• Korean Journal of Poultry Science
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• v.43 no.4
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• pp.253-261
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• 2016

Egg quality is a very important factor for both consumers and producers. Factors affecting egg quality include strain and age of hens; egg storage temperature, time, and humidity; laying season; and feeding. This study aimed to determine the effect of hen age and egg storage time on egg quality. A total of 700 eggs obtained from Hyline Brown commercial layers were used for this experiment, and they were separated into two hen age groups (30 vs. 60 weeks) with eight treatments and four storage times (day 0, 10, 20, and 30). The egg weight; shell color, thickness, and density; albumen height; Haugh unit (HU); yolk color; and the yolk and albumen pH and viscosity were measured for the egg quality assessment. The results showed that the age of the hen and egg storage time significantly affected almost all parameters of the internal and external egg quality. The shell thickness, albumen height, HU, yolk color, pH of yolk and albumen, and yolk viscosity significantly decreased with increasing hen age. The egg shell color was significantly lighter in eggs from 60-week-old hens than in those from 30 weeks-old hens. The egg weight; shell weight, thickness, and density; albumen height, HU; and albumen viscosity significantly decreased, but the yolk color and pH of the yolk and albumen increased with increasing egg storage time. The interaction effects between the storage time and hen age were significant in shell thickness, albumen height, yolk color, and yolk and albumen pH and viscosity. The eggs obtained from 60-week-old hens showed significantly lower shell thickness, albumen height, and HU values, which are considered typical egg quality measurements, than values of eggs from 30-week-old hens. Therefore, increasing hen age and egg storage time caused the deterioration of egg quality. In conclusion, this study demonstrated that hen age is the major factor affecting the quality of fresh eggs, whereas the storage time is the determinant factor affecting the quality of stored eggs.

• 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.

• Food Science of Animal Resources
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• v.30 no.1
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• pp.36-41
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• 2010

The Hen's egg is widely used in many processed foods as an ingredient and is one of the most prevalent food allergens in children. To detect egg proteins in processed foods, we developed a competitive indirect enzyme-linked immunosorbent assay (ciELISA) using an anti-ovomucoid (OM) antibody, which was produced by immunization of rabbits with OM, the most heat-stable component of the egg proteins. The detection limit of this quantitative assay system was 30 ng/mL. Cross-reactivity of the anti-OM antibody toward OM, ovalbumin, skim milk, casein, whey protein isolate, and isolated soy protein was 100, 0.4, 0.2, 0.04, 0, and 0%, respectively. In the spike test of egg white powder in milk replacer, commercial sausage, and in-house sausage, the assay recoveries ($mean{\pm}SD$) were $129{\pm}13.7%$, $73.9{\pm}12.5%$, and $65.5{\pm}13.6%$, respectively. When egg white in a commercial crab meat analog and sausage was determined by ciELISA, the assay recovery was found to be 108% and 127%, respectively. The combined results of this study indicate that this novel ciELISA for OM detection could be applied for the quantification of hen's egg proteins in processed foods.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.8
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• pp.1103-1109
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• 2002

