• Journal of Fisheries and Marine Sciences Education
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• v.22 no.4
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• pp.529-536
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• 2010

This study was conducted to effect of extruded pellets (EPs) and moist pellet (MP) diet on growth and fish health parameters in farm cultured olive flounder Paralichthys olivaceus. Two replicate groups of 2,600 fish per each tank (initial weight of $30.1{\pm}0.2$ g) were fed one of the three EPs (EP1, EP2 and CEP) and one MP for 13 months. In field feeding experiment conducted in commercial flounder farm, survival, growth (30-600 g) and condition factor of fish fed experimental EP1 and EP2 were comparable to those of fish fed MP, but considerably higher feed efficiency and protein efficiency ratio were observed in fish fed experimental EPs. Viable cell counts from diet and water from MP diet were considerably higher than those from EP diet, and lysozyme activity from EP diet was higher than that from MP diet. GOT and GPT of fish fed the EP diet were considerably lower than those from MP group, but total protein and glucose concentration of fish fed the EP groups were not significantly different from that of fish fed the MP. Therefore, these results strongly suggest that EP diets could be developed to replace MP diet without adverse effects on growth performance and to enhance the immunity and protective ability of olive flounder against fish disease such as Vibro, Edwardsiella and Strptococcus.

• Journal of Fisheries and Marine Sciences Education
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• v.27 no.3
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• pp.879-889
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• 2015

The outbreak of viral diseases caused by viral haemorrhagic septicaemia virus (VHSV) and red seabream iridovirus (RSIV) have been reported in cultured olive flounder, Paralichthys olivaceus. VHSV has been a serious viral disease that infects the olive flounders in South Korea. Clinical signs of VHSV infection are skin darkening, abdominal distension and haemorrhages. Outbreaks of fish iridoviral disease was first reported from red seabream, Pagrus major farms in Japan. Recently, iridovirus infection have occurred frequently from olive flounder farms in South Korea. In this study, disease surveillance was performed to monitor the prevalence of VHSV and RSIV in olive flounder in 2014. The samples were collected from 60 different olive flounder farms in Jeju from April, May, September, November and December in 2014. RT-PCR (VHSV) or PCR (RSIV) results showed that VHSV were detected in 5 farms, but RSIV has not been detected in any farms. The migration of olive flounder was restricted for the quarantine in 5 farms of VHS outbreak. The nucleocapsid protein (N) gene and glycoprotein (G) gene sequences of the 5 Korean VHSV isolates were successfully amplified and sequenced. Phylogenetic analysis was performed using the VHSV sequences reported here together comparison with the nucleotide sequences available from the GenBank database. Phylogenetic analysis indicated that most of Korea VHSV belong to the genotype IVa and closely related to the strains from Japan and China.

• Korean Journal of Ichthyology
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• v.19 no.3
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• pp.193-200
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• 2007

The samples of cultured flounder (Paralichtys olivaceus) were collected from Tongyeong and Yosu in Korea and Nagasaki in Japan and processed to analyses of body and serum. Body size and weight were not significantly different between Korea and Japan produced. But the body weight of average size of flounder produced from Nagasaki was the highest from the samples. The average of fish body was not significantly different from the samples. The water content of fish body was lower in samples from Nagasaki and fat content was higher in the samples from Nagasaki and followed by Yosu and Tongyeong. The percentage of body water, fat and protein contents was Nagasaki, Yosu and Tongyeong in the order of high values. Japanese flounder showed relatively high content of body fat and muscle. The cholesterol of serum was highest in the samples of Yosu. The triglyceride of serum was highest in the samples of Nagasaki. Lipoprotein was highest in the samples of Nagasaki and enriched fat content in LDL fraction.

• Journal of fish pathology
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• v.22 no.3
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• pp.211-218
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• 2009

In this study, we have compared the genome of marine birnavirus (MABV) detected from starry flounder Platichthys stellatus and olive flounder Paralichthys olivaceus. A molecular analysis based on the nucleotide sequence (433 bases) of VP2-NS-VP3 region revealed that MABV (08-KU) from starry flounder showed 98% similarity with MABV Y6 isolated from Yellowtail Seriola quinqueradita in Japan (Accession no: AY283781) and with other aquabirnaviruses identify more than 76%. Comparison with MABV strains (06-KP, 08-KC) from olive flounder and MABV Y6 strain showed 97-98% sequence identities. Phylogenetic analysis was performed in order to examine the relationship among previously determined aquatic birnaviruses isolates showed that MABV and IPNV strains were classified into seven clusters. Three isolates from starry flounder and olive flounder in this study, belong to the genogroup VII including MABV Y6 strain and other aquabirnaviruses isolated from marine fish and molluscan shellfish in Japan. This report is the first description of a MABV from starry flounder in Korea.

