• 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.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.9
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• pp.1318-1323
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• 2008

Corn distiller's dried grains with solubles (DDGS) is a completely new feed ingredient in the Korean feed market. There is an ever increasing need for the Korean feed industry to import and make the best of it as a high protein and high energy feed ingredient. A layer feeding trial was conducted for 10 weeks to investigate the effects of addition of light-colored DDGS to layer diets on laying performance, egg qualities and yolk fatty acid composition. Also, the economics of using DDGS in the Korean situation was analyzed. Nine hundred Hy-line Brown layers, 24 weeks of age, were employed in a feeding trial consisting of four dietary treatments (0, 10, 15, and 20% DDGS), and five replicates per treatment. All experimental diets were prepared as iso-protein (17%) and iso-calorie (TMEn 2,780 kcal/kg). The use of DDGS up to 20% in layer diets did not exert any influence on feed intake, laying rate, total egg mass, mean egg weight and feed conversion ratio (p>0.05). The color and breaking strength of eggshell, as well as the albumin height and Haugh unit were not affected by the addition of DDGS up to 20% in the diet. The yolk color was significantly increased by DDGS supplementation (p<0.05). As the DDGS level increased, the oleic acid content decreased, and the linoleic acid increased (p<0.05) in egg yolk. The degree of saturation of yolk fatty acids was not affected by DDGS supplementation. The inclusion of light-colored DDGS up to 20% in layer diets resulted in a decrease of feed cost per kg without any undesirable effect on laying performance. In conclusion, the light-colored DDGS (L* 56.65) could be used up to 20% in layer diets without any harmful effect on laying performance, and possibly provide economic benefits to the Korean poultry industry.

• Asian-Australasian Journal of Animal Sciences
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• v.33 no.4
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• pp.588-596
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• 2020

Objective: The objective of this study was to investigate the effects of low doses of organic trace minerals (iron, copper, manganese, and zinc) on productive performance, egg quality, yolk and tissue mineral retention, and fecal mineral excretion of laying hens during the late laying period. Methods: A total of 405 healthy hens (HY-Line White, 50-week-old) were randomly divided into 3 treatments, with 9 replicates per treatment and 15 birds per replicate. The dietary treatments included feeding a basal diet + inorganic trace minerals at commercial levels (CON), a basal diet + inorganic trace minerals at 1/3 commercial levels (ITM), and a basal diet + proteinated trace minerals at 1/3 commercial levels (TRT). The trial lasted for 56 days. Results: Compared to CON, ITM decreased (p<0.05) egg production, daily egg mass, albumen height, eggshell strength, yolk Fe concentration, serum alkaline phosphatase activity and total protein, and increased (p<0.05) egg loss and feed to egg ratio. Whereas with productive performance, egg quality, yolk mineral retention, and serum indices there were no differences (p>0.05) between CON and TRT. The concentrations of Fe and Mn in the tissue and tibia were changed notably in ITM relative to CON and TRT. Both ITM and TRT reduced (p<0.05) fecal mineral excretion compared to CON. Conclusion: These results indicate that dietary supplementation of low-dose organic trace minerals reduced fecal mineral excretion without negatively impacting hen performance and egg quality.

• Korean Journal of Organic Agriculture
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• v.22 no.4
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• pp.815-823
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• 2014

Green tea has been known to show beneficial effects on alleviating stress. The present study was conducted to determine the effects of dietary green tea on quality of eggs, during storage, laid by laying hens treated with corticosterone in order to mimic the current practice of the egg market. Hens were fed for 2 weeks one of three diets containing green tea at 0.0, 0.4 or 1.0%. Each dietary group was divided into two subgroups receiving corticosterone at 0 or 30 mg/kg for 1 week. Eggs, laid at 5-7 days following the initiation of corticosterone treatment, were stored at $10^{\circ}C$ for 1 or 5 weeks and then analyzed for egg quality. After 1 week of storage, egg weight was significantly increased by green tea (p<0.025) but decreased by corticosterone (p<0.0001), but no interaction was observed between both. Corticosterone decreased shell color (p<0.0001) but green tea significantly decreased shell strength (p<0.006). Yolk color, albumen height and Haugh unit were not affected by both treatments. After 5 weeks of storage, corticosterone resulted in reduced egg weight (p<0.01) and eggshell color (p<0.001) and increased shell strength, which were not attenuated by green tea. Taken together, the results of the current study show that dietary corticosterone reduces egg quality during storage, which are attenuated in part by dietary green tea.

