• International Journal of Industrial Entomology and Biomaterials
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• v.16 no.2
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• pp.93-99
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• 2008

The turnip aphid is a worldwide pest, damaging mainly to crucifers. In order to understand the life parameters of Lipaphis erysimi for the eventual goal of control, the developmental periods, survival rates, lifespan, and fecundity of the species were investigated under five temperature regimes ($15^{\circ}C-35^{\circ}C$). Furthermore, the efficacy of several environment-friendly agricultural materials (EFAMs) that are on the market was subjected to test in order to obtain further accurate information. The developmental period of the turnip aphid nymph was longest at $15^{\circ}C$ as 16.9 days, shortened as temperature goes up to $25^{\circ}C$ (5.4 days), and then somewhat increased at $30^{\circ}C$ (5.9 days), suggesting that the most efficient temperature for nymphal development could be around $25^{\circ}C$. Mortality of the nymphal turnip aphid was obvious at $35^{\circ}C$, whereas it was minimal at other temperature schemes. The longevity of adults shortened as temperature goes up to $30^{\circ}C$. In particular, the maximum lifespan for adults continued for 55 days at $15^{\circ}C$, but shortened to 21 days at $30^{\circ}C$. The total fecundity was 35.7 at $15^{\circ}C$, 81 at $20^{\circ}C$, 64.2 at $25^{\circ}C$, and 6.6 individuals at $30^{\circ}C$, showing the highest fecundity at $20^{\circ}C$. After the turnip aphids were successfully stabilized in indoor environment the insecticidal activity was tested and mortality was determined 12, 24, 36, and 48 hrs after EFAMs are treated. Several on-the-market EFAMs showed more than 90% of insecticidal activity within 24 hrs or 48 hrs, but a few showed less than 90% activity, signifying importance of selection of proper EFAMs.

• Journal of fish pathology
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• v.20 no.2
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• pp.129-137
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• 2007

Skeletal deformity in hatchery-reared river puffer (Takifugu obscurus) fingerlings occurred. The vertebral abnormality was recognized with naked eyes 80 days after hatching. Affected fish had a good appetite but no clinical signs were found except the vertebral abnormality. As more than 90% of the hatchery-reared fish exhibited vertebral abnormality, the fingerlings could not be used for commercial seeds any more. Morphological changes in the vertebrate and the swim bladder were observed with a soft X-ray. Histopathological changes on the caudal muscle around the deformed vertebrae, gill, and spleen were also examined to clarify the cause of the deformity. Spinal curvature occurred between vertebrae 10 and 12, but any malfunction of the swim bladder was not found. The diameters of the muscle fibers around the deformed vertebrae were much smaller and more irregular than those in normal fish, and the gabs between the fiber bundles were greatly enlarged. No evidence of inflammation response was found in the muscle layer. In the hatchery, feed was putting at the position of water inflow, which might attract the fingerings to move toward the feed in spite of incomplete development of their caudal muscle fibers. From these results, it is suggested that the high speed of water current in rearing aquaria might be associated with the development of vertebral abnormality.

• Journal of Aquaculture
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• v.3 no.1
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• pp.39-48
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• 1990

The growth response of the yellow perch, a highly proteinaceous food feeder in nature, to different protein levels (50, 40 and $27\%$) in formulated diets was determined over a 20-week period. Approximately $23\%$ of dietary protein could be spared by substituting less expensive carbohydrate and lipid materials without any noticeable ill-effects or reduction in weight gains. In turn, there was no statistically significant difference between total weight gains of fish fed at three different levels of protein diets, although fish on the 50 and $40\%$ protein diets grew better in the first few weeks. A shift in the protein requirements occur-red after about 10 weeks of rearing. Growth efficiencies(growth/food intake) became nearly the same at all levels of protein and decreased consistently throughout the remainder of the study period. The results indicate that young yellow perch(6g initial weight) can grow normally with the $27\%$ protein diet after about 10 weeks of initial feeding with higher protein diets(or regular commercial diets).

• Journal of Microbiology and Biotechnology
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• v.17 no.4
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• pp.547-559
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• 2007

Bacillus thuringiensis (Bt) was first described by Berliner [10] when he isolated a Bacillus species from the Mediterranean flour moth, Anagasta kuehniella, and named it after the province Thuringia in Germany where the infected moth was found. Although this was the first description under the name B. thuringiensis, it was not the first isolation. In 1901, a Japanese biologist, Ishiwata Shigetane, discovered a previously undescribed bacterium as the causative agent of a disease afflicting silkworms. Bt was originally considered a risk for silkworm rearing but it has become the heart of microbial insect control. The earliest commercial production began in France in 1938, under the name Sporeine [72]. A resurgence of interest in Bt has been attributed to Edward Steinhaus [105], who obtained a culture in 1942 and attracted attention to the potential of Bt through his subsequent studies. In 1956, T. Angus [3] demonstrated that the crystalline protein inclusions formed in the course of sporulation were responsible for the insecticidal action of Bt. By the early 1980's, Gonzalez et al. [48] revealed that the genes coding for crystal proteins were localized on transmissible plasmids, using a plasmid curing technique, and Schnepf and Whiteley [103] first cloned and characterized the genes coding for crystal proteins that had toxicity to larvae of the tobacco hornworm, from plasmid DNA of Bt subsp. kurstaki HD-1. This first cloning was followed quickly by the cloning of many other cry genes and eventually led to the development of Bt transgenic plants. In the 1980s, several scientists successively demonstrated that plants can be genetically engineered, and finally, Bt cotton reached the market in 1996 [104].

