• Korean Journal of Medicinal Crop Science
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• v.19 no.5
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• pp.319-324
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• 2011

This study was carried out to investigate the effect of Lythrum salicaria L. ethanol extract on anti-obesity effects in rat fed a high fat diet for 8 weeks to induce obese rat model. Male SD rats were divided into normal group, control (high fat diet) group, positive control (Garcinia Cambogia extracts) group, high fat group supplemented with ethanol extracts of Lythrum salicaria L. (EELS). The body weight gain and control (high fat diet) were increased by a high fat diet, but decreased in the EELS. At the end of the experiment, the body weight in high fat diet groups was higher than that of normal diet group, while the body weights of EELS and positive control group were significantly reduced by 16.62%, as compared with that of high fat diet group (p < 0.05). The levels of serum triglyceride, total cholesterol in EELS group were significantly decreased as compared with high fat diet group (p < 0.05). The liver and mesenteric adipose tissue weights of control (high fat diet) increase than that for normal group, whereas EELS and positive control group were significantly decreased (p < 0.05). Levels of triglyceride in liver were significantly lower in EELS group than those in high fat diet group (p < 0.05). These results indicate that Lythrum salicaria L. extract may improve lipid metabolism and reduce fat accumulation and body weight.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.6
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• pp.770-776
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• 2017

This study investigated the effects of recombinant eel gonadotropin hormone (rJeGTH) produced in silkworms, with and without a carboxyl-terminal peptide from equine chorionic gonadotropin (eCG), on the induction of sexual maturation in female eels Anguilla japonica. Experiments were conducted both in vivo and in vitro. In in vitro trials, germinal vesicle breakdown (GVBD) induction did not significantly differ between rJeFSH and $rJeFSH{\cdot}eCG$ treatments and the control group. However, previous studies did find that rJeLH and $rJeLH{\cdot}eCG$ treatments induced GVBD in female eels. Our in vitro exploration of $estradiol-17{\beta}$ ($E_2$) levels in immature ovarian tissues revealed significantly higher $E_2$ levels in the group treated with $rJeFSH{\cdot}eCG$ $1{\mu}g/mL$ than in the control group. In contrast, the in vivo experiments showed no effect of recombinant hormones on the sexual maturation of feminized eels. Previous studies and our own in vitro results have clearly shown that rJeGTH and $rJeGTH{\cdot}eCG$ have a positive effect on the sexual maturation of feminized eels. To develop the activity of rJeGTH in vivo, further studies should confirm circulation time and activity of these hormones in eels' bloodstream, modify the structure of the recombinant gene, and implement additional glycosylation.

• Journal of Aquaculture
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• v.16 no.4
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• pp.273-278
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• 2003

The present study provides nutritional characteristics of body composition based on the different collected locations and body sizes in wild eels, Anguilla japonica. Eels were collected in Kyungho river, near the Sachun bay (Gyeongnam) and Inchun river, near Gochang, Jeonnam. Eels were divided by size into the following groups: less than 100 g (Gochang: 75.8$\pm$17.6 g, Sachun: 89.3$\pm$6.42 g) and more than 200 g group (Gochang: 215$\pm$8.95 g, Sachun: 236$\pm$11.7 g). The moisture content of individuals in Gochang area (Gw) was higher than that in Sacheon area (Sw). In the results of proximate analysis, the ranges of moisture, crude protein, crude fat, and crude ash were 63∼72, 16∼20, 6.1∼15.4 and 2.2∼2.8%, respectively. Moisture and crude fat were significantly different (P<0.05) based on the captured locations. In fatty acid composition, the ranges of saturates, monoenes, polyenes, and n-3 PUFA content were 38.0∼48.0, 51.5∼58.5, 1.95∼4.12 and 0.68∼1.53%, respectively. It was significantly different (P<0.05) based on the captured locations. In the amino acid composition, the ranges of essential and non-essential amino acids were 7.11∼12.5 and 8.34∼ 12.9%, respectively. These values were not significantly different (P>0.05) based on the captured locations, however these were significant different (P<0.05) based on their body weight. Therefore, these results indicated that the different body composition depends on the different captured locations and body sizes. Furthermore, it is necessary to examine more varied locations and body sizes for their body composition in eels.

