• Korean Journal of Poultry Science
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• v.38 no.3
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• pp.165-171
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• 2011

This study was conducted to investigate the effects of dietary supplementation of copper-soy proteinate (Cu-SP) on the performance of laying hens. A total of 1,000 Hy-Line Brown laying hens of 32 wks old were assigned to one of the following 5 dietary treatments: Control, Cu-SP 50, 100, 150, 200 (50, 100, 150, 200 ppm Cu supplementation as Cu-soy proteinate). Each treatment was replicated 4 times with fifty birds per replication, housed in 2 birds cages. Fifty birds units were arranged according to randomized block design. Feeding trial lasted 5 wks under 16L : 8D lighting regimen. There were no significant differences among treatments in hen-day and hen-house egg production, egg weight, broken & soft egg production. Feed intake and feed conversion rate (FCR) were significantly (P<0.01) lower in Cu-SP treated groups than Control. Eggshell thickness was significantly (P<0.01) higher in Control than Cu-SP 100, 150 and 200. Egg yolk color index was significantly (P<0.01) higher in Cu-SP 200 than other treatments. Egg shell color index was significantly (P<0.05) higher in Cu-SP 150 and Cu-SP 200 than Cu-SP 100. Concentration of copper, iron and zinc of the egg yolk were not significantly influenced by treatment. There were no significant differences in the level of leukocytes and erythrocytes in the chicken blood. The result of this experiment showed that dietary supplementation of Cu-SP at the level of 50ppm of Cu can reduce feed intake and FCR.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.2
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• pp.294-300
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• 2010

This experiment was conducted to investigate the effects of Opuntia humifusa (OPH) extracts and methyl sulfonyl methane (MSM) supplementations on the laying productivity, egg quality and sensory characteristics of eggs in hens. Six hundred forty, 35-wk-old Lohmann brown, laying hens were randomly divided into four groups: 1) water (control), 0.12% OPH extract, 0.1% MSM, and 0.12% OPH extract+0.1% MSM. They were mixed into the feed and given for 5 weeks. Egg production rates, egg weight, feed demand ratio were not significantly different among the groups. However, OPH or MSM decreased broken egg rates by increasing thickness and firmness of egg shell but they did not show the additive effects. In addition, OPH or MSM enhanced Haugh unit, an indicator of freshness of egg, and viscosity of egg white and egg yolk. OPH or MSM maintained the freshness of eggs better the control during their storage for 10 day at $4^{\circ}C$. However, OPH+MSM did not show additive effects in their freshness. Sensory test revealed that OPH or MSM decreased fishy taste and greasy flavor and they improved texture. Overall OPH or MSM enhanced the preference of eggs. In conclusion, the supplementation of either OPH or MSM enhances egg freshness and egg quality in laying hens but they should not be supplemented together due to no additive effects.

• Journal of agriculture & life science
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• v.53 no.2
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• pp.121-129
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• 2019

This study carried out to determine control factors for the improvement of productivity of laying hens suffering heat stress during hot weather. A total of 48,451 ISA Brown layers were housed in a farm located in Gyeongsangnam-do, Republic of Korea. Five thermo-hydrometer loggers were installed inside the house to collect data of dry-bulb temperature and relative humidity. The experiment continued for 81 days when the summer season begins from 19th June to 7th September, 2018. This study analyzed the correlations among layers' production index and daily average, highest, and lowest temperature; daily average, highest, and lowest relative humidity; and daily average, minimum, and maximum THI. The result indicated that feed consumption, hen-day egg production, egg weight, and FCR decreased as the daily average, highest and lowest dry-bulb temperature and THI rise (p<0.01). On the other hand, water intake increased as the daily average, highest and lowest dry-bulb temperature and THI rise (p<0.001). The relative humidity was not considered to have direct correlations to the layers' production index (p>0.05). However, it was noticeable that the mortality did not have significant relations with daily average and highest temperature; THI; or daily average, highest and lowest relative humidity while it was relevant to the daily lowest temperature and THI (p<0.05). In conclusion, to enhance the productivity of laying hens in a hot climate, it is recommended that daily average, highest, and lowest dry-bulb temperature and THI are maintained as low as possible. Especially, the daily lowest temperature is needed to lower to 20℃, which is the lowest critical temperature for layers.

