• Korean Journal of Agricultural Science
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• v.49 no.1
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• pp.173-173
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• 2022

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.14 no.8
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• pp.641-647
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• 2002

Objectives of this paper are to investigate the effect of roughness of micro-hatching tubes on the absorption performance and to develop on experimental correlation of Nusselt as a function of the roughness. Three different micro-scale hatched tubes and a bare tube were tested in the present experiment. $H_{2}O/LiBr$ solution is used as working fluid. It was found that absorption performance of micro-scale hatched tubes were improved upto 2 times with an error band of ${\pm}25%$ compared with the bare tube. An experimental correlation of Nusselt was developed as a function of the roughness.

• Korean Journal of Poultry Science
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• v.24 no.3
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• pp.117-126
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• 1997

This study was conducted to estimate the hatching and growing performance, and heterosis of Korean Native Chicken(KNC), Rhode Island Red(RIR) and KNC XRIR crossbred. A total of 1,274 female pullets were produced from KNC, RIR and KNC x RIR crossbred kept in National Live-stock Research Institute, Korea. The experiment was conducted for 20 weeks from Sep. 2, 1995 to Jan. 20,1996. Hatchabilities of KNC dark brown strain x RlR(DR), KNC light brown strain x RlR (LR) and KNC dark black strain x RlR(BR) were 77.3%, 73.6% and 72.5%, respectively. Viabilities up to 20 weeks of age were not significantly (P>0.05) different among purebreds and crossbred. Body weights of DR, LR and BR were 1,890 g, 1,849 g and 1,967 g, respectively, at 20 weeks of age. The feed conversion ratio(feed /gain) of DR, LR, and BR were 5.88, 6.07 and 5.87, respectively, up to 20 weeks of age. Average shank lengths of DR, LR and BR were 97.1 mm, 98.9 mm and 99.4 mm, respectively, at 20 weeks of age. The heterosis effects were estimated to be -0. 48%, and 12.58%, respectively, in fertility and hatchability. Up to 20 weeks of age, the heterosis effects were estimated to be 0.07%, 13.49%, -5.77%, and 3.52% in viability, body weight, feed conversion ratio, and shank length, respectively.

• Korean Journal of Poultry Science
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• v.44 no.3
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• pp.161-172
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• 2017

This study was conducted to determine the effect of Saccharomyces cerevisiae (SC) as a dietary probiotic and evaluated the most suitable feeding interval for this probiotic on growth performance, carcass yield, and meat quality parameters in broiler chickens. In total, 1,050 one-day-old Cobb 500 chicks were randomly assigned to one of seven dietary treatment groups, in a $2{\times}3$ factorial arrangement with 3 SC dosages (0.6%, 1%, and 1.4%) and two feeding intervals [long term (LT) for 35 days and short term (ST) for 28 days after hatching], with a negative control diet (NC; 0% SC). Triplicate experiments were performed with 50 birds per cage. Broilers fed a diet including SC showed increased (p<0.01) daily gain and feed efficiency compared to the control. Further, broilers fed the 1.4% SC supplemented diet showed a significantly increased (p<0.01) average daily gain (ADG) and feed conversion ratio (FCR) compared to broilers fed the 0.6% and 1% SC incorporated diets. Similarly, broilers fed an LT SC diet showed a greater (p<0.01) increase in ADG and FCR compared to broilers fed an ST SC diet. Moreover, broilers fed an LT SC diet displayed a reduced (p<0.05) meat pH, gizzard weight, and increased (p<0.05) meat water-holding capacity compared to broilers fed an ST SC diet. Broilers fed the 1.4% SC supplemented diet showed increased (p<0.05) thigh muscle weight compared to broilers fed the 0.6% and 1% SC supplemented diets. In conclusion, broilers fed LT SC diets showed improved growth performance and carcass quality parameters compared to broilers fed ST SC diets, and the NC diet, from hatching to day 35.

• Korean Journal of Ichthyology
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• v.22 no.1
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• pp.25-33
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• 2010

Effects of different salinity levels on spawning performance, embryonic development and early viability of a euryhaline medaka species, Oryzias dancena, were examined. O. dancena were able to spawn eggs in a wide range of salinity from 0 to 70$^{\circ}/_{\circ\circ}$, however, the spawning frequency was lowered in complete freshwater (0$^{\circ}/_{\circ\circ}$) and in highly salted water (70$^{\circ}/_{\circ\circ}$). Fertilization success was negatively affected when the environmental salinity was higher than the salt concentration found in normal seawater. Embryonic viability and hatching success were also inversely related with the salinity levels. Typical abnormality was observed in developing embryos incubated at high salinities (30, 45 and 60$^{\circ}/_{\circ\circ}$). In addition, the time to hatch was significantly delayed with increasing salinities: peak hatching occurred at 12~14 days post fertilization (dpf) in freshwater and at least at 17 to 18 dpf in 60$^{\circ}/_{\circ\circ}$. Mean survival rates of the hatched larvae up to 7 days post hatching (dph) were at least 97% in salinity levels ranging from 0 to 30$^{\circ}/_{\circ\circ}$. However, larvae reared in 45 and 60$^{\circ}/_{\circ\circ}$ experienced significant mortality, especially in the early phase, resulting in only 75% and 64% survival rates up to 7 dph, respectively.