• Parasites, Hosts and Diseases
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• v.53 no.5
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• pp.619-625
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• 2015

The present study was performed to determine the infection status of swamp eels with Gnathostoma sp. larvae in Myanmar. We purchased total 37 Asian swamp eels, Monopterus albus, from a local market in Yangon in June and December 2013 and 2014. All collected eels were transferred with ice to our laboratory and each of them was examined by the artificial digestion technique. A total of 401 larval gnathostomes (1-96 larvae/eel) were detected in 33 (89.2%) swamp eels. Most of the larvae (n=383; 95.5%) were found in the muscle. The remaining 18 larvae were detected in the viscera. The advanced third-stage larvae ($AdL_3$) were 2.3-4.4 mm long and 0.25-0.425 mm wide. The characteristic head bulb ($0.093{\times}0.221mm$ in average size) with 4 rows of hooklets, muscular long esophagus (1.025 mm), and 2 pairs of cervical sacs (0.574 mm) were observed by light microscopy. The average number of hooklets in the 1st, 2nd, 3rd, and 4th rows was 41, 45, 48, and 51, respectively. As scanning electron microscopic findings, the characteristic 4-5 rows of hooklets on the head bulb, a cervical papilla, tegumental spines regularly arranged in the transverse striations, and an anus were well observed. Based on these morphological characters, they were identified as the AdL3 of Gnathostoma spinigerum. By the present study, it has been confirmed for the first time that Asian swamp eels, M. albus, from Yangon, Myanmar are heavily infected with G. spinigerum larvae.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.14 no.1
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• pp.29-31
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• 1981

The eels Anguilla japonica were reared in an indoor aquarium of $1m{\times}1m{\times}0.67m$ from June 7 to August 8, 1980. The eels used for the experiment were the smallest ones which were left over from 1974 to 1976 groups, of which the others grew out years earlier. The eels were fed pelletized feed, with the results of 1.05 to 1.678 in feed coefficient, and 0.96 to $1.46\%$ in daily growth rate. The results are well comparable to those of paste feed, which has been being used in the eel farming industry up to date and will be as well used in the future, if any innovative way will not be developed. If pelletized feed can be used without any other hazards, the cost of feed will be remarkably reduced by eliminating costly $\alpha-starch$ which is absolutely necessary for the paste feed preparation, and also by preventing scattering of feed materials which is always associated with paste-feed during feeding time.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.7 no.4
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• pp.179-186
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• 1974

The followings are some results obtained from a series of experiments for the culture of eels from the elver stage in the laboratory from April 1973 to June 1974. 1. The optimum temperature turned out as 30t in the early stage culture. 2. The exponential curve of growth rate for a ten day period at the temperature between $20^{\circ}C$ and $30^{\circ}C$ was represented by the following equation: $$R=0.0056296\;T^{1.80740}$$ 3. The elvers and small eels that were kept improperly for a long time before this experiment also showed the same growth rate, compared with other healthful eels captured directly from the estuarine areas. 4. Those that showed retarded growth among a group of eels during the culture recovered the normal growth rate if graded out and kept in the other aquarium. 5. Feeding rate was not affected when the content of ammonia was less than 5 ppm, but it decreased by half when the content exceeds 6 ppm. 6, The elimination of fecal stuffs and uneaten dispersed feed was very important for the maintaining the water in quality.

• Analytical Science and Technology
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• v.13 no.2
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• pp.200-207
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• 2000

The growth mechanisms of graphite spherulite both in the nodular cast iron and the high pressuretreated Ni-C alloy were investigated by SEM, HRTEM and EELS. The internal microstructure and lattice image of graphite spherulite extracted from Ni-C alloy were compared with those of graphite spherulite extracted from the nodular cast iron. The ratios of $sp^2$ and $sp^3$ bonding in the respective graphite spherulite measured by EELS, are compared each other. The graphite spherulite of Ni-C alloy had little internal defects and much $sp^3$ carbon species compared to that of the nodular cast iron. Present difference in microstructural features and bonding characters indicated that the graphite spheruites in the high pressuretreated Ni-C alloy grew by different mechanism compared with those in the nodular cast iron.

