• Journal of Practical Agriculture & Fisheries Research
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• v.11 no.1
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• pp.113-123
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• 2009

This study was carried out to determine effects of long-term supply of Cordyceps militaris mycelia on cordycepin content in milk in dairy cows. Ten Holstein cows in the early stages of lactation were divided into two groups. Control group received no supplement whereas treatment group received 6% of C. militaris mycelia of their dry matter intake for 6 months. Feed intake, milk urea nitrogen and somatic cell counts were not affected by long-term supply of C. militaris mycelia for the whole period. In addition, milk yield and milk composition were not affected by long-term supply of C. militaris mycelia at any time of the periods with the exception of milk protein content and yield. The average of milk protein content and yield from the whole period was higher for C. militaris mycelia supplement group than for the control group. As expected, cordycepin in whole blood and milk was not detected in the control group. The range of cordycepin content in the treatment was 0.31~0.38µ/ml and 0.18~0.26(µ/ml for whole blood and milk, respectively. Individual variation was found to be very high and, furthermore cordycepin was undetected in some milk samples. Thus, no clear pattern could be seen in cordycepin content in milk throughout the whole period. Overall, the results of the present study suggest that the transfer efficiency of cordycepin to milk by supplementing C. militaris mycelia in dairy cows was unpredictable and low.

• Journal of Practical Agriculture & Fisheries Research
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• v.10 no.1
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• pp.43-58
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• 2008

This research was conducted to determine the alternative tool of chemical spray for rice cultivation using the unmanned helicopter(Yamaha, R-Max Type 2G-remote controlled system) at farmer's field in Korea. The unmanned helicopter tested was introduced form Japan. In Korea the application of chemicals by machine sprayer for pest management in rice cultivation has been ordinarily used at the farmer's level. However, it involved a relatively high cost and laborious for the small scale of cultivation per farm household. Farm population has been highly decreased to 7.5% in 2002 and the population is expected to rapidly reduce by 3.5% in 2012. In Japan, pest control depending on unmanned helicopter has been increased by leaps and bounds. This was due in part to the materialization of the low-cost production technology under agricultural policy and demand environmentally friendly farm products. The practicability of the unmanned helicopter in terms of super efficiency and effectiveness has been proven, and the farmers have understood that the unmanned helicopter is indispensable in the future farming system that they visualized. Also, the unmanned helicopter has been applied to rice, wheat, soybean, vegetables, fruit trees, pine trees for spraying chemicals and/or fertilizers in Japan Effect of disease control by unmanned helicopter was partially approved against rice blast and sheath blight. However, the result was not satisfactory due to the weather conditions and cultural practices. The spray density was also determined in this experiment at 0, 15, 30, and 60cm height from the paddy soil surface and there was 968 spots at 0cm, 1,560 spots at 15cm, 1,923 spots at 30cm, and 2,999 spots at 60cm height. However, no significant difference was found among the treatments. At the same time, there was no phytotoxicity observed under the chemical stray using this unmanned helicopter, nor the rice plant itself was damaged by the wind during the operation.

• Journal of Practical Agriculture & Fisheries Research
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• v.4 no.1
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• pp.110-118
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• 2002

This study was conducted to investigate the physiology of optimal reproductive age in Hanwoo for protection to decrease of reproductivity and improvement of production of offspring. Thirty two cows were devided into 4 groups of treatments : T1(12 months of age and 0.5kg daily gain), T2(12 months of age and 0.8kg daily gain), T3(15 months of age and 0.5kg daily gain) and T4(18 months of age and 0.5kg daily gain). The days of the first heat of treated cows were 263.3±6.4 days and average weight was 181.1±11.3kg. The conception rates of first insemination were 25%(T1) and 75%(T4), and the number of insemination of T3 and T4(both 1.5) was lower than those of T1 and T2(2.3 and 2.4), respectively. With regard to estrus return after the first parturition, T1, T2, T3 and T4 showed 66.2,76.7, 62.4 and 68.5 days, respectively, indicating the average days of estrus return was 65.7. Plasma progesterone(P4) concentration was nearly the same during the observation periods of treated cows and P4 began to be detected after 12months. Only 5(15.6%) out of 32cows showed normal estrus cycle and ovulation before 12 months. During the peri-parturition period, P4 concentration was rapidly decreased and there was no detection of P4 from parturition to 40 days after milking. P4 would be released again on 45 day after parturition. The results imply that the optimal reproductive age of Hanwoo heifers would be around at the 14 months of age, 110cm height and 265kg weight.

• Journal of Practical Agriculture & Fisheries Research
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• v.11 no.1
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• pp.35-51
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• 2009

Three different Cordyceps militaris(Paecilomyces tenuipes and Cordyceps militaris from grain or pupae) were analysed for their chemical composition, fatty acids composition and the concentration of amino acids, cordycepin and heavy metal to obtain basic information on them as feed supplements for livestock. The crude protein content of C. militaris from grain and pupae was 76.16 and 75.45%, respectively, being higher than that of P. tenuipes(57.21%). The concentration of linoleic acid was much higher but that of linolenic acid was much lower for C. militaris from grain than for the others. The cordycepin content was significantly higher for C. militaris from grain than for that from pupae (1.64% vs 0.68% on a DM basis). But cordycepin was not detected in P. tenuipes. Heavy metal contents(Cr, Pb, Cd, Hg) for all C. militaris were below the allowance levels recommended by Ministry of Agriculture and Forestry in Republic of Korea.

