• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.2
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• pp.100-105
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• 2006

This study was conducted to evaluate the effects of extruded pellet (EP) diets, as compared to a raw fish moist pellet (MP) diet for olive flounder, Paralichthys olivaceus, grown in commercial-scale aquaculture for 1 year. Four diets with duplication per diet were formulated for this experiment: two experimental EP diets (EP1 and EP2), one commercial EP diet (CEP), and a raw fish MP diet (MP). The MP diet consisted of 80% frozen horse mackerel and 20% commercial binder meal. Fish weighing $30.1{\pm}0.1 g$ ($mean{\pm}SD$) were distributed randomly to each aquarium as a group of 2,600 fish. Weight gain (WG) and feed efficiency ratio (FER) of fish fed EP2 and MP were higher (P<0.05) than those of fish fed CEP, while those of fish fed EP1 did not differ (P>0.05) from those fed EP2 and MP. However, fish fed the MP diet had a higher survival rate than fish fed the other diets. Fish fed EP2 had higher serum, phospholipids and total protein levels, and lower levels of serum glutamic-oxaloacetic transaminase (GOT), glutamic-pyruvic transaminase (GPT), and total cholesterol than fish fed MP (P<0.05). Dorsal muscle and liver proteins and lipid of fish fed EP1 were higher (P<0.05) than those of fish fed CEP, while those of fish fed EP1 and MP did not differ from those of fish fed EP2 (P>0.05). These results strongly suggest that EP1 could be developed to replace MP for grow-out stage production of olive flounder without adverse effects on growth performance.

• Journal of Aquaculture
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• v.21 no.4
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• pp.244-251
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• 2008

We evaluated the optimum dietary lipid level and feeding rates of extruded pellets (EP) in juvenile flounder Paralichthys olivaceus during the summer season. The first experiment was conducted to determine the optimum dietary lipid level in juvenile flounder. Five isonitrogenous EP (52% crude protein) with increasing dietary lipids (6, 8, 10, 12 and 14%) were fed to satiety to triplicate groups of the juveniles ($18.4{\pm}0.11g$) twice a day for 6 weeks. Weight gain (WG) of fish fed EP with 10% lipid was significantly higher than those of fish fed EP with 6 and 14% lipid (P<0.05). Broken line model analysis suggested that the optimum dietary lipid level could be $9.08{\pm}0.37%$ for the maximum WG in juvenile flounder. The second experiment was conducted to determine the optimum feeding rate using experimental diet contained 10% lipid level that had the highest WG in first experiment. The feed intake of triplicate groups of the juveniles ($13.4{\pm}0.15g$) was restricted to four different feeding rates of 2.0, 2.5, 3.0 and 3.5% of their body weight $day^{-1}$ and to satiation using experimental diets. WG and feed efficiency (FE) of fish was affected by feeding rates. WG and specific growth rate of fish fed the diets increased with increasing feeding rate, however no significant differences (P>0.05) in WG and specific growth rate were observed between the fish fed 3.5% of their body weight $day^{-1}$ and to satiation. FE of fish fed 3.5% of their body weight $day^{-1}$ was significantly higher than those offish fed 2.0% of their body weight $day^{-1}$ and to satiation (P<0.05). Broken line model analysis suggested that the optimum dietary feeding rate could be $3.56{\pm}0.06%$ for the maximum WG in juvenile flounder. These results indicated that the optimum lipid level and feeding rate could be $9{\sim}10%$ (Energy: 4,774kcal and PIE ratio: 108mg protein/kcal in diet) and 3.5% of their body weight $day^{-1}$in juvenile flounder, respectively.

