• Journal of fish pathology
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• v.37 no.1
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• pp.71-78
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• 2024

Streptococcosis, caused by Streptococcus iniae and Streptococcus parauberis is an important bacterial disease that affects in olive flounder in Korea. In Korea, multivalent bacterial vaccines are used to prevent streptococcal diseases in aquaculture. In this study, commercial vaccines containing formalin-inactivated bacterial cells of S. iniae and S. parauberis were administered at six fish farms and one unvaccinated fish farm were designated for investigation (Wando; 4 sites and Jeju; 3 sites). Blood was collected from vaccinated and unvaccinated olive flounders, and titers of antibodies against S. iniae and S. parauberis in serum were analyzed using ELISA. After a one shot vaccination in the farms at Jeju (farm A) and Wando (farm D), the proportion of individuals with specific antibodies against S. parauberis OD values of 0.4 or higher was 60% and 53.5%, respectively. But after booster vaccination, the proportion of individuals with serum OD values of 0.4 or higher was higher substantially increased to 96.6% (farm A) and 100% (farm D). The levels of S. parauberis specific antibodies of olive flounder were increased after vaccination in three fish farms (farm D, E, and F), but not S. iniae specific antibodies.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.6
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• pp.614-620
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• 2009

We report non-specific immune responses and its disease resistance against Edwardsiella tarda by alga mixture (HE; Hizikia:Ecklonia) in olive flounder for the first time. Five isonitrogenous (44% crude protein) and isocaloric (17.1 MJ $kg^{-1}$) diets were formulated to have 0%, 2%, 4%, 6% and 8% of the alga mixture. One of five experimental diets was fed triplicate groups of fish (30 fish/group) to apparent satiation in a flow through system. After a two week feeding, blood was sampled at 3, 6, 12, 24 h after the last feeding for a kinetic measurement of nitroblue tetrazolium (NBT) activity and healthy fish with similar sizes in each tank were selected and injected with 1 mL of E. tarda suspension ($1.0\times10^7$ CFU/mL) to evaluate the disease resistance of the fish. Dietary supplementation of alga mixtures resulted in significantly higher non-specific immune responses compared with the fish fed the control diet. The cumulative mortality was significantly lower in the fish groups fed alga mixture containing diets than control group in the challenge test with E. tarda. Therefore, the results in this study indicate that dietary supplementation of Hizikia and Ecklonia mixtures enhance the non-specific immune responses and a disease resistance of olive flounder.

• Journal of fish pathology
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• v.23 no.3
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• pp.389-398
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• 2010

Effects of various concentration of yuzu Citrus junos Siebold ex Tanaka in the diets on growth, blood chemistry and disease resistance of olive flounder were determined. Fifteen hundred fish averaging 200~270g were fed on moist pellet containing yuzu at the concentrations of 0%(control), 2.5%, 5% and 7.5% for 3 months. After feeding trial, weight gain of fish fed 2.5% and 5.0% yuza diet was higher than those of fish fed 0% and 7.5% yuza diet but not significant(P>0.05). No differences in hematological and physiological indices of olive flounder were found among the experimental diets except for total cholesterol. Serum lysozyme activity was not significantly different among fish fed experimental diets but bactericidal activity of fish fed 7.5% yuza diet was significantly different from those of fish fed 0, 2.5 and 5% Yuza diets. Survival rates of fish fed 2.5% yuza diet at experimental infection with Edwardsiella tarda and Streptococcus sp. were higher than those of the other experimental groups but not significant. In conclusion, Dietary inclusion of 2.5~5% yuzu seems to have positive effects for fish health condition and disease resistance.

• Journal of fish pathology
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• v.23 no.1
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• pp.57-67
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• 2010