• Journal of Practical Agriculture & Fisheries Research
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• v.20 no.1
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• pp.163-174
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• 2018

Rice cultivation is immensely affected by many climatic factors including temperature, precipitation, etc, and imbalanced climatic conditions negatively affect the growth of rice. In this study, we investigated the effects of different agroclimatic zones of Chungnam Province on rice quality and examined the correlations between climatic characteristics and rice yield components. Average temperatures and rainfall were higher in 'Western Sobaek Inland' than those in the 'South Western coastal zone, and precipitation records showed a wide variation among counties due to typhoons during the examined periods. The average accumulative temperature affecting the magnitude of production during reproductive growth periods was higher in "Cheon-An", "Gong-Ju", "Yeon-Gi (Se-Jong)", "Bo-Ryeong", and "Dang-Jin" counties than those in other counties. The plant height was higher in 'Western Sobaek Inland' counties such as "Yeon-Gi(Se-Jong)" and "Cheon-An", and 'Southern Charyeong Plain' counties such as "Cheong-Yang", "Dang-Jin", and "A-San", than those in other counties. The number of tillers during the 40 days after rice transplantation in "Seo-Cheon" and "Bo-Ryeong" counties increased compared to other counties. This result was relevant to the fact that the date of rice transplantation in those counties was 3 to 4 days later than those in other counties of Chung-Nam Province. The average yield (milled rice basis) was the highest in 'Western Sobaek Inland' zone, showing 3,756 kg ha^-1, followed by 'Southern Charyeong Plain' zone showing 3,621kg ha^-1, and was the lowest in 'South Western coastal zone by 3,315kg ha^-1. "Yeon-Gi(Se-Jong)" and "Dang-Jin" counties showed the highest yields of 4,100kg ha^-1. "Seo-San", "Seo-Cheon", and "Tae-An" counties were relatively lower yields of 3,240~3,280kg ha^-1 in comparison of other counties.

• Korean Journal of Remote Sensing
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• v.39 no.6_2
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• pp.1635-1650
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• 2023

Under global warming, the steadily increasing sea surface temperature (SST) severely impacts marine ecosystems,such as the productivity decrease and change in marine species distribution. Recently, the catch of Todarodes Pacificus, one of South Korea's primary marine resources, has dramatically decreased. In this study, we analyze the marine environment that affects the formation of fishing grounds of Todarodes Pacificus and develop seasonal habitat suitability index (HSI) models based on various satellite data including Geostationary Ocean Color Imager (GOCI) data to continuously manage fisheries resources over Korean exclusive economic zone. About 83% of catches are found within the range of SST of 14.11-26.16℃,sea level height of 0.56-0.82 m, chlorophyll-a concentration of 0.31-1.52 mg m^-3, and primary production of 580.96-1574.13 mg C m^-2 day^-1. The seasonal HSI models are developed using the Arithmetic Mean Model, which showed the best performance. Comparing the developed HSI value with the 2019 catch data, it is confirmed that the HSI model is valid because the fishing grounds are formed in different sea regions by season (East Sea in winter and Yellow Sea in summer) and the high HSI (> 0.6) concurrences to areas with the high catch. In addition, we identified the significant increasing trend in SST over study regions, which is highly related to the formation of fishing grounds of Todarodes Pacificus. We can expect the fishing grounds will be changed by accelerating ocean warming in the future. Continuous HSI monitoring is necessary to manage fisheries' spatial and temporal distribution.

• Journal of Aquaculture
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• v.21 no.4
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• pp.265-271
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• 2008

Upper temperature tolerance of the turbot Scophthalmus maxim us, one of the popular aquaculture species in European community and China, was evaluated in terms of survival and growth at $20^{\circ}C$, $23^{\circ}C$, $26^{\circ}C$, or $29^{\circ}C$. Best growth was achieved at temperature $20^{\circ}C$ in this experiments. The fish exposed to $20^{\circ}C$ or $23^{\circ}C$ were comparable in survival, condition factor and feed conversion efficiency reminiscent of the latter temperature to be agreeable for the fish. The temperature over $23^{\circ}C$ appeared to be the temperatures beyond the fish can tolerate. For instance, the fish exposed to 26 showed mortality of 60.9% by day 60; none of the fish exposed to $29^{\circ}C$ survived beyond day 7. Culture densities between 80 and $200\;fish/m^2$ did not influence the survival, growth, condition factor and specific growth rate of the fish. The final production of the culture density experiment was $10\;kg/m^2$ on average. These results imply that the location where water temperature remains lower than $25^{\circ}C$ during summer can be a candidate site for the turbot aquaculture.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.8
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• pp.1141-1149
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• 2014