• Journal of Animal Science and Technology
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• v.64 no.4
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• pp.717-726
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• 2022

The study evaluated different molt-inducing methods to achieve the main goal of molting in commercial layers during molting and post-molting periods. A total of 400 60-week-old Lohmann Brown layers were randomly divided into five groups (eight replicates of 10 birds for each group). Laying hens in the fasting control group received no diet from day 1 to day 10. The second group received a molt-inducing diet recommended by the breeding company. The third group received a wheat bran-based diet. The fourth group received a commercial layer diet with 8,000 ppm zinc (as zinc oxide, ZnO). The fifth group received an induced molting diet given to the second group with 8,000 ppm zinc, respectively. Egg production in the fasting control group and groups fed a diet with ZnO were significantly lower (p < 0.001) than those in groups fed the molt-inducing and wheat bran-based diets without ZnO during molting. Egg laying in the fasting control group was rapidly reduced and stopped on the 5.9th day of molting. In both groups having molt treatment with ZnO, egg production was similarly reduced and ceased on the 6.9th day and 7.0th day of molting, respectively, none of them differed significantly from the control. Layers fed molt-inducing diet or wheat bran-based diet did not reach the cessation of laying even on the 28th d of molting period. Relative weights of the ovary and growing oocytes of layers subjected to fasting or fed diets with ZnO were significantly lower than those of other groups. During the first two weeks of post molting, layers fed molt-inducing diet with ZnO showed higher egg production than the other two groups (p < 0.01). The eggshell strength in the group fed the commercial diet with ZnO was significantly higher than those fed the molt-inducing diet or wheat bran-based diets at 6 weeks of post molting (p < 0.05). These results suggest that the non-feed withdrawal molting using ZnO is more effective in inducing molting and increasing post-molt egg production and egg quality than other methods using a molt-inducing diet alone or wheat bran-based diet without ZnO.

• 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.

• Korean Journal of Poultry Science
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• v.35 no.2
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• pp.171-176
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• 2008

Animal welfare advocates, claim that the induced molting by fasting be avoided. This study was conducted to evaluate the effect of molting induced by various feeding methods on productivity and egg quality in laying hens. We used 400 flocks of 60-week-old leghorn laying hens in four treatments(five replicates of 20 hens each): fasting method (C), feeding single corn grain diet (T1), feeding single wheat bran diet (T2) and feeding single alfalfa meal diet (T3). As the result of the experiment, egg production and daily egg mass significantly decreased only in T1 compared with the control during the $1{\sim}4th$ week after the secondary egg laying (P<0.05). Although the amount of feed intake was significantly less in T1 group during the $1{\sim}4th$ week compared to the control, no significant difference was detected during the total period (P>0.05). In addition, no significant difference of feed conversion was observed between treatment groups. In terms of egg quality, the egg shell thickness was significantly improved in T1 group than the control group by feeding only corn at the 10th and 14th week after the secondary egg laying (P<0.05), but the significant decrease was observed at the corn (T1) and wheat bran (T2) fed treatment groups than the control group at the 26th week of the experiment (P<0.05). The eggshell strength and haugh unit did not show any difference by the molting methods. Egg yolk color was significantly decreased in T1 and T2 group than the control group at the 6th week (P<0.05). However, T1 and T2 group resulted to show significantly high egg yolk color at the 18th week of the experiment (P<0.05). As the result of the experiment, no large difference was observed in the productivity by the feeding molting method and by the fasting induced molting method. In addition, the single diet fed feeding induced molting method by using alfalfa revealed to show more satisfactory trend than the corn or wheat bran single diet fed feeding induced molting methods even if no statistically significant difference was found in terms of egg productivity.

• Korean Journal of Poultry Science
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• v.49 no.4
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• pp.181-188
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• 2022

This study was conducted to investigate the effects of the metabolic energy levels of Korean native chicken breeder diets on laying performance, egg quality, fertility and hatchability. On the basis of dietary metabolic energy values (2,800, 2,700, and 2,650 kcal/kg), 168 twenty-week-old 'Woorimatdag' breeders (maternal line) were divided into three treatment groups (four replications per treatment with each replicate containing 14 birds) and reared until 32 weeks of age. We found that the body weight of hens increased with age, although there were no significant differences among treatments with respect to body weight or egg weight. Egg production ratio at 20-24 and 24-28 weeks of age tended to be low in birds fed the 2,700 and 2,650 kcal/kg diets, although the differences among treatments were none significant. Feed intakes was significantly decreased as the metabolic energy level reduced (P<0.05). There were no significant differences among treatments with respect to feed conversion ratio or the strength and thickness of eggshell. Similarly, we detected no significant differences among the three metabolic energy levels with regards to fertility, hatchability, or chick weight. In conclusion, our findings indicate that during the initial phase of laying, the metabolic energy level of 'Woorimatdag' breeder diets could be lowered to 2,700 kcal/kg without significantly influencing the laying performance of breeders or egg quality, fertility and hatchability, and chick weight.

