• Journal of Korean Society on Water Environment
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• v.23 no.1
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• pp.144-154
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• 2007

The acute and chronic toxicity of ambient and effluent water discharged to Lake Shihwa were investigated by using Vibrio fischeri, Daphnia magna and Oryzias latipes. Physicochemical characteristics including biochemical oxygen demand (BOD) and nine heavy metals in a total of 15 water samples were evaluated and were satisfied with relevant Korean Water Quality Standards (KWQS) except for Hg in one sample. Acute toxicity was observed in five samples collected from three sampling locations. When impacts on reproduction and growth after chronic exposure were evaluated with D. magna, all the samples showed significant chronic effects. Reproduction appeared relatively more sensitive endpoint. In 21 days chronic tests on O. latipes, survival, mean egg number per female per day, hatching success rate and time to hatch were affected by increasing sample concentration. The organ-level changes such as gonadosomatic index (GSI), and hepatosomatic index (HSI), and molecular biomarker of vitellogenin (Vtg) induction that evaluated with O. latipes increased as exposure concentrations increased. It is noteworthy that the samples that did not exceed the KWQS resulted in acute and chronic toxicities. The results suggested that numeric criteria based on physicochemical parameters may not be protective of aquatic ecosystem. Acute and chronic toxicity tests with organisms representing different trophic groups should be supplemented in order to provide adequate level of environmental protection.

• Korean Journal of Ichthyology
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• v.23 no.2
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• pp.158-162
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• 2011

Growth and spawning ecology of Cobitis lutheri (Teleoste: Cobitidae) were investigated in the Samcheon Stream, Mangyeong River, Jeollabuk-do, Korea from 2005 to 2006. Age group of C. lutheri estimated from the total length indicated that the 40 ~ 60 mm group is 1 year old, the 60 ~ 80 mm group is 2 years old, and the 80 ~ 110mm group is 3 ${\leq}$ years old. The sex ratio (Male/Female) was 0.78, and the female was 20 ~ 30 mm larger than the male. Lamina circularis at the base of pectoral fins in the males as a secondary sexual character was created 12 months after hatching. A change of lateral coloration of males was observed from April to September. The spawning season was early to middle July with water temperatures of $24{\sim}26^{\circ}C$. The average number of eggs was $1,127{\pm}453$ with the egg diameter of $1.09{\pm}0.02$ mm.

• Korean journal of applied entomology
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• v.60 no.2
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• pp.185-191
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• 2021

A Quarantine Pest Research Facility (QPRF) had been build in Animal and Plant Quarantine Agency and designed to ensure alien pests are safety contained inside the laboratory. Functions of QPRF including insect rearing, research, and physical containment facility were verified to check suitability as a research laboratory using the beet armyworm, Spodoptera exigua. As insect rearing and laboratory facility, S. exigua completed its development for 32.2 days at 25℃. Egg hatching, pupation, and adult eclosion showed 80, 86.6, and 90%. Two pesticides, fluxametamide and hydramethylnon showed high susceptibility against S. exigua larvae by spraying and dipping methods. As physical containment facility, male adults, which were artificially released from laboratory, did not capture in delta trap installed sex pheromone lure during winter season. Based on these results, QPRF will be used for study on alien insect species.

• Korean Journal of Organic Agriculture
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• v.26 no.3
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• pp.439-452
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• 2018

This study was carried out to establish of environment-friendly control system and to survey the occurrence status of Ricania shanthungensis in Jeonnam province from 2016 to 2017. R. shanthungensis occurred at 1,344 ha in 61 towns of 15 cities in Gwangju and Jeonnam province. At four sites in the stationary area, the densities of eggmass and pupae were lower in 2017 than in 2016, the hatching rate decreased, and the first hatching time, emergence of adults, and the start of spawning tended to be slower. Telenomus sp., an egg parasitoid of R. shanthungensis, was found in most areas. Sunchon had the highest rate of 46.1%, followed by Muan 40.6, Goksung 29.2, Gurye 25.8, and Gwangju 17, respectively. The optimum spraying time for the control of R. shanthungensis was early March. The spraying material and the dilution multiples are 10 times of the machine oil at environmental friendly cultivation and 500 times of the chlorpriphosphate wp. at normal cultivation. When sprayed these materials, 95% of egg prohibited to hatch. There was more than 80% of the insecticidal effects on the organic materials of the machine oil emulsion, the Sophora root extrect + microbial extract agent, and the castor emulsion. For adults, Sophora root extrect + microbial extract, neem extract, and machine oil were better. Four kinds of chemical pesticides such as dinotefuran wp were effective for nymph and adult control. We have developed an adult catching device using the most preferred daylight color and behavioral habits of R. shanthungensis. The capture device consisted of two daylight compact lamps (30W and 20W), a yellow plate, and a catcher using water, and caught about 700 individuals a day. Based on the above results, we have established a system for controlling and life cycle of R. shanthungensis in Jeonnam province.

