• Journal of fish pathology
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• v.20 no.1
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• pp.71-81
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• 2007

Photobacterium damselae subsp. damselae and 4 Vibrio spp.(V. anguillarum, V. splendidus, V. harveyi and V. ordalii) were isolated from the diseased olive flounders, Paralichthys olivaceus. The isolates were tested on the pathogenicity in vitro. The properties of extracellular products(ECPs) were investigated with enzymatic activities, hemolytic activities toward the sheep and olive flounder erythrocytes, and cytotoxicity activities on the cell-line. And potential signal transduction pathways of the bacterial internalization were detected by using signal transduction inhibitors. P. damselae was high in phospholipase activity, hemolytic activity to olive flounder erythrocytes and cytotoxicity activity. And P. damselae had diversified internalizing pathways as compared to isolated vibrios. Therefore, these activities may be related with pathogenicity of P. damselae.

• Journal of Aquaculture
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• v.19 no.2
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• pp.95-98
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• 2006

This study was performed to determine possibility of compensatory growth of juvenile olive flounder fed a commercial feed during the summer season. Five treatments of fish with triplicates were prepared: C, S1, S2, S3 and S4. Fish in the control group (C) was hand-fed with the commercial feed to apparent satiation twice daily for 6 days a week during 6 weeks. Fish in S1, S2, S3, and S4 experienced 1, 2, 3, and 4 weeks of starvation before fed to satiation twice daily for 5, 4, 3, and 2 weeks, respectively. The feeding trial lasted far 6 weeks. Survival of flounder in C, S1 and S2 was significantly (P<0.05) higher than that offish in S4. Weight gain and specific growth rate (SGR) of flounder in C and S1 were significantly (P<0.05) higher than those of fish in S2, S3 or S4. And weight gain and SGR of flounder in S2 and S3 were significantly (P<0.05) higher than those of fish in S4. Feed consumption of flounder tended to increase with weeks of feeding. Feed efficiency ratio and protein efficiency ratio for flounder in C, S1, S2 and S3 were significantly (P<0.05) higher than those for fish in S4. Moisture content of the whole fish in C was lowest, but highest for fish in S4, respectively. Crude protein content of the whole fish in C was highest, but lowest far fish in S4, respectively. Crude lipid content of the whole fish in C, S1 and S2 was significantly (P<0.05) higher than that of fish in S4. In conclusion, full compensatory growth was obtained in juvenile olive flounder fed for 5 weeks after 1-week feed deprivation during the summer season. Compensatory growth of fish was well supported by improvement in feed efficiency ratio and protein efficiency ratio.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.9
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• pp.1367-1375
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• 2008

This study was conducted to investigate the effects of phytase in diets containing cottonseed and soybean meal (CS) on growth performance, feed utilization and digestibility of protein and phosphorus in juvenile olive flounder (initial body weight 2.5 g), Paralichthys olivaceus. Four experimental diets replacing 0%, 30%, 30% and 40% fish meal protein with CS in equal proportion were formulated to be isonitrogenous and isocaloric (designated as CS0, CS30, CS30+P, CS40+P, respectively). Phytase of 1,000 FTU/kg was supplemented in diets CS30+P and CS40+P. Three groups of fish (25 fish per group) were fed one of the experimental diets for 10 weeks. No significant differences were observed in growth performance of fish groups except for the CS40+P diet. Apparent digestibility coefficients of protein and phosphorus in fish fed phytase-containing diets were significantly higher than those of fish fed the CS0 diet. Serum cholesterol was significantly reduced in fish fed the CS-containing diets. Antioxidant activities in the diets and liver of fish were significantly increased with the increment of dietary CS. Gossypol was only detected and found in liver of the fish fed the CS-containing diets. The findings suggest that supplementation of microbial phytase could improve the apparent digestibility of protein and phosphorus in juvenile olive flounder fed the CS-containing diets.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.4
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• pp.365-369
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• 2001

