• 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.

• Journal of Animal Science and Technology
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• v.63 no.6
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• pp.1275-1285
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• 2021

The objective of the present experiment was to investigate the effect of dietary palm kernel meal (PKM) and β-xylanase supplementation on productive performance, egg quality, fatty liver incidence, and excreta characteristics in laying hens. A total of 320 Hy-Line Brown laying hens (33 weeks of age) were allotted to 1 of 4 treatments with 8 replicates in a feeding trial. Each replicate consisted of 10 consecutive cages with 1 hen per cage. The corn-soybean meal-based control diet was prepared. Additional diet was prepared by including 10% of PKM in the control diet with a partial replacement of corn, soybean meal, and animal fat. In addition, 0.025% β-xylanase was supplemented at the expense of celite to those 2 diets to produce 4 treatment diets in a 2 × 2 factorial arrangement. All hens were provided the diet and water ad libitum for 8 weeks. Results indicated no significant interactions between inclusion of dietary PKM and β-xylanase for all measurements; therefore, the main effects were mainly discussed. Hens fed diets containing 10% PKM had greater (p < 0.05) feed intake and yolk color than those fed diets containing no PKM. However, dietary PKM did not influence fatty liver incidence and excreta characteristics. Dietary β-xylanase supplementation had no effects on all measurements, regardless of inclusion of PKM. In conclusion, PKM can be a potential feed ingredient for laying hens at the inclusion of 10% in the diet. It appears that dietary β-xylanase used in the current experiment has little effect on layer productivity, regardless of inclusion of 10% PKM in the diet.

• Animal Bioscience
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• v.34 no.3_spc
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• pp.457-462
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• 2021

Objective: The aim of this study was to investigate the effects of Enteromorpha powder supplementation on reproduction-related hormones and genes in the late laying period of Zi geese. Methods: A total of 312 (1-year-old) Zi geese with similar laying rate were randomly divided into 2 groups with 6 replicates each, each with 21 female geese and 5 male geese. The control group was fed with a basal diet and the test group was fed with a diet containing 3% Enteromorpha powder. The trial period lasted for 7 weeks. Results: Our results showed that the laying rate was improved in the test group at each week of trial (p<0.01), and the levels of estradiol in serum and prolactin in ovary were increased compared with the control group (p<0.05). Conclusion: Based on above results, Enteromorpha powder supplementation at 3% could promote reproductive performance during the late laying period of Zi geese.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.7
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• pp.1015-1020
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• 2012

An experiment was conducted to evaluate the effects of bacteriophage supplementation on egg performance, egg quality, excreta microflora, and moisture content in laying hens. A total of 288 Hy-line brown commercial laying hens (36-wk-old) were randomly allotted to 4 treatments in this 6-wk trial and dietary treatments included: i) CON, basal diet; ii) T1, CON+0.020% bacteriophage; iii) T2, CON+0.035% bacteriophage; iv) T3, CON+0.050% bacteriophage. There were 6 replicates for each treatment with 6 adjacent cages (2 hens/cage). Laying hens in T2 and T3 treatments had higher (p<0.05) egg production than those in CON and T1 treatments during wk 0 to 3. In addition, egg production in T1, T2, and T3 treatments was increased (p<0.05) compared with that in CON treatment during wk 4 to 6. At wk 4 and 5, birds in T2 group had higher (p<0.05) HU than those in CON. In addition, at wk 5 and 6, HU in birds fed T1 and T3 diets was greater (p<0.05) than those fed CON diet. E. coli and Salmonella spp. concentrations in excreta were decreased (p<0.05) by T1, T2, and T3 treatments. However, egg weight, egg shell color, yolk height, yolk color unit, egg shell strength, egg shell thickness, egg gravity, and excreta moisture content were not influenced by dietary treatments during the entire experimental period. In conclusion, bacteriophage supplementation has beneficial effects on egg production, egg albumen, and excreta microflora concentration in laying hens.

• Animal Bioscience
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• v.34 no.3_spc
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• pp.443-448
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• 2021

Objective: Astaxanthin is a natural super antioxidant. The present study was carried out to investigate the effect of astaxanthin rich Phaffia rhodozyma (PR) supplementation in diets on laying production performance, egg quality, antioxidant defenses and immune defenses in laying hens. Methods: A total of five hundred and twelve 60-week-old Lohmann Brown laying hens (2,243±12 g) were randomly assigned to four groups, each including 4 replicates with 32 birds per replicate. Astaxanthin rich PR was added to corn-soybean meal diets to produce experimental diets containing 0 (Control), 800 mg/kg, 1,200 mg/kg, and 1,600 mg/kg PR, respectively. The astaxanthin content in the diet was 0.96 mg/kg, 1.44 mg/kg and 1.92 mg/kg respectively. Results: Results showed that dietary PR supplementation tended to increase daily feed intake (p = 0.0512). There was no effect of astaxanthin rich PR on Haugh units, albumen height, egg shape index, eggshell strength, and eggshell thickness at weeks 6 (p>0.05). However, egg yolk color was significantly improved (p<0.05). In addition, astaxanthin rich PR supplementation significantly increased serum glutathione peroxidase and superoxide dismutase activity (p<0.05), increased serum immunoglobulin G content (p<0.05), and reduced malondialdehyde content (p<0.05) in laying hens. Conclusion: In conclusion, astaxanthin rich PR can improve the color of egg yolk, enhance the antioxidant defenses, and regulate the immune function.

