• Korean Journal of Poultry Science
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• v.31 no.2
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• pp.101-108
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• 2004

This study was conducted to evaluate the effect of iron reinforcing agent on the performance in laying hens for seven weeks. One hundred ninety eight 30-wk-old Brown Tetran layers were assigned to 9 treatments: control containing 45 mg Fe from iron sulfate per kg diet (FE-45), FE-90 (control multiplied two times), FE-180 (control multiplied four times), YM-45 containing 45mg Fe from yeast mutant, YM-90 (YM-45 multiplied two times), YM-180 (YM-45 multiplied four times), YF-45 containing 45mg Fe from ferritin containing yeast, YF-90 (YF-45 multiplied two times), YF-180 (YF-45 multiplied four times) in the experiment. Each treatment had four replications of 6 birds each. In the average egg production, the YF-180 was highest and the FE-45 (the control) was lowest; the YM-180, YF-90, and YF-180 were significantly (P＜0.05) higher than the control. In the comparisons of egg weight and egg mass, the YF-180 was significantly higher (P＜0.05) than the FE-90 or the control. In the FCR, the YM-90 was highest and the YF-45 was lowest. There was no significant difference between the control and YM-90 although the YF-45 was significantly (P＜0.05) lower in FCR than the control. In the eggshell thickness, the YF-180 was the thickest and the FE-90 was the thinnest; the YF-45 or the YF-180 was significantly thicker (P＜0.05) than the control. In the eggshell strength, the YF-45 was the strongest and the YM-45 was the weakest; the YM-90, YF-45, and YF-180 were significantly stronger (P＜0.05) than the control. In the cholesterol level of egg yolk, the control (FE-45) was the highest and the YF-45 was the lowest; there was a significantly different (P＜0.05) between these two treatments. In conclusion, in case of adding organic iron to feed for layers, it gives improvement on performance of layers and develop chemical composition of eggs.

• Korean Journal of Poultry Science
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• v.30 no.2
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• pp.83-90
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• 2003

This study was conducted to determine the effects of stocking density on performance and physiological responses of egg-type breeder layers in cages. A total of 264 Hy-Line Brown egg-type breeder layers at the age of 32 weeks were divided into 4 groups with 3 replicates of 22 birds (20 females, 2 males) per replicate and assigned to four stocking density treatments with 22 birds per cage with different sizes (980, 735, 640 and 560 $\textrm{cm}^2$/bird). The birds were fed the same experimental diet ad libitum for 12 weeks, and laying performance, egg and eggshell qualities, fertility and hatchability were determined. At the end of the experimental period, 9 birds were selected in each treatment in order to measure the scores of plumage condition. Antibody titers to Newcastle disease and infectious bronchitis were also determined. No significant differences were observed in laying performances, eggshell strength, Haugh unit, fertility and hatchability among the treatments. In birds housed 640 $\textrm{cm}^2$ per bird, eggshell thickness were significantly lower (P<0.05) than those of the other groups from 7 to 12 weeks. There was no significant difference in antibody titers to Newcastle disease. In birds housed 980 $\textrm{cm}^2$ per bird, antibody titers to infectious bronchitis were significantly (P<0.05) higher than those of the other groups. With increase in the level of stocking density, the scores of plumage condition were also significantly decreased (P<0.01). This study demonstrated that moderate increment of stocking density did not resulted in reduction in laying-performances of egg-type breeder layers. However, it seemed that the higher stocking density might give more stress to the birds from physical stimuli and thus were harmful environment causing higher mortalities compared to the lower ones.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.2
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• pp.226-229
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• 2005

