• Animal Bioscience
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• v.36 no.6
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• pp.899-907
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• 2023

Objective: The better understanding of laying pattern of birds is crucial for developing breed-specific proper breeding scheme and management. Methods: Daily egg production until 50 wk of age of six chicken breeds including one layer (White Leghorn, WL), three dual-purpose (Rhode Island Red, RIR; Columbian Plymouth Rock, CR; and Barred Plymouth Rock, BR), one synthetic dwarf (DY), and one indigenous (Beijing-You Chicken, BYC) were used to characterize their clutch traits and egg production. The age at first egg, egg number, average and maximum clutch length, pause length, and number of clutches and pauses were calculated accordingly. Results: The egg number and average clutch length in WL, RIR, CR, and BR were higher than those in DY and BYC (p<0.01). The numbers of clutches and pauses, and pause length in WL, RIR, CR, and BR were lower than those in DY and BYC (p<0.01). The coefficient variations of clutch length in WL, RIR, CR, and BR (57.66%, 66.49%, 64.22%, and 55.35%, respectively) were higher than DY (41.84%) and BYC (36.29%), while the coefficient variations of egg number in WL, RIR, CR, and BR (9.10%, 9.97%, 10.82%, and 9.92%) were lower than DY (15.84%) and BYC (16.85%). The clutch length was positively correlated with egg number (r = 0.51 to 0.66; p<0.01), but not correlated with age at first egg in all breeds. Conclusion: The six breeds showed significant different clutch and egg production traits. Due to the selection history, the high and median productive layer breeds had higher clutch length than those of the less productive indigenous BYC. The clutch length is a proper selection criterion for further progress in egg production. The age at first egg, which is independent of clutch traits, is especially encouraged to be improved by selection in the BYC breed.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.2
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• pp.225-231
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• 2008

Oxidative stress plays a crucial role in the laying stage which is a critical period for chick survival. We investigated the relationship of neonatal chick performance, brain antioxidant status and vitamin E supplementation level in hens. Starting at 17 weeks, hens were randomly divided into five groups. The control group received a basal diet without supplemental vitamin E (VE, dl-${\alpha}$-tocopherol acetate). Other groups received the same basal diet supplemented with vitamin E (40, 80, 120 and 160 mg/kg) through growth to egg production. Hens were artificially inseminated at 28 weeks of age and egg yolks were collected at day two. All remaining eggs were hatched. Yolk vitamin E content, hatchability and fertility of eggs were evaluated. Brains of the newly hatched chicks were further evaluated for their oxidative stress status, antioxidative status and vitamin E levels. Increased reproductive performance was observed in fertility and hatchability in the group supplemented at 40 mg/kg. Egg yolk and neonatal brain ${\alpha}$-tocopherol was highest in eggs from hens fed 120 mg/kg and 80 mg/kg supplemental vitamin E, respectively. Brain MDA, ROS and iron levels were significantly higher in unsupplemented hens (p<0.01). SOD activity was significantly higher in the group supplemented at 160 mg/kg than in all other groups. We concluded that maternal supplementation of vitamin E had beneficial effects on fertility, hatchability of eggs, neonatal brain oxidative status and SOD activity.

• Korean Journal of Poultry Science
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• v.27 no.3
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• pp.243-254
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• 2000

