• Korean Journal of Poultry Science
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• v.33 no.3
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• pp.195-202
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• 2006

Two experiments were conducted to investigate the effect of dietary selenium sources on performance and selenium retention in broiler chickens and laying hens. In experiment 1, the effects of dietary selenium sources and levels on the weight gain, feed intake, feed conversion, and selenium retention of meat in broiler chickens were investigated. for each growth phase, the basal diet was supplemented with 0 (control), 0.12 and 0.24 ppm Se from sodium selenite (SS) and 0.12, 0.24 and 0.60 ppm Se from selenium yeast(SY). Weight gain was significantly increased(P<0.05) in supplemental 0.24 and 0.60 ppm SY compared to the 0.24 ppm SS by diet during day 1 to 35, but feed intake and feed conversion were not affected by the source or the level of Se. Selenium concentrations of breast and leg muscle were significantly increased(P<0.05) in supplemental SS and SY compared to the control, and linearly increased(P<0.05) as dietary. Se level increased by SY, but there was no difference in supplemental 0.12 ppm SS compared to 0.24 ppm SS. In experiment 2, 12-week-experiment using Hy-Line laying hens(31 wk of age) was conducted to compare the effects of selenium sources and levels on egg production, egg weight, daily egg mass, feed intake, feed conversion, egg quality, and selenium retention of egg in laying hens. A corn-soybean meal basal diet was supplemented with 0 (control), 0.06 and 0.12 ppm Se from sodium selenite (SS) and 0.06, 0.12 and 0.30 ppm Se from selenium yeast(SY). Feed conversion was significantly improved(P<0.05) in supplemental 0.06 ppm SS compared to the control, but egg production, egg weight, daily egg mass, and feed intake were not affected by source and level of Se. Haugh unit was not affected by source or level of Se. Yolk color was significantly(P<0.05) higher in supplemental 0.3 ppm SY compared to the control and other supplement in week 12. Eggshell breaking strength was significantly(P<0.05) higher in supplemental 0.06 ppm SY(P<0.05). Thickness of eggshell was not affected by source or level of Se. Se concentrations of egg was significantly improved(P<0.05) in supplemental SS and SY compared to the control, and was significantly increased(P<0.05) as dietary Se level increased by SS and SY, especially SY more effective compared to the SS.

• 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.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2005.11a
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• pp.31-43
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• 2005

Isoflavones are naturally occurring plant chemicals belonging to the 'phytoestrogen' class. The isoflavones are strikingly similar in chemical structure to natural estrogens. The phenolic ring is a key structural element of most compounds that bind to estrogen receptors. Dietary components that recently have received attention for their action as phytoestrogens are soy isoflavones. Soy products are the most significant dietary sources of isoflavones. Recently It is concerned clinical nutrition of isoflavone that is driven by reason of alternative sources of exogenous estrogen are constantly being needed. Estrogen therapy after the menopause offers protection from cardiovascular disease, reduces the extent of osteoporosis and relieves menopausal symptoms. Exogenous estrogen treatment is a fear of possible increased risk of developing breast cancer and because of side effects. Daily intake of soybean or soy food can affirmative effect to disease occurrence, that is based on mechanical investigation, experimental results of animals and human. Research into isoflavone is going on various field to relieve hormone - dependent disease such as cancer, menopausal symptom, cardiovascular disease and osteoporosis. Isoflavone is plenty in soybean meal, soy by-product, but only limited information is available on isoflavone efficacy into animal husbandry. Thus we conducted three experiments to investigate the effects of dietary isoflavone on productivities, antioxidative responses and bone metabolism in poultry. Dietary supplementation of isoflavone resulted in preventing the lipid oxidation of plasma and egg yolk. Dietary isoflavone improved bone development in egg-type growing chicks and broilers in terms of tibial strength. It was suggested that the proper use of feed additives such as isoflavone might provide means of improving antioxidative effect, skeletal strength, egg and eggshell quality.

