• Fisheries and Aquatic Sciences
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• v.14 no.4
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• pp.355-361
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• 2011

Effects of aluminum (Al) on plasma vitellogenin (VTG), alkaline-labile phosphorus (ALPP), calcium (Ca), glutamate pyruvate transaminase (GPT), the hepatosomatic index (HSI), and hepatic Al concentration were examined in estradiol-$17{\beta}$ ($E_2$)-administered immature rockfish Sebastes schlegeli. Fish were injected intraperitoneally with $E_2$ (5 mg/kg body weight [BW]) and/or Al (0, 0.1, 1, 5, and 10 mg/kg BW) and plasma and liver samples were extracted 7 days later. After sodium dodecyl sulfate polyacrylamide gel electrophoresis, the relative amount of VTG was determined by integrated optical density. VTG accounted for 23.6% of the total proteins in the control group, but this value decreased with increasing Al administration. Al reduced the concentrations of ALPP and Ca in a concentration-dependent manner and significant reduction occurred at Al concentrations greater than 5 mg/kg. The concentration of GPT increased in a concentration-dependent manner in all Al-administered rockfish. The concentrations of Al in the liver also increased, and HSI was decreased, in a concentration-dependent manner. These results suggest that Al inhibits $E_2$-induced VTG production by being toxic to hepatocytes in marine fish.

• Journal of fish pathology
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• v.17 no.3
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• pp.191-198
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• 2004

Temporal changes of plasma vitellogenin (VTG), alkaline-labile protein phosphorus (ALPP), calcium (Ca), glutamate pyruvate transaminase (GPT) and hepatosomatic index (HSI) were examined in the $estradiol-17\beta$ ${E_2}$-administered immature rockfish, Sebastes schlegeli. Fish were intraperitoneally injected with ${E_2}$ (5 ㎎/kg B.W.) in 70% ethanol and then plasma were extracted at 0, 1, 3, 6, 9, 12 and 15 days. VTG band was detected at a molecular weight position of about 170 kDa on Day 3 in SDS-PAGE. This band became more distinct at 6 days but its was gradually thinned with time-course, and not detected at 15 days. Plasma ALPP and Ca increased suddenly at 1 day and the highest concentrations were detected at 6 days and then these concentrations decreased gradually with time-course. ALPP and Ca concentrations at 15 days after E2 administration were very similar to that before E2 administration. GPT was increased at 1 day and higher GPT was detected at 3 days. However, GPT was gradually decreased with time-course. GPT and HSI at 15 days after E2 administration were also very similar to that before E2 administration. HSI was also increased at 1 day and the highest value was detected at 3 days and then gradually decreased with time-course. These results suggest that plasma ALPP, Ca, GPT and HSI could be utilized as a biomarker of exogenous E2 exposure in coastal ecosystem, because the changes of ALPP, Ca, GPT and HSI after E2 administration are very similar to that of VTG.

• Journal of fish pathology
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• v.21 no.2
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• pp.81-91
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• 2008

Vibrio harveyi, one of the major causal agent of vibriosis, affects a diverse range of marine vertebrates and invertebrates over a wide geographical area. The aims of this study were to investigate the characteristics of extracellular products (ECPs) from an isolate of the pathogenic non‐luminous V. harveyi and the luminous V. harveyi. And ECPs of V. harveyi were examined the pathogenicity to the black rockfish, Sebastes schlegeli, and histopathological traits of internal organs injected by ECPs. Four strains of V. harveyi cultures produced ECPs showing various enzymatic activites (caseinase, gelatinase, phospholipase, lipase, haemolysin). The ECPs showed strong cytotoxicity on macrophages of black rockfish, Sebastes schlegeli and olive flounder, Paralichthys olivaceus. Especially, the virulence of ECPs from the isolate of V. harveyi FR 2 was higher in the intraperitoneally injected black rockfish. Also, the ECPs of V. harveyi FR 2 caused the expansion of sinusoids in the liver, the activation of ellipsoid in the spleen and the sloughing of the epidermal cell in the intestine. It was suggested that the ECPs from V. harveyi play an important role in the pathogenicity process of the V. harveyi.

