• Korean Journal of Soil Science and Fertilizer
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• v.34 no.6
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• pp.387-393
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• 2001

To use as a fundamental data for the sustainable agriculture, which is nowadays a major trend to keep the productivity and conserve the environment, 487 paddy soil samples were collected from 21 regions of the Gyeongnam Province and analyzed the chemical characteristics and microbial population of the soil. The microbial population densities were bacteria $298{\times}10^5$($4{\sim}3000{\times}10^5$ range), fungi $63{\times}10^3$($2{\sim}441{\times}10^3$ range), actinomycetes $19{\times}10^5$($0.2{\sim}1250{\times}10^5$ range), Bacillus sp. $53{\times}10^4$($4{\sim}890{\times}10^4$ range) and Pseudomonas sp. $198{\times}10^4CFU\;g^{-1}$($4{\sim}1724{\times}10^4CFU\;g^{-1}$ range), respectively. The microbial populations of the soil were in general higher in southern area than in the northern area of the Gyeongnam Province. The average ratio of bacteria/fungi population was 473. As soil clay content increased, the populations of aerobic bacteria, actinomycetes and Pseudomonas sp. were remarkably decreased. The ratio of aerobic bacteria and fungi was 1554 in sandy loam and clay loam 1144, while Bacillus sp./fungi ratio was 11 in clay loam and 10 in loam. On the topographical differences, aerobic bacteria and Bacillus sp./fungi ratio were the higher in coastal plains than any other areas. The microbial population densities from different soil types were generally lower in ill-drained paddy field than those of other paddy field. The content of $P_2O_5$, K, Ca, $NO_3-N$ and EC in soil were positively correlated to the population densities of aerobic bacteria, actinomycetes, fungi, Bacillus sp. and Pseudomonas sp.. The soil organic matter and Mg content were also positively correlated to the population densities of aerobic bacteria, actinomycetes, fungi and Bacillus sp.

• Journal of The Korean Society of Grassland and Forage Science
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• v.30 no.1
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• pp.49-58
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• 2010

This experiment was carried out to estimate the nutritive value of mixed-sowing winter forage crop and whole crop barley by investigating the effects of feeding mixed-sowing winter forage crop and whole crop barley in KBG (Korean black goat) on feed intake, average daily body weight gain, nutrient digestibility and nitrogen retention. The 12 male KBG were divided into four experimental groups - i.e. T1: barley silage added group, T2: mixed-sowing hairy vetch silage added group, T3: mixed-sowing field peas added silage, T4: mixed-sowing Italian rye grass added silage group. Three KBG per each treatment were allotted into individual metabolic cages by Latin-square design. The results from this study are as follow. The DMI (dry matter intake) and organic matter intake in T4 were significantly (p<0.05) higher than those in T1 and T3 and crude protein intake in T4 also recorded the highest among treatments (p<0.05). The highest values in intakes of ADF and NDF were observed in T4 followed by T2, T1 and T3 in order. The average daily body weight gains in T4 and T2 were significantly (p<0.05) higher than those in TI and T3. The dry and organic matter digestibility in T2 and T4 were significantly (p<0.05) higher than those in T1 and T3. The crude protein digestibility in T1 was significantly (p<0.05) lower than those in T2 and T4. The nitrogen intakes in T2 and T4 were significantly (p<0.05) higher than those in T3. The results obtained from this study suggested that the feeds supplemented with whole crop barley with hairy vetch and Italian rye grass mixture silage increased KBG productivity resulted from increases in feed intake, nutrient digestibility and nitrogen retention.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2002.11a
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• pp.124-125
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• 2002

Two experiments were conducted to investigate the response of chitosan supplementation in diet on the major economic traits of broiler in two different breeds. In the both experiments, the Arbor Acres and Ross breeds were used as experimental stocks and two groups were assigned in each breed. The control group birds(CON) were fed with basal diet only and the experimental group birds(EXP) were fed with basal diet added with 10.5mg chitosan/bird/day. The chitosan was supplied to birds from day-old in experiment 1 and from 15-day-old in experiment 2. In experiment 1, the mean body weight at 35-day-old were significantly(P〈0.05) heavier by 121.2 g and 243.7 g in the EXP groups than in the CON groups of Arbor Acres and Ross, respectively. Whereas, the mean body weights at 35-day-old in experiment 2 were lighter by 91.7 g and 70.2 g in the EXP groups than in the CON groups of Arbor Acres and Ross, respectively : however, the comparisons between breeds in the mean body weight at 35-day-old did not show significant difference in each other in both breeds. In the mean feed conversion ratio of Arbor Acres from 14 to 35-day old in experiment 1, it did not show significant difference between EXP and CON groups although the feed conversion ratio of the EXP group of Ross was significantly higher(P〈0.05) than the CON group. In experiment 2, the feed conversion ratios from 14 to 35-day-old did not show significant differences between the two breeds. The percentage of mean abdominal fat depositions of EXP groups in both breeds In experiment 1 were significantly(P〈0.05) higher than those of CON groups. And the percentage of mean abdominal fat deposition of Ross was significantly(P〈0.05) lower than that of Arbor Acres. In experiment 2, the percentage of mean abdominal fat depositions did not show significant difference between EXP and CON groups in both breeds. Whereas, the interaction effects between breed and experimental groups on the above economic traits did not show significant in both experiments.

