• Journal of fish pathology
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• v.18 no.1
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• pp.81-89
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• 2005

The toxic effects of pentachlorophenol (PCP) on haematological parameters in olive flounder (Paralichthys olivaceus) after chronic exposure to dietary PCP (0.1, 0.5 and 1.0 mg/kg diet) for 2, 4 and 6 weeks were studied. A significant decrease in total RBC count, haemoglobin concentration and hematocrit value was noted in fish exposed to PCP compared to the non-exposed fish. The PCP treatment group showed significantly lower concentration of serum total protein and albumin, and significantly higher serum chloride, magnesium and total bilirubin levels compared with those in the control group. However, PCP had no major effects on serum glucose, total cholesterol, phosphate and calcium ions in flounder. These results demonstrated that PCP have induced adverse haematological impacts in the olive flounder, Paralichthys olivaceus. Because we found damages in blood-forming function and disruption in blood homeostasis due to chronic exposure to PCP, it is needed to develop further experimental studies for the risk assessment of this environmental pollutant.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.5
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• pp.457-461
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• 2010

To estimate the effect of selective breeding on the improvement of growth in olive flounder Paralichthys olivaceus, we compared the growth of a strain selected for rapid growth to that of an unselected strain from a commercial hatchery. The fish strains were fed with either moist pellets (MP) (dry matter, 59.8% crude protein; 14.1% lipid) or extruded pellets (EP) (dry matter, 50.4% crude protein; 13.8% lipid) for 190 days and were reared under similar conditions. The mortality rates were less than 2% and were not significantly different among the experimental groups. The growth rate of the selected fish was significantly greater than that of the unselected fish regardless of the diet type, and both strains fed MP grew significantly faster than those fed EP. The selected fish consumed more feed than the unselected fish. However, there was no significant difference in the feed efficiency between the selected and unselected fish. These results demonstrate that the selected fish exhibited superior growth rates, and that this was associated with a greater intake of food. Thus, selective breeding may be useful for improving the growth of commercial olive flounder.

• Journal of Aquaculture
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• v.19 no.3
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• pp.183-187
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• 2006

A 12-week experiment was conducted to determine the effect of feeding and starvation on survival, growth and the phenotypic trait in olive flounder, Paralichthys olivaceus. Survival and growth of the starved fish group was significantly lower than those of the fed fish group throughout the experiment. Starvation resulted in a retardation in growth, which provided the examples of the reduction in final body weight, growth rate, specific growth rate and condition factor whereas the fed fish group grew well and maintained in good condition. The starved fish group had lower gutted body weight, but similar viscera index and dressing percentage compared to those of the fed fish group. These results suggested that the phenotypic trait used fur starvation and feeding in this study appeared to be an useful index of the nutritional status in olive flounder.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.52 no.1
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• pp.49-58
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• 2019

This study was conducted to investigate the effects of different dietary lipid sources on the growth, feed utilization, body composition and tissue fatty acid profile of olive flounder Paralichthys olivaceus. Five isonitrogenous and isocaloric diets were formulated by adding various lipid sources including soybean oil (SO), eicosapentaenoic acid triglyceride (EPATG) and ethyl ester (EPAEE) forms, docosahexaenoic acid triglycerides (DHATG) and a 1:1 blend of soybean oil and DHATG. Triplicate groups of fish ($6.8{\pm}0.01g$) were fed one of the experimental diets to apparent satiation twice daily for 8 weeks. Fish fed the DHATG diet had the highest growth, protein efficiency ratio and feed efficiency values which were significantly higher than those fed the SO and EPAEE diets. Whole body proximate composition and somatic parameters were not influenced by the dietary treatments. Muscle of fish fed with SO diets were rich in 18:1n-9, 18:2n-6 and 18:3n-3, whereas those of fish fed with EPATG, EPAEE and DHATG diets were rich in n-3 highly unsaturated fatty acids (HUFA). These findings indicated that the inclusion of n-3HUFA oils in olive flounder feed could be beneficial for the fish while simultaneously increasing the concentration of beneficial n-3HUFA in fish fillets destined for the human consumer.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.5
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• pp.567-576
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• 2014

This study investigated the physiological effects of a diet containing calcium oxide (CaO) on the olive flounder, Paralichthys olivaceus. The results indicate that the amount of calcium in the blood was higher in the calcium group compared with the controls. The aspartate amino transferase (AST) and alanine amino transferase (ALT) levels were lower in the calcium group, while lysozyme activity was higher in the calcium group. Histologically, fish in the calcium group had more hepatocytes in the liver and more intact scales. In addition, an attack experiment using Vibrio anguillarum (KCTC-2711) and Edwardsiella tarda (KCTC-3657) showed that the survival was higher in the calcium group compared with the controls. These results suggest that feeding fish CaO when they require it, such as during periods of gonadal maturation and rapid growth, will increase their immunity and resistance to pathogens.