Streptococcus spp. of bacterial pathogen of fish were isolated from the cultured flounder (Paralichthys olivaceus) in fish farm of Jeju Island. Clinical signs of the infected flounder which are the most commons symptoms are as follows: erratic swimming, darkening of the body colour, unilateral or bilateral exophthalmia, corneal opacity, hemorrhages in the opercular and the bases of the fins, and the ulceration of the body surface. Biochemical characteristics of pathogenic fish Streptococcus spp, were gram positive, spherical form, catalase negative, oxidase negative and $\beta$-haemolytic, respectively, The viable cells counted from the tissue of the diseased flounder were the largest in the order of the ulcer, the kidney, the blood and the brain, The drugs used were ampicillin, ciprofloxacin, doxycycline, gentamycin, tetracycline, erythromycin, streptomycin and oxytetracycline, Streptococcus spp. were found to be sensitive to ampicillin, ciprofloxacin, doxycycline and gentamycin, but were resistant to tetracycline, erythromycin, streptomycin and oxytetracycline. The pathogenicity of Streptococcus spp. on the cultured flounder with an abdominal cavity injection was high. The haemolytic activity of the toxin against the sheep red blood cells reached the maximum after 30 min incubation at $37^{\circ}C$ or $50^{\circ}C$. The toxin showed highest activity at pH $5.5\sim6.5$.

• Korean Journal of Ichthyology
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• v.12 no.3
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• pp.180-185
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• 2000

The effects of bisphenol-A(BPA), a monomer of plastics used in many consumer products, on vitellogenin(VTG) synthesis were examined in primary hepatocyte culture of olive flounder, Paralichthys olivaceus. The hepatocytes were precultured for 2 days, and then estradiol-$17\beta(10^{-6}M)$ and BPA were simultaneously added to the incubation medium. The hepatocytes were cultured for 6 more days and then spent medium was analyzed by SDS-PAGE. BPA increased the rate of VTG to total protein concentrations in a concentration-dependent way, and a significant difference was obtained at concentrations of $10^{-6}M$ and $10^{-5}M$ (P<0.05). In particular, the rate of VTG to total protein concentrations was 26.36% at $10^{-5}M$ of BPA, and its level did not differ from the control level with $E_2$ alone. $E_2$ and/or BPA-primed VTG synthesis was markedly inhibited to about 80% of the control(with $E_2$) by the addition of tamoxifen($10^{-6}M$) to the incubation medium. Furthermore, In vivo $E_2$-primed VTG synthesis was significantly inhibited by in vitro $E_2$-free incubation of hepatocyte to about 22% of the control (with $E_2$) on Day 6. The effect of reducing was delayed in a BPA concentration-dependent way. These results suggest that BPA induce VTG synthesis by estrogenic activity through estrogen receptor mediated response and prolong VTG synthesis on vitellogenesis in olive flounder.

• Journal of fish pathology
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• v.34 no.2
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• pp.201-212
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• 2021

Olive flounder (Paralichthys olivaceus) (Weight 110.9±17.1 g, length 22.3±1.2 cm) were exposed to waterborne nitrite at 0, 30, 60, 120, 240, 480 and 960 mg NO₂^-/L according to water temperature at 20℃ and 25℃ for 96 hours. The lethal concentration 50 (LC₅₀) of olive flounder, P. olivaceus exposed to waterborne nitrite was 513.87 mg NO₂^-/L at 20℃ and 208.35 mg NO₂^-/L at 25℃, which means a significant difference in LC₅₀ by the water temperature. Hemoglobin and hematocrit were significantly decreased by waterborne nitrite exposure. The inorganic component, plasma calcium, was significantly decreased, and the organic components such as plasma glucose and cholesterol were significantly decreased showing a similar tendency with calcium. In enzymatic components, the AST and ALP were also significantly decreased by nitrite exposure. The results of this study indicate that exposure to nitrite can affect the survival and hematological physiology of P. olivaceus, and the effect of exposure to nitrite had a significant effect on nitrite toxicity depending on the water temperature.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.4
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• pp.411-418
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• 2023

Genome wide association studies (GWAS) identify genetic loci associated with quantitative traits in genomic selection. Although several studies have compared performance of various algorithms, no study compares them in olive flounder Paralichthys olivaceus. This study compared the GWAS results of four mixed linear model (MLM) algorithms and one Fixed and random model Circulating Probability Unification (FarmCPU) algorithm in olive flounder. Considering gender and genetic association matrices as fixed and random effects, the MLM had stable performance without inflation for λ_GC (genomic inflation factor) of -log₁₀P. The FarmCPU algorithm had some appropriate λ_GC of -log₁₀P, and an upward tail was identified in quantile-quantile plots. Therefore, the models were suitable for detecting genetic variants associated with olive flounder growth traits. Moreover, significant genotypes appeared several times at chromosome 22, around which quantitative trait loci are expected to exist. Finally, in both models, some of the most genetic variants were found in genes related to growth traits, confirming their reliability. These results will be helpful when applied to the genomic selection of olive flounder growth traits in the future.