Effects of temperature ($13{\pm}1.5^{\circ}C$, $23{\pm}1.5^{\circ}C$) on the pharmacokinetic properties of nalidixic acid (NA), piromidic acid (PA) and oxolinic acid (OA) were studied after oral administration to cultured olive flounder, Paralichthys olivaceus. Serum concentrations of these antimicrobials were determined after oral administration of a single dosage of 60 mg/kg body weight (average 700 g). At $23{\pm}1.5^{\circ}C$, the peak serum concentrations of NA, PA and OA, which attained at 10 h, 24 h and 30 h post-dose, were 11.55, 3.79 and $1.12{\mu}g/m\ell$, respectively. At $13{\pm}1.5^{\circ}C$, the peak serum concentrations of NA, PA and OA, which attained at 10 h, 15 h and 30 h post-dose, were 6.36, 1.4 and $1.01{\mu}g/m\ell$, respectively. Better absorption of NA and PA was noted at $23{\pm}1.5^{\circ}C$ compared to $23{\pm}13^{\circ}C$. The elimination of NA from serum of olive flounder was considerably faster at $23{\pm}1.5^{\circ}C$ than at $13{\pm}1.5^{\circ}C$. However, both absorption and elimination of OA were not affected significantly by temperature. The kinetic profile of absorption, distribution and elimination of these antimicrobials in serum were analyzed by fitting to a one- and two compartment model, with WinNonlin program. In the one compartment model for NA, AUC, Tmax and Cmax at $23{\pm}1.5^{\circ}C$ were $258.26{\mu}g{\cdot}h/m\ell$, 10.67 h and $8.91{\mu}g/m\ell$, respectively. The AUC, $T_{max}$ and $C_{max}$ at $13{\pm}1.5^{\circ}C$ were $341.45 {\mu}g{\cdot}h/m\ell$, 7.72 h and $6.23{\mu}g/m\ell$, respectively. In the one compartment model for PA, AUC, $T_{max}$ and $C_{max}$ at $23{\pm}1.5^{\circ}C$ were $248.12{\mu}g{\cdot}h/m\ell$, 21.15 h and $3.09{\mu}g/m\ell$, respectively. The AUC, $T_{max}$ and $C_{max}$ at $13{\pm}1.5^{\circ}C$ were $103.89{\mu}g{\cdot}h/m\ell$, 12.89 h and $1.22{\mu}g/m\ell$, respectively. In the two compartment model for OA, AUC, $T_{max}$ and $C_{max}$ at $23{\pm}1.5^{\circ}C$ were $138.20{\mu}g{\cdot}h/m\ell$, 23.95 h and $1.06{\mu}g/m\ell$, respectively. The AUC, $T_{max}$ and $T_{max}$ at $13{\pm}1.5^{\circ}C$ were $159.10{\mu}g{\cdot}h/m\ell$, 28.03 h and $1.02{\mu}g/m\ell$, respectively.

• Korean Journal of Microbiology
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• v.49 no.2
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• pp.172-178
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• 2013

The strains were added to the feed in the concentration of $10^3$, $10^5$, and $10^7$ CFU/kg and 2% of fishes were given the feed twice a day (8 AM and 5 PM) for 12 weeks. In result of the nonspecific immune response study to examine Respiratory burst activity, Lysozyme activity and Phagocytosis activity every two weeks until the end of the study, all test samples showed greater activities than control samples and improved immune activity with Bacillus sp. IS-2. The mortality test performed by artificial infection using Streptococcus iniae, a pathogenic bacterium, after the completion of this study also showed over 55% greater survival rate in all test samples. In result of performing PCR using the universal primer to verify that the probiotic stays in the intestines of the fishes, all test samples showed PCR product of 1,465 bp. Based on the above findings, it was concluded that Bacillus sp. IS-2 in the feed improved farmed flatfish's immune system and resistance against diseases as the probiotics. Also, the physiological indicators discovered by this study would be useful for identifying the mechanisms of probiotics.

• Journal of fish pathology
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• v.26 no.3
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• pp.255-263
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• 2013

The innate immune response is fundamental defense response of vertebrates and invertebrates. Especially, the innate immune response important for larvae that lack of resistance to infectious diseases in the early stages. Galectin is one of the kinds of lectin and presents in the fish mucous that involves innate immune response. Galectin have been studied from various fishing species, but expression analysis of galectin is still unclear during early developmental stage in olive flounder. In this study, we investigated gene expression of galectin-1 from various developmental stage and tissues. We excised several tissues including the muscle, fin, eye, gill, brain, stomach, intestine, kidney, spleen and liver from adult olive flounder and confirmed gene expression of galectin-1 using RT-PCR and quantitative real-time PCR. Expression of galectin-1 was significantly higher in muscle, stomach and intestinal tissue than other tissue in adult fish (5 and 29 months). Also, galectin-1 gene was detected from 0 DAH and gradually increased to 35 DAH and since then decreased after stomach development period. Induction of galectin-1 during the early developmental stage suggest that muscle, fin and eye tissue is formed and begins the secretion of galectin this period. In addition, increased expression levels at 35 DAH suggest that due to complete formation of stomach and intestine, increase of secretion and activation of enzyme. This study shows that expression of galectin-1 during early developmental stages and adult period in olive flounder and can be expect that galectin-1 play essental role in the innate immune system throughout the whole life time. Galectin-1 is primary barrier such as skin and digestive tissue against pathogen infection, also digestive tract developmental period is important for pathogen invasion can be expected that it will serve. Mass mortality due to the disease in seed production is continuing damage, therefore these result will be meaningful about infectious disease during early developmental stages as a basic data for the study.

