• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.3
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• pp.217-222
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• 2010

Two 15-week feeding trials were conducted to investigate how the rate and frequency of feeding affected the winter growth of olive flounder ($13^{\circ}C$). In the first experiment, triplicate groups of fish (initial mean weight $117{\pm}6.0$ g) were fed extruded pellets twice a day at feeding rates of 0.1, 0.25, 0.4, 0.55, and 0.57% (satiation) body weight per day (BW/d). The weight gain, specific growth rate, and feed efficiency increased significantly (P<0.05) with the feeding rates from 0.1 to 0.55% BW/d, but no significant differences in these parameters were found for fish fed diets of 0.55% BW/d and satiation. The moisture and ash contents of whole body of fish tended to decrease as the feeding rate increased, but the opposite trend was found for crude lipid content. In the second experiment, triplicate groups of fish (initial mean weight $117{\pm}6.3$ g) were fed extruded pellets to apparent satiation at the three different feeding frequencies: one meal 2 days, one meal a day and two meals a day. The weight gain and specific growth rate of fish fed one meal 2 days were significantly (P<0.05) lower than those of fish fed one or two meals a day, whereas no significant differences in the weight gain and specific growth rate were found between fish fed one and those fed two meals a day. Feed efficiency and condition factor were not significantly affected by feeding frequency. Based on these results, a feeding rate of 0.3% BW/d is recommended as maintenance feeding level, and the optimum feeding frequency is one meal a day with satiation feeding for the growth of olive flounder (117-147 g) during winter ($13^{\circ}C$).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.4
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• pp.339-347
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• 2000

An algicidal bacterium, Micrococcus sp. LG-5 against the harmful dinoflagellate, Cochlodinium polykrikoides was isolated. The optimal conditions for the highest algicidal activity of bacterial culture filtrate showed in the range of $20{\~}30^{\circ}C$, at pH 7.0 and $3.0{\%}$ of NaCl concentration. In addition, $IC_(50)(mean of 50{\%} inhibitory concentration)$ of the culture filtrate against C. polykrikoides after incubation of 5 days was $0.482{\%}$. To investigate heat and pH stability of the culture filtrate of Micrococcus sp. LG-5, the culture filtrate ($pore size, 0.1 {\mu}m$) was heated to $121^{\circ}C for 15 min$ and adjusted pH from 2.0 to 10.0. There were no significant changes in algicidal activity by heat treatment and the pH change between pH from 5.0 to 10.0. The algicidal substances produced from Micrococcus sp. LG-5 were mainly detected in the fraction of $10,000{\~}1,000$ MWCO (molecular weight cut-off). The culture filtrate of Micrococous sp. LG-5 showed antimicrobial activity against Enterococcus faecalis, Escheiichia coli, Uebsiella pneunioniae and Vibrio altinolyticus, but did not show against Pseudomonas aeminosa, P. Buorescens, Salmonella typhi, Staphylococcus aureus, V. cholerae and V parahaemolyicus. The culture filtrate of Micrococcus sp. LG-5 was examined against 16 phytoplankton species and showed the algicidal activity against Ajexandzium tuarense, Eutreptiella Drnnastin, Gymnodinium catenatum, G. mikimotoi, G. sanguineum, eyodinium impuaicum, Heterocapsa triquetra, Heterosipa akashiwo, Prorocentrum micans and Pyraminonas sp.. However no algicidal effects of Micrococcus sp. LG-5 were observed against Chlamydomonas sp., Cylindrotheoa closterium, P. mininum, P. triestimum, Pseudonieschia sp. and Sczipuiella trochoidea. On the other hand, algicidal activity on the tested marinelivefood was not detected except for Isochrysis galbana. In addition, physiological responses of cultured olive flounder (Paralichthys oliraceus) exposed to $1 and 10{\%}$ of the culture filtrate of Micrococcus sp. LG-5 were measured. There were no clear changes in AST, GGT, creatinine, urea, total cholesterol, total protein, albumine, $Mg^(+2), Ca^(+2), Na^+, K^+, and Cl^-$. These results indicate that olive flounders were not affected when they were exposed to the culture filtrate of Micrococcus sp. LG-5.

