• Journal of fish pathology
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• v.33 no.1
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• pp.7-14
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• 2020

A disease that manifested severe anemia of the gills occurred in the olive flounder (Paralichthys olivaceus), which was cultured for 5-6 months with a recirculation water system in the laboratory. Microscopic observations showed immature parasite in the gills and mature adults in the oral cavity. The matured parasite was 5.60-9.32 (7.42) mm in total length, with 4 pairs of clamps on the pedunculated haptor, which was separated from the body proper by a long isthmus. From the morphological observations of the larvae, it was identified as Neoheterobothirum hirame belonging to the monogenea. The average hematocrite of infected fish was 10.3 ± 2.8%, significantly lower than that of normal flounder 31.4 ± 4.2%. Histopathologically, fish infected with N. hirame exhibited reduced numbers of erythrocytes in blood vessels of the gill filament and lamellae, reduced red pulp area of the spleen, and hepatocyte atrophy. From the above results, the cause of severe anemia in olive flounder was identified as N. hirame infection. This study shows an example where the growth of pathogens can be a problem in the recirculation system due to low water exchange rate.

• Journal of Animal Science and Technology
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• v.53 no.2
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• pp.99-106
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• 2011

This study estimated the genetic parameters of growth-related traits from 11-month-old olive flounder (Paralichthys olivaceus) base population in which wild and cultured broodstocks were introduced. The heritability of body weight, total length, body height, body shape, and condition factor of the base population was estimated to be 0.754, 0.753, 0.789, 0.438, and 0.369, respectively. Genetic correlations between body weight and total length, between body weight and body height, and between total length and body height were 0.969, 0.960, and 0.960, respectively, showing highly positive correlation. Genetic correlations between body weight and body shape, between total length and body shape, between body height and body shape were -0.403, -0.344, and -0593, respectively, showing low negative correlation. Overall, olive flounder might be an appropriate selective breeding species with the high heritability of the traits in an 11-month-old population.

• Journal of fish pathology
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• v.23 no.1
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• pp.37-45
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• 2010

In this study, we carried out research on the level of single and multi-drug resistance of bacteria isolated from cultured flounder Paralichthys olivaceus. One hundred sixty one bacteria were isolated from cultured olive flounder Paralichthys olivaceus in Korea and the isolates consisted of Edwardsiella tarda (n=32), Vibrio ichthyoenteri (n=37), Vibrio spp. (n=54), Streptococcus parauberis (n=28) and Streptococcus spp. (n=10). These E. tarda isolates were highly resistant in the order of tetracycline (84.4%) and oxolinic acid (71.9%). V. ichthyoenteri and Vibrio spp. showed resistance ampicillin (94.6% and 81.5%) and tetracycline (56.8% and 42.6%). S. parauberis isolates were resistant ampicillin (57.1%), tetracycline (57.1%) and erythromycin (35.7%). Of the isolates, 84.4% of E. tarda, 73.0% of V. ichthyoenteri, 57.4% of Vibrio spp., 42.8% of S. parauberis and 70.0% of Streptococcus spp. isolates exhibited multi-drug resistance against more than two antibiotics.

• Korean Journal of Microbiology
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• v.42 no.3
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• pp.199-204
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• 2006

Streptococcosis of olive flounder(Paralichthys olivaceus) is an important bacterial disease in Jeju island. In this study, we investigated monthly infection pattern of this disease in different size of the flounder fish. Even though the disease occurred throughout the year, the infection ratio was relatively higher in the months with warm water season. The infection was more prevalent in adult flounder over 30 cm total length compare to these of small size fish. Two infectious species of streptococcosis pathogens were detected by multiplex PCR assay. Detection ratios of Streptococcus iniae and S. parauberis reached up to 46% and 54%, respectively, from June 2003 to May 2005 in Jeju island. S. iniae occurred intensively from September to October, whereas S. parauberis reported from March to May. S. iniae and S. parauberis infections of cultured flounder share some common features, but clinical findings showed considerable differences between two diseases. Distended abdomen, protruded anus and ascitic fluid in the peritoneal cavity are evident lesions detected in S. iniae infection, whereas, flounders infected by S. parauberis showed prominent lesions such as darkened surface and haemorrhaging in the non-ocular side. Both streptococcosis pathogens were sensitive to antibiotics, such as ampicillin and amoxicillin. However, S. iniae strains were more sensitive to doxycycline, erythromycin and oxytetracycline than S. parauberis strains.

• Development and Reproduction
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• v.13 no.4
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• pp.239-247
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• 2009

Hatching rate, larval deformation and growth rate of selected olive flounder (Paralichthys olivaceus) for rapid growth were compared to those of the unselected fish. Fish were spawned on the same day and cultured under the similar conditions. The selected fish had a significantly higher eggs hatching rate, and lower larval deformation. The selected fish grew significantly faster, and at the end of the experiment (8 weeks after hatching) averaged 50.49${\pm}$2.67 mm in total length, 16.30${\pm}$0.08 mm in body height, and 1.036${\pm}$0.118 g in weight, compared to 40.55${\pm}$3.13 mm, 13.50${\pm}$0.96 mm, and 0.557${\pm}$0.073 g for unselected fish, respectively. The selected fish had a significantly higher body shape index, however lower condition factor than the unselected fish. The results of the present study demonstrate that the selected fish of the olive flounder for rapid growth had superior growth and improved body shape.

