting to the new diet. Both Tsaiya ducks and Leghorn hens were then each randomly divided into five groups and each group of five birds were fed with the experimental diets containing 690, 1070, 1690, 2150 or 2380 mg/kg Mg, respectively for 21 days. Eggs were collected in order to measure eggshell quality, Mg and Ca content of the eggshell. At the end of the experiments, blood samples of all birds were taken from their brachial veins for measuring the concentration of Mg and Ca in the plasma. Experimental results appeared that the dietary Mg content did not significantly affect egg production, egg weight, eggshell breaking strength and thickness in both Tsaiya ducks and Leghorn hens. In Tsaiya ducks, however, the plasma Mg concentration was affected by the dietary Mg content, but the plasma Mg almost reached a plateau (4.66 mg/dl) as long as the dietary Mg level was over 1070 mg/kg. In Leghorn hens, the plasma Mg level was significantly increased from 1.66 mg/dl to 4.03 mg/dl when the dietary Mg content in the diet had been increased from 690 mg/kg to 2380 mg/kg, suggesting that the plasma Mg concentration seems to be directly influenced by the Mg absorbed in the intestine. In the Tsaiya ducks, however, the dietary Mg level did not significantly affect the eggshell Mg content (from 0.113% to 0.123%). Whereas, there was a negative correlation between the eggshell thickness and eggshell Mg content (r = -0.50, p<0.01), revealing that the increase in eggshell Mg content probably associated with the impairment of eggshell quality in Tsaiya ducks. In Leghorn hens, however, there was no significant correlation between eggshell quality and eggshell Mg content, although the Mg content in the eggshell was also increased from 0.279% to 0.427% when the dietary Mg had been elevated from 690 mg/kg to 2380 mg/kg.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.10
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• pp.1477-1482
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• 2016

This study was conducted to investigate the effects of diets with varying levels of calcium on egg production, shell quality and overall calcium status in aged laying hens. A total of five hundred 70-wk-old Hy-Line Brown layers were divided five groups and fed one of the five experimental diets with 3.5%, 3.8%, 4.1%, 4.4%, or 4.7% Ca, for 10 weeks. There were no significant differences in feed intake, egg production and egg weight among groups. The cracked eggs were linearly reduced as dietary Ca levels increased to 4.7% (p<0.01). A significant linear improvement for eggshell strength and thickness were determined with increasing dietary Ca levels (p<0.01). The contents of serum Ca and phosphorus were not affected by dietary Ca levels. With increase in dietary Ca levels, the tibial breaking strength slightly increased. There were no significant differences in the tibial contents of ash, Ca and phosphorus among groups. In conclusion, eggshell quality, as measured by appearance, strength and thickness of eggshell, were influenced by dietary Ca content as expected (p<0.05). These results suggested that aged laying hens require relatively higher level of Ca than required levels from current Korean feeding standards for poultry.

• Korean Journal of Poultry Science
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• v.49 no.2
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• pp.53-60
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• 2022

This study investigated correlations between egg quality indicators to identify external egg quality traits to predict internal egg quality using non-destructive and convenient measurements. Thirteen indicators, including Haugh unit, albumen height, eggshell breaking strength, eggshell thickness, eggshell color (CIE L^*, CIE a^*, CIE b^*), and reflectivity value, egg weight, egg length, egg width, shape index, and yolk color, were investigated. A total of 180 brown eggs were obtained from one 27-week-old flock of Hy-line brown-laying hens raised in a cage system. Correlations were evaluated using Pearson's correlation coefficient (r). The results showed strong correlations between Haugh unit and albumen height, eggshell color CIE L^* and reflectivity, egg weight and width, egg weight and length, eggshell color CIE L^* and CIE a^*, eggshell color CIE a^* and reflectivity, and shape index and egg length (P<0.001). Moderate correlations were observed between eggshell breaking strength and eggshell thickness, eggshell color CIE a^* and CIE b^*, and shape index and egg width (P<0.001). Eggshell color CIE L^* was correlated with eggshell breaking strength (P<0.01), and eggshell color CIE a^* was correlated with Haugh unit, albumen height (P<0.01), and eggshell breaking strength (P<0.001). The present study showed significant correlations between eggshell color and other quality indicators. Thus, this study suggests that eggshell colors based on reflectiveness and the CIE L^*a^*b^* value can be used to estimate the Haugh unit, albumen height, eggshell breaking strength, and thickness.

• 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.15 no.2
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• pp.297-302
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• 2002

The effects of eggshell pigmentation and egg size (medium and large) on the spectral properties and characteristics of eggshells were examined in eggs from two genetic groups of breeder flocks. Birds from meat (Hybro, pigmented eggshell, PES) and layer (Leghorn, non-pigmented eggshell, NPES) at 40 and 46 weeks of age, respectively, were used. Measurements of per cent shell (PS), shell thickness (ST), shell volume (SV), shell density (SD), egg shell conductance (EC) and physical dimensions of eggs were made. The spectral properties of eggshells were measured over the wavelength (WL) range of 200 to 1,100 nm. Eggshell absorbed approximately 99.8 percent of the light and transmitted only about 0.12 percent with a maximum light transmission at the near-infra-red region of about 1075 nm. It attenuated shorter WL and transmitted longer WL. Eggshell pigmentation and egg size influenced light transmission into the egg. The NPES had higher EC and transmission of light and lower PS and SD than those of the PES. Large size eggs had higher EC, SD, SV, transmission of light and egg physical dimensions than those of medium size eggs. It is concluded that genetic make up of birds and egg size influenced eggshell characteristics including EC and that, as a consequence, the difference in the spectral properties of eggshells. The pigmentation of eggshell influenced the amount and WL transmitted into the egg. The size and EC of eggs influenced the amount of light transmitted through the eggshell. EC is a good indicator for the ability of eggshell to transmit light.