An experiment was conducted to produce eggs enriched with vitamins $D_3$, K and iron in eggs. Six hundred 97-wk-old ISA Brown force molted hens were allocated to completely randomized block arrangement of six dietary treatments: T1; control (C), T2; C+4,000 IU vitamin $D_3$+2.5 mg vitamin K+100 ppm Fe, T3; C+8,000 IU vitamin $D_3$+5.0 mg vitamin K+100 ppm Fe, T4; C+12,000 IU vitamin $D_3$+7.5 mg vitamin K+100 ppm Fe, T5; C+16,000 IU vitamin $D_3$+10.0 mg vitamin K+100 ppm Fe, T6; C+20,000 IU vitamin $D_3$+12.5 mg vitamin K+100 ppm Fe. Fe was supplemented with Fe-methionine. Each treatment consisted of five replicates of ten cages with two birds per cage. Egg production and egg weight were highest in T2 and incidence of soft and broken egg was highest in T6. Haugh unit was not different among treatments although it tended to be increased as dietary vitamins $D_3$ and K increased. Eggshell strength was not different among treatment. Concentrations of vitamin $D_3$ and K in egg yolk increased and plateaued approximately 20 days after feeding supplemented diets. The level of these vitamins peaked at 12,000 IU/kg vitamin $D_3$ and 7.5 mg/kg vitamin K supplementation and then decreased at the higher than these supplementation levels. The peak concentrations of vitamin $D_3$ and vitamin K were 4.6 times and 4.8 times greater than the control, respectively. Supplementary Fe also increased Fe content in egg yolk. It is concluded that vitamin $D_3$ and K in eggs can be effectively enriched by proper supplementation time and level of these vitamins.

• Journal of Environmental Science International
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• v.17 no.5
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• pp.537-546
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• 2008

The experiment was conducted to determine the effect of the mixed herbal medicine for the substitution of antibiotics on the performance of laying hens. Day old hyline 1,500 layer chicks were randomly assigned to 4 treatments. Control were 600 and three each treatment was 300. Eggs were collected at every weeks for measuring egg production and week 26, 27, 28 for chemical analyses. Chemical analyses were done for fatty acid profile of egg yolks, amino acid, antibiotics residue in eggs(collect eggs after supplying OTC 21ppm/bird/day to control for four day at 26, 27, 28) during the laying period($19{\sim}77wk$). On $0{\sim}4$ week, T-3 showed higher feed intake than those fed the other diets and on $5{\sim}13$ week, T-2 showed highest feed intake among treatments. After birds were moved ($14{\sim}18$ wk) CT-3 showed highest, but for overall rearing period, there was not significantly different among treatments. In conclusion the mixed herbal medicine did not tended to influence palatability to rearing birds. Egg quality(egg yolk color, haugh unit, eggshell breaking strength) showed no difference among treatments. Ratio of unsaturated fatty acid (mg/100g)/saturated fatty acid (mg/100g) was not difference among treatments, but linolenic acid and docosahexaenoic acid(DHA) of the mixed herbal medicine treatments showed higher then control. The antibiotics residue of CT, T treatments egg was not detected and control was not detected or below allowance. In conclusion the mixed herbal medicine can be possible to feed laying hen without antibiotics.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.7
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• pp.980-985
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• 2000

Influences of Japanese green tea powder (GTP) supplementation to commercial diet on laying performance and egg quality were studied by using 60 laying hens. The experimental diet with or without 0.6% GTP was given ad libitum to the birds during the period from 6 to 71 weeks of age. The birds started egg production from 21 wk of age regardless GTP feeding. Body weight, feed intake, egg weight tended to decrease with GTP supplementation, while egg production rate tended to increase. Haugh unit score was significantly increased with GTP, which accompanied with the increased albumen height. These were observed almost throughout the laying period over 50 wk. Gel proportion in thick albumen was decreased as storage time is prolonged, then higher values of the gel proportion were recorded in the eggs from GTP group. Thick albumen of the eggs from GTP-fed layers had more carbohydrate than that from control layers. All these indicate physical stability of thick albumen in the eggs from GTP group. Thiobarbituric acid content of egg yolk tended to remain lower in the eggs from GTP group during 5-10 days of storage at room temperature. Levels of egg yolk cholesterol and yolk lipid were significantly reduced by GTP feeding. There were no significant differences in eggshell weight, shell thickness and shell strength between the two groups. Thyroid gland and liver from hens slaughtered at 71 wk of age did not differ in weight irrespective of GTP feeding. The present results suggest that GTP could modify components of edible part of egg, leading to the characteristics favourable to consumers such as high durability of thick albumen and less cholesterol in yolk, without altering general performance of the layers throughout this year round experiment.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.11
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• pp.1610-1615
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• 2008