• Journal of Aquaculture
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• v.6 no.3
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• pp.213-219
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• 1993

Two studies were carried out: to compare commercial flounder diets (C1-C6) with a laboratory-formulated diet (S), and to evaluate moist pellet (MP) prepared with or without raw fish for olive flounder culture. In experiment I, three replicates of 20 fish (42 g in average) each were fed S or each of C1-C6 for four weeks at $17^{\circ}C. For experiment 2, three replicates of 400 fish (78 g in average) each were fed $100\%$ laboratory-formulated grower diet (G), 50\%\;G+50\;%$ frozen mackerel containing $70\%$ moisture or $50\%\;C6$ (the same diet as that used in Exp. 1) +$50\%$ frozen mackerel for six weeks. Weight gain of fish fed S was significantly (P< 0.05) higher than that of fish fed C2 or C3 (26.7 vs 15.4 or 17.5g/fish over the 4-week period, respectively). Feed efficiency was significantly (p<; 0.05) lower in fish fed C2 than in fish fed S but was not different (P> 0.05) between the fish fed Sand the other commercial diets. No significant differences in weight gain were found among the fish fed $100\%\;G,\;50\%\;G+50\%$ frozen mackerel or $50\%$ C6+frozen mackerel. The results of our studies indicate that most of the commercial flounder diets can be improved for better growth, when we compared these diets with a laboratory-formulated diet, and the growth of flounder fed MP containing no raw fish was as good as that of those fed MP prepared with raw fish.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.1
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• pp.23-30
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• 1995

This study was undertaken to clarify the effects of electrical stimulation on physicochemical and rheological properties of the plaice (Paralichthys olivaceus) muscle at early period after death. The plaices were electrically stimulated in seawater bath (110V/60Hz) for 15sec., 35sec., and 60sec. and killed instantly with spiking at the head. Killed samples were stored at $5^{\circ}C$, and the changes in rigor index, ATP breakdown, lactate accumulation, and breaking strength of muscle through storage were investigated. Electrical stimulation effectively accelerated rigor-mortis, lactate accumulation , and ATP breakdown. As the time of electrical stimulation was lengthened, the onset of rigor-mortis of all samples were accelerated Just after killing, and the amount of lactate was rapidly increased, But, significant differences were not observed in variance of rigor-mortis and lactate concentration. Electrically stimulated plaices showed decreasing in ATP to $4.58{\mu}mole/g$ for 15sec., $4.13{\mu}mole/g$ for 35sec., and $2.39{\mu}mole/g$ for 60sec. samples as compared with $5.5{\mu}mole/g$ of unstimulated samples. As the time of electrical stimulation was lengthened, ATP in samples were decomposed more rapidly. The rate constant of ATP breakdown were $0.244hr^{-1}$ for 15sec., $0.358hr^{-1}$ for 35sec., and $0.479hr^{-1}$ for 60sec.. The level of breaking strength in muscle of the plaice was $1050.30\pm50.23g$ immediately after killing. Values of breaking strength in samples electrically stimulated for 35sec. increased rapidly just after killing among all samples. However, the breaking strength was not increased through the whole storage time in samples stimulated for 60sec.. The value and time roaching to the maximum breaking strength for each samples stimulated electrically for 15, 35 and 60 second were $1264.43\pm35.76g$ and 2hr, $1357.68\pm22.50g$ and Ohr, and $1012.18\pm57.36g$ and Ohr. Breaking strength in all samples electrically stimulated decreased significantly (P<0.05) after reaching the maximum values.

• Journal of Fisheries and Marine Sciences Education
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• v.27 no.1
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• pp.98-107
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• 2015