• Fisheries and Aquatic Sciences
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• v.10 no.1
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• pp.1-7
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• 2007

The induction of cellular and humoral immunity and cytokine gene expression by synthetic CpG oligodexoynucleotides (CpG-ODNs) has not been investigated systematically in olive flounder Paralichthys olivaceus in vivo. We optimized the proper concentration of CpG-ODNs using an in vitro assay for the superoxide anion $(O_2^-)$. CpG-ODNs induced $O_2^-$ and nitric oxide (NO) production, lysozyme activity, and the proinflammatory cytokine gene expression of $IL-1{\beta}$ and $TNF-{\alpha}$ in olive flounder significantly in vivo, whereas non-CpG-ODNs did not produce these effects or produced them to a lesser extent. This implied that CpG-ODNs could stimulate cellular and humoral immunity and cytokine gene expression in olive flounder. This is the first evidence of NO production and the first study on the mRNA expression of the proinflammatory cytokine genes $IL-1{\beta}$ and $TNF-{\alpha}$ in olive flounder in response to CpG-ODNs. Comparison of the variation in NO production and lysozyme activity to that of other studies led us to postulate that a group-specific difference exists in the immune responses of olive flounder against CpG-ODNs. Furthermore, the detailed immunostimulatory spectrum of CpG-ODNs in olive flounder could be a useful index with which to analyze the effect of CpG-ODNs against the challenge test prior to field applications.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.5
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• pp.480-484
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• 2002

Accumulation of cadmium (Cd) was investigated in organs (gill, liver, kidney, intestine) of olive flounder (Paralichthys olivaceus) exposed to sub-lethal concentration (5, 10, 50, 100 $\mu$g/L) of Cd for 30 days. Cd exposure resulted in an increased Cd accumulation in liver of flounder for exposure periods and Cd concentration, and Cd accumulation increased linearly with the exposure time. At 20 days of Cd exposure. the order of Cd accumulation in organs was Bill>intestine>liver>kidney and after 30 days of exposure, Cd accumulation in organs was intestine>liver>gill>idney. An inverse relationship was observed between the accumulation factor (AS) and the exposure level, but AE shows an increase with exposure time.

• Korean Journal of Ichthyology
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• v.19 no.4
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• pp.257-265
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• 2007

We constructed a cDNA library of testis from olive flounder (Paralichthys olivaceus) and a total of 248 expressed sequence tag (EST) clones were generated. In order to understand the molecular compositions of the olive flounder testis organs, the expression profiles of the identified clones in the cDNA library were analyzed. Gene annotation procedures and homology searches of the sequenced ESTs were locally done by BLASTX for amino acid similarity comparisons. Of the 248 EST clones, 156 ESTs showed significant homology to previously described genes while 92 ESTs were unidentified or novel. Comparative analysis of the 156 identified ESTs showed that 6 (3.8%) clones were representing 5 unique genes identified as homologous to the previously reported olive flounder ESTs, 100 (64.1%) clones representing 94 unique genes were identified as orthologs of known genes from other organisms, and orthologs were established for 50 (32.1%) clones representing 44 genes of known sequences with unknown functions. Furthermore, the testis library showed a more even distribution of cDNA clones with relatively fewer abundant clones that tend to contribute redundant clones in EST projects; thus, the testis library can supply more unique and novel cDNA sequences in olive flounder EST project.

• Journal of Aquaculture
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• v.20 no.3
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• pp.199-202
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• 2007

We isolated a 317 bp of partial cDNA for doublesex-and mab-3-related transcription factor-1 (DMRT-1) from the testis of olive flounder, Paralichthys olivaceus using RT-PCR. Based on the multiple sequence alignment, olive flounder DMRT-1 shared relatively high sequence homology (82 to 94%) with orthologues from other teleost species such as Atlantic halibut, Hippoglossus hippoglossus, black porgy, Acanthopagrus schlegeli and rainbow trout, Oncorhynchus mykiss. DMRT-1 mRNA was predominantly expressed in the testis of olive flounder. In our investigation for the effect of testosterone treatment in vivo on induced expression of ovarian DMRT-1 transcript, mRNA levels of DMRT-1 in ovary were significantly up-regulated by testosterone treatments (0.3 or $3.0{\mu}g$ testosterone/g body weight for 12 to 36 hours) as judged by RT-PCR analysis. In overall, transcriptional stimulation of DMRT-1 during treatments was more affected by doses of testosterone than treatment durations. This result strongly suggests that the regulation of DMRT-1 be tissue- and gender-specific in olive flounder, and also provides useful baseline knowledge on the testosterone-mediated regulation in the reproductive physiology of this species.

• 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.