• Korean Journal of Microbiology
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• v.54 no.4
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• pp.369-378
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• 2018

This study was conducted to evaluate effects of dietary microbial probiotics on the growth and disease resistance of olive flounder (Paralichthys olivaceus) in a recirculating aquaculture system (RAS), and the effects of the probiotic bioaugmentation on the microbial community structure and water quality. For the analysis, 80 juvenile fish (average weight, $25.7{\pm}7.6g$; average length, $15.2{\pm}1.7cm$) were fed a basal diet containing a commercial microbial product CES-AQ1 (CES; $1{\times}10^9\;CFU/kg$ diet) in an RAS for 8 weeks. Weight gain, the specific growth rate, feed efficiency, and protein efficiency ratio of the fish fed the CES diet in the RAS were 1.5~2.5 times higher than those of fish fed the basal diet alone, or the basal diet containing oxytetracycline (OTC), yeast plus bacterium, or Bacillus subtilis in a still water system. There was no significant difference in the pathogen challenge test between fish fed the OTC diet and fish fed the CES diet in the RAS, suggesting the CES-AQ1 probiotic used in the RAS as a potential replacement for antibiotics. The RAS biofilter maintained the highest microbial diversity and appeared to harbor microbial communities with ammonium oxidation, denitrification, and fish pathogen suppression functions. Ammonia, which is hazardous to fish, was significantly decreased to < 0.5 mg/L in 19 days, indicating the effectiveness of probiotic supplementation to maintain good water quality in RAS. These results suggest that the intestinal microbial communities of fish are stabilized by a probiotic-containing diet (CES) and that bioaugmentation with probiotics may be an eco-friendly and economical supplement for aquaculture of olive flounder, promoting both good water quality and fish health in an RAS.

• Journal of Aquaculture
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• v.19 no.4
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• pp.231-235
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• 2006

The effects of mycelium cultural extract supplemented diet, hematology and disease resistance against Vibrio anguillarum in juvenile flounder, Paralichthys olivaceus were evaluated. Fish were fed the Phellinus linteus with Coriolus militaris versicolor mixed mycelium cultural extract supplemented diet, Phellinus linteus mycelium cultural extract supplemented diet and Coriolus militaris tmycelium cultural extract supplemented diet a commercial diet for 12 week. The body weight and length gain from the fish fed on daily the phellinus with coriolus versicolor mixed mycelium cultural extract supplemented diet, phellinus linteus mycelium cultural extract supplemented diet and Coriolus versicolor mycelium cultural extract supplemented diet of each mycelium cultural extract were higher than the control and the Glutamic oxalacetic transaminase (GPT) were of lower than the control. The relative precent survival rate (RPS) after an artificial challenge with $7{\times}10^5\;CFU$ of Vibrio anguillarum per fish was higher than the control.

• Journal of Life Science
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• v.19 no.1
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• pp.87-93
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• 2009

We have investigated the effects of the culture broth of lactic acid bacteria (LAB) cultured in herb extract on growth, hematological parameter, nonspecific immune responses and disease resistance of olive flounder (Paralichthys olivacells) and parrot fish (Oplegnathus fasciatus) for 12 weeks. Weight gain of olive flounder fed diet with mixture was not significant among the control group. But In parrot fish, was significantly higher 20g than control group. The feed efficiency of olive flounder were 25% higher in the experimental groups than in the control. There were no significant differences in feed efficiency among each group on parrot fish. Treatment of olive flounder contents of GOT and GPT in serum decreased after 8 weeks. But there were no significant differences in GLU and TP among each group. Also, there was no significant of NBT reduction. The activities of lysozyme were higher in experimental group of olive flounder than in the control after 8 weeks. On the other hand, activities of lysozyme were triple higher in the experimental group of parrot fish than in the control after 12 weeks. In the oliver flounder case, the survival rate (%) after an artificial challenge with $10^7$ CFU/ml of Vibrio anguillarum and Streptococcus iniae per fish, was 18% higher in the experimental groups than the control. The higher survival rate of parrot fish were 17% and 16% in the experimental groups than the control respectively.

• Journal of fish pathology
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• v.20 no.3
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• pp.201-209
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• 2007

Viral hemorrhagic septicemia (VHS) is one of the most serious viral disease of farmed rainbow trout and some marine fishes in Europe and North America. It has been reported in various marine fish species of Asian countries and induced cause mass mortality in Japanese flounder (Paralichthys olivaceus) culturing in Korea. The aims of this study were to monitor VHSV in wild marine fishes and to give critical information for controling the disease through prophylactic methods. Prevalence of the viral disease, geological distribution and reservoir of the virus were investigated using wild marine fishes captured in southern coast and east china sea for two years. (Reverse Transcriptase Polymerase Chain Reaction) RT-PCR results showed that VHSV were detected in 17 (10.6%) out of 160 fish. G gene sequences of viral strains isolated in this study were closely related to that of a reference strain, KVHS01-1, belonging to VHSV genotype Ⅰ. The results suggest that some of wild marine fishes are VHSV carriers and may spread the pathogen directly to fish farmed in coastal area.