• Korean journal of applied entomology
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• v.42 no.2
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• pp.139-144
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• 2003

The effect of $CO_2$-treatment on interrupting diapause of Bombus ignitus was examined to provide a means for year-round rearing of the bumblebee. When mated young queens were exposed to 65% or 99% $CO_2$ for 30 min daily during two consecutive days, oviposition rate increased to 75% and 77%, respectively, comparing 50% in $CO_2$-untreated queens. At the same time, the days needed to first oviposition shortened to 17-18 days in $CO_2$-treated queens, comparing to 30 days in $CO_2$-untreated queens. $CO_2$-treatment at the second day after mating was appropriate to the oviposition and colony development. $CO_2$-treatment showed a positive effect on the oviposition and colony development, but less than them of overwintered queen in numbers of produced progeny. It can be concluded that $CO_2$-treatment to B. ignitus is insufficient to produce commercial grade bumblebee colony in spite of its capability for promoting oviposition, because the treatment failed to form a big colony.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.16 no.2
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• pp.59-67
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• 1983

An experiment on the rearing of tilapia stocked in closed recirculating tanks eliminating biological filter beds was carried out at the Fish Culture Experiment Station of the National Fisheries University of Pusan, from May 18 through October 21, 1982, and the growth rates, feed conversion, water quality, spawning prevention and space utilization efficiency were discussed. Finally discussed is the feasibility on the establishment of commercial production units. On the water quality, the water temperature ranged from $22.8^{\circ}C\;to\;29.1^{\circ}C$, and total ammonia arround 10 ppm or slightly up. Maintaining phytoplankton bloom was not successful probably because of the active consumption by the heavily stocked tilapia. Several attempts were made by changing the culture water with green water from a nearby earthen pond with results of fading-away in a couple of days. Feed conversions were relatively high ranging from 0.9 to 1.2 except for experiment 1 when the fish were not fully recovered from weakened wintering state. The feed used was partly laboratory prepared $25\%$ protein diet and mostly commercially available $39\%$ protein carp feed. Spawning was completely controlled during the experiment, resulting from density effect, which ranged from 10kg to 40.7kg per square meter with water depth of 0.5 to 0.6m. Space utilization efficiency was very high. Daily net production from the experiment division 3, which showed the highest result, was 6.206 kg per tank, which is calculated 3,235 metric tons per hectare per year, This time, water temperature ranged from 27.8 to $29.1^{circ}C$, average being $28.4^{circ}C$, and total ammonia arround 10 ppm. An estimation for the commercial set-up of the production system based on the results of experiment divisions which had initial stocking rate $15\;kg/m^2$ or up, is made. If the total facility, 8 tanks comprising $56\;m^2$ in surface area, is used for the present study, the yield would become 5,639 kg from 200 day rearing, which would be possible under double sheets vinyl house without additional heating, and it is thought feasible in the economic view point, when 10 or more units are operated.

• Korean Journal of Environment and Ecology
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• v.30 no.4
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• pp.694-704
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• 2016

Various infectious and parasitic diseases are known to be the main factors that cause decline in the global amphibian population. In Korea, commercial frog farms have been running since 2005. However, until now, studies on diseases including studies on parasitic diseases that occur in farm frogs have not been conducted. In this study, we studied and compared the acanthocephalan infection rates and the number of parasites in the body cavity, stomach, and small and large intestines of the Dybowskii's brown frogs collected from inside and outside the frog farms in Inje, Goesan, Gongju and Boryeong. In addition, we classified the acanthocephalan parasites into genera by analyzing their nuclear 18S rRNA genes. On an average, 51.7% of the investigated frogs were infected by acanthocephalans, which belong to the Centrorhynchus genus. The infection rate of the frogs collected in the Inje farm was 15%, significantly lower than those from the Goesan, Gongju and Boryeong farms. The rate in Goesan was 55%, which is lower than Gongju (80%) and Boryeong (90%) although it is not statistically significant. No difference was found in the infection rate and in the number of parasites in male and female frogs and between the groups collected from inside and outside of the farms. The number of infected parasites negatively correlated with the body condition of the frogs. The most parasites were found in the stomach followed by the small and large intestines and the body cavity. This study is the first report on the Centrorhynchus acanthocephalan infection of amphibians in Korea and it suggests the necessity for acanthocephalan parasite management and for conducting further disease-related studies in commercial frog farms.