• Parasites, Hosts and Diseases
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• v.53 no.3
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• pp.349-353
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• 2015

Anisakis simplex sensu stricto (s.s.), Anisakis pegreffii, Anisakis berlandi (=A. simplex sp. C), and Anisakis typica are the 4 major species of Anisakis type I larvae. In the Republic of Korea (Korea), A. pegreffii, A. berlandi, and A. typica larvae in fish hosts has seldom been documented. In this study, molecular analysis was performed on Anisakis larvae from the sea eels (Astroconger myriaster), the major source of human anisakiasis in Korea, collected from Tongyeong City, a southern coastal area of Korea. All 20 sea eels examined were infected with Anisakis type I larvae (160 larvae; 8 per fish). Their species were analyzed using PCR-RFLP patterns and nucleotide sequences of internal transcribed spacers (ITS1, 5.8 subunit gene, and ITS2) and mitochondrial cytochrome c oxidase 2 (cox2). Most (86.8%; 112/129) of the Anisakis type I larvae were A. pegreffii, and 7.8% (10/129) were A. typica. The remaining 5.4% (7/129) was not identified. Thus, A. pegreffii is the major species of anisakid larvae in sea eels of the southern coast of Korea.

• Korean Journal of Veterinary Research
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• v.50 no.1
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• pp.29-35
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• 2010

Yersinia (Y.) ruckeri has been recognized as a serious bacterial pathogen to several kinds of fish, including rainbow trout. However, there are no reports about the characteristics and pathogenicity of Y. ruckeri isolated from farm-cultured eels. In this study, we isolated and characterized Y. ruckeri from the farm-cultured eel Anguilla japonica in Korea. We investigated the phenotypic and genotypic characteristics of Y. ruckeri and tested the virulence of Y. ruckeri isolates on experimentally infected eels. Examination of the flagellar morphology of Y. ruckeri by electron microscopy showed peritrichous flagella in its cell body. Biochemical reaction studies showed overall identical profiles between the isolates and the reference strain of Y. ruckeri in API 20E and API ZYM tests. We sequenced the 16S rRNA of the Y. ruckeri (1,505 bp) for the genotypic characterization (National Center for Biotechnology Information accession number EU401667). Comparison of the 16S rRNA sequences with previously reported Y. ruckeri strains revealed similar phylogenetic relationships. In the virulence assay of the Y. ruckeri on eels, the eels exhibited listlessness, but Y. ruckeri was reisolated from those of the gills and kidneys.

• Journal of fish pathology
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• v.21 no.3
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• pp.229-239
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• 2008

The aim of this study was to acquire level on the occurrence of five fluoroquinolones(FQs) residue among cultured eels in Jeonbuk province. Samples were collected from the four local area(Kunsan, Gochang, Wanju and Osu) and surveyed on the distribution of FQs residual level in edible muscle using HPLC method. A total of 90 samples of eel was monitored for detection of the FQs residue. Among them, 30 eels(33.3%) were detected the FQs single or paired, respectively. The detection ratios were showed Osu(40%, 8/20), Gochang(33%, 13/44), Wanju(30%, 6/20) and Kunsan(30%, 3/10) in order, respectively. The ratio was equivalent to over 30% of overall in sampled area. The most frequently detected FQs were perfloxacin(PF) followed by enrofloxacin(EF), ciprofloxacin(CF), ofloxacin(OF) and norfloxacin(NF). Eight different combinations of FQ residual patterns were observed as single(5 type, 21%) or as paired(3type, 12,5%) respectively and frequently encountered patterns were PF(37%) and PF-EF(23%). The residual level of FQs was evaluated in the range of 1-75 ug/kg and the most prevalent levels of FQs was found in 1-25 ug/kg(35 fish, 85%) followed by 26-50 ug/kg(5 fishes, 11%) and 51-75 ug/kg(1 fishes, 3.3%). These results could be possible that the cultured eels were mostly exposed with PF, EF and CF, and might be treated with a variety of fluoroquinolones for prevention of bacterial disease.