• Journal of Aquaculture
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• v.20 no.1
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• pp.51-55
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• 2007

This study was conducted to evaluate the muscle quality of the olive flounder fed on extruded pellet (EP) diets compared with a raw fish moist pellet (MP) diet for olive flounder, Paralichthys olivaceus in a commercial scale for a year. The sensory and physical qualities and palatable compounds were compared for evaluation of muscle quality in fish. Four diets were formulated for this experiment: two experimental EP diets (EP 1 and 2), one commercial EP diet (CEP) and MP diet. Crude lipid of fish fed EP1 and EP2 was significantly higher (P<0.05) than that of fish fed CEP, but not significantly different from that of fish fed MP (P>0.05). In the palatable compounds, the free amino acids composition were much alike in that of all the diets. Proline, glycine and alanine from fish fed diet EPs were the most abundant compound among amino acid compositions. There was little difference in the free amino acid compositions of all flounder from localities and the growing conditions between wild and cultured fishes. Taurine of fish fed EP1 was dominantly high over that of fish fed EP2, CEP and MP. In all nucleotides and their related compounds, ATP and IMP from fish fed EP diets were higher (P<0.05) than those of fish fed MP. In the sensory score, overall-acceptability of fish fed EP2 were significantly higher (P<0.05) than that of fish fed EP1, CEP and MP. Hardness of physical properties from fish fed EP2 was significantly higher (P<0.05) than those of fish fed CEP (P<0.01). These results strongly suggest that diets EP could be developed to replace MP diet for the grow-out stage of olive flounder without adverse effect on growth performance.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.3
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• pp.243-249
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• 2009

This study was conducted to determine the proper inclusion levels of squid liver powder (SLP) and dehulled soybean meal (DHSM) as a fish meal (FM) replacement in the diets for olive flounders. All the experimental diets were formulated to be isonitrogenous (50% crude protein, CP) and isocaloric (17.1 kJ energy $g^{-1}$ diet). Four diet were formulation of FM with SLP (DHSM) were tested at 0, 25, 50, 75% (SLP(DHSM)$_0$, SLP(DHSM)$_{25}$, SLP(DHSM)$_{50}$ and SLP(DHSM)$_{75}$, respectively). Triplicate groups of 12 fish with an average body weight of 5.56$\pm$0.1 g (mean$\pm$S.D.) were fed one of three experimental diets for 7 weeks. Weight gain (WG) and the specific growth rate(SGR) of fish fed SLP(DHSM)$_0$ and SLP(DHSM)$_{25}$ diets were significantly higher than those of fish fed SLP(DHSM)$_{50}$ and SLP(DHSM)$_{75}$ diets (P<0.05). Also, WG and SGR of fish fed SLP(DHSM)$_{50}$ had significantly higher WG and SGR than that of fish fed SLP(DHSM)$_{75}$ (P<0.05). The feed efficiency (FE) and protein efficiency ratio (PER) of fish fed SLP(DHSM)$_0$ and SLP(DHSM)$_{25}$ were significantly higher than those fed SLP(DHSM)$_{50}$ and SLP(DHSM)$_{75}$ (P<0.05). The whole-body crude lipid content of fish SLP(DHSM)$_{75}$ was significantly higher than that of fish fed SLP(DHSM)$_{50}$ (P<0.05). However, there were no significant differences in whole-body moisture, crude protein and crude ash of fish fed all diets. Based on these growth performance results, the SLP(DHSM) combination replace up to 25% FM protein by the ANOVA test in juvenile olive flounder diets.

• Journal of fish pathology
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• v.19 no.2
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• pp.173-181
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• 2006

Miamiensis avidus is a scuticociliate causing mortality in olive flounder Paralichthys olivaceus. To evaluate immune response of olive flounder against M. avidus, 2.6×106cells/fish of Formalin killed cell (FKC) was intraperitoneally (i.p.) injected, and 2.4 × 106cells/㎖ of sonicated FKC was immersion immunized to 14.9 cm (26.8g) fish. Fish were immunized 2 times with 2 weeks intervals. Antiserum from immunized fish caused agglutination and immobilization of the ciliate. In ELISA test, immunized group exhibited higher titers than control group. In addition, i.p. immunized fish showed higher phagocytic ratio, phahgocytic index and chemotaxic activity. To evaluate in vivo efficacy of FKC on fish, 1.43 × 105cells/fish was i.p.. injected, and 2.2 × 105 cells/㎖ of sonicated cell was immersed into 8.6cm (6.3g) fish. After 2 times immunization with 2 weeks intervals, fish were infected with 2.0 × 104 and 2.0 × 103 cells/ml of live ciliates by immersion. After 3 weeks, cumulative mortality was lower in the i.p. immunized group and mortality was delayed in immersion immunized group. In conclusion, specific immune response of oliver flounder against M. avidus was elevated after immunization and these immune response may prevent and/or delay for the M. avidus infection to olive flounder.