• Korean Journal of Environmental Biology
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• v.22
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• pp.1-10
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• 2004

We conducted three experiments to estimate the toxicity of POPs (persistent organic pollutants) on two copepod species (Acartia erythraea and A. omorii) and Artemia sp.; (1) 48 h-LC$_{50}$ of A. omorii with the five PAHs [polycyelic aromatic hydrocarbons anthracene, benzo〔a〕pyrene, fluoranthene, phenanthrene, pyrene〕 which were often detected in the Gwangyang Bay, (2) toxicity of benzo〔a〕pyrene and TBT on Artemia in different temperatures (1$0^{\circ}C$, 15$^{\circ}C$, 2$0^{\circ}C$), (3) effects of benzo〔a〕pyrene and TBT on egg Production rate, hatching rate and fecal Pellet Production of two copepod species (A. erythraea and A. omorii) fed on Heterocapsa triquetra (dinoflagellate) exposed in benzo〔a〕pyrene. Toxic chemicals which were most effective to A. omorii were flueranthene (48 h-LC$_{50}$ 19.20 $\mu\textrm{g}$ L$^{-1}$ ) and benzo〔a〕pyrene (48 h-LC$_{50}$ 29.89 $\mu\textrm{g}$ L$^{-1}$ ). The toxi- city of chemicals to Artemia increased when temperature increased. The toxicity of TBT was about 100 times higher than that of benzo〔a〕pyrene at 15$^{\circ}C$. Food materials (Heterocapsa triquetra) exposed in benzo〔a〕pyrene, affected negatively the rate of egg production, hatching rate and the fecal pellet production of the copepods at the high concentration. It is suggested that an increase in the concentration of benzo〔a〕pyrene might offset the production of copepods in marine ecosystems. This study suggests that copepods may be used as n indicator for early warning of the risk of POPs in marine ecosystems.

• Research in Plant Disease
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• v.22 no.4
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• pp.227-235
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• 2016

Plant disease caused by root-knot nematode is a major problem in crop production. Using of chemical pesticides, one of the most efficient methods to control nematodes, have raised issues in toxicity to humans and animals and environmental pollution. In this study, to select actinomycete strains that have potential to serve as a microbial agent for control of nematodes, we investigated nematicidal activity of culture broth from 670 Streptomyces isolates. A culture filtrate of KRA15-528 isolate that was identified as S. flavogriseus on the basis of 16S rRNA sequence analysis, showed strong nematicidal activity against second stage of juveniles of Meloidogyne incognita and inhibited egg hatching; exposure to 10% of culture filtrate resulted in 71% juvenile mortality at 48 hours afters treatment and suppressed egg hatching by 54% at 9 days after treatment. When the KRA15-528 culture filtrate was partitioned with ethyl acetate and butanol, ethyl acetate layer exclusively showed strong activity; 91%, 53%, 30% of mortality at 1,000, 500, $250{\mu}g/ml$, respectively. Additionally, the culture filtrate suppressed gall formation on cucumber plant by M. incognita with no phytotoxicity. These results suggest that S. flavogriseus KRA15-528 has potential to serve as a microbial nematicide for the control of root-knot nematode disease.

• Korean Journal of Environmental Biology
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• v.21 no.2
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• pp.149-157
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• 2003

This study focused on relationships between Pb and Cd concentrations and the difference of success reproductive progress in urban (Seoul) and industrial complex (Ansan) areas. Results of the Pb analysis for the feral pigeons from Seoul (egg contents:1.64 $\mu\textrm{g}$ wet $g^{-1}$, adults in bones: 29.5 $\mu\textrm{g}$ wet $g^{-1}$ and the Ansan industrial complex (egg contents: 1.13 $\mu\textrm{g}$ wet $g^{-1}$, adults in bones: 10.5 $\mu\textrm{g}$ wet g-1) showed that the Pb level of eggs and adults is significantly different between the two colonies (p<0.05). Cd concentrations in liver and kidneys of adult pigeons were also significantly different between Seoul(liver: 0.24 ${\mu}g$ wet $g^{-1}$, kidney: 1.05 $\mu\textrm{g}$ wet $g^{-1}$ and the Ansan (liver: 0.14 $\mu\textrm{g}$ wet $g^{-1}$, kidney: 0.43 $\mu\textrm{g}$ wet $g^{-1}$ colonies (P<0.05). Clutch size of Feral Pigeons living in Seoul was similar between the two colonies, 1.9$\pm$0.3 in Seoul and 2.0$\pm$0.0 in Ansan. The length, breadth, and thickness of eggs were not significantly different between the two colonies (p>0.05). Incubation period in Seoul (17.8 days) did not differ from the Ansan (17.4 days). No difference in growth rate (body weight, wing length, and tarsus length) was found between the two test groups (p>0.05). In Seoul, 65.2% were hatching, and 42.1% fledging. The Proportion of hatching and fledging in the Ansan was 60.7% and 45.0%, respectively. The significant differences between the two colonies for reproductive sucess were not found (p>0.05). With regard to the reproductive effects to the heavy metals, the Pb and Cd concentrations feund in the two colonies were not as high as those considered in results of toxic effects in other species.