• 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.37 no.4
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• pp.415-421
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• 2010

This work was carried out to investigate chemical composition and meat quality of crossbred Korean native chickens (KNC). Ninety 1-d male chicks were used in this work and were divided into 4 groups as A: (KNC egg-meat type C strains $\times$ KNC meat type S strains) (female) $\times$ KNC meat type H strains (male), B: (KNC egg-meat type C strains $\times$ KNC meat type H strains) (female) $\times$ KNC meat type S strains (male), C: (KNC native R strains $\times$ KNC meat type S strains) (female) $\times$ KNC meat type H strains (male), D: (KNC native L strains $\times$ KNC meat type H strains) (female) $\times$ Ross broiler (male) strains. They were fed the broiler diets for 12 weeks at the flat house and twenty seven chickens were slaughtered at week 5 and 10. Chicken thigh and breast were weighed and physicochemical compositions and sensory characteristics were investigated. Physical compositions of meats have no difference among strains at 5 week, and B strains differed from other strains at 10 week (P<0.05). The pH, moisture, and collagen content of meat from B strains were lower than other strains at 5 week. Ash and collagen of A strains were the lowest at 10 week (P<0.05), but others have no difference among strains. In sensory test, juiciness of D strains was the highest at 5 week, and tenderness of B strains was the lowest at 10 week (P<0.05). In conclusion, the crossbreeding of KNC did not affect physical traits but affected chemical composition of the chicken meat slaughtered at 5 week.

• Korean Journal of Poultry Science
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• v.37 no.4
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• pp.423-431
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• 2010

This work was carried out to investigate on the retail cut yield and the meat quality of crossbred ducks. A total of 360 pullets that were produced from 4 mating methods used in this work. Four mating method were A) native ducks (female) $\times$ native ducks (male), B) meat-type ducks (female) $\times$ native ducks (male), C) native ducks (female) $\times$ meat-type ducks (male), and D) meat-type ducks (female) $\times$ meat-type ducks (male). Ducks were bred at the flat house, and selected nine ducks with similar weights from each treatment at the certain weeks (A, B, C 8 weeks; D 6 weeks). Selected ducks were slaughtered, calculated the retail cut yield(wing, back, neck, breast, leg), analyzed the physico-chemical compositions, and tested the sensory evaluation. Wing and neck meat ratios of D treatment were lowest (P<0.05), and breast meat ratio of B treatment was high (P<0.05) compared to other treatments. pH of duck meat was no difference among treatments, fat and protein contents of B treatment was highest, and collagen contents of D treatment was highest among all treatments. Meat color and physical compositions was no difference among treatments. Juiciness of D treatment meats was highest, and there was no difference between B and D treatments. Finally, mating method of native duck and meat-type duck affected on the retail cut yield, but did not improve on the physico-chemical compositions and sensory evaluation.

• Korean journal of applied entomology
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• v.50 no.2
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• pp.157-165
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• 2011

Enterobacteria were isolated in the gut of the predacious multicolored Asian ladybird beetle, Harmonia axyridis, and their effects to the development of H. axyridis were examined. Populations of H. axyridis in this experiment were collected from Kimjae at Cheonbuk province (JK population), Geumsan at Chungnam province (CK population) and laboratory population at Laboratory of Insect Physiology in Chungnam National University, Daejeon. Thirty-four enterobacteria isolates were purified and isolated from the digestive tract of H. axyridis, and a total of 4 strains were classified into group by analysis of 16S rRNA gene sequences. About 70% of total isolates were phylogenetic groups of Bacillus genus and Staphylococcus genus, and they were commonly separated from the digestive tract of H. axyridis. After investigating their susceptibility against antibiotics with 18 representative enterobacteria isolates, ofloxacin and penicillin were selected for examination in this study of their ability to inhibit the growth of all of isolates. In order to remove the enterobacteria from the aphids, ofloxacin and penicillin were given to the green peach aphid, Myzus persicae, and the turnip aphid, Lipaphis erysimi. These aphids were provided to H. axyridis as prey. The weight of pupa, developmental periods of each larval instar, the number of eggs and their hatching ratio of H. axyridis with treatment aphids were lower compared with non-treatment aphids. Staphylococcus saprophyticus is a representative enterobacteria and commonly isolated from the digestive tract of H. axyridis. In the absence of S. saprophyticus, the developmental periods of each larval instar increased; however, the weights of pupa, the number of eggs, and their hatching ratio decreased.