• Korean Journal of Ichthyology
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• v.21 no.4
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• pp.221-226
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• 2009

Six microsatellite DNA markers were used to investigate the genetic variability between wild populations and cultured stocks of olive flounder Paralichthys olivaceus. The average of observed (Ho) and expected heterozygosity (He) ranged from 0.722 to 0.959, and from 0.735 to 0.937, respectively. There was no distinguishable difference between the wild populations and cultured stocks in terms of the observed and expected heterozygosities. However, number of alleles per locus differed markedly between the two fish groups: 19.7 to 21.8 for the wild populations and 12.0 to 14.7 for the cultured stocks. This result gives important information concerning the production of seedling for the improvement of genetic diversity in this species.

• Korean Journal of Veterinary Research
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• v.47 no.3
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• pp.291-298
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• 2007

Olive flounder, Paralichthys olivaceus is one of the most important cultured fish in Korea, its farming has been negatively impacted by viral, bacterial and parasitic diseases. Streptococcal infection was considered as a serious problem because of significant economic losses in olive flounder farm industry. The development and evaluation of vaccine for protection against infection by this agent were required. We evaluated the safety and efficacy of ${\beta}$-hemolytic Streptococcus (S.) iniae vaccine on olive flounder Three hundreds of flounders (weight $119.8{\pm}20.7g$, body length $22.6{\pm}1.4cm$) were reared in 0.5 tons aquaria in land-marine tank system. Seawater was provided from the sea of Inchon in Korea, and water temperature was set to $22^{\circ}C$ and $25^{\circ}C$ in the vaccination and challenge test, respectively. We used the formalin-inactivated ${\beta}$-hemolytic S. iniae (F2K) vaccine (M VAC INIAE; Kyoritsu seiyaku, Japan) originated in Japan. The vaccine was intraperitoneally administered to fish. Both of vaccinated group and control group were challenged with intraperitoneally injection by virulent S. iniae SI-36 isolates with $1.0{\times}10^7CFU/fish$ at 3 weeks after vaccination. Difference on mortality of control and vaccinated group (90.0 and 15.0%, 76.5 and 8.0% respectively) at two trials were found significant (p<0.05), and relative percent survival were 83.4% and 89.5%, respectively. The dead fishes were showed dark pigmentation of skin, abdominal extension, hemorrhagic ascites, and liver necrosis, and isolated the S. iniae strain from ascites, liver and kidney. We confirmed the safety and efficacy of ${\beta}$-hemolytic S. iniae vaccine by determinations of the optimal management condition and artificial challenge test in olive flounder.

• Journal of fish pathology
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• v.6 no.2
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• pp.205-218
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• 1993