• Development and Reproduction
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• v.16 no.1
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• pp.9-18
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• 2012

The effects of the estrogenic compound 4-nonylphenol (4-NP) on vitellogenesis in juvenile olive flounder ($Paralichthys$ $olivaceus$) and rockfish ($Sebastes$ $schlegeli$) exposed continuously at 10, 50 and $100{\mu}g{\ell}^{-1}$ levels for 7 days were compared. The expression of VTG mRNA level and protein using specific probes were examined. The levels of plasma estradiol-17 ${\beta}(E_2)$ and testosterone (T) were assessed by radioimmunoassay (RIA). Plasma $E_2$ concentrations increased significantly in two female fish species exposed to $100{\mu}g{\ell}^{-1}$ of 4-NP over concentrations in control fish. Plasma T concentrations increased in $P.$ $olivaceus$. Four days after exposure, the level of VTG mRNA expression increased in $P.$ $olivaceus$ and $S.$ $schlegeli$ exposed to $20{\mu}g{\ell}^{-1}$ of 4-NP. In addition, plasma VTG protein expression was seen in $P.$ $olivaceus$ and $S.$ $schlegeli$. In $S.$ $schlegeli$ and $P.$ $olivaceus$ exposed to 4-NP, the changes were noticed mainly in hepatocytic vaculation after 7 days of exposure. Thus, 4-NP may disrupt vitellogenesis in immature fish both directly and indirectly via disrupted steroidogenesis and liver pathology. Immature $S.$ $schlegeli$ were the most sensitive to 4-NP exposure in vitellogenesis.

• Journal of Aquaculture
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• v.18 no.4
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• pp.236-244
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• 2005

Experiments were performed to investigate the effects of the different anesthetic MS-222 and lidocaine-HCl doses on the blood physiological responses, on the time required for anesthesia and recovery, and on the survival rates of black rockfish (Sebastes schlegeli). Plasma cortisol was its highest levels (96.1$\pm$12.1 ng/ml) at 6 hours after the administration of 300 ppm of MS-222, and in all groups, plasma cortisol levels were higher than the initial levels during the anesthetic experiment. Fish receiving lidocaine-HCl also exhibited higher than initial plasma cortisol levels at almost experimental intervals. The middle size fish exhibited the highest glucose level (143.3$\pm$14.5 mg/dl) at 50 ppm of anesthesia after 1 hour, and every level was significantly higher than the initial level for at least 12 hours. Glucose levels in fish to which lidocaine-HCl was administered were comparable to the levels seen in conjunction with MS-222 treatment. In fish anesthetized with MS-222, K+ levels in the small size fish were significantly elevated after 1 hour, while Na+ levels did not change in any of the groups throughout the experiment. Anesthetic time was significantly attenuated with increases in the concentrations of MS-222 and lidocaine-HCl. We also noted a correlation between anesthetic time and fish size, in that larger fish took a longer time, followed by the middle size and then the small size fish. The all fish size groups showed above $95\%$ survival rates at every experimental concentration in MS-222 and 300-400 ppm in lidocaine-HCl. The results may indicate that 100-200 ppm MS-222 and 400 ppm lidocaine-HCl are the most effective doses as sedatives for the black rockfish and these doses could be used as the suitable anesthetics doses.

• Journal of Aquaculture
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• v.9 no.2
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• pp.169-178
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• 1996

This experiment was conducted to develop an experimental model and a semipurified diet for vitamin C requirement study in juvenile Korean rockfish, Sebastes schlegeli. Prior to the start of the feeding trial, fish were fed the control diet for four weeks to deplete their body reserves of vitamin C, Then fish were divided into six groups and given one of the laboratory developed semipurified diets supplementing either 0 (control), 25, 50, 75, 150, o. 1500 mg L-ascorhic acid (AA)/kg diet for eight weeks. Fish fed control diet had lower hematocrit than did fish from groups fed the other diets (P<0.05). Also these fish had significantly lower percent weight gain (WG), feed conversion ratio (FCR) and muscle AA than did fish fed diets containing 150 and 1500 mg AA/kg diet (P<0.05). Diet analysis of vitamin C showed that the control diet had 39,7 mg AA/kg diet. Therefore, these fingings suggest that the experimental model and the semipurified diet can be useful for vitamin C requirement study, and the dietary vitamin C requirement is greater than 40 mg AA/kg diet, but 150 mg AA/kg diet is adequate for the maximum growth in juvenile Korean rockfish.

