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

• Journal of fish pathology
• /
• v.15 no.2
• /
• pp.49-56
• /
• 2002

Effects of Temperature on the Pharmacokinetics of norfloxecin (NFX) were studied in the cultured carp,Cyprinus carpio, and cel, Anguilla japonica, using high performance liquid chromatography (HPLC) originally developed for quinolone determination in livesrocks. Pharmacokinetics of NFX was apparently affected by ambiem water temperature. In a two-compaament model for carp after oral dosage of 20 mg/K01 at $13^{\circ}C$ and $23^{\circ}C$ and 5.20/hr, respectively. In carp the $K_{\iota\nu}$, $T_{max}$and $C_{max}$ for carp at $13^{\circ}C$ were 13.30/hr, 17.44 ${\mu}g$/$m\ell$ and 7.00 ${\mu}g$/$m\ell$, respectively. The" correspoeding values at $23^{\circ}C$ were 3.93/hr, 15.40 ${\mu}g$/$m\ell$ and 9.44 ${\mu}g$/$m\ell$, respectively. The AUC and T were 355.66 ${\mu}g$ hr/$m\ell$, and 12.70 hr at $13^{\circ}C$ and 417,24 ${\mu}g$ hr/$m\ell$ and 13.86 hrs at $23^{\circ}C$, respectively. Similar trends were revealed in the NFX pharmacokinetics of eel kept under the two water temperature regimes aftee oral NFX dosage of 20 mg/kg. These pharmacokinetkal results have some implication in the optimal usage of recently introduced antibacterials in farmed fish, which were originally adapted for poultry and mammalian species.

• Journal of fish pathology
• /
• v.23 no.3
• /
• pp.357-367
• /
• 2010

The pharmacokinetic properties of amoxicillin trihydrate (Amox) were studied after single oral administration and single intravenous injection to cultured eel, Anguilla japonica, respectively (average $220{\pm}10\;g$, $28{\pm}1^{\circ}C$). Plasma samples were taken at 3, 5, 10, 15, 24, 30, 48, 96 and 144 h post-dose. The kinetic profile of absorption, distribution and elimination of Amox in plasma were analyzed fitting to a two-compartment model by WinNonlin program. In oral dosage of 40 and 80 mg/kg body weight, the peak plasma concentrations of Amox, which attained at 3~12 h post-dose, were 3.4 and $3.3\;{\mu}g/ml$, respectively. In intravenous injection with 1 mg/kg, the peak plasma concentrations of Amox, which attained at 9 h post-dose, was $7.2\;{\mu}g/ml$. The following parmeters were calculated for a single oral dosage of 40 and 80 mg/kg body weight, respectively: AUC (the area under the concentration-time curve)= 464 and $667\;{\mu}g{\cdot}h/ml$; $T_{max}$ (time for maximum concentration)= 2.1 and 3.6 h; $C_{max}$ (maximum concentration)= 3.04 and $3.4\;{\mu}g/ml$. Following intravenous injection at 1 mg/kg, this parameters were AUC= $748\;{\mu}g{\cdot}h/ml$; $C_{max}=4.2\;{\mu}g/ml$. The apparent oral bioavailability at 40 and 80 mg/kg were 1.6 and 1.1%, respectively. Despite using the trihydrate form of amoxicillin, the oral bioavailability was low in eel.

• Journal of Fisheries and Marine Sciences Education
• /
• v.27 no.3
• /
• pp.672-681
• /
• 2015

Edwardsiellosis has become a serious diseases problem in cultured eels for many years. This study was performed to investigate possibility of vaccination against edwardsiellosis caused by Edwardsiella tarda. We conducted a immersion and/or oral vaccination using formalin-killed E. tarda in eel Anguilla japonica. Three groups of fish ($26.8{\pm}1.2g$, $7.1{\pm}0.7g$ and $2.2{\pm}0.4g$) were used in this study. The protection (relative percentage survival, RPS) and serum antibody response (agglutination titer) were evaluated in the vaccinated fish. No correlation between agglutination titer and survival rate was observed in vaccinated fish. However, there was a satisfactory protective (RPS>50%) in vaccinated fish. Immersion (10 mg/mL, 1 hr) and immersion (10 mg/mL, 1 hr) plus oral (10 mg/g, 10 days) of $26.8{\pm}1.2g$, immersion (10 mg/mL, 1 hr) plus oral (10 mg/g, 10 days) of $7.1{\pm}0.7g$ showed RPS of 62.6%, 52.2% and 56.8%, respectively.