On the development of hirame(Paratichtys olivaceus) culture, outbreak of scuticociliata infection was reported to cause severe damage in Japan. To establish effective measures for isolation and cultivation of this ciliate, we tried to culture this pathogenic ciliate using medium for bacteria and fish cell lines in vitro. Scuticociliata from the brain tissues of infected fish was aseptically inoculated to CHSE-214 cells cultured in MEM-10 without antibiotic. Scuticociliata grew well and the number of ciliate reached $10^6\;cells/ml$ at temperatures of $15^{\circ}C$ to $20^{\circ}C$ for 10d. The number of ciliate cultured in the cell lines is 10 times higher than the numbers cultured in the liquid medium alone. This ciliata could be cloned by dilution method. Scuticociliata isolated could grow well on 42 different cell lines that were established from marine fish, warm freshwater fish, and salmonids. This ciliate could be preserved in liquid nitrogen for more than 6 months. Subsequently, we observed the optimal temperature and salinity for growth, and tested the sensitivities of this organism to formaldehyde, flagyl(Metronidazole), Ekuteshin(Combination compound of sulfamonometoxin and ormethoprim), and ozonixation. Optimal temperature for growth was $25^{\circ}C$ and salinity was 1.0 to 1.5%. Washed scuticociliata was killed by formaldehyde at the concentration of 50ppm for 10min, but was not completely killed even at a high concentration of 400ppm for 20min in MEM-5. Flagyl and Ekuteshin can inhibit the growth of scuticociliata at the concentration of 1,000 and $100{\mu}g/ml$ in MEM-10, respectively. More than 99% of this scuticociliata could be killed by ozonization at a dose equivalent to $1.0mg/\ell$ oxidant for 30sec in sea water. Isolated scuticociliata showed the pathogenicity to the cultured hirame by artificial infection(I. P. injection, $10^5\;cells$/fish). The number of scuticociliata in the water could be counted by most probable number(MPN) method using tissue culture, and the minimum detectable number was $1.8\;cells/\ell$. The number in the reservoir tank for water supply to the culture tank was 110 cells/l. After cleaning by elimination of the sediments from of the reservoir tank and disinfected with formaldehyde, number of scuticociliata decreased and was counted less than $1.8\;cells/\ell$ and infection rate of cultured hirame was decreased.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.4
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• pp.411-416
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• 2015

Olive flounder Paralichthys olivaceus production has increased gradually in recent years, but prices have fallen. Thus, the development of a variety of processed foods incorporating olive flounder would help to increase the income of fishermen. This study was conducted to investigate the best method for olive flounder ball processing. Clean olive flounder were divided into five portions. Olive flounder meat (100 g with added egg white 39 g) was chopped and then mixed with 10 mL fresh cream and ingredients. The dough was molded into the shape of a ball. The olive flounder balls were then processed by two different methods. In the first method, the flounder ball was boiled in water for 3 min then vacuum-packed in polyethylene film and stored at $-20^{\circ}C$ for 7 days. After 7 days, the ball was thawed and heated in a microwave for 2 min (Sample-1). In the second method, the ball was vacuum-packed in polyethylene film without boiling and then stored at $-20^{\circ}C$ for 7 days before thawing and boiling in water for 3 min (Sample-2). After heating, both types of olive flounder balls were evaluated. Various factors (including the viable bacterial count, chemical composition, pH, hardness, thiobarbituric acid level, salinity, and free amino acid content) were measured, and a sensory evaluation was conducted. Based on the results of the sensory and hardness evaluations, Sample-1 was deemed to be superior to Sample-2.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.6
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• pp.460-465
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• 2006

An 8-week feeding trial was conducted to investigate the effects of dietary supplementation with probiotics as a feed additive for Juvenile olive flounder (Paralichthys olivaceus). Three experimental diets supplemented with Bacillus polyfermenticus (BP), Bacillus licheniformis (BL), or Bacillus polyfermenticus plus Saccharomyces cerevisiae, (BP+SC) at $1.0{\times}10^7CFU/kg$ diet on a dry-matter basis were prepared. The basal diet was used as a control. After the 8-week feeding trial, the respiratory burst activity (NBT assay) of fish fed the BP + SC diet was significantly higher than that of fish fed the control diet. Fish fed the BP, BL and BP + SC diets had significantly lower cumulative mortality than did fish fed the control diet after the third day of the challenge test (P<0.05). However, there were no significant differences among fish fed the experimental diets in weight gain, feed efficiency, protein efficiency ratio, hematosomatic index, condition factor, survival rate, or Iysozyme activity. Results could suggest that dietary B. polyfermenticus, B. licheniformis, and B. polyfermenticus +S. cerevisiae enhance nonspecific immunity and disease resistance in juvenile olive flounder.