Olive flounder contains rich amount of lysine which is required for children's growth. Moreover, it is good foodstuffs for elderly, convalescent and diabetics because of low lipid content and high digestibility. This study was investigated for the purpose of obtaining basic data which can be applied to the processing of olive flounder steak. Olive flounder 100 g were chopped, mixed with vegetable (onion 20%, celery 10%, carrot 15%, garlic 1% of chopped olive flounder meat) and ingredient (bread crumbs 20 g, onion 15 g, celery 10 g, egg 1 ea, tarragon 1/2 t, blanc sauce 20 g, fresh cream 20 mL, salt and pepper pinch). Mixed dough was molded into steak shape ($12{\times}7cm$) and was processed by two types of products, Steak-1 {Roasting for 2 minutes in a frying pan wrapped with olive oil and then vacuum packaging in polyethylene film ($20{\times}30{\times}0.05mm$), and then storage at $-20^{\circ}C$ for 7 days, next thawed and warmed by microwave for 2 minutes} and Steak-2 {vacuum-packaging in polyethylene film ($20{\times}30{\times}0.05mm$), and then storage at $-20^{\circ}C$ for 7 days, after thawed, roasted during 2 minutes in a frying pan wrapped with olive oil}. The factors such as pH, TBA value, amino-N, free amino acid, chemical composition, color value (L, a, b), texture profile, sensory evaluation and viable bacterial count of the olive flounder steak (Steak-1, Steak-2) were measured. From the result of sensory evaluation, Steak-2 showed a bit more high scores than Steak-1 but it was difficult to distinguish significant difference (color, odor, taste, texture and acceptance) between Steak-1 and Steak-2 products.

• Journal of Aquaculture
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• v.5 no.2
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• pp.127-142
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• 1992

A feeding experiment was carried out to investigate the availability and feasibility of fish processing by-products as a substitute for frozen round fish in moist pellet diets for flounder, Paralichthys olivaceus. A control diet was prepared by incorporating $50{\%}$ frozen horse mackerel and $50{\%}$ commercial binder feed. In test diets the frozen horse mackerel of the control diet was replaced with either tuna scrap, tuna viscera, flatfish offal, deskinned hagfish, or tuna viscera ($20{\%}$) with frozen horse mackerel ($30{\%}$). Eighty flounders, 13.4 g in mean body weight, were stocked in 12 aquaria ($250\;{\ell}$ each) and fed six experimental diets for the first 28-day experiment. For the second 23-day experiment, forty flounders,44.8 g in mean body weight, were stocked and fed the same experimental diets. All treatments were duplicated. There were no significant differences in growth, feed efficiency and nutrient utilization among fish fed experimental diets containing either frozen horse mackerel, deskinned hagfigh, flatfish offal or tuna viscera with frozen horse mackerel. However, the feeding performances of fish fed experimental diets containing tuna scrap or tuna viscera were significantly lower than those of the control diet (P<0.05). There were no significant differences among the treatments on the proximate analysis values of the whole body. However, the crude lipid content of liver of the fish fed the experimental diet containing tuna scrap was significantly lower than that of the others. The results indicate that deskinned hagfish, and flatfish offal could be successfully substituted for frozen fish portion of moist pellet diets for flounder, but tuna viscera could only be partially substituted.

• Korean Journal of Food Science and Technology
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• v.45 no.6
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• pp.700-707
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• 2013

The purpose of this study was to monitor physicochemical changes of olive flounder (Paralichthys olivaceus) muscle by iced water pre-treatment. Moisture content, crude fat content, nucleotide content, texture (hardness and toughness), and rigor mortis were assessed. The sensory evaluation was performed with a nine-point hedonic test. K-values, a parameter of fish flesh freshness, were also calculated from the content of nucleotides and their corresponding decomposition products. Pre-treatment of flounder flesh with iced water was found to be fresher compared to the control, as determined by a difference in the K-values. Iced water pre-treatment hastened postmortem stiffness, as judged from the rigor index, and increased inosine monophosphate (IMP), which is known to be a savory taste compound, more quickly as adenosine triphosphate (ATP) degradation proceeded.

• Journal of fish pathology
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• v.22 no.3
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• pp.263-273
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• 2009

