• Parasites, Hosts and Diseases
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• v.57 no.4
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• pp.439-444
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• 2019

Since Kudoa septempuntata was identified as a causative agent of food poisoning associated with raw olive flounder Paralichthys olivaceus, interest and concern regarding the parasite have increased. However, there have been no investigations or reports of other Kudoa species infecting the fish (except for K. paralichthys, which infects the brain) in Korea. We found cysts filled with myxospores of Kudoa species in muscles of cultured olive flounder specimens and identified these to the species level. Mature spores were quadrate, measuring $8.7{\pm}0.5{\mu}m$ in length, $9.2{\pm}0.4{\mu}m$ in thickness, and $12.9{\pm}0.6{\mu}m$ in width. The spores containing 4 polar capsules had a length of $2.1{\pm}0.2{\mu}m$ and a width of $1.8{\pm}0.3{\mu}m$. The partial 18S and 28S rDNA of isolates showed 99-100% similarities with K. ogawai. Using these morphological and molecular analyses, the species was identified as K. ogawai. This study is the first report of K. ogawai infection in cultured olive flounder in Korea.

• Fisheries and Aquatic Sciences
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• v.8 no.3
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• pp.132-137
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• 2005

Olive flounder (Paralichthys olivaceus) is one of the most commercially important species of farmed marine fish in Korea. Although techniques for rearing the larva of this species are improving, production costs are also increasing due to microbial influences and genetic degradation caused by successive culturing. Since the demand for healthy seed, which requires eggs of good quality of, is high, we examined the effects of nutrient composition on the size of P. olivaceus eggs. We analyzed floating (live) and sunken (dead) eggs of P. olivaceus from five different hatcheries for their size and amino and fatty acid composition. The sizes of eggs and oil globules from floating vs. sunken eggs were significantly different at p<0.05. No significant relationships were observed, however, among larval length, hatching percentage, and egg and oil globule size. The dry weight and amino acid levels of floating eggs were greater than those of sunken eggs (p<0.05), but no difference in fatty acid content was observed.

• Development and Reproduction
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• v.23 no.2
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• pp.149-160
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• 2019

This study examined the effects of different photoperiod conditions on olive flounder (Paralichthys olivaceus), a commercially important species in Korea. Daily variations in the expression of mRNA for the growth-related genes arylalkylamine N-acetyltransferase2 (AANAT2), preprosomatostatin1 (PSS1), and growth hormone (GH) were examined under a 12 h light:12 h dark photoperiod. All the genes were expressed at higher level during the dark period. Melatonin injections increased the expression of GH, but did not significantly affect the expression of PSS. Under short-day conditions (10 h:14 h), the fish gained more weight than under long-day conditions (14 h:10 h). A long nighttime induced melatonin secretion and increased the expression of GH mRNA, promoting weight gain in this species. Therefore, we thought that the long day condition in raising olive flounder may be effective in inducing body growth.

• Journal of fish pathology
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• v.16 no.2
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• pp.91-102
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• 2003

The present study was investigated the effects of chlorine dioxide ($CIO_2$) on the rcspimtory metabolism of olive flounder (Parolichlhys olivaceus) imtermittently exposed to seawater chlorinated by $CIO_2$:. Oxygen consumption of flounder before and after once or twice $CIO_2$-treatment with 12 hr- or/and 24 hr-interval were serially measured with automatic intenniteent-flow respirometer system (AIRS). The oxygen consumption rates of flowKier exposed to 0.10 and 0.20 ppm$CIO_2$, were not different from the control fish prior to the once or twice chlorinations . On the other hand, the respiratory metabolic rates of flounder exposed to 0.30 ppm$CIO_2$ were significantly increased 15% and 22 - 23% after the once and twice chlorinations compared to the control fish. respectively. The flounder exposed In 0.40 and 0.50 ppm$CIO_2$: died within 4 hr and I hr. respectively. The elevation( respiratory metabolism in flounder exposed toO.30 ppm$CIO_2$ and above is considered due to physiological stress caused by $CIO_2$ exposure.

• 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.

• Journal of Aquaculture
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• v.8 no.1
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• pp.69-76
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• 1995

Hybrid fish were induced between olive flounder (Paralichthys olivaceus) female and spotted flounder (Verasper variegatus) male by artificial inseminations. Survival, growth and morphological changes in larval stage of hybirds were examined and compared to their parental species. Survival and growth up to 25 days after hatching of the hybrids were more similar to those of olive flounder than to those of spotted flounder (P<0.05). The ratio of yolk length to yolk width in hybrids was similar to that of female parents (P<0.05). The oil globule were resorbed within 18 days after hatching in hybrids and 14 days after hatching in olive flounder, and spotted flounder has no oil globule. These results indicated that survival, growth and morphological changes in larval stage of hybrids were similar to those of maternal olive flounder.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.5
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• pp.696-703
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• 2015