The effect of supplemental microbial phytase and non - phytate phosphorus(NPP) levels on layer productivity and nutrient digestibility were conducted in 640 21 weeks - old HyLine brown layer for 12 weeks. Supplemented phytase levels were 0, 300, 500 and 1,000 DPU/kg diet. NPP levels were adjusted with tricalcium phosphate(TCP), which were 0(0.11% NPP), 0.5(0.20), 1.0(0.29) and 1.5%(0.38). ME, CP and Ca levels were maintained at 2,800㎉/kg diet, 16% and 3.5%, respectively. Egg production was increased with phytase compared to without phytase(P〈0.05). Increasement of egg production was higher latter of experimental period. Egg production was not different to phytase levels. Egg production in TCP levels were increased in above 0.5% compared to 0% TCP. Difference of egg production by TCP was higher after 6 week. Especially, egg production to supplemental phytase was higher in 0% TCP. Egg weight was not different to phytase and TCP levels. Egg mass was increased with phytase compared to without phytase, but not difference significantly. There was similar to phytase levels. Egg mass in TCP group was increased in TCP supplementation(P〈0.05). Feed intake was not different in phytase levels, and greater with increasing TCP levels(P〈0.05). Feed conversion was improved with phytase(P〈0.05), and not difference in TCP levels. All of nutrients digestibility tended to improve with phytase, P(P〈0.05), especially. There were not different among phytase levels. The effect of adding phytase was higher in low phosphorus diets compared normal levels. Eggshell breaking strength and eggshell thickness also improved in added phytase(P〈0.05). Tibial ash and P content were slightly increased with phytase, and Ca content also was higher(P〈0.05) compared without phytase. We concluded that supplemental phytase in low phosphorus diet was showed to increase laying performance, feed efficiency, nutrients digestibility, egg quality, and bone development. Phytase supplementation was able to compensate for low NPP diet. We also thought optimum phytase level is 300 DPU, and can decrease NPP supplementation adding phytase in later diet.

• Asian-Australasian Journal of Animal Sciences
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• v.11 no.6
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• pp.702-707
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• 1998

An experiment was conducted to evaluate the effect of a microbial enzyme (Roxazyme-$G^{(R)}$), a multicarbohydrases preparation, supplementation to the wheat-based layer diets. Diets were formulated to include different levels of wheat replacing yellow corn on isocaloric and isonitrogenous basis. The energy value of wheat in the enzyme supplemented diets was adjusted (spec-modified) to have 5% more ME than the wheat in diets without enzyme. A total of 864 Hy-$Line^{(R)}$ brown layers were assigned to 4 dietary treatments: 10% wheat (T1), 25% wheat (T2), 25% wheat (spec-modified)+ 0.01 % Roxazyme-$G^{(R)}$ (T3), and all wheat (spec-modified)+0.01% Roxazyme-$G^{(R)}$ (T4). Hen-day egg productions of T1 and T4 were significantly (p < 0.05) greater than that of T2 but not different from T3. Hen-housed egg production of T4 was significantly (p < 0.01) greater than those of T1 and T3 but not different from T2. Egg weights of T1 and T2 were significantly (p < 0.0 1) greater than that of T4. Feed consumption of T2 was significantly (p < 0.01) lower than other treatments. Feed conversion ratio (feed/egg mass) was not significantly different among treatments. Eggshell thickness of T1 was significantly (p < 0.01) greater than other treatments but ratio of broken eggs was not significantly different among treatments. Haugh unit of T4 was significantly greater (p < 0.05) than that of T2. Egg yolk color was significantly (p < 0.01) influenced by treatments in which enzyme treatment potentiated the yolk pigmentation. It was concluded that a multi-carbohydrases supplementation enables complete replacement of yellow com with wheat without loss of productivity and major egg quality parameters.

• Asian-Australasian Journal of Animal Sciences
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• v.33 no.9
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• pp.1463-1469
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• 2020