• Journal of fish pathology
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• v.22 no.2
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• pp.155-162
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• 2009

The mass mortality of Korean rockfish, Sebastes schlegeli that occured at the fish farms in Tongyeong and Geoje City regions between late August and early September in 2006 was investigated. Sixty two fish showed no significant external symptoms except ulcerative lesions with reddish foci on the skin. From the internal observations and diagnosis results, some yellowish brown liver, intestine bleeding, atrophy and congestion in the abdominal cavity of the fish were found. In the gill, swelled filaments caused by foreign material accumulation and mucus secretion were observed. However, the main cause of the fish mass mortality in both sampling regions could be due to physiological weakness induced by significant change of water temperature causing by typhoon Wookong during the summer in 2006.

• Journal of Aquaculture
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• v.16 no.2
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• pp.88-93
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• 2003

Diets containing 3000 kcal/kg at the crude protein (CP) level of 40% (Diet 1) and 4000 kcal/kg at the CP level of 50% (Diet 2) were fed to the juvenile rockfish, Sebastes schlegeli (35.6 g) at 3-4% body weight for a period of 28 days. Diet 2 promoted significantly higher growth and feed efficiency than Diet 1. Oxygen uptake increased with increasing body weight. The oxygen uptake-body weight relationship of diets 1 and 2 were best expressed by y=0.3218 $e^{0.0592x}$ (R=0.8494) and y=0.3612 $e^{0.0532x}$ ($R^2$=0.8805), respectively. Assimilation efficiency (AE), gross growth efficiency ( $K_1$) and net growth efficiency ( $K_2$) of the fish fed on Diet 2 were 73.8, 16.0 and 22.6%, respec- tively. Fish fed on Diet 2 showed significantly higher AE, $K_1$ and $K_2$ than those fed on Diet 1. Hence Diet 2 con- taining 4000 kcal/ kg with crude protein of 50% is recommended for the Korean rockfish.kfish.

• Journal of fish pathology
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• v.23 no.2
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• pp.221-227
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• 2010

Effects of temperature ($13{\pm}1.5^{\circ}C$, $23{\pm}1.5^{\circ}C$) on the pharmacokinetic properties of oxolinic acid (OA) were studied after oral administration to cultured black rockfish, Sebastes schlegeli. Serum concentrations of OA were determined using HPLC-UV detector after a single dosage of 60 mg/kg body weight (average about 500 g). The peak serum concentrations of OA at $23{\pm}1.5^{\circ}C$ and $13{\pm}1.5^{\circ}C$ were $0.60{\mu}/ml$ at 30 h and $2.22{\mu}g/ml$ at 10 h post-dose, respectively. Better absorption of OA was noted at $13{\pm}1.5^{\circ}C$ compared to $23{\pm}1.5^{\circ}C$. The elimination of OA from serum was considerably faster at $23{\pm}1.5^{\circ}C$ than at $13{\pm}1.5^{\circ}C$. Both absorption and elimination of OA were affected significantly by temperature. The kinetic profile of absorption, distribution and elimination of OA in serum was analyzed by fitting to a two compartment model, with WinNonlin program. The AUC, Tmax and Cmax at $23{\pm}1.5^{\circ}C$ were $42.16{\mu}g{\cdot}h/m\ell$, 26.13 h and $0.43{\mu}g/ml$, respectively. The AUC, Tmax and Cmax at $13{\pm}1.5^{\circ}C$ were $131.98{\mu}g{\cdot}h/ml$, 8.81 h and $2.04{\mu}g/ml$, respectively.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2002.05a
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• pp.107-108
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• 2002