• Journal of Aquaculture
• /
• v.21 no.1
• /
• pp.7-12
• /
• 2008

Toxicity of ten commercial disinfectants(hydrogen peroxide, sodium hypochlorite, chlorine dioxide, povidon iodine, formaldehyde, glutaraldehyde, quaternary ammonium compounds(QAC), didecyl dimethyl ammonium chloride(DDAC), ortho-dichlorobenzene, and copper sulfate) was measured by chinook salmon embryo-214 cell line and three fish species: flounder Paralichthys olivaceus, black rockfish Sebastes pachycephalus, and black sea bream Acanthopagrus schlegelii. The $LC_{50}$ levels of 24 hours acute toxicity with the ten disinfectants were tested in three species of fish. Effectiveness of ten chemical disinfectants were varied by each chemical as well as by species. Hydrogen peroxide showed the higest activity at 201, 269, and 139 ppm in the flounder, the black rockfish, and black sea bream, respectively. DDAC showed the lowest activity at 2.1, 1.0, and 1.5 ppm in the flounder, the black rockfish, and black sea bream, respectively. The highest variation was observed in copper sulfate by both the chemicals and the species.

• Journal of fish pathology
• /
• v.8 no.1
• /
• pp.57-67
• /
• 1995

Twenty-four hours, acute toxicity and the histopathological effect of formaline to flounder, Paralichthys olivaceus larvae were examined. The $LC_{50}$ values obtained to farmaline were 2,520 ppm in 1 hour treatment. 1.610 ppm in 2 hours treatment, 868 ppm in 4 hours treatment and 141 ppm in 24 hours treatment. Many pathological features such as hypertrophy of mucous and epithelial cells in secondary gill lamella, hyaline droplet degeneration of tubular epithelial cells in the proximal convoluted segment of renal tubules, focal or massive necrosis in liver cells and pycnotic nucleus in heart cells were recognized. The above results were discussed in relation to the application of formaline as therapeutic agent in flounder disease.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.56 no.5
• /
• pp.606-614
• /
• 2023

This study was conducted to optimize the size of olive flounder Paralichthys olivaceus (OF) as a material of sikhae and to investigate the quality characteristics. The results on the protease activity of OF meat, protein and ash contents of the bone, and yields and hardness of fish bone during fermentation time suggest that the suitable fish weight for sikhae was less than 250 g. The proximate compositions of the OF sikhae fermented under optimum condition (fermentation for 9 days at 15℃), were 73.0% moisture, 12.0% crude protein, 1.3% crude fat and 2.4% ash. The salinity, titration acidity and amino acid nitrogen contents per 100 g sikhae were 1.7 g, 2.46 g, and 311.3 mg, respectively. The lactic acid bacteria concentration in the sikhae were 8.84 log CFU/g, which were higher than those (5.78-6.62 log CFU/g) of 5 kind of commercial flounder sikhae. The functional properties, such as ACE inhibitory activity (69.0%), antioxidative activity (69.3%), α-glucosidase inhibitory activity (22.7%), xanthine oxidase inhibitory activity (88.2%), and nitrite scavenging activity (96.4%) of the sikhae were superior to those of 5 kind of commercial flounder sikhae.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.56 no.4
• /
• pp.380-387
• /
• 2023

Stocking density is associated with Paralichthys olivaceus growth; thus, fish should be rapidly reared at high densities for commercial reasons. Studies have reported that high stocking density retards growth; however, few have investigated the malformations caused by stocking density stress. This study compared the growth and malformation rates of P. olivaceus at different densities and stress- and immune-related gene expression between malformed and normal fish. Forty days post-hatching, fish (total length, 1.49±0.02 cm) were reared at 800 (low density; LD), 1500 (medium density; MD), and 4000 (high density; HD) fish/m², and the growth rate was measured weekly. On day 30, RNA was extracted from the kidneys, and the expression of stress-, immune-, and malformation-related genes was analyzed using qRT-PCR. The malformation rate in the HD groups was approximately three times higher (62%) than that in the LD and MD groups (approximately 20%), and growth was lower regarding length and weight. The stress-related (HSP70 and GPX) and immune-related (PIR and IgM) genes showed higher mRNA expression in the HD group and malformed fish than in the LD group and normal fish. However, TLR3 showed the opposite results. In summary, high stocking density suppressed growth and increased malformation risk in P. olivaceus.

• Development and Reproduction
• /
• v.16 no.1
• /
• pp.9-18
• /
• 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 Marine Bioscience and Biotechnology
• /
• v.2 no.3
• /
• pp.168-173
• /
• 2007

of expressed sequence tags (ESTs) is an efficient approach for gene discovery, expression profiling, and development of resources useful for functional genomics. To analyze the transcriptome of olive flounder, Paralichthys olivaceus, we have conducted EST analysis using cDNA libraries made from muscle of P. olivaceus. Redundant ESTs were assembled into overlapping contigs by using the assembly program ICAtools software. We found that the 221 ESTs were composed of 21 clusters and 35 singletons, suggesting that the overall redundancy of the library was 74.7%. Of the 221 clones, 218 clones (98.6%) were identified as known genes by BLAST searches and 3 clones (1.4%) did not match to any previously described genes. Based on major functions of their encoded proteins, the identified clones were classified into 13 broad categories. Sequence analysis of the ESTs revealed the presence of microsatellite-containing genes which may be valuable for further gene mapping studies. This study contributes to the identification of many EST clones that could be useful for genetics and developmental biology of olive flounder.