• Korean Journal of Environmental Biology
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• v.22
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• pp.86-92
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• 2004

The marine viral density in the Gwangyang Bay was abundant about 2.0${\times}$10$^{8}$ particles ml$^{-1}$ . For each season, viral abundances were recorded from 9.0${\times}$10$^{8}$ particles ml$^{-1}$ in summer to 0.7${\times}$10$^{6}$ particles ml$^{-1}$ in winter. The spatial distributions of the viral, bacterial and phytoplankton biomass in the Gwangyang Bay were mostly highey in closed estuarine system (Station 2, 5, 10, 12, 16, 20) than open ocean system (Station 28, 38, 42, 46, 51), And the othey closed estuarine system (Station 22, 26, 32, 34) indicated higher viral abundances, lower bacterial and plankton biomass than open oceanic system. In depths of some stations, the bacterial abundances exceeded a hundred fold than viral abundances. Seasonal abundances of marine viruses and their host systems were dynamically changed, and their seasonal variations were closely correlated. In summer, viral and bacterial abundances were increased, and phytoplankton chlorophyll $\alpha$ concentrations were maintained in average values. In winter, viral and bacterial abundances were dramatically decreased, and chlorophyll a concentrations were decreased, but, immediately increased. The viral abundances were peaked in August 2001, and bacteyial abundance, in August 2001 and June 2002, while chlorophyll a concentrations were peaked in April. 2002. In total host and viral abundances, it was seemed that their pools were maintained to steady-states by viral mortality, and viral abundance maintained steady-states. In our assessments, this report is a unique research about marine viral ecology of the Gwangyang Bay in Korea.

• The Korean Journal of Ecology
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• v.28 no.5
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• pp.305-320
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• 2005

Recently 64 species in Korea have been ranked as rare and endangered taxa by the Ministry of Environment using two categories, I and II. The original threat categories produced by the Ministry of Environment were developed to provide a standard for specifying animals and plants in danger of extinction and has been influential sources of information used in species conservation in Korea. However, the criteria by Ministry of Environment were applied to the whole taxa only by regional boundaries, especially in South Korea, rather than international context, and it also lacked an explicit framework that was necessary to ensure repeatability among taxa because of the absence of quantitative criteria to measure the likelihood of extinction. The World Conservation Union (IUCN) has developed quantitative criteria for assessing the conservation status of species. The threatened species categories, the 2000 IUCN Red List, proposed by SSC (Species Survival Commission) of IUCN have become widely recognized internationally. Details of threatened Korean plants, identified by applying the IUCN threat categories and definitions, were listed and analyzed. The number of species identified as threatened was only 34 out of 64 taxa (48.4%), while the rest of taxa were rejected from the original lists. Many of the species (51.6%, 33 taxa) excluded from the original list proposed by Ministry of Environment do not qualify as Critically Endangered, Endangered or Vulnerable because these taxa were widely distributed either in Japan or in China/far eastern Russia and there is no evidence of substantial decline in these countries. An evaluation of taxa in Korea has been carried out only based on subjective views and qualitative data, rather than quantitative scientific data, such as rates of decline, distribution range size, population size, and risk of extinction. Therefore, the national lists undermine the credibility of threatened species lists and invite misuse, which have been raised by other cases, qualitative estimate of risk, political influence, uneven taxonomic or geographical coverage. The increasing emphasis on international responsibilities means that global scale is becoming more significant. The current listings by Environment of Ministry of Korea should be challenged, and the government should seek to facilitate the resolution of disagreements. Especially the list should be flexible enough to handle uncertainty and also incorporates detailed, quantitative data. It is suggested that the highest priorities for the Red List should be given to endemic species in Korea first. After setting up the list of endemic species to Korea, quantitative data on population size and structure, distributional range, rated of decline, and habitat fragmentation should be collected as one of long term projects for the Red list categories. Transparency and accountability are the most important key factors. Also, species assessors are named and data sources referenced are required for the future objective evaluations on Korean plant taxa.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.5 no.4
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• pp.285-294
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• 2000

In order to determine the horizontal and vertical distributions of metals and prospect the recent metal pollution history in Nakdong Estuary, we took surface and core sediments. Maximum value of organic matter occurs at the upstream site located 4 km from Nakdong barrage, and the concentration of trace metals (Zn, Cu, and Pb etc.) decrease seaward in the estuary. The sedimentation rates, based on $^{210}$Pb$_{ex}$ and $^{137}$Cs activities, were 0.34 cm/yr in inside of barrage (core 1) and 0.25 cm/yr in Changrim (core 4). Sediment mixing layer does not exist in core 1, where anoxic condition is known to be prevail. The topmost sediment layer of core 4 (<3.5 cm) is severely mixed. At sites 1 and 4, concentrations of Cu slowly increased during the period of 1920-1970, rapidly increased during 1970-1990, and followed by slight decrease after 1990. Zn contents increased in early 1960s and peaked in 1993, and followed by decrease after 1990s. Pb has increased continuously since early 1970s. At the downstream of the barrage, Cu and Zn have increased in the topmost layer. The trend of increase of Cu is evident after 1950 (11 cm in sediment depth). Overall trend of heavy metal concentration clearly indicates the pollution has been increasing after the construction of the barrage.