• Korean Journal of Agricultural Science
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• v.49 no.1
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• pp.19-29
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• 2022

The present experiment was conducted to evaluate the effects of single-sex or mixed rearing on the growth and laying performance, blood parameters, egg quality, and feather scores of laying hens in an aviary system. A total of 2,928 (females, 2,856; males, 72), Hy-Line Brown chickens at 20 weeks were evenly assigned to two treatments: termed here the single-sex (only female) and mixed-sex (female to male 20 : 1) conditions. They were allowed an ad libitum diet for 20 weeks in an aviary system. There were eight replicates of each treatment, each consisting of 12.42 m²·birds^-1 (n=183), respectively. The body weight and uniformity in the mixed-sex condition were higher than those in the single-sex condition, but egg production did not show any significant differences between the two types of treatment for 20 weeks. The mixed-sex group showed an effect through stress parameters (corticosterone), whereas the feather score on the back was low at the end of the experiment. These results suggest that the presence of males affect corticosterone level for mating but can reduce the vigilance and aggressive behavior of laying hens.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.12
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• pp.1743-1749
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• 2000

An experiment was conducted to investigate the effect of supplementation of commercial phytase and ${\beta}-glucanase$ to wheat-soybean meal based layer diets. Control (17% CP) and reduced protein (13.5% CP) diets were compared with and without phytase and/or ${\beta}-glucanase$. Reducing dietary crude protein levels reduced the amount of N excreted by laying hens with no adverse affect on egg production or overall feed conversion ratio. There was, however, a slight reduction in average egg weight. When phytase was added to the control protein diets it was possible to reduce the level of dicalcium phosphate in the diet without a loss in performance and daily P output was reduced significantly. When phytase was added to the reduced protein diets, however, there was a dramatic loss in performance in the last four weeks of the study. Supplementation of ${\beta}-glucanase$ to wheat based layer diet did not appear to have beneficial affects in terms of laying performance and reducing nitrogen or phosphorus excretion. Combination of phytase and ${\beta}-glucanase$ had no positive effects on laying performance or reduction of DM, N and P.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.5
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• pp.694-699
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• 2009

The present study was conducted to evaluate the effect of chilled drinking water on the productivity of laying hens under constant high ambient temperature. A total of seventy-two, 123-day-old Hy-line brown layers was divided into two equal groups. The first group (UDWG) was given unchilled water ($23.0{\pm}2.5^{\circ}C$) as a control, and the second group (CDWG) was given chilled water ($16.0{\pm}0.5^{\circ}C$). The laying hens were kept at $30^{\circ}C$ constant temperature with 50% relative humidity and were exposed to 17 h of light per day. Feed intake, egg production, egg quality (egg weight, shell weight, shell thickness, egg color, yolk color, and Haugh unit), and blood samples were collected and analyzed. The results showed that the feed intake of CDWG laying hens was significantly higher (11.64%) than the UDWG counterparts (p<0.01). Egg production of CDWG was also significantly higher (11.27%) than the UDWG counterparts (p<0.001). Furthermore, we observed that the CDWG laying hens had significantly higher (11.72%) levels (p<0.10) of blood calcium, with a corresponding value of 21.92 mg/dl compared to the UDWG hens (19.62 mg/dl). The higher calcium concentration in the CDWG animals may contribute to increased egg production. The CDWG laying hens also contained higher (12.53%) phosphorus concentrations in blood compared to the UDWG (4.22 mg/dl vs. 3.75 mg/dl), although not statistically different (p>0.10). Egg weight and egg quality were not affected by chilled drinking water. In conclusion, providing chilled drinking for laying hens under high ambient temperature improved feed intake and egg production.

• Journal of the Korea Institute of Military Science and Technology
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• v.4 no.1
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• pp.73-82
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• 2001

In this Paper, slack is computed from a comparision of the cable pay out rate and the ship ground speed in accordance with laying conditions, and the speed controller of the cable engine based on an $H^{\infty}$ servo control is designed for adjusting the cable engine in order to lay a desired amount of slack. The controller is designed to have the robust tracking property of the cable engine under disturbances. The performance of the designed controller is evaluated by computer simulation, and, consequently, a feasibility study for laying the submarine cable stably is done through analyzing simulation results.

• Korean Journal of Poultry Science
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• v.49 no.4
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• pp.189-197
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• 2022

This study was conducted to compare the egg productivity, egg quality, and blood characteristics of laying hens with different laying rates, and the frequency and cumulative duration of the sitting behavior observed before laying was investigated. Twelve 45-week-old Hy-Line Brown laying hens were randomly assigned to two treatment groups with three replicates. Treatment groups were classified as layers laying over 80%(high egg performance layers; HEP) and layers laying below 50%(poor egg performance layers; PEP). The experiment lasted 4 weeks. HEP showed higher hen-house egg production ratio and egg mass and lower feed conversion ratio(FCR) (P<0.05) compared with PEP, although egg weight was higher in PEP (P<0.05). In terms of egg quality, PEP showed differences in eggshell quality (eggshell color, eggshell thickness, and eggshell weight) (P<0.05). Additionally, HEP showed high triglycerides(TG), and PEP showed high alanine transaminase(ALT) level (P<0.05) in serum collected in the morning. In the afternoon, the HEP showed higher lactate dehydrogenase(LDH) levels (P<0.05). No differences in the Ca: P ratio were observed between layers with different laying rates. One hour before egg laying, HEP exhibited sitting behavior 4 times on average, each lasting 25 minutes. In conclusion, egg production and quality differ between HEP and PEP, and HEP showed frequent sitting behavior before egg laying. However, additional research is necessary to explore approaches other than specific behavioral observation to distinguish poor layers in the flock for application in farms.