• Korean Journal of Microbiology
• /
• v.27 no.3
• /
• pp.225-230
• /
• 1989

Infectious Pancreatic Necrosis Virus (IPNV) is one of the most important pathogens for inland fish farming and had been first reported in Korea from returning adult chum salmon (Oncorhynchus keta) at hatcheries on the east coast. During the past years, several viruses identified as IPNV were isolated not only from chum salmon, but also from gold fish (Carassius auratus), eel(Anguilla japonica), and rainbow trout (Salmo gairdneri). An isolate, coded DRT, from fingerlings of pan-cultured rainbow trout in Daechung Dam showed different serotype from three known reference serogroups of IPNV such as VR-299, Sp, and Ab. Antisera to three of these serotypes, however, partially neutralized the infectivity of this isolate. Anti-Sp type was rather effective than either anti-VR-299 or anti-Ab, implying DRT could be more closely related to Sp. DRT has been purified and its RNA genome segments were compated showing that the isolate does not belong to any of known serogroups even with some common antigenicity.

• Journal of Aquaculture
• /
• v.17 no.4
• /
• pp.275-281
• /
• 2004

The present study was conducted to evaluate dietary requirements for essential fatty acids (EFAs) such as linoleic acid (LA, l8:2n-6), -lenolenic acid (LNA, 18:3n-3), or docosahexaenoic acid (DHA, 22:6n-3), eicosapentaenoic acid (EPA, 20:5n-3) and arachidonic acid (ARA, 20:4n-6) in juvenile eel Anguilla japonica cultured in a recirculating system for 16 weeks. The experimental diets contained 50% crude protein, 10% crude lipid and 3800 kcal/kg energy.Brown fish meal and blood meal were used as the main protein sources, while coconut oil, com oil and linseed oil were used as the lipid source to yield target fatty acids ratios. At the end of the trial, the effects of essential fatty acids supplementation on weight gain (WG), specific growth rate (SGR), feeding efficiency (FE), proximate composition andwhole body fatty acids contents were examined. WG, SGR, and FEof eels fed diet D2, D3, was significantly higher (P<0.05) than those of fish fed the other diets. Whole body HUFA concentration of eels fed D 1 was significantly lower (P<0.05) than those fed the other diets. HUFA/SFA (saturated fatty acids) ratio of whole body in eels fed diets D2, D3 and D6 were significantly higher than that of eels fed diet D1 (P<0.05).DHA/EPA ratio of whole body in eels fed diet D7was significantly higher than those fed the other diets; and eels fed diet D5 showed the lowest DHA/EPA ratio among all the dietary treatments (P<0.05).Based on the experimental results, we concluded that LNA (n-3) and LA (n-6) were necessary for optimum growth of juvenile eel, and the dietary requirement of LNA and LA were 0.35∼0.5% and 0.5∼0.65%, respectively.

• Journal of fish pathology
• /
• v.24 no.3
• /
• pp.247-254
• /
• 2011

The purpose of this study was to obtain reference data of parameters for hematological health diagnosis in cultured freshwater fish and also evaluate application of automatic dry-type chemistry analyzer (FUJI DRI-CHEM 3000) used to those blood tests. A blood profile of total 200 fish for rainbow trout (Onchorhynchus mykiss), israel carp (Cyprinus carpio), tilapia (Oreochromis niloticus) and eel (Anguilla japonica) cultured in Inland Fisheries Research Institute of NFRDI was determined by hemoglobin (Hb) and plasma chemistry tests: total protein (TP), albumin (ALB), alkaline phosphatase (ALP), blood urea nitrogen (BUN), lactate dehydrogenase (LDH), triglyceride (TG), total cholesterol (TCHO), creatinine (CRE), aspartate aminotransferase (AST), alanine aminotransferase (ALT), glucose (GLU). The values of ALT, TG, LDH, ALB, TCHO, AST and ALP were outside from the minimum and/or maximum of the established detectable range of the analyzer. ALT and TG were not detectable in the range of 67%~61.5%. LDH, ALB and TCHO were not detectable in the range of 36~17%. AST and ALP were not detectable in the range of 5.5~0.5%. However, the values of BUN, CRE, GLU, Hb and TP were below the detectable limits of the analyzer.