• Korean Journal of Poultry Science
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• v.10 no.2
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• pp.91-96
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• 1983

Present study was carried out to find out an optimum interval for artificial insemination in aged and poor laying hens, Brown colored, hundred and twenty commercial laying hens at about 530 days old and 20 S. C. W. Leghorn males at 580 days old were adopted Egg production rate during the experiment was 61.6% and number of eggs examined was 2,283. The intervals for the insemination were 2, 4 and 6 days for experimental groups T-1, T-2 and T-3, respectively. Eggs were collected on every 6th day and examined for fertility by candling after 5 days of incubation. Average fertility rates for T-1, T-2 and T-3 groups appeared 87.5, 81.1, and 65.1%, respectively. The fertility of T-3 group was significantly lower than those of T-1 and T-2 groups(P＜0.05). The highest fertility rate was obtained on the second day after the insemination for all groups, i. e. 90.7, 84.0 and 71.7% for T-1, T-2 and T-3, respectively. Thereafter, a tendency of gradual decline in fertility was observed. This study suggests that the optimum interval for artificial insemination in aged hens is 2 days. The fertility tended to be improved by repeated injection. For the 2-day interval group, the highest rate (98.2%) was obtained on the 6th insemination.

• Journal of the Korea Organic Resources Recycling Association
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• v.14 no.4
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• pp.121-131
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• 2006

This study was designed to determinate the effects of dried leftover food and green tea by-product on laying hens performance and egg quality in hens. A total of 210 "Tetran Brown" layers 50-weeks of age were assigned to 7 treatments in a completely randomized design. Each treatment had five replicates per treatment with six layers per replication. Seven dietary treatments were a control diet (formula diet) and dried leftover food (DLF) mixed in 10, 20, 30 and 40% to the control diet substituting the corn grain and soybean meal, control diet containing 1.0% GTB without DLF supplementation and control diet containing 30% DLF plus 1.0% GTB supplementation. The trial period was for 8 weeks. The egg production rate of layers was significantly increased in 10, 20 and 40% DLF treatments compared to that of the control treatment (P<0.05). The egg weight was significantly decreased in 10% DLF treatment compared to that of the control (P<0.05). The feed intake of layers was higher in 20% DLF and 30% DLF plus 1.0% GTB treatment than that of the control (P<0.05). The feed conversion ratio significantly decreased in 10% DLF and control plus 1.0% GTB treatments compared to that of the control (P<0.05). The egg yolk cholesterol not varied among the DLF and control treatments (P>0.05). However, the linolenic acid content of egg yolk was significantly increased in DLF and control treatments both containing 1.0% GTB supplementation.

• Journal of Animal Science and Technology
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• v.44 no.1
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• pp.55-60
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• 2002

Two experiments were conducted to investigate the effect of dietary supplementation of plant phytase (Phytazyme$^{(R)}$) in corn-soybean meal based diets on utilization of phytase-bound phosphorus in laying hens and evaluate nitrogen(N) digestibility and phosphorus(P) availability in breeders. In the experiment one, three levels of the Phytazyme$^{(R)}$(0.05, 0.1, and 0.2% of diet) were added to diets containing a half of control TCP level(0.96%) for 4 wks. Feed consumption, egg production rate, egg weight and eggshell quality were recorded weekly. At the end of experiment, 8 birds per treatment were sacrificed, liver weight were weighed and right tibiae were removed for determination of P content. The second experiment was conducted to evaluate the P availability and nitrogen digestibility in breeders fed same diets for 2 wks. Feed and excreta were collected to determine the P and N contents for the last three days of experiment two. Addition of Phytazyme$^{(R)}$ resulted in no effects on feed intake, egg product rate, egg weight and egg shell quality. P excretion decreased and its availability enhanced as phytase supplementation increased in diets. Dietary supplementation of Phytazyme$^{(R)}$ above 0.1% level in corn-soybean meal based diets did not have an adverse effect on production and decreased level of phosphorus in excreta.

• Korean Journal of Poultry Science
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• v.30 no.4
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• pp.281-287
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• 2003

This experiment was carried out to study the effect of dietary Monascus culture on the cholesterol contents of egg yolk, muscle and serum of layers with 180 Isa-Brown laying hens for 10 weeks. Control group(C) was fed the commercial laying hen diet and 2.67(T1), 5.33(T2) and 8.00(T3)% of Monascus culture which contained 0.6% monacolin-k added to control diet so as to supply the monacolin-k 20(T1), 40(T2) and 60(T3) mg respectively, per hen-day with 125g diet. Hen-day egg production and average egg weight were not affected by the dietary Monascus culture, but feed intake and feed conversion per kg egg were significantly decreased(P<0.05) as the dietary Monascus culture increased. Cholesterol contents of egg yolk measured 4~5 weeks after feeding the Monascus culture and those of thigh meat measured at the end of experiment were significantly decreased(P<0.05) as the dietary Monascus culture increased. Average cholesterol contents of serum showed a trend to decrease as the dietary Monascus culture increased without significant difference.