• Korean Journal of Poultry Science
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• v.42 no.3
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• pp.247-256
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• 2015

There are approximately 1,500 broiler farms in Korea, each raising 55,000 birds. Ninety-five percent of the farms are contracted with Integration Company. According to the Korean broiler performance index, broilers in Korea are marketed at 32 days with 1.52 kg of body weight. In contrast, the market age and body weight of broilers are 47 days/2.8 kg in the United States and 42 days/2.5 kg in Europe. Because of the younger market age of the Korean broiler, the pre-starter feed is important. Chicks exhibit poor absorption of dietary nutrients up to 7 days after hatching due to an immature digestive system and low enzyme secretion rate and activity. At the beginning of hatching, chicks obtain their nutrients from the egg yolk sac. It is highly recommended that chicks, after consuming the nutrients in the egg yolk sac, are given supplemented pre-starter feed to increase early growth rates and improve the performance of broiler production. Pre-starter nutrient requirements are not expressed in NRC, so Korean feeding standards for poultry and commercial breeding companies determine the nutrient requirements of pre-starter broiler chickens. Three approaches are followed to formulate specially designed pre-starter feeds for broiler chicks: (i) selective use of raw materials, (ii) proper standards of nutrient supply, and (iii) application of feed additives such as exogenous enzymes. In the selection of raw materials, those with high digestibility can be used. The absorption rate of carbohydrates in grains can be increased through feed processing at high temperature and high pressure. Soy proteins and fish meal can also be added as protein sources. As an energy source, vegetable oils are preferred over animal fats because of the former's high digestibility. It is suggested that the levels of proteins and amino acids are higher in pre-starter feed than in starter feed. With regard to energy, the sources of energy are more important than the levels of energy in feed. Feed additives such as exogenous enzymes can be used to improve nutrient digestibility. In addition, organic acids and plant extracts can be used as alternatives to animal growth promoters to stimulate immunity and prevent diseases. The growth performance of broilers is affected by various factors, such as management and disease control, in addition to the nutritional strategy; however, nutritional strategies play an important role in improving the productivity of broilers. Therefore, nutritional strategies, along with management and disease control, are required for improving the productivity of broilers in Korea.

• Korean Journal of Poultry Science
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• v.40 no.3
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• pp.263-270
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• 2013

The vent sexing and the auto-sexing by using sex-linked traits are general sexing methods of day-old chicks. Currently, the feather sexing which is based on the differences in the feather characteristics at hatching is the representative sexing method of chicken, because the late-feathering is sex-linked trait. The feather sexing can be used if the breed has dominant feathering gene (K) in maternal and recessive gene ($k^+$) in paternal. Therefore it is necessary to identify the association of feathering genes and quantitative traits in chickens. In this study, we investigated the influence of the rate of feathering on productive traits in Korean Native Chicken. In results, there was no significant difference between early-feathering chickens and late-feathering chickens in reproductive performance such as fertility and hatchability. Livability, body weights, egg production, egg weight and egg quality also did not significantly differ between early- and late-feathering chickens. Age at first egg was the only trait of those tested in which significant difference was observed. The early-feathering chickens laid eggs 3 days earlier than late-feathering chicken. As a result, there is no influence of feathering phenotypes on productive performance in Korean Native Chickens. Consequentially, establishing the feather sexing strain is available using the Korean Native Chicken breed without considering of the effect of feathering genes on productive traits.

• Ecology and Resilient Infrastructure
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• v.4 no.2
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• pp.75-82
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• 2017

This study was executed to know the effect of the habitat size on huanren brown frog (Rana huanrensis) larvae's growth. We've conducted the study on Mt. Surak in Sanggye-dong, Nowon-gu, Seoul. Our study site was discriminated the huanren brown frog larvae's habitat into the three different areas, such as small area (S1, $3.91m^2$), middle area (S2, $4.42m^2$), and large area (S3, $38.37m^2$) in the same water channel. We measured two times per a week the 15 huanren brown frog larvae's body length, and developmental stages (foreleg, hind leg, tail length) including the environmental factors (humidity, air temperature and water temperature) of the study site from March 30 to June 28 in 2016. The only hatching rate was measured for the three egg sacs at the S2 study site. We found that the average hatching rate was $76.84{\pm}18.23(%)$ at S2. Generally, because of less precipitation during our study periods, all habitat areas for our study site were gradually decreased. The middle area, S2, was not reduced, the small area, S1, was reduced more than a fourth, and the largest area, S3, was drastically reduced more than half from initial area. There was no statistically difference among the three study sites for the three environmental factors (average humidity, average air temperature, and average water temperature) by F-test, but there were significant difference among the three site for the larvae's body length (F-test p< 0.05). Therefore, the larger of habitat areas, the larger of the larvae length as well as the faster of the larvae's developmental stages. When we measured the body lengths of immature huanren brown frogs, the immature frog of S1 was smallest, the immature frog of S3 was middle lenght, and the immature frog of S2 was largest. There were statistically different among the three study sites for the immature huanren brown frogs (F-test, p< 0.05). Because the S2 study site was relatively stable without rarely changing the study area, it meant that huanren brown frog was sensitive to habitat areas. Based on the results of this study, if we study on the effect of the altitude on the growth rate of huanren brown frog, it must be helpful in understanding the habitat environment of the population of huanren brown frog.