• Korean Journal of Poultry Science
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• v.37 no.2
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• pp.117-123
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• 2010

This work was carried out to investigate the effect of the induced molting with low-protein and energy diet on the postmolt performance of layers. Eighty White Leghorn layers (61-old-wk) with over 80% egg production were used for 12 weeks in this work. Treatments were non-molt control (CO), fasting treatment for 10 days (FW), molt treatment with low-protein and low-energy molting diet for 3 weeks (LO), and molt treatment with standard molting diet for 3 weeks (ST) as 4 treatments (2 replications/treatment and 10 birds/replication). Body weight (BW) loss was 26.5% of initial BW at 2 week in FW treatment, and was 17.3% and 14.2% in both LO and ST treatments (P<0.05). Layers in molting treatments were fed with commercial layer diet after completion of molting since BW of layers was recovered for 7 weeks. Heart weight ratio was shown as 0.47, 0.43, 0.46 and 0.46% at CO, FW, LO and ST treatments, respectively, and liver weight ration of body weight was shown as 2.56, 1.30, 1.47 and 1.52%, respectively. Thus, those of molting treatments decreased compared to non-molt control (P<0.05). Oviduct weight ratio were shown as 3.95, 1.17, 1.54 and 1.67%, respectively, and similar with the results of liver (P<0.05). Feed intake decreased at LO and ST treatments during molting period and increased from the 5th week compared to control. Egg production decreased at 1 week in molt treatment and stopped at 2 week in FW, 3 week in LO, and 4 week in ST treatments. The birds started to lay egg at 4 week in FW and at 5 week in LO and ST treatments. Egg production was recovered until 50% at 6 week in FW and was recovered as 66.1 and 71.6% at 8 week in LO and ST treatment, respectively. Egg weights were similar among all treatments. Eggshell thicknesses were 0.41, 0.47, 0.46 and 0.46 mm at CO, FW, LO and ST treatment, respectively, but the higher in molt treatments than control (P<0.05). Eggshell breaking strength was 3.83 and 3.81 kg/$cm^2$ in FW and LO treatment, respectively, and high compared to control. However, eggshell breaking strengths were 3.54 and 3.78 kg/$cm^2$ and were not statistically different. Haugh units were 75.6, 81.1, 80.6 and 79.9 in 4 treatments and high in molt treatment. Finally, dietary low-protein and low-energy may induce molt as few effect on performance of layers.

• 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.23 no.2
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• pp.85-98
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• 1996

Results of experiments on the nutrient requirements and feeding system of broiler breeder hens were reviewed, and daily requirements of energy and protein were calculated using the prediction equations reported by Scott(1977) and NRC(1981). The experimental reports on daily ME needs of broiler breeder hens were ranged from 400 to 450 kcal, however, the ME needs of caged hens were 92~93% to those of floor-housed hens due to the difference of ME need for activity. The ME needs of broiler breeders decreased with increasing environmental temperature corresponding to a drop of 25 kcal per day for each 5˚C rise. About 80~90% of the daily ME needs were used for body rnaintenance and activity of hens. Experimental results on daily protein needs of broiler breeder hens were ranged from 18 to 22 g, however, calculated protein needs decreased as the BW gain and eggmass output decreased after peak production, and about 60~65% of the daily protein needs were used for egg production. In the current practice, broiler breeder hens are restricted in feed, and consume their daily allowance in the first 2 to 6 h after dawn. The results suggest that eggshell quality can be significantly improved in hens fed during the afternoon when shell calcification is initiated, with no adverse effect on laying rate and fertility of eggs.