• Korean Journal of Poultry Science
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• v.50 no.4
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• pp.311-323
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• 2023

This study aimed to investigate the impact of Bacillus subtilis-based probiotics and oregano essential oil on the production performance, egg quality, and intestinal morphology of late-phase laying hens (69-weeks). A total of 150 laying hens of 69-week-old were randomly allotted into 6 treatment groups with 5 replicates of 5 birds in each replicate. Laying hens were divided into high (H) and average (A) egg production groups prior to the trial. The hens in each group were supplemented with Bacillus subtilis, or oregano essential oil: CON, a basal diet; BS, basal diet plus 3 × 10⁸ CFU/kg feed Bacillus subtilis; OEO, basal diet plus 0.3 g/kg feed oregano essential oil. Egg performance, blood characteristics, egg quality, and intestinal morphology of the late-phase laying hens were evaluated. Both BS and OEO significantly enhanced (P<0.05) egg production compared to CON in high egg production. The blood characteristics indicated no significant differences based on the egg production and the supplementation of BS and OEO in the late-phase laying hens. The eggshell strength was significantly improved (P<0.05) in both OEO compared to both CON. A significantly decreased (P<0.05) the villus height to crypt depth ratio (VH/CD) in the ileum compared to H, and in the treatment groups supplemented with BS and OEO, VH/CD showed a significant increase (P<0.05) compared to both CON. These results suggest that the supplementation of Bacillus subtilis and oregano essential oil in the diet of late-phase laying hens could serve as a potential strategy to enhance egg production, egg quality, and gut health.

• Korean Journal of Poultry Science
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• v.29 no.3
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• pp.213-223
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• 2002

This study was conducted to investigate the influence of feeding various Lactobacillus on production performance, nutrients digestibility, intestinal microflora, and fecal $NH_{3}$ gas emission in laying hens. Three hundred and sixty ISA Brown layers, 21 weeks of age, were randomly allotted to nine treatments, with low replicates per treatment. Nine treatments consisted of Control(no Lactobacillus), Lactobacillus crispatus avibrol(LCB: KFCC-11195), Lactobaciilus reuteri avibro2(LRB: KFCC-11196), Lactobacillus crispatus avihenl(LCH: KFCC-11197), Lactobacillus vaginalis avihen2(LVH: KFCC-11198). Each Lactobacillus was added at two levels ($10^{4}$and $10^{7}$ cfu/g diets). Egg production, and egg weight were measured daily. A metabolism trial was conducted following the 12-week feeding trial, during which egg qualities, intestinal microflora and fecal $NH_{3}$ gas emission were examined. Egg production and daily egg mass improved significantly by the addition of various Lactobacillus(P<0.05), of which effect was more notable during the latter part of the feeding trial. But, no significant differences were found among Lactobacillus strains and between two levels of supplementation. Egg weight and feed intake showed no difference among all treatments. Feed conversion ratio of birds fed lactobacillus was significantly improved compared to that of the Control(P<0.05), but not different among lactobacillus treatments. Digestibility of crude protein, ether extract and crude ash improved significantly in lactobacillus treatments(P<0.05). However, there were not statistically different by adding levels and strains. Total counts of Lactobacillus spp. in ileum of layers fed Lactobacillus were significantly higher than that of the control, but no consistent trend was found in cecum. There were no significant differences in intestinal yeast and anaerobes counts among all treatments. The Lactobaciilus supplementation did not exert my effect on the eggshell quality and Haugh unit. Fecal $NH_{3}$ gas emission decreased significantly in Lactobacillus treatments, and showed no difference between the two supplementation levels. From the result of this study, it could be concluded that dietary supplementation of Lactobacillus, regardless of their species, Improves the laying performance and decreases the fecal ammonia gas emission. The proper level of supplementation appears to be $10^{4}$ cfu/g of diet.