• Korean Journal of Fisheries and Aquatic Sciences
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• v.40 no.3
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• pp.128-132
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• 2007

We identified a microsatellite marker, Poli121TUF, which appears to be significantly linked (P<0.001) with a lymphocystis disease virus (LCDV)-resistance gene in the olive flounder, Paralichthys olivaceus. The olive flounder is an economically important food fish, that is widely cultured in Korea, Japan, and China. Lymphocystis disease has spread in these countries and has seriously reduced the economic value of the fish. LCDV causes lymphocystis cells (LC) to form on the body surface, fins, gills, mouth, and intestine. Fish with LC lose commercial value due to their deformed appearance. The identified micro satellite marker can be used as a candidate locus for marker-assisted selection (MAS) in order to enhance the efficiency of selection for LCDV resistance in the olive flounder.

• Fisheries and Aquatic Sciences
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• v.8 no.4
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• pp.235-242
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• 2005

Baker's yeast, Saccharomyces cerevisiae, has been widely used as a food organism for rotifers used in the larval production of marine fish. However, the nutritional value of the yeast is relatively poor compared with that of the marine alga Chlorella. We examined the nutritional value of another yeast, Candida utilis, and whether its food value could be increased through manipulation such as a cell wall treatment. Candida utilis and S. cerevisiae and their manipulated varieties were assessed with regard to the growth and nutrition of the rotifer Brachianus plicatilis. Larvae of the flounder Paralichthys alivaceus were cultured with rotifers fed on the yeast species, and the dietary value of the rotifers for the larvae was examined. Rotifers that were fed C. utilis grew faster than those provided with S. cerevisiae. Rotifers grew slightly faster on manipulated yeast than on non-manipulated yeast varieties. Of the two yeast species, C. utilis had better dietary value for rotifers. Flounder larvae cultured with rotifers that had fed on C. utilis displayed better growth and survival ($\%$) than did those cultured with rotifers that had fed on S. cerevisiae. Although the manipulated variety of C. utilis was better than the non-manipulated variety in terms of rotifer growth, the flounder larvae survived ($\%$) and grew better when they were fed rotifers that had eaten non-manipulated C. utilis. However, the nutritional value of this yeast species was still lower than that of Chlorella.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.6
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• pp.785-790
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• 2011

This study investigated the nutritive quality of olive flounder Paralichthys olivaceus fed either moist pellet (MP) or moist pellet mixed with mushroom extract (MPME) for 6 months. There was no significant difference in crude protein or extractive nitrogen in the muscle of flounder fed MP versus MPME (P > 0.05). The total amino acid content in the muscle of flounder fed MP was $15.22{\pm}5.24$ g/100 g, compared to $19.90{\pm}2.90$ g/100 g for flounder fed MPME. Essential amino acid content was $7.04{\pm}2.21$ g/100 g in the muscle of flounder fed MP versus $8.94{\pm}2.50$ g/100 g for MPME. Total amino acid content was higher in the muscle of olive flounder fed MPME, while essential amino acid content was higher in flounder fed MP. The ratio of non-essential amino acids to essential amino acids was $0.86{\pm}0.07$ for flounder fed MP and $0.81{\pm}0.08$ for flounder fed MPME. There was no significant difference in free amino acid content and fatty acid composition. The breaking strength of muscle of olive flounder fed MP was higher ($1.44{\pm}0.51\;kg/cm^2$) than in flounder fed MPME ($1.29{\pm}0.30\;kg/cm^2$). There was no evidence that dietary additives, such as mushroom extract, increase growth rate or nutritive quality of olive flounder.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 1998.06a
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• pp.224-225
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• 1998

• Journal of fish pathology
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• v.16 no.1
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• pp.51-59
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• 2003

Streptococcal infection is one of the most serious disease of cultured olive flounder, Paralychthys olivaceus in Korea and caused by more than one species. However, there has been considerable confusions about the taxonomic position of the fish pathogenic streptococci. In this study, We performed the randomly amplified polymorphic DNA(RAPD) pattern analysis to evaluate the possible classification in 8 streptococci isolated from diseased olive flounder and reference strains based on their DNA structure. RAPD PCR with DNA solution prepared by simple boiling and 10-mer random primer was appeared to be a good tool for discrimination of different streptococcal strains. Phenotypical characters by simple biological test and API 20 Strep corresponded well to the specific profiles of RAPD in streptococcal isolates of this study. Therefore, the RAPD profile was considered as one of differential characters to discriminate the streptococcal isolates from diseased olive flounder.

• Fisheries and Aquatic Sciences
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• v.2 no.2
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• pp.167-171
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• 1999

This study was designed to develop biomarkers of coastal pollution using biochemical indices of flounder (Paralichthys olivaceus) by changes in lactate dehydrogenase (LDH) activity in the serum and cholinesterase activities in brain membranes. For this purpose acetylcholiesterase (AChE) activity, butyrylcholinesterase (BChE) activity, LDH/AChE ratio and LDH/BChE ratio of cultured flounders at 5 different sites on the southern coast of Korea were compared to those of wild flounders caught in the Pohang, eastern coast of Korea as a control group. Relatively high LDH activities were measured in the serum of flounders cultured on the southern coast of Korea (0.101-0.145 unit) than those in the Pohang control group (0.093 unit). AChE activities were significantly low $(about\;10-20\%)$ in brain membranes of cultured flounders compared to those in the Pohang control group. The ratios of LDH/AChE and LDH/BChE were consistently higher $(136-178\%,\; 155-214\%)$ in cultured flounders than those of Pohang control group. Thus, we propose that the ratios of LDH/AChE and LDH/BChE in flounders could be applicable for the diagnosis of marine pollution.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.3
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• pp.204-208
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• 2009