• Korean Journal of Poultry Science
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• v.44 no.4
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• pp.267-274
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• 2017

This study was conducted to investigate the effect of feeding with dietary silicate based complex mineral (SCM) on the performance of laying hens. SCM at five levels (0%, 0.2%, 0.4%, 0.6% and 0.8%) was added to commercial diets, and fed to four hundred fifty Hy-Line Brown from fifty four to sixty five weeks of age. Egg production increased as the addition of dietary SCM to basal diets increased up to 0.6% (P<0.05). Furthermore, Feed intake increased in a manner similar to that of egg production (P<0.05). However, there was no difference in feed efficiency among the treatments. Eggshell thickness and breaking strength were significantly higher for the chickens fed with SCM than control from sixty weeks old to the end of experiment (P<0.05). Similarly, albumen height and Haugh unit were significantly higher for the chickens fed with SCM compared to those of control group (P<0.05). AST of birds fed SCM showed significantly higher than control (P<0.05). However, blood neutral fat level tended to increase in SCM treatments. Moreover, bone mineral density increased with SCM addition up to 0.4% (P<0.05). IL-2 (Interleukin-2) and IL-6 (Interleukin-6) levels appeared to be improved in the chickens fed with SCM addition diets, although not statistically different from all treatments. The results of this study indicated that the optimum SCM for improving the performance, egg quality and immunological competence of laying hens from 54 to 65 weeks of age was 0.6%.

• Korean Journal of Poultry Science
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• v.33 no.4
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• pp.303-308
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• 2006

This study was conducted to investigate the effects of mud flat bacteria origin pretense supplementation on e99 qualify, nutrient digestibility and total protein concentration of serum in laying hens. A total of two hundred fifty two laying hens were randomly allocated into three treatments with seven replications for eight weeks. Dietary treatments included 1) CON (basal diet), 2) PRO1 (basal diet + 0.05% pretense) and 3) PRO2 (basal diet + 0.1% pretense). During the entire experimental peripd, hen-day egg production was not affected by treatments (P>0.05). Difference of yolk height was increased in PRO1 treatment compared with CON treatment (P<0.05). Difference of egg weight was increased in PRO2 treatment compared with CON and PRO1 treatments (P<0.05). Shell quality, yolk color unit, haugh unit and egg yolk index were not affected by treatments (P>0.05). DM digestibility was improved in CON and PRO2 treatments compared with PRO1 treatment (P<0.05). N digestibility was improved in PRO2 treatment compared with CON treatment (P<0.05). Total protein concentration in serum were not affected by treatments (P>0.05). In conclusion, mud flat bacteria origin pretense was effective for improving egg weight, yolk height and nutrient digestibility in laying hens.

• Korean Journal of Poultry Science
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• v.32 no.1
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• pp.9-14
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• 2005

This study was conducted to investigate the effects of Bacillus subtilis on the egg qualify, blood characteristics and fecal $NH_3-N$ in laying hens. A total of two hundred fifty two laying hens were randomly allocated into three treatments with seven replications for six weeks. Dietary treatments included 1) CON (control; basal diet), 2) BS0.2(control + $0.2\%$ Bacillus subtilis) and 3) BS0.4 (control +$0.4\%$ Bacillus subtilis). For overall Period, hen-day egg production tended to increase by the Bacillus subtilis $0.4\%$ in the diets, but was no significant difference. Egg weight, egg shell breaking strength, egg shell thickness, Haugh Unit, yolk color unit and egg yolk index were not affected by treatments. Difference of egg weight and egg shell breaking strength in the BS0.2 treatment tended to increase without significant difference. Difference of egg yolk index in laying hens fed Bacillus subtilis was increased (P<0.05). The concentrations of red blood cell (RBC) and white blood cell (WBC) were not significant difference. $NH_3-N$ concentration in feces with BS0.4 treatment was significantly (P<0.05) lower than control. In conclusion, dietary Bacillus subtilis could decrease fecal $NH_3-N$.