• Journal of Marine Life Science
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• v.8 no.2
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• pp.166-177
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• 2023

The giant freshwater prawn (Macrobrachium rosenbergii) suffers economic losses in aquaculture facilities due to problems such as poor body color and carapace weakness. While this species is farmed on an animal-based diet, in the wild it consumes a detritus diet with a high proportion of plant matter. The plant matter they consume in the wild is not only a source of basic nutrients, but also carotenoids, which are responsible for body color. Korean goldenbell (Forsythia koreana) is a flowering tree widely distributed in Korea, and its leaves contain carotenoids comparable to yellow carrots. In this study, we investigated the effects of feeding Forsythia leaves to M. rosenbergii on their body color and health. The experimental diets were 100% commercial feed (control), CON, 80% commercial feed plus 20% Forsythia leaf powder, FP, and 80% commercial feed plus 20% unprocessed Forsythia leaves, FL, and each diet was fed to juvenile prawn with an average weight of 1.1 ± 0.2 g for 10 weeks. In terms of body color, the CON prawn were consistently clear ivory in color, while the FP and FL prawn changed from blue to dark brown as the days of rearing progressed. Survival and growth were not significantly different between CON and FP or FL. Histological comparison of the hepatopancreas revealed that the vacuole size of B cells, the constituent cells of the hepatopancreatic tubule, was significantly larger in FP and FL compared to CON. The vacuoles of B cells are responsible for the absorption and digestion of nutrients, suggesting that the supply of Forsythia leaves may have had a positive effect on the health of the M. rosenbergii. The above results show that the use of Forsythia leaves in the aquaculture of M. rosenbergii can be expected to improve body color and health without inhibiting growth.

• Korean Journal of Poultry Science
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• v.6 no.2
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• pp.75-81
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• 1979

This study was carried out to select superior dual purpose hens which could spread to poultry farming for subsidiary work and general farmhouse. Three hundred and fifty chicks of 7 kinds of 2-way crossbred from mating of Rhode Island Red, New Hampshire and Australorps were tested for dual purpose performance. The results obtained were as follows: 1. The average viability of brooding, rearing and laying Period hen were 92.3% 98.3% and 93.1% respectively. There was significant difference at 1% level among crossbreds for brooding viability, but other viabilitys were no significant difference. 2. The average body weight of 8 weeks was 854.41g, but there was no significant difference among crossbreds, respectively. Average body weight at 300 days, 500 days were 2507.15g, 2632.25g respectively, but there was significant difference at 1% level among crossbreds. 3. Sexual maturity of individual and 50% egg production were 173.7 days and 199.4 days, respectively. There was significant difference at 5% level among crossbreds. 4. The average hen day egg production was 65.3% and the highest was R.N crossbred (70.5%). There was significant difference at 5% level among crossbreds and average hen housed egg Production was 20.2 eggs and the highest was 220.4 eggs in R.A. crossbred. 5. The average egg weight was 57.36g and the highest was A.N crossbred (58.3g). Therc was no significant difference among crossbreds. 6. The average feed consumption per hen per day by stag. was 42.9g (brooding period), 83.7g (rearing period), 131.1g (laying period). Average feed requirement per 1kg. egg production was 3.79 and th. R.A. crossbred was superiority (3.42). 7. On the basis of the results of this study, the R.A and R.N crossbreds were best for superior dual commercial chicks under farming management conditions.

• Journal of Aquaculture
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• v.18 no.3
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• pp.147-153
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• 2005

The objective of this study is to elucidate the growth pattern of dark-banded rockfish, Sebastes inermis Cuvier, produced by aquaculture in Korea. Larvae from 250 maternal full-sibs were reared until 1,350 days after parturition. During the rearing period, growth equations on days after parturition (X) to the total length (TL) and body weight (BW) were estimated as TL=0.0217X $(r^2=0.8867)$ and $BW=0.0001X^2+0.0713X\;(r^2=0.9858)$, respectively. The relationship between BW and TL was $BW=0.0072TL^{3.4373}\;(r^2=0.9945)$. An increases in the eye diameter (ED) of dark-banded rockfish larvae on days after parturition (X) could be expressed as $ED=-2E-5X^2+0.0326X\;(r^2=0.9886)$. Relative growth equations on TL to head length (HL), snout length (SL), ED and postorbital head length (PHL) were calculated as $HL=0.2652TL\;(r^2=0.9758),\;SL=0.0613TL\;(r^2=0.9602),\;ED=0.0752TL\;(r^2=0.9715)$ and $PHL=0.2652TL\;(r^2=0.9501)$, respectively. Since there were few reports on the long-term growth experiment of this species due to difficulties in rearing techniques, results of this study would give a useful information to the biology and commercial culture techniques of dark-banded rockfish.