The withdrawal time of erythromycin in cultured olive flounder was investigated to ensure the food safety of the fish treated with erythromycin. The oral administration of erythromycin was carried out using the experimental diet containing erythromycin (200 mg/kg) daily dose of 40 mg/kg body weight. The 45 day experimental period was broken into 7 days of habituation, 8 days of medication and 30 days of additional feeding without antibiotics. The erythromycin concentration in the flounder muscle had been increased gradually with medication. After 5 days of medication, the concentration increased to its maximum level of 6.05 mg/kg. After discontinuing the antibiotic, the erythromycin concentration decreased drastically and day 9 was below 0.1 mg/kg. The erythromycin concentration had slowly declined from the 6th to the 20th day after medication and disappeared completely after 25 days. From these results, the time needed to reduce the erythromycin level to the 0.2 mg/kg limit adopted by the ED and Japan was suspected to be 4-6 days. Therefore, a reasonable withdrawal time following ED and Japanese regulatory guidelines for erythromycin in the cultured flounder could be estimated to be 10 days.

• Journal of Aquaculture
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• v.12 no.3
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• pp.221-228
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• 1999

The effects of sparp changes of water temperature (WT) on the stree response and physiological change of the cultured olive flounder (Paralichthys olivaceus) were examined by manipulating WT (3 patterns) in a running seawater culture system. In the first group (Exp. I), the WT was decreased from 18$^{\circ}C$ to 11$^{\circ}C$ within 6 hours and increased back to the original WT quickly. WT was decreased from 2$0^{\circ}C$ to 11$^{\circ}C$ within 5 hours and main-tained at 11$^{\circ}C$ for 10 hours. and then increased to 2$0^{\circ}C$ in the second group (Exp. II). In the third group(Exp. III) WT was decreased to 11$^{\circ}C$ within 5 hours (type A) or 10 hrs. (type B). In Exp. I and III, the level of serum cortisol was increased from 2.5$\pm$0.3 ng/ml and 2.6$\pm$0.9 ng/ml to 13.6$\pm$3.0 ng/ml and 12.4$\pm$3.2ng/ml, respectively, with WT decrease. However, no consistent tendency in the change of serum glucose level was shown according to WT decrease. In Exp. III, the glucose level of fish in type A was decreased until 5 hours and increased at 7 hours, then decreased until 12 hours where as the glucose level in type B was decreased until 5 hours and stayed at the level of 15.7 mg/dl. The serum osmolality was reduced with WT decrease and the response of serum electrolytes in this experiment conflicted, and a tendency in total protein, AST and ALT was not found following WT decrease. In conclusion, olive flounder responded to the stress caused by WT decrease and acclimated to this condition when the lower temperature was maintained. But there was no stress response in the blood of olive flounder when WT was increased. On the other hand, the degree of stress response in olive flounder was various according to the range and gradient of WT change.

• Journal of Fisheries and Marine Sciences Education
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• v.25 no.5
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• pp.1079-1087
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• 2013

The pharmacokinetics of florfenicol (FF) after oral administration was studied in the cultured olive flounder, Paralichthys olivaceus, using high performance liquid chromatography (HPLC). After single administration of FF (20 mg/kg body weight) by oral route in olive flounder ($700{\pm}50$ g, $23{\pm}1.5^{\circ}C$), the concentration in the serum was determined at 1, 5, 10, 15, 24, 30, 50 and 168 h post-dose. The kinetic profile of absorption, distribution and elimination of FF in serum were analyzed fitting to a two-compartment model by WinNonlin program. The area under the concentration-time curve (AUC), maximum concentration ($C_{max}$), time for maximum concentration ($T_{max}$) and elimination time were 22.51 ${\mu}g{\cdot}h/mL$, 0.84 ${\mu}g/mL$, 8.62 h and 447 h, respectively. The results of this study related to dosage and withdrawal times could be used for prescription of FF in field for the treatment of bacterial diseases in olive flounder.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.3
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• pp.337-345
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• 2015

To investigate the causes of emaciation in cultured olive flounder Paralichthys olivaceus in Korea. We performed histological examinations and polymerase chain reaction (PCR) with a new primer set. In most cases, the most severe emaciation was observed in the abdominal area Using PCR on extracted livers, kidneys, spleens, gills, brains, and intestines, we found that areas around the kidneys and intestines were as almost always positive. In significantly emaciated fish, PCR was positive in all internal organs except the gills. In addition, the homology of 812-bp nucleotide sequences of the 28S rRNA gene was more than 99% in emaciated fish. Partial homology with Myxobolus spp. and Cystodiscus axonis, whose data were obtained from GenBank was 86% and 88%, respectively. Histological examinations detected spores in kidneys and intestines but not in other organs. We also performed cohabitation experiments to determine whether infections could be exchanged among species or only within species. Uninfected olive flounder and red sea bream, Pagrus major, cohabitating with emaciated olive flounder showed 100% and 0% cumulative mortality, respectively. Thus the cause of emaciation in cultured olive flounder of Korea is likely due to a new parasite.