Objective: The effects of maternal and offspring dietary vitamin A (VA) supplementation on early body weight, digestive tract function and immune function in goslings were studied. Methods: Yangzhou geese (180 d old) were randomly divided into 5 experimental groups of 15 females and 3 males (the males were kept until slaughter). Eggs were collected for hatching during the peak laying period. A total of 96 goslings were selected from each treatment group (each fed a basic diet supplemented with 0, 4,000, 8,000, 12,000 or 16,000 IU/kg VA) and randomly divided into 2 groups, with 6 replicates in each group and 8 goslings in each replicate. The gosling diet was supplemented with 0 or 9,000 IU/kg VA. Results: i) Villus length, villus width and the muscle thickness of the duodenum, jejunum and ileum were increased and the crypt depth was reduced after adding 12,000 IU/kg VA to the goslings' diet (p<0.05). Adding 9,000 IU/kg VA to the offspring diet increased the length of the duodenal villi and width of the ileum and decreased the crypt depth of the ileum (p<0.05). ii) Supplementing the maternal diet with 12,000 IU/kg VA increased immune organ weight, the immune organ index and immunoglobulin content in goslings (p<0.05). The bursa weight and immunoglobulin G content of offspring were higher in the 9,000 IU/kg VA supplementation group than in the group with no supplementation (p<0.05). Conclusion: Offspring growth and development were affected by the amount of VA added into maternal diet. The negative effect of maternal VA deficiency on offspring can be compensated by adding VA to the offspring diet. Continued VA supplementation in the offspring diet after excessive VA supplementation in the maternal diet is unfavorable for gosling growth and development.

• Journal of Biosystems Engineering
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• v.31 no.5 s.118
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• pp.436-442
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• 2006

This research was conducted to design and develop a wired monitoring system for judging if sick or dead layers (SDL) exist in multi-tier layers battery (MLB) by machine vision, and to analyze its performance. In this study, 20 Brown Leghorn (Hi-Brown) layers aged 37 weeks old, were used as the experimental animals. The intensity of concern paid by layers on feed was over 90% during 5 minutes and 30 seconds after providing feed, and normal layers (NL) had been standing to take feed for that period. Therefore, in this study, the optimal judging time was set by this test result. The wired monitoring system developed was consisted of a driving device for carrying machine vision systems, a control program, a RS232 to RS485 convertor, an automatic positioning system, and an image capture system. An image processing algorithm was developed to find SDL in MLB by the processes of binary processing, erosion, expansion, labeling, and reckoning central coordinate of the captured images. The optimal velocity for driving unit was set up as 0.13 m/s by the test results for wired monitoring system, and the proximity switch was controlled not to be operated for 1.0 second after first image captured. The wired monitoring system developed was tested to evaluate the remote monitoring performance at lab-scale laying hen house. Results showed that its judgement success.ate on normal cage (without SDL) was 87% and that on abnormal cage (with SDL) was 90%, respectively. Therefore, it would be concluded that the wired monitoring system developed in this study was well suited to the purpose of this study.

• Journal of Ocean Engineering and Technology
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• v.29 no.6
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• pp.470-474
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• 2015

The demand for subsea cables and pipelines that transfer marine energy resources onshore has recently increased. Laying these underground after trenching is one engineering method to stabilize exposed subsea cables and pipelines. This experimental study found the optimum conditions for operating two types of waterjet arms mounted on an ROV trencher. A waterjet arm for trenching the seabed was scaled down at a ratio of 1:6, and a comparative analysis was conducted using diverse parameters. The results of this research provide a practical fundamental database to assist in making decisions about the ROV trencher performance in advance.

• Korean Journal of Organic Agriculture
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• v.10 no.4
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• pp.47-60
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• 2002

'Probiotics' as a live microbial feed supplementation which beneficially affects the host animal by improving its microbial balance and it is known to as a substitue for antibiotics in livestock feed industry. Lactic acid bacteria as a Lactobacillus sp. is formed acid and decrease pH in gastro-intestine that is result in suppress harmful microorganism. Lactobacillus sp. also produces vitamin and a variety amino acids. Yeast as a saccharomyces sp. secretes digestive enzymes, decreases ammonia emission and increases feed palatability by alcohol and glutamic acid. The effects of dietary probiotics in monogastric animals that improve weight gain and feed efficiency ratio and decrease diarrhea accurence frequency in pigs. Also, probiotics increase egg production ratio and beneficial microorganisms in laying hens. In broiler, they have more gain weight and lower blood cholesterol concentrations by probiotics. However, the other study reported probiotics supplementation in animal diets has no effect on ADG, G/F or performance. Thus, future study in these area will allow for more efficient use of the probiotics, selection of more superior microorganism and development of more efficient environment-friendly probiotics like a photosynthetic bacteria.