There is an increasing number of reports describing Streptococcus parauberis as an important pathogen of cultured olive flounder Paralichthys olivaceus and starry flounder Platichthys stellatus in Korea. We tried to determine the effects of water temperature (14${^{\circ}C}$ and 21${^{\circ}C}$) on the pathogenicity in Streptococcal disease caused by S. parauberis. We have challenged 180 olive flounder by i.p injection to $2.0{\times}10^{7}$ live cells/fish. Mortality was monitored for 21 days post challenge. And histopathological characterizations as infection degree, tissue degeneration and/or bacterial distribution were investigated with H&E stain and in situ hybridization technique. Fifty percent and 16.7% of mortality occurred within 21 days at 21${^{\circ}C}$ and 14${^{\circ}C}$ water temperature, respectively. In most cases, the typical symptoms of olive flounder infected with S. parauberis were darkness of the skin, lethargy, mild abdominal distension cause by ascites, splenomegaly, congested liver and internal organs paleness. The pericardial sac contained large amounts of cloudy fluid. Numerous whitish nodules, which were variable in size and often confluent, were randomly scattered throughout the myocardium. Especially, pericarditis and/or myocarditis was observed in all tested fishes after death. Positive in reaction with S. parauberis were found in all tissues in situ hybridization analysis. The relative numbers of S. parauberis in heart were much more than in liver, spleen, kidney and stomach. We evaluated that S. parauberis strain causes serious damage in the pericardium, shortness of breath and the blood disorder. Therefore, pericarditis and myocarditis caused by S. parauberis were closely related to mortality of olive flounder.

• Journal of Aquaculture
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• v.18 no.1
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• pp.26-30
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• 2005

A 10-week feeding trial was conducted to determine the optimum feeding rate of two extruded pellets (EP1 and EP2) and raw fish-based moist pellet (MP) for juvenile flounder. Two replicate groups of the fish (average weight of 27 g) were fed EP and MP three times daily at different feeding rate (satiation and $85\%$ satiation). Weight gain of fish was not affected by diet, but affected by feeding rate. Weight gain with satiation feeding group showed :t tendency to higher compared to that of fish with $85\%$ satiation feeding at the same diet. Feed efficiency of fish was affected by diet, but not feeding rate. Feed efficiency of fish fed the EP1 and EP2 was higher than that of fish fed the MP at the same feeding rate. Daily feed intake was affected by diet and feeding rate. Daily feed intake of fish fed with satiation was higher than that of fish with $85\%$ satiation at same diet, and this variable of fish fed the MP was higher than that of fish fed the EP 1 and EP2. Protein efficiency ratio of fish fed the MP was significantly lower than that of fish fed the EP1 and EP2 regardless of feeding rate. Lipid content of whole body was affected by diet, and that of fish fed the EP2 and MP at satiation feeding was the highest. It can be concluded that satiation feeding will be good and EP is better than MP for growth of juvenile flounder grown from 27 g to 51 g.

• Journal of Life Science
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• v.21 no.8
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• pp.1149-1155
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• 2011

Myostatin (MSTN) belongs to the transforming growth factor-${\beta}$ superfamily or growth and differentiation factor 8 (GDF-8), and functions as a negative regulator of skeletal muscle development and growth. Previous studies in mammals have suggested that myostatin knock-out increased muscle mass and decreased fat content compared to those of the wide type. Recently, several studies on myostatin have beenconducted on the block myostatin signal pathway with myostatin antagonists and the MSTN regulation with RNAi to control myostatin function. This study was performed to analyze growth and muscle alteration of Oncorhychus masou by treatment with recombinant myostatin prodomains derived from fish. We designed myostatin prodomains derived from P. olivaceus (pMALc2x-poMSTNpro) and S. schlegeli (pMALc2x-sMSTNpro) in a pMALc2x expression vector, and then purified the recombinant proteins using affinity chromatography. The purified recombinant proteins were treated in O. masou through an immersion method. Recombinant protein treated groups did not show a significant difference in weight, protein, or lipid composition compared to the control. However, there was a difference in the average number and area for histological analyses in the muscle fiber. At twelve and twenty-two weeks from the initial treatment, there were differences in averagefiber number and area between the 0.05 mg/l treated-group and the control, but the numbers were similar to those of the control during the same time period. At twelve weeks, however, 0.2 mg/l treated-group had an increase in average fiber number and decrease in average fiber area compared to the control. At twenty-two weeks, the pMALc2x-sMSTNpro 0.2 mg/l treated-group was induced and showed a decrease in average fiber number and increase in average fiber area. The results between twelve and twenty-two weeks showed that the fiber numbers had decreased, whereas average fiberarea had increased due to sMSTNpro. It is understood that the sMSTNpro induced only hyperplasia at twelve weeks, after which it induced hypertrophy. Recombinant myostatin prodomains derived from fish may induce hyperplasia and hypertrophy in O. masou depending upon the time that has elapsed.