This study investigated the effect of 2-bromo-$\alpha$-ergocryptine (anti prolactin agent) on plasma levels of prolactin, oestradiol-17$\beta$ and progesterone in domestic hen during the active period of lay. Fifty healthy female White Leghorn birds were administered with anti prolactin agent (2-bromo-$\alpha$-ergocryptine, Sigma-USA., methane sulphonate salt, $C_{32}H_{40}BrN_5O_5.CH_4SO_3$) subcutaneously @100$\mu$g/kg body weight at weekly intervals from 17th to 36th week of age. Another group of fifty birds as controls were given placebo in place of bromocriptine. The level of prolactin remained lower in treated birds than in the control birds from 19 to 36 weeks of age. Level of prolactin even in the control group was found to decrease during the peak production period. Oestradiol-$17{\beta}$ and progesterone concentration in treated birds were significantly (p<0.01) higher than the controls during the treatment. Egg production, is positively correlated with oestradiol-$17{\beta}$ (r=0.02; r=0.67) and progesterone (r=0.49; r=0.90) in control and treated groups respectively where as prolactin level is positively correlated with egg production in the control birds (r=0.07). Prolactin levels were negatively correlated with egg production (r=-0.55) in treated birds; and oestradiol-$17{\beta}$ (r =-0.71; r=-0.53) and progesterone (r=-0.22; r=-0.27) respectively in control and treated groups. The total number of pause days during the treatment period decreased significantly (p<0.01) in the treated group compared to the control group. The reduction in pause days in treated group resulted in 1.76% increase in egg production over that in control group. The increase in egg laying days and the total egg production were found to be significant (p<0.01). These results indicate that a lower level of prolactin in circulatory blood enhances egg production in the domestic hen.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2001.11a
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• pp.58-60
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• 2001

Two experiments were conducted to study the effects of nutrient level and feeding method of split diets for a.m. and p.m. on laying hen performance. In both studies, ISA Brown layers were kept in laying hen cages and treatments were represented by three or four replicates each containing 25 or 34 birds. In Experiment 1, the control group(C) was fed a conventional single diet throughout the day and split diet groups(T1, T2 and T3) were offered high energy/protein - low Ca diet and low energy/protein - high Ca diets in a.m. and p.m., respectively. In split diet groups, ME and CP consumption, and feed cost required per day and per kg egg mass were significantly reduced(P＜0.05) compared to C group, while the hen-day egg production, average egg weight and daily feed intake were not different among treatments. In the second study, C and T1 groups were fed the diets same to the C and T2 groups in Experiment 1, respectively. And T2 group was fed the diet mixed with the split diets for a.m. in mash and p.m. in pellet used in T1 group. In T1 and T2 groups, daily feed intake and average egg weight were significantly reduced(P＜0.05), while the hen-day egg production was not influenced by the feeding system. Daily ME and CP consumption, and feed cost were reduced(P＜0.05) in T1 and T2, while the ME, CP and feed cost required per kg egg mass were not different to the C group. In both study, eggshell qualities were improved(P＜0.05) by split diet feeding. It was concluded the feed and nutrients consumption, feed cost per day or per kg egg mass could be spared by introducing split diets for a.m. and p.m., and the feeding method of mixed diet of split diets was also convenient and effective for sparing feed cost and improvement of eggshell quality.

• Korean Journal of Poultry Science
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• v.13 no.1
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• pp.31-40
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• 1986

The energy metabolism with the normal laying hen and progesterone injected non-laying hen are compared. 1. The FHP of 109.7Kcal for laying hen was 25.5 percent higher than the 87.4 Kcal found for non-laying hen. 2. The MEm's of laying hen and non-laying hen were 149, and 135Kcal/Kg$\^$0.75/day and NAME's of the diets were 77 and 83 percent, respectively. For the laying hen shown negative retention in body energy during the experiment, the 77 percent NAME was the value of supporting egg production. For the non-laying hen shown the positive retention in body energy and zero egg production, the 83 percent NAME was of growth. 3. A change in body weight of 1g was comparable to 3.54 Kcal for laying hen, and 5.0 Kcal for non-laying hen, when calculated on regression equations between body weight change and body energy retention(BE). The figures indicate that the tissue energy is used with an efficiency of 70 percent for egg production. 4. Plasma level of triiodothyronine(T3) for the laying hen is appeared to be higher than that of non-laying hen, although the levels of thyroxine (T4) are equal both in laying and non-laying hen. 5. Activities of four hepatic enzymes(ATP citrate lyase, fructose diphosphate aldolase, isocitrate dehydrogenase and glutamte pyruvic transaminase) were significantly greater in the laying hen than in the non-laying hen.