• Journal of Fisheries and Marine Sciences Education
• /
• v.27 no.5
• /
• pp.1508-1521
• /
• 2015

Vibrio harveyi is a pathogenic marine bacterium causing systemic symptoms resulting in mass mortalities in fishes and shrimps in aquaculture. Outer membrane proteins(OMPs) are related to the pathogenicity and thus good targets for diagnosis and vaccination for Gram negative bacteria. Recently vaccination strategies using the OMPs have been suggested to control vibriosis in several fish species. In this study, we have isolated V. harveyi from diseased marine fishes from different regions of Korea and investigated genetic variations of four OMP genes including OmpK, OmpU, OmpV and OmpW. Consequently, OmpK and U genes could be divided into 3 subgroups of type I, II, III and type A, B, C, respectively, without any correlation with geographical regions and species while OmpV and W were highly homologous. OmpW gene of V. harveyi FP4138 was fully sequenced and predicted the deduced amino acid sequence to form ${\beta}-barrel$ with hydrophobic channel. Indeed, the immunogenicity of recombinant OmpW produced in Escherichia coli was assessed by vaccinating flounder. As a result, the high antibody response with antibody titer of $4.2{\pm}0.7$ and protection with relative percent survival of 60% against artificial infection of V. harveyi were demonstrated. This result indicates that OmpW is a virulence related factor and it can be a vaccine candidate to prevent a high mortality caused by V. harveyi infection in olive flounder, Paralichthys olivaceus.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.50 no.5
• /
• pp.534-540
• /
• 2017

This study was conducted to determine the circadian rhythm and the effect of starvation for the health assessment of olive flounder Paralichthys olivaceus, reared under 12:12 LD (light:dark) cycle and fed 1% of their body weight once a day. The blood collection was implemented from 10 fish every 3 hours for a day, and analyzed to serval health parameters of the experimental fish. Plasma cortisol, glucose and total protein concentration reflected diel rhythms with high level of photophase and low level of scotophse despites of glutamic oxalacetic transaminase (GOT) and glutamic pyruvate transaminase (GPT) showing no rhythmicity, while electrolyte (sodium, potassium and chloride ion) concentrations arrived at the peak 18 hour and then slowly down. In the experiment of starvation, the result showed that there were no significant differences of the health parameters between the starved group and the fed. In short, our findings described the existence of circadian cortisol with glucose in flat fish, and indicated that the starvation does not almost affect the health of fish.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.36 no.3
• /
• pp.283-289
• /
• 2003

The effect on kidney, gill, and hepatopancreas of juvenile olive flounder, Paralichthys olivaceus were investigated by histological method under limit concentration of effulent of PCBs for 60 days. The free surface of epithelial cell layer in the renal tubules of kidney showed a strong positive reaction in alcian blue during all exposure period. There were also observed swelling of hemocyte in glomerulus and macrophage. At 60 days after exposure, epithelium of the renal tubules was fused and some of organism $(20\%)$ showed damage of glomerulus and eosinophlic cell in epithelium of the renal tubules. The phenomena such as the activation and increase of the chloride cell, and swelling of hemocyte in the capillary of gill were observed during all exposure period. At 60 days after exposure, swelling of the gill filament and mucous cell appeared in gill and some of organism $(30\%)$ showed swelling of the gill lamellar. Swelling of hemocyte in the capillary of hepatopancreas was observed and the free surface of epithelial layer of the bile duct showed positive reaction in alcian blue during all exposure period. Degenerated zymogen in the pancreas and swelling of the hepatocyte were occurred at 60 days after exposure.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.53 no.4
• /
• pp.620-627
• /
• 2020

Oxygen consumption and blood physiology of olive flounder Paralichthys olivaceus (mean body weight 106.6±6.8 g, mean±SD) was investigated at salinities of 34.0 (control), 33.7, 33.3, 32.6, 31.3, 28.6, 23.1, 12.2 and 0.0 psu at 20.0℃, respectively. Stepwise salinity changes (34.0→33.7→33.3→32.6→31.3→28.6→23.1→12.2→0.0 psu) with an interval of 24 h for each salinity induced a significant (P<0.05) increase of oxygen consumption rate (OCR) in fish exposed from 31.3 to 0.0 psu compared to that of control fish. The maximum OCR was found in fish exposed to 23.1 psu, which was accompanied by 36.2% higher energy consumption than the control fish. Fish exposed to each salinity for 24 h induced a significant decrease of blood plasma Na⁺ in 0.0 psu and Cl^- in 12.2 and 0.0 psu (P<0.05), and increase of plasma glutamic oxaloacetic transaminase (GOT) in 0.0 psu compared to the control fish (P<0.05). The results of this experiment show that P. olivaceus exposed to concentrations below 31.3 psu requires more energy costs to adapt to salinity changes than 34.0 psu under our experimental conditions.