The present study was conducted to investigate a supplemental effect of magnesium hydrogen phosphate (MHP, $MgHPO_4$) as an alternative phosphorus (P) source on growth and feed utilization of juvenile far eastern catfish (Silurus asotus) in comparison with three conventional P additives (monocalcium phosphate (MCP), dicalcium phosphate (DCP) and tricalcium phosphate [TCP]) as positive controls. A basal diet as a negative control was prepared without P supplementation and four supplemental P sources were added at the level of 2%. Five groups of 450 fish having mean body weight of 11.3 g following 24 h fasting after three week adaptation period were randomly distributed into each of 15 tanks (30 fish/tank). Fish were hand-fed to apparent satiety twice a day for 8 weeks. Fish fed MHP had weight gain (WG), protein efficiency ratio and specific growth rate comparable to those fed MCP. Fish fed MHP and MCP had feed efficiency (FE) significantly higher (p<0.05) than those fed DCP. Fish groups fed control and TCP showed the lower FE than the other groups which was significantly different (p<0.05) from those of fish fed the other diets. Survival rate was not significantly different (p>0.05) among treatments. Fish fed control had the lowest hematocrit, which was significantly different (p<0.05) from that of fish fed MHP. Fish fed MCP and MHP had plasma P higher (p<0.05) than fish fed the other diets. Relative efficiencies of MCP, DCP and TCP to MHP were found to be 100.5 and 101.3%, 92.0 and 91.6%, and 79.1 and 80.9% for WG and FE, respectively. P availability was determined to be 88.1%, 75.2%, 8.7%, and 90.9% for MCP, DCP, TCP, and MHP, respectively. Consequently, MHP recovered from wastewater stream showed that as an alternative P source its performance was comparative with MCP on growth and feed utilization of juvenile far eastern catfish.

• Development and Reproduction
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• v.17 no.4
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• pp.345-351
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• 2013

This study examines the effects on fertilization rate (FR), hatching rate (HR), and normal individual rate after artificial fertilization using frozen thawed sperm according to the cryoprotectant (DMSO) concentration and the period of cryopreserved sperm of longtooth grouper, Epinephelus bruneus. Performing artificial fertilization using frozen-thawed sperm, after freezing the sperm at different DMSO concentration of 5.0%, 7.5%, 10.0% respectively, FR were (DMSO 5.0%: $99.5{\pm}0.8%$, DMSO 7.5%: $99.5{\pm}0.7%$, and DMSO 10.0%: $99.6{\pm}0.6%$). The results are not significantly different from the control fresh sperm (100%). HR also (DMSO 5.0%: $96.2{\pm}2.3%$, DMSO 7.5%: $95.3{\pm}3.6%$, 10.0%: $96.6{\pm}1.8%$) were not significantly different in each group. The normal individual rate after hatching using with control fresh sperm ($98.4%{\pm}0.5$) and DMSO concentration level of 5.0% ($97.8{\pm}0.1%$) were not significantly different. However, with 7.5% ($97.2{\pm}0.6%$) and 10.0% DMSO concentrations ($95.9{\pm}0.2%$) are lower than the normal individual rate after hatching observed in the control and 5.0% DMSO. Performing artificial fertilization using frozen-thawed sperm at different frozen period (2 days, 2 years, and 3 years), 10% DMSO FR and HR of 3 years (FR; $66.8{\pm}1.8%$, HR: $82.0{\pm}12.9%$) and 2 years (FR; $78.5{\pm}14.8%$, HR: $79.3{\pm}0.6%$) cryopreserved sperm were lower than control (FR; 100%, HR: $91.1{\pm}3.6%$) and 2 days cryopreserved sperm (FR; $99.6{\pm}0.6%$, HR: $96.6{\pm}1.8%$). These results suggest suitable DMSO concentration ranges of cryopreservation sperm for E. bruneus is 5 to 10% and with 2 to 3 years cryopreservation period, cryopreservation sperm can be useful for seed production.

• Korean Journal of Ichthyology
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• v.27 no.1
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• pp.10-15
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• 2015

Giant grouper (Epinephelus lanceolatus) is a endangered species considered as a vulnerable grade-organism in the International Union for Conservation of Nature (IUCN) red list. As a fundamental baseline study for establishing a giant grouper broodstock management system, the efficiency for parentage analysis was evaluated by using microsatellite makers previously available in this species. The eight microsatellites generated a total 52 alleles from 32 individuals, the mean expected heterozygosity was 0.663, and mean inbreeding coefficient was 0.011, consequently suggesting that the present broodstock has retained the high level of genetic diversity. However, our analysis also recommended the collection of more broodfish for more stable brood line, since the estimated value of the effective population size was proven to be 35. The average probability of identity was $6.85{\times}10^{-11}$. NE-2P and NE-PP of paternity non-exclusion probabilities were 0.00835 and 0.00027, respectively. As the result of principle coordinate analysis, the genotype of broodstock was not overlapped, suggesting that the management system of giant grouper based on eight selected microsatellite markers might be effective, although further validation with extended number of broodfish might also be needed in future. Data of present study could be a useful basis to avoid the unwanted selection of broodfish that possess close genetic relationship with current broodstock, and consequently to establish effective broodstock management system allowing the production of progeny with high genetic diversity.