• Korean Journal of Poultry Science
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• v.40 no.3
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• pp.277-281
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• 2013

The experiment was undertaken to see the effects of Bacillus sp. on the growth performance and disease resistance to Salmonella sp. infections. The use of probiotic microbes in poultry is commonly practiced. In this study, Bacillus subtilis was tested using a total of 120 chicks of age of 1 day after hatching. The growth traits examined were body weight gain and feed conversion rate. And also, the Salmonella resistance of Bacillus subtilis was tested after the chicks were orally administered with Salmonella pullorum by gavage force injections. The result showed that Bacillus subtilis yielded a high feed efficiency, consequently increased growth rate. For the effect of Bacillus subtilis on Salmonella infection, Bacillus subtilis significantly improved the resistance to Salmonella pullorum infection. Various clinical symptoms of Salmonella infection were highly decreased by addition of Bacillus sp.

• Asian-Australasian Journal of Animal Sciences
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• v.6 no.3
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• pp.331-337
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• 1993

In order to understand the effect of duck hepatitis B virus (DHBV) on the economic performance of ducks, Three groups (DHBV congenitally infected, experimentally infected and DHBV negative) Brown Tsaiya ducks (Anas platyrhyncha) were used for experimental animals. Artificial insemination and pedigree hatching were applied in the propagation of ducklings, and the efficiency of vertical transmission and experimental infection was analyzed through the detection of DHBV DNA in the sera of 8-week-old offspring. The observation of the records of the first year indicated that the persistent infection had no significant effects on the performance of ducks, except the egg number of survival ducks up to 40 week of age. Thus DHBV infection did not appear to give ill effects to the economic performance of ducks in first laying year. A higher infection rate (85.3%) was obtained in congenital transmission than that (75.5%) of experimental infection. Both modes of infection did not reach 100% infectious rate, although some ducks developed transient viraemia in a tracing of DHBV DNA for 24 weeks to 11 challenged ducklings.

• Asian-Australasian Journal of Animal Sciences
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• v.33 no.2
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• pp.305-312
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• 2020

Objective: The present trial was conducted to determine the influence of different dietary fatty acid (omega-3 and omega-6) sources on reproductive performance of female broiler breeders and growth performance and carcass traits of their progeny. Methods: Two hundred and twenty, 25 weeks old Ross-308 male (20) and female (200) broiler breeders were used in the experiment for the period of 6 weeks. All birds were randomly divided into four dietary treatments (containing 2% soybean oil, 2% sunflower oil, 2% flaxseed oil, and 2% fish oil) each with five replicates of one male and ten females. Throughout this experiment hatching performance of broiler breeders, progeny growth performance and carcass parameters were recorded. Results: The results showed that the inclusion of different fatty acid sources in female broiler breeders diet had no significant effects (p>0.05) on number of fertile eggs, post-hatch mortality, and fertility rate. The soybean oil supplemented group had significantly (p<0.05) higher late embryonic mortality compared to other three treatments. Conclusion: It was concluded that inclusion of 2% of different sources of omega-3 and omega-6 fatty acids (especially 2% flax seed oil) in broiler breeders' diet can reduce late embryonic mortality. The other reproductive characteristics of parents and growth and carcass characteristics of progeny remained unaltered by dietary sources of omega-3 and omega-6 fatty acids.

• International Journal of Industrial Entomology and Biomaterials
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• v.15 no.1
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• pp.9-16
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• 2007

The present study was aimed to screen different antibiotics in vivo for their effects against the bacterium Bacillus coagulans in silkworm Bombyx mori in three experimental conditions viz., a) healthy larvae treated with the antibiotics b) larvae which were first inoculated with Bacillus coagulans immediately after the $2^{nd}$ moult and treated with the antibiotics from 24 hour after inoculation up to the end of the $5^{th}$ instar(pre-inoculated larvae) and c) larvae which were treated with the antibiotics right from hatching up to the end of the $5^{th}$ instar and inoculated with Bacillus coagulans immediately after the $2^{nd}$ moult(post-inoculated larvae). All the antibiotics used in this study stimulated better performance in improving the rearing performance and economic characters of the cocoons in healthy, pre-inoculated and post-inoculated larvae, besides reducing the mortality of infected larvae. Cephelexin and Tetracycline were more effective than the others in their overall performance under all the three experimental conditions. Chloramphenical caused greater increase in the length of the reelable silk filament, but was not as good in elevating the other parameters compared to the remaining antibiotics. Of the four concentrations of antibiotics tested, 2.0% performed better under all the three experimental conditions.

• Food Science of Animal Resources
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• v.27 no.4
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• pp.401-408
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• 2007

This study examined the histochemical and physiological characteristics during Korean native Ogol chickens (KNOC) development. The body weight, Pectoralis major and soleus muscle weights, and muscle samples were taken at hatching as well as at 3, 5, and 15 weeks of age. The fiber characteristics of the Pectoralis major and soleus muscles from the KNOC at hatching to 15 weeks of age were determined, and the deoxyribonucleic acid (DNA), ribonucleic acid (RNA), and protein concentrations were measured from the left Pectoralis major muscles. A greater increase in body and muscle weights was detected between hatching and 3 weeks of age than during any other period. Moreover, the cross sectional area (CSA) of the fibers, as well as the total concentration of DNA, RNA, and protein also showed a greater increase betweenhatching and 3 weeks of age than during any other period. The KNOC breed is a dual purpose breed, however, the it has lower body and muscle weights than commercial meat type chickens or layer type chickens. Moreover, the KNOC breed has a small muscle fiber CSA of and a low nucleic acid concentration.