• Journal of Practical Agriculture & Fisheries Research
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• v.23 no.1
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• pp.81-87
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• 2021

Olive flounders which were cultured in commercial fish farm showed abnormal swimming behavior in November 2020. Then, gradual mortality was observed in the fish farm. During the diagnosis, bacterial strain KNCFKW-PN1 was isolated from the kidney of the dead fish. Based on the sequence of gyrase B subunit gene, KNCFKW-PN1 was proved to be Pseudoalteromonas nigrifaciens, showing 99.59% nucleotide identity with that of P. nigrifaciens LMG 2227^T. According to the result of antibiotic susceptibility test, P. nigrifaciens KNCFKW-PN1 showed intermediate resistance to ciprofloxacin, and was resistant to ampicillin, cefepime, cefotaxime, ceftazidime, and amikacin. This is the first report of the isolation of multiple-antibiotic-resistant P. nigrifaciens from olive flounder.

• 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.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.45 no.5
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• pp.430-437
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• 2012

The effects of low temperature and starvation on the physiochemical characteristics of the muscle of the olive flounder Paralichthys olivaceus, were examined. Fish were deprived of feed for 28 days at 2, 4, 6, 8, 10, 12, and $20^{\circ}C$ in order to establish suitable conditions for live fish transportation. Throughout most of the 4 weeks of feed restriction, the physiochemical characteristics of the muscle of olive flounder were found to be dependent on the acclimation temperature. The breaking strength of muscle did not show a significant reduction during feed restriction at 2 and $4^{\circ}C$. With increasing temperatures, however, the breaking strength of muscle differed significantly according to the individual and feed restriction period (P<0.05). The moisture content in muscle acclimated at 10, 12, and $20^{\circ}C$ increased steadily over the feed-restriction period, while the crude lipid content decreased during the same period (P<0.05). At water temperatures above $2-8^{\circ}C$, no significant differences were shown during the same period. After it reached 6, 8, 10, 12, and $20^{\circ}C$, the muscle had an accumulation of lactate, and a loss of ATP. There was no change in the lactate or ATP content during the feed restriction period at 2 and $4^{\circ}C$, although there were differences among the water temperature groups. These results clearly show that temperature can have an important influence on the of muscle of physiochemical characteristics of muscle during live fish transportation.

• Journal of fish pathology
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• v.30 no.1
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• pp.41-49
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• 2017

Probiotic principles can be applied in aquaculture for the purpose of growth and immunity stimulation, disease prevention and eventually better production performance. This study was to assess effects of combinations of microbes containing two Bacillus sp., plus one Lactobacillus sp. as the basal preparation (BSL-LAB), and additional Nitrosomonas sp. (nitrifying bacteria consortium, NBS) in olive flounder (Paralichthys olivaceus). The effects examined were growth parameters, hematologic parameters, innate immunity and pathogen challenge test. Fish were assigned to 4 treatments as Control (no probiotics), Group A (Bacillius and Lactobacillus to culture water), Group B (Bacillius and Lactobacillus both in water and feed), Group C (same as Group B with additional Nitrosomonas in feed). Fish were allocated to the above 4 groups, each group being composed of triplicate 30 fish, for a 7-week feeding in the laboratory. Positive effects were observed both in growth and pathogen sensitivity with all three probiotic combinations. Such effects were attributed to improved innate immune functions. This result indicates that the tested probiotic microbes are beneficial to olive flounder aquaculture.

• Journal of fish pathology
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• v.22 no.1
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• pp.91-95
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• 2009

The pharmacokinetic properties of oxytetracycline (OTC) were studied after intramuscular injection to cultured olive flounder, Paralichthys olivaceus. Plasma concentrations of OTC were determined after dosage of 12.5, 25 and 50 ㎎/㎏ body weight in olive flounder (average 600 g, $23{\pm}1{^{\circ}C}$). Plasma samples were taken at 3, 5, 10, 15, 24, 32, 48, 72, 120, 168, 240 and 360 h post-dose. With 25 and 50 ㎎/㎏, the peak plasma concentrations of OTC, which attained at 5 h post-dose, were 0.99 and 1.49 $\mu{g}/m\ell$, respectively. However, the peak plasma concentration of 12.5 ㎎/㎏ was 0.35 $\mu{g}/m\ell$ after 10 h post-dose. Plasma concentrations of OTC were not measurable at 360 h post-dose in all doses. The kinetic profile of absorption, distribution and elimination of OTC in plasma were analyzed fitting to a 1-compartment model by Win-Nonlin program. The following parameters were calculated for 12.5, 25 and 50 ㎎/㎏ body weight, respectively: AUC (the area under the concentration-time curve)?D���D24.98, 44.67 and 50.45 $\mu{g}$ $h/m\ell$ $T_{1/2}$ (half-life) ?D���D0.42, 0.59 and 0.41 h; $T_{max}$ (time for maximum concentration)?D���D8.46, 6.34 and 2.66 h; $C_{max}$ (maximum concentration)?D���D0.30, 0.63 and 1.13 $\mu{g}/m\ell$.