• Korean Journal of Ichthyology
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• v.30 no.1
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• pp.1-8
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• 2018

We tried to determine the optimum salinity for a cultured of olive flounder (Paralichthys olivaceus) by investigating after exposing the fish at different salinity (10, 15, 20 and 25 psu) for 24 and 48 hours compared with control group (fish before transfer to experimental tank). As a control groups, we compared an analyzed with other experimental groups using olive flounder in natural sea water. Hematological parameters including hematocrit (Ht) and hemoglobin (Hb), cortisol and glucose, aspartate aminotransferase (AST) and alanine aminotransferase (ALT), $NH_3$, osmolality, total protein (TP), $Na^+$, $K^+$ and $Cl^-$ mostly exhibited significant changes at 10 and 15 psu groups compared with control groups for 24 and 48 hours exposed. Plasma SOD (superoxide dismutase) and CAT (catalase) activity also increased with experimental groups (10 and 15 psu) compared to the control groups. The expression of HSP70 mRNA was also higher at low-salinity (10 and 15 psu) than at control group. In particular, after 24 hours exposed, it expression to 15 psu groups showed a significant difference compared to the control group. However, after 48 hours exposed, it expression was higher in the 10 psu groups than the control. It is assumed that the changes in the hematological responses and hormone, homeostasis and metabolism were resulted in to protect fish body from stress. Based on these results, we are expected that it will be used as basic data for the culture of olive flounder prepared for low salinity.

• Journal of Life Science
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• v.7 no.1
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• pp.10-16
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• 1997

This study was designed as a part of efforts to investigate the biochemical pollutant markers for diagnosis of marine pollutions by changes in oxygen radicals and their scavenger enzymes of the flounder (Paralichthys olivaceus)in Yellow Sea of Kores. Protein contents in brian and muscle of cultured flounder in Yellow Sea were remarkably lower(30-45% and 25-45%, respectively) than those of wild flounders in Pohang(control) of East Sea. Lipid peroxide(LPO) levels in serum of cultured and wild flounders in Yellow Sea were significanltly higher (30-80% and 125-145%, respectively)than those of wild flounder in Pohang. Hydroxide radical formations and superoxide dismutase(SOD) activities in serum of cultured flounders in Yellow Sea were significantly 15-30% and 15-35% lower than those of wild flounders in Pohang, but glutathione peroxidase (GSHPx) activities in brain of cultured flounders in Yellow Sea were significantly 15-25% higher than those of wild flounders in Pohang. It is believed that significantly decreases of protein contents in brain anad muscle, remakable increases of malondialdehyde(LPO) in serum and glutathione peroxidase (GSHPx)in brain of cultured flounders of Yellow Sea may be used as a biochemical pollutant markers for diagnosis of marine pollutions.

• Microbiology and Biotechnology Letters
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• v.50 no.3
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• pp.347-353
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• 2022

In this study, the effect of a synbiotic mixture of probiotics and 3% inulin on the growth, non-specific immune response, and mortality due to disease resistance of Paralichthys olivaceus was investigated. The results revealed that an 8-week diet of synbiotic-added feed, had no significant effect on the growth of P. olivaceus, Analysis of the hematological parameters revealed that there was a significant difference in the content of AST, total protein, and cholesterol among the groups, whereas there was no significant difference in the ALT and glucose contents. Further, there was no significant difference in the lysozyme activity of the synbiotic and control group after 8 weeks' feeding. In addition, when the symbiotic mixture was used rather than probiotics alone, the NBT activity of the synbiotic group increased compared to that of the control group. Moreover, when only probiotics were used, the cytokine expression in the spleen of the samples was significantly lower than that in the control group, whereas the expression was significantly higher in the spleen of the synbiotics group. However, there was no significant difference in the cytokine expression in the liver, intestine, and kidney of the three groups. Lastly, after injection for 2 weeks, the mortality rates of the control group towards Edwardsiella tarda, Streptococcus parauberis, and Streptococcus iniae were 95, 85 and 85%, respectively; those of the probiotics group were 85, 80, and 80%, respectively; and those of the synbiotics group were 80, 80, and 85%, respectively.