We investigated the characteristics of embryonic and abnormal organ development in haploid olive flounder, Paralichthys olivaceus, by comparing egg development and histological sections in haploid and diploid individuals. After the mid-blastula transition, abnormal development was observed in haploid fish, including delayed epiboly and malformation of the germ ring and embryonic body. In haploid flounder, Kupffer’s vesicles are irregularly shaped and of variable size compared to diploids. The embryonic body of haploids was shorter and broader than that of diploids and the tail length and size were variable. Most haploid embryos failed to hatch and the few larvae that did, did not survive for more than 6 h. The histological analysis of haploid larvae revealed deformed development in diverse organs, including the eye, otic vesicles, notochord, and neural tube. These results may be related to an abnormality in the axial system of haploid larvae. This study confirmed that the abnormalities of haploid olive flounder were similar to the reported characteristics of haploid syndrome. The abnormalities are caused by delayed epiboly and involution and deformity of Kupffer’s vesicle during egg development.

• Fisheries and Aquatic Sciences
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• v.18 no.2
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• pp.151-158
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• 2015

We evaluated the effects of rice distillers dried grain (DDG) as a partial replacement for fish meal in the practical diet on growth performance, feed utilization, and body composition of juvenile olive flounder Paralichthys olivaceus. Six isonitrogenous and isocaloric diets were formulated to contain 0%, 7%, 14%, 21%, 28%, and 35% DDG (designated DDG0, DDG7, DDG14, DDG21, DDG28, and DDG35, respectively). Three replicate groups of juvenile olive flounder averaging $9.6{\pm}0.2g$ were fed one of the experimental diets to visual satiety twice daily for 8 weeks. Neither survival nor daily feed intake was affected by the dietary DDG levels. Weight gain of the flounder fed the DDG28 and DDG35 diets was lower than that of flounder fed the DDG7 diet. The feed efficiency of flounder fed the DDG28 diet was lower than that of flounder fed the DDG0, DDG7, and DDG14 diets. The protein efficiency ratio of flounder fed the DDG28 diet was lower than that of flounder fed the DDG7 diet. The proximate composition of muscle was not affected by the dietary DDG levels. The plasma contents of total protein, glucose, cholesterol, glutamate oxaloacetate transaminase, phospholipid, and triglyceride were not affected by the dietary DDG levels. The results of this experiment suggest that DDG has the potential to replace fish meal and could be used up to 21% DDG without any negative effects on the growth and feed utilization of juvenile flounder.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.2
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• pp.169-174
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• 2017

Immunoglobulin M (IgM) was purified from olive flounder Paralichthys olivaceus sera using mannan-binding protein (MBP) and protein L affinity columns (designated as MBPIgM and ProLIgM, respectively). A monoclonal antibody (MAb) against olive flounder IgM was produced. The MBPIgM and ProLIgM had apparent molecular weights of 77, 73, and 28 kDa in SDS-PAGE. Nine hybridomas secreting MAbs against olive flounder IgM were established: five MAbs for MBPIgM (1, 2, 3, 4, and 5) and four for ProLIgM (6, 7, 8, and 9). Western blotting indicated that seven MAbs recognized heavy (H; MAbs 1, 2, 3, 4, 5, 6, and 7) chains and one recognized light (L; MAb 9) chains of IgM, while MAb 8 did not recognize IgM. The results of enzyme-linked immunosorbent assay (ELISA) with bovine serum albumin (BSA, antigen) and the nine MAbs revealed that the optical density (OD) values of sera differed significantly between BSA- and non-immunized fish, despite some sera from non-immunized fish with slight high OD values. These results suggest that the MAbs produced in this study reacted specifically with the IgM from olive flounder.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.2
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• pp.148-156
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• 2018

This study was conducted to evaluate dietary hydrolyzed pig bristle meal (PBM) for juvenile olive flounder Paralichthys olivaceus. In Experiment 1 (EXP-1), six experimental diets were prepared to contain 0, 3, 6, 9, 12 and 15% PBM (designated Con, PBM3, PBM6, PBM9, PBM12 and PBM15, respectively). Triplicate groups of olive flounder (initial body weight, 8.69 g) were fed the diets to apparent satiation for 8 weeks during the optimal water temperature season ($20.5{\pm}2.12^{\circ}C$). All PBM supplemented groups except for PBM3 showed significantly lower growth performance and feed utilization compared to the control group. The protein digestibility of PBM3, PBM6, and PBM9 diets did not significantly differ from that of the control diet. In Experiment 2, 1% mono-calcium phosphate was added into the experimental diets used in Exp-1. Triplicate groups of olive flounder (10.6 g) were fed the diets to apparent satiation for 8 weeks during the low water temperature season ($12.5{\pm}1.12^{\circ}C$). The growth performances and feed utilization of fish fed all diets except for PBM15 diet did not significantly differ from those of the control diet. This study indicates that hydrolyzed PBM can replace fish meal by up to 12% with limiting amino acids and mono-calcium phosphate in diets for juvenile olive flounder.