• Journal of Aquaculture
• /
• v.16 no.4
• /
• pp.267-272
• /
• 2003

This study investigated sex determination through serum steroid hormone level and compared hematological characteristics of one-year old cultured eels, Anguilla japonica. Four different groups were divided with total length at 40∼45, 45∼50, 50∼55, and 55∼60 cm. Males dominated eels of 40∼50 cm in total length group, while females dominated eels of more than 50 cm. All females and males were immature. Hematocrit levels of males (total length: 40∼50 cm) were higher than those of females (total length: 50∼60 cm). Hemoglobin content also differed between males and females. Glutamate oxaloacetate transaminase (GOT) levels of 40∼45 cm males tended to be higher (157$\pm$3.46 IU/L) than that of other sized males, but there were no significant differences between groups (P<0.05). The highest GOT levels were found in of 55∼60 cm females (148$\pm$3.46 IU/L) compared with that of other female groups (P<0.05). Glutamate pyruvate transaminase (GPT) levels of males and females in the 55∼60 cm size range was significantly higher thanothers (P<0.05). The result of this study indicated steroid hormone content of males and females were very low, but testosterone (T) and estradiol-17$\beta$, (E2) contents of females were higher than those of males. For further research of sex determination in cultured eels, it needs to investigate in more defined body length.

• Journal of Marine Life Science
• /
• v.8 no.1
• /
• pp.32-42
• /
• 2023

Fish reproduction is regulated by various neurohormones secreted from the brain and gonadotropic hormones secreted from the pituitary. Reproduction of eel (Anguilla japonica) is also regulated by these hormones. However, how the neurohormones regulate the secretion of pituitary hormones during sexual maturation is not completely understood. Previous studies have shown that neurohormones such as progesterone (P4), melatonin and serotonin (5-HT) are involved in the regulation of reproductive processes in some fish. In this study, the eel pituitary was primary cultured, and stabilized pituitary cells were treated with P4, 17β-estradiol (E2), melatonin, or 5-HT. The effect of these treatments on the expression of FSHβ, LHβ, GH and SL mRNA was, then, investigated. P4 increased the expression of FSHβ and LHβ in pituitary cells, and melatonin increased the expression of GH and SL as well as FSHβ and LHβ. However, 5-HT did not significantly affect the expression of these mRNA. These results suggest that P4 and melatonin may play some important roles in the early sexual maturation of eels.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.30 no.2
• /
• pp.282-290
• /
• 1997

Hepatocytes of Anguilla japonica have been prepared using a collagenase perfusion technique. The isolated cells attached efficiently to fibronectin-coated culture dishes and subsequently formed monolayers in serum-free medium. These cultures maintained in appropriate medium at least for 10 days with minimal cell loss. The effects of estradiol and pituitary hormones on vitellogenin (Vg) synthesis were examined in primary hepatocyte culture of the immature eels. In fish, as in other oviparous vertebrates, estrogen is a major inducer of Vg synthesis. However, $estradiol-17\beta(E_2)$ alone was insufficient to induce Vg synthesis in cultures of eel hepatocytes. Combination of $E_2$ with growth hormone (GH) and/or prolactin (PRL) markedly stimulated Vg synthesis. Even in cultures exposed to $E_2$ or precultured without hormones for 8 days, $E_2$ alone could not fully induce Vg synthesis. The synthesis of Vg was dramatically increased when hepatocytes were cultured in medium supplemented with $E_{2}+GH+PRL$ for 6 days. At this point, even though GH and/or PRL were eliminated from the medium, Vg synthesis was not influenced by these factors during culture of further 3 days. These results indicate that pituitary hormones, in particular GH and PRL, play important roles in the regulation of Vg synthesis in primary cultures of eel hepatocytes.