• Journal of fish pathology
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• v.15 no.2
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• pp.93-97
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• 2002

The scuticociliate, a histophagous ciliate, is known to cause high cumulative mortalities in juvenile olive flounder Paralichthys olivaceus rearing in land-based tank facilities. This study examined effects of bath treatment of 3 chemical agents including formalin, hydrogen peroxide and sodium chloride. and freshwater against scnricociliates infected olive flounder. Although 100 ppm formalin and freshwater did not completeIy eliminale ue scuticociliates within the internal organ of fish, chemicals were effective to prevent scuticociliatosis from spreading. It confirms the efficacy of the chemical with treating the diseased fish for at least 4 consecutive days.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.6
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• pp.882-888
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• 1998

This study was designed as a part of efforts to investigate the biochemical pollutant markers for diagnosis of marine pollutions by changes in lipid components of the flounder (Paralichthys olivaceus) in the South Sea of Korea, Hemoglobin levels in serum of cultured flounders in the South Sea were lower ($4\~17\%$) than those of wild flounder in Pohang as a control group. Triglyceride (TG), Total and low density lipoprotein (LDL)-cholesterol contents in serum of cultured flounders in the South Sea were $12\~25\%,\;9\~19\%$ and $17\~25\%$ respectively which are higher than those of wild flounder in Pohang. Atherogenic index (AI) and T-Chol/PL ratios in serum of cultured flounders in the South Sea were significantly higher($26\~43\%$ and $17\~26\%$ respectively) than those of wild flounder in Pohang. These results suggest that near-coastal water as well as neritic water of the South Sea might be affected by pollutant input as well as the Yellow Sea of Korea.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.1
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• pp.37-41
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• 1999

This study was designed as a part of efforts to investigate the biochemical pollutant markers for diagnosis of marine pollutions by changes in cholinesterase activity of the flounder (Paralichthys olivaceus) in tie South Sea of Korea. Aceflcholinesterase (AChE) activities in brain and muscle of cultured flounders in the South Sea were significantly lower ($10\~20\%$ and $12\~19\%$, respectively) than those of wild flounder in Pohang of the East Sea as a control. Buthrylcholinesterase (BChE) activites in brain and muscle of cultured flounders in the South Sea were also remarkably lower ($25\~40\%$ and $22\~35\%$, respectively) than those of wild flounder in Pohang. Lactate dehydrogenase (LDH) activites in serum of cultured flounders in South Sea were significantly higher ($10\~55\%$) than those of wild flounder in Pohang. It suggests that AChE, BChE and LDH activities of the flounders clould be used as effective biochemical markers for early warning of environmental damages caused by organophosphorus pesticides.

• Fisheries and Aquatic Sciences
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• v.16 no.2
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• pp.93-99
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• 2013

In 2009, a systemic megalocytivirus infection associated with high mortality was detected for the first time in cultured starry flounder Platichthys stellatus in Korea. Diseased starry flounder had pale bodies and gill coloring and enlarged spleens. Histopathological examinations revealed basophilic enlarged cells in various organs of diseased starry flounder. Polymerase chain reaction (PCR) was performed on tissue samples using three published primer sets developed for the red sea bream iridovirus. PCR products were detected for all primer sets, except 1-F/1-R, which are registered by the World Organization for Animal Health (OIE). The part of the gene corresponding to the full open reading frame encoding the viral major capsid protein (MCP) was amplified by PCR. PCR products of approximately 1,581 bp were cloned, and the nucleotide sequences were analyzed phylogenetically. The MCP gene of the starry flounder iridovirus, designated SFIV0909, was identical to that of the turbot reddish body iridovirus (AB166788).

• Journal of Life Science
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• v.20 no.4
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• pp.614-617
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• 2010

We sequenced a 522 bp fragment including the $tRNA^{Thr}$, $tRNA^{Pro}$ gene and the first half of the control region from 29 wild and cultured olive flounder specimens from Korea. Out of 522 nucleotide sites, 49 (9.4%) were variable, 23 haplotypes being found. Most haplotypes are unique in the wild population and only four were shared by cultured specimins. The nucleotide diversity and differences between wild and cultured populations were $0.025{\pm}0.013$ and $0.015{\pm}0.008$, and $12.94{\pm}6.00$ and $7.83{\pm}3.75$, respectively. Haplotype diversity was $0.98{\pm}0.02$ and $0.49{\pm}0.09$ in the wild and cultured populations, respectively. These results show that marked reductions of genetic variability in the hatchery strains were observed in the number of mitochondrial DNA haplotypes and haplotype diversity when compared to the wild populations. Furthermore, we detected significant population differentiation between both populations. The mtDNA sequencing technique used to evaluate the genetic variability of hatchery strains compared to that of the wild population is potential for genetic monitoring of olive flounder hatchery stocks.

• Fisheries and Aquatic Sciences
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• v.2 no.1
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• pp.85-92
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• 1999

We examined the expression patterns of heat shock proteins in primary cultured hepatocytes from flounder (Paralichthys olivaceus) exposed to heat shock. The expression of hsp90, hsp70, hsp40, hsp30, and hsp27 was induced and major polypeptides were hsp70, hsp30 and hsp27. Northern blot analysis showed that expression of hsp70 was inhibited by transcriptional inhibitor actinomycin D, suggesting that expression of hsp70 gene is regulated at the transcriptional level. Prolonged exposure of cells to an elevated incubation temperature $(30^{\circ}C)$ induced the transient synthesis of hsp90, hsp70, hsp40, and hsp30 whereas maintenance of cells at a slightly higher incubation temperature $(32^{\circ}C)$ induced the continuous syntheses of these hsps. When cells were incubated at a higher temperatures $(35^{\circ}C\;or\;37^{\circ}C)$, the synthesis of hsps was almost similar to that of hsps in cells exposed to 32't except for the induction of hsp27 synthesis. These results that temperature and incubation time for optimum expression of each hsp during prolonged heat shock are different.