Natto is a Japanese traditional soybean product fermented by Bacillus natto. The effects of dried fermented soybean (natto) supplement on egg production and egg qualities of layer chickens was studied with regard to the effective use of various waste foods in Japan. Dried natto, prepared by heating at $60^{\circ}C$, was added to a basic diet at a level of up to 3%. Forty 166-wk-old layer chickens (Rhode Island Red) were randomly divided into 4 groups and five layer chickens were used in each group with two replicates. Layer chickens in group 1 were fed a basic diet as the control. The remaining 3 groups were fed the basic diet supplemented with dried natto at levels of 1, 2, and 3% (w/w), respectively. The result did not show improvements in egg production or feed conversion ratio of layer chickens even when 3% dried natto was added to the control diet. The egg qualities including egg weight, eggshell strength and thickness, yolk color, yolk weight, albumen height, and Haugh unit were also not improved. However, the feeding of dried natto changed the cholesterol content in the egg yolk. The supplementation of dried natto showed the tendency to decrease the yolk cholesterol after 12-wk of feeding compared to the control diet though it did not change plasma cholesterol levels in the blood. On the other hand, yolk cholesterol decreased significantly after 12-wk of feeding 3% dried natto (p<0.05).

• Animal Bioscience
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• v.34 no.11
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• pp.1802-1810
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• 2021

Objective: The purpose of this study was to evaluate the effects of supplementing herbal active ingredients (YGF251) which can promote the secretion of insulin-like growth factor-1 (IGF-1) in the diet on production performance, egg quality, blood hematology, and excreta gas emission in laying hens. Methods: A total of 288 ISA Brown (41-week-old) laying hens with an initial body weight of 1.83±0.68 kg were randomly assigned to 1 of 4 dietary treatments in a randomized block design based on body weight. Each treatment had 12 replicate cages having 6 adjacent cages per replicate (hens are kept in cages alone). The experimental period was 35 days. Dietary treatments were based on the corn-soybean meal-wheat-based basal diet and supplemented with 0.00%, 0.05%, 0.10%, or 0.15% YGF251. Results: There was a linear increased egg weight in weeks 1 to 5 (p<0.05), egg mass in week 1 (p<0.05) and weeks 1 to 5 (p<0.05), egg strength on day 7 (p<0.05), 21 (p<0.01), and 35 (p<0.01), eggshell thickness on day 21 (p<0.05) and 35 (p<0.01), haugh unit on day 21 (p<0.01) and 35 (p<0.05), serum IGF-1 concentration on day 21 (p<0.05) and 35 (p<0.01), and serum total protein concentration on day 35 (p<0.05) were observed with the supplementing YGF251 increased in the diet, while feed conversion ratio in weeks 1 to 5 (p<0.05) and excreta ammonia emission (p<0.01) decreased linearly with the dose of YGF251 increased. Conclusion: Dietary supplementation of YGF251 positively affected the production performance and egg quality of laying hens through increasing serum IGF-1 concentration in a dose-dependent manner. Moreover, YGF251 supplementation improved barn environment by reducing excreta noxious gas emission.