• Korean Journal of Poultry Science
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• v.44 no.1
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• pp.11-18
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• 2017

The purpose of this survey was to collect basic data on breeding systems of animal welfare-approved laying hen farms in Korea. Questionnaires were mailed to 64 animal welfare-approved farms, and 20 questionnaires (31.3%) were returned. The housing systems were fabric coverlet (4 farms, representing 20%), naturally farmed (Yamagisi, 7 farms, 35%), and steel panel-framed housing (9 farms, 45%). The 20 farms had stocking densities of $2{\sim}3birds/m^2$ (2 farms; 10%), $4{\sim}5birds/m^2$ (10 farms; 50%), and $6{\sim}7birds/m^2$ (8 farms; 40%). Breeding methods were floor-housed (14 farms; 70%), free-range (3 farms; 15%), and floor plus free-range (3 farms; 15%). Stocking density was $4{\sim}6birds/m^2$ at most of the farms with fabric coverlet and naturally farmed housing and $6{\sim}7birds/m^2$ at seven farms (of 9 farms) with a steel panel-framed housing. The daily feed intake of 11 farms (55%) was between 120 and 130 g, which included 3 farms (15%) with fabric coverlet, 3 farms (15%) with naturally farmed housing, and 5 farms (25%) with steel panel-framed housing. The age of peak production was 24~28 weeks overall 20 farms. Over 80% of production on fabric coverlet, naturally farmed, and steel panel-framed house farms was on 3, 4 and 6 farms, respectively. Respiratory disease on the 20 farms represented 55% of total disease incidence, and of each housing type represented 75% (fabric coverlet), 70% (naturally farmed) and 33% (steel panel-framed). E. coli disease was only found in the steel panel-framed housing. Most of the animal welfare-approved eggs were sold at large markets or a real sale markets. Egg price was 200~250 won per egg. These results indicate the current situation of animal welfare-approved farms and could be caused that windowless poultry house was applied to animal welfare approved farms.

• Journal of Animal Science and Technology
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• v.45 no.3
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• pp.369-376
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• 2003

This experiment was conducted to investigate the influence of different levels of metabolizable energy (ME) and crude protein (CP) on post-molt performance and egg quality of spent laying hens. Four hundred and thirty two, ISA Brown hens at sixty six weeks of age after molt induction were fed six experimental diets containing three ME (2,750, 2,800, 2,850 kcal/kg) with two CP (15, 17%) levels in a factorial design. The influence of ME and CP were evaluated on egg production, egg weight and feed intake throughout 24 weeks of production. Egg mass and feed conversion ratio (FCR) were measured during the experimental period. Haugh unit, yolk color and eggshell breaking strength were measured at 5%, 50%, peak, post peak and end stage of egg production. The hens fed 2800 kcal/kg diet along with 15% CP recorded the highest outcome of egg production (P<0.05). The egg weight has been shown to increase with hens receiving 2,800 kcal/kg ME. Daily egg mass tended to increase in hens fed with 15% CP and 2,800 kcal/kg ME. Feed intake decreased significantly with the level of ME and CP in the diet increased (P<0.05). Yolk color was improved significantly in eggs laid by the hens receiving 17% CP than 15% diet. It also tended to be higher in 17% CP with 2,800 or 2,850 kcal/kg ME diet treatments. Egg shell breaking strength increased with hens receiving diets of 15% CP and 2,800 kcal/kg. From this experiment it can be concluded that the ME level of 2,800 kcal/kg coupled with 15% CP could be used to achieve the higher egg production and better eggshell strength in induced molting hens.