• Korean Journal of Poultry Science
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• v.43 no.1
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• pp.15-20
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• 2016

This research was carried out to determine the effect of Cudrania tricuspidata fruit (CTF) on the performance of laying hens, egg quality, yolk fatty acid composition, Immunoglobulin G (IgG) and blood composition. A total 288 Brown Nick laying hens of 48 weeks old replaced into 4 groups with 4 replicates of 18 birds in each. Treatments were added with 0, 0.25, 0.5, 1.0% CTF containing dried seed and pulp. Metabolizable energy (ME) and crude protein (CP) were 2,800 kcal/kg and 16.0% in basal diets, respectively. Egg production and daily eggmass were significantly increased in 1.0% CTF addition treatment compared to those of other treatments (P<0.05). Egg weight and feed intake were not different among treatments. Feed conversion ratio showed the lower result in 1.0% CTF treatment than other treatments (P<0.05). Eggshell color was not influenced by the addition of CTF. Albumin height, Haugh unit and eggshell breaking strength was not statistically different, but seemed to be higher as dietary CTF addition increased. Yolk color was increased as dietary CTF increased and was the highest in 1.0% CTF group (P<0.05). Fatty acids were not shown the consistency in yolk. Blood cholesterol and triglyceride (TG) of birds fed CTF were significantly low compared to those of control. IgG was also statistically higher in CTF treatments than control (P<0.05). As the results of this experiment, the addition of 1% CTF would be the most effective on performance and egg quality, whereas the 0.25% CTF addition in basal diets seemed to be optimum to improve the blood cholesterol, TG,high density lipoprotein cholesterol (HDL-CHOL), IgG in laying hens.

• Korean Journal of Poultry Science
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• v.35 no.4
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• pp.391-398
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• 2009

The objective of the present study was to compare of the effects of four molting methods on performance of laying hens. In total, 120 White Leghorn layers (62 weeks of age) were used. The four molting methods consisted of 10 days of feeding and the first 3 days of water withdrawal (FW1, 2) followed by ad libitum access to a layer diet 1 and 2 from day 11; 28 days of restricted feeding (NFW1); 28 days without withdrawing their feed (NFW2). Egg production of postmolt decreased until $3{\sim}4$ days at FW1 and FW2 treatments and until $16{\sim}18$ days at NFW1 and NFW2. 50% recovery of egg production were 7, 6, 7 and 5 week at FW1, FW2, NFW1, and NFW2 treatments, respectively. At day 14 of postmolt, the weight of livers, hearts, and oviducts decreased at molting treatments (P<0.05). Egg quality was improved on egg weight, eggshell thickness, eggshell break strength, and Haugh unit except egg yolk color (P<0.05).

• Korean Journal of Poultry Science
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• v.33 no.4
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• pp.255-262
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• 2006

Two experiments were conducted to investigate the effect of dietary organic selenium levels on performance and selenium retention in broiler chickens and laying hens. In experiment 1, the effects of dietary organic selenium levels on the weight gain, feed intake, feed conversion, and selenium retention of meat and liver in broiler chickens were investigated. For each growth phase, the basal diet was supplemented with 0 (control), 0.60, 1.20, 1.80 and 2.40 ppm Se from selenium yeast(SY). Weight gain, feed intake, and feed conversion were not affected by the selenium addition in diets. Breast muscle Se levels were linearly increased (P<0.05) as dietary Se level increased by SY. Selenium concentration of liver tissue was increased (P<0.05) in supplemental SY compared to the control, and was increased (P<0.05) in supplemental 1.20, 1.80 and 2.40 ppm SY compared to the 0.60 ppm SY. In Experiment 2, 12-week-experiment using Hy-Line laying hens (68 wk of age) was conducted to examine the effects of dietary organic selenium on egg Production, egg weight, daily egg mass, feed intake, feed conversion, egg quality, and selenium concentration of eggs. A corn-soybean meal basal diet was supplemented with 0 (control), 0.30, 0.60, 0.90 and 1.20 ppm Se from selenium yeast (SY). Egg Production was significantly improved(P<0.05) in supplemental 0.30 and 0.90 ppm SY compared to the control and 0.60 ppm SY during week 1 to 12, but daily egg mass, feed intake, and feed conversion showed no difference in supplemental SY and control. Haugh unit, yolk color and eggshell breaking strength showed no difference in supplemental SY and control. Eggshell thickess was significantly (P<0.05) higher in supplemental 0.60 and 1.20 ppm SY compared to the 0.90 ppm SY in week 9. Egg Se levels were linearly increased (P<0.05) as dietary Se level increased by SY.

• 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.