• Korean Journal of Agricultural Science
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• v.50 no.2
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• pp.249-256
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• 2023

The purpose of this experiment was to determine the influence of providing laying hens with extra feed on egg production and egg quality parameters. A total of 480 laying hens (38-weeks old), were divided into five treatment groups (eight replicate cages/treatment and 12 layer/replicate) according to their starting body weight (1.98 ± 0.05 kg) in this four-week feeding trial. Five different feed allowances of the same diet (105, 110, 115, 120, and 125 g·day^-1·bird^-1) were assigned to layers. Daily inspections of remaining feed (around 0.1g) and layer mortality (0%) showed no harmful impact of supplying extra feed to layers. Providing 120 and 125 g of feed per day to layers resulted in the highest final body weight, large-egg ratio, and improved yolk color among all treatment groups. Layers receiving 125 g of feed daily had the highest egg weight, but the highest egg production ratio was observed in layers receiving 110 g of feed/day. The additional supply of feed did not have a negative impact on the productive performance or egg quality of the layers. The provision of 125 g feed per day led to an improvement of large-egg ratio, egg weight, and yolk color, but likely led to obesity of the layers, which manifested as an increase in body weight and a decline in the egg production ratio. We concluded that 110 grams of feed was the proper quantity after taking into consideration the significance of the health of the laying hen to the overall production performance.

• Korean Journal of Poultry Science
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• v.50 no.1
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• pp.15-22
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• 2023

This study was to investigate the relationship between chick weight in the growing period and the laying performance of Korean native chicken (KNC) breeders. We measured the body weights of 1,384 KNC breeders at 1-140 days of age at two-week intervals. The age at first egg laying, hen-day and hen-housed egg production, and the egg weights were investigated. Correlation coefficients between the body weight and egg production traits were analyzed. The results showed that the correlation coefficients between body weight and age at first egg laying were significantly positive before 4 weeks, but negative after 8 weeks of age. The correlation coefficients between body weight and egg production rate were estimated to be negative before 8 weeks and positive after 12 weeks of age. Coefficients of hen-day and hen-housed egg production were similar. There was little correlation between body weight and egg weight at 32 weeks of age, whereas a low positive correlation was with egg weight at 50 weeks. In conclusion, there was little correlation between body weight and laying performance before 8 weeks of age, whereas a significant positive correlation was with body weight after 12 weeks. The results suggest that as the chick's weight increases in the late growing stage, sexual maturity is faster, the egg production rate is higher, and the egg weight increases. Therefore, the weight management of KNC female breeders is very important in the late growing stage, and the body weight of chicks must be maintained above the standard weight.

• Journal of Nutrition and Health
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• v.4 no.4
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• pp.69-72
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• 1971

These experiments were designed to study the Hg contents in Korean Hens Egg by origin, kind, organ, and cooking methods. The following samples were studied. Place of origin Seoul (Legon) Su Woun (Legon) Pusan (Legon) Ulsan (Legon) Tae Gu (Legon) Kwang Ju (Legon) Seoul (New Hampson) Seoul (Native) No of sample 12 12 12 10 10 10 10 10 The following result were obtained. 1. The Hg contents of hen's egg of Seoul origin was 0.087 p.p.m., that of Ulsan origin was 0.077 p.p.m.. Its contents of Tae Gu, Kwang Ju origin were 0.052 p.p.m. and 0.048 p.p.m.. High contents of Hg showed in egg that produced in large cityies ana industrial area. 2. For the kind of egg, the Hg contents of Legon kind was 0.087 p.p.m and that of Native kind was 0.031 p.p.m.. Its contents of Legon kind was higher than that, of Native significantly. 3. By the organ of egg, the contents of Hg in egg yolk was 0.064 p.p.m. that showed 87 percent Hg contents of whole egg, and its value of egg white was 0.009 p.p.m.. 4. About cooking methods, the contents of Hg in parboiled egg was 0.007 p.p.m., that of fried egg was 0.015 p.p.m.. Especially the cooked eggs were significantly lower than row eggs in Hg contents.