• Korean Journal of Agricultural Science
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• v.46 no.3
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• pp.689-703
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• 2019

The term quality or freshness of eggs in industrial production still poses concerns regarding whether washing is necessary. Therefore, the aims of this study were to examine the effects of different storage times and temperatures and to perform a comparison between washed and unwashed eggs. A total of 1000 washed and 1000 unwashed egg samples were stored at three different temperatures (5, 10, and $25^{\circ}C$) for 0 - 8 weeks and were used for the data collection. On the designated day, the eggs were processed to evaluate their internal and external quality traits, such as the Haugh unit, airspace volume, eggshell strength, pH, and microbiological profile. Significant differences (p < 0.05) were observed between the washed and unwashed eggs for each quality trait. The results indicate that storage between 5 and $10^{\circ}C$ better preserved the quality of eggs compared with the storage at $25^{\circ}C$ throughout the days of the storage. Overall, this study suggests that the storage time and temperature have a vital role in maintaining the quality of eggs which were significantly affected during storage. In addition, all the quality parameters differed between the washed and unwashed samples which is further responsible for deteriorating the quality of the eggs.

• Korean Journal of Poultry Science
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• v.48 no.4
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• pp.319-325
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• 2021

In this study, we investigated the effects of feeding diets with different levels of energy and nutrient density on the egg quality of laying hens during the pre-peak and peak periods. A total of 192 (Hy-line brown) laying hens were used in a 15-week trial. The hens were randomly allotted to one of four treatments, each with four replicates (12 hens per replication). We assessed the effects of four level of dietary energy (2,710, 2,850, 2,870 and 2,890 kcal/kg) and three levels of nutrient density (Methionine + Cysteine: 0.56%, 0.85%, 0.80% and Crude Protein: 14.5%, 19%, 18%). Differences in the energy and nutrient density contents of diets showed no significant effect (P>0.05) on the average daily gain, average daily feed intake, feed conversion ratio, egg weight, or egg production of hens during the pre-peak and peak periods. However, hens subjected to 2,890 kcal/kg during the pre-peak period were found to lay eggs with significantly thicker shells, and yolk color was found to be significant enhanced in hens fed this diet during the pre-and peak periods. In contrast, we detected no significant effects of dietary energy or nutrient density on the Haugh unit or eggshell strength. In summary, increasing the energy level of diets from 2,710 to 2,890 kcal/kg was found to have positive effects on the shell thickness and yolk color of eggs produced by laying hens.

• Journal of Animal Science and Technology
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• v.52 no.5
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• pp.389-398
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• 2010

The objective of this study was to investigate the effects of three strains of Bacillus subtilis (B. subtilis) supplemented to diets on egg production, egg quality, egg yolk cholesterol levels, the profile of cecal microflora, and tibia characteristics in laying hens. One hundred sixty 76-week-old Hy-Line Brown layers were randomly divided into 4 groups with 4 replicates per group (10 birds per replicate). Birds in the control group were fed a corn-soybean meal based diet. The remaining three treated groups were fed the control diet containing either 0.05% B. subtilis Ch3 (T1), 0.05% B. subtilis Ch3 + B. subtilis W1 (T2) or 0.05% B. subtilis commercial product (T3) for 6 weeks, respectively. There were no differences in feed intake, egg weight, egg production and egg mass among the groups. The dietary supplementation of B. subtilis improved eggshell strength and Haugh units compared to those of control (P<0.05). The activities of GOT and GPT in serum were not also affected by the dietary treatments. The population of total microbes and lactic acid bacteria in cecum were significantly increased by the dietary B. subtilis (P<0.05), but not the coliforms. The cholesterol concentration in egg yolk and serum in the treated groups were significantly decreased compared to those of control (P<0.05). Also, The levels of phospholipids in serum were significantly decreased compared to those of control (P<0.05). The supplementation of three strains of B. subtilis to diets significantly increased the contents of tibia ash compared to that of control (P<0.05). Thus, this study showed significant improvements in egg quality, such as eggshell strength and Haugh unit, by dietary B. subtilis strains. The B. subtilis strains added to the diets modulated the profiles of cecal microflora, reflecting beneficial effects in laying hens.