• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.5
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• pp.557-561
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• 2010

This feeding experiment was conducted to investigate the effects of dietary inclusion of some additives on growth performance, hematological parameter and fatty acid composition of growing flounder. Triplicate groups of fish (average weight 120 g) were fed one of five diets containing 5% kelp meal (Ke), 10% krill meal (Kr), 1% garlic powder (Ga), 1% citrus meal (Ci) or control diet (Con) without supplementation for 15 weeks. After the feeding experiment, survival was not significantly different among the groups fed the different diets. Weight gain of fish fed the Ci diet was significantly higher than that of fish fed the Kr diet, but not significantly different from Con, Ke and Ga treatments. Feed efficiency and protein efficiency ratio of fish fed the Ga diet were significantly higher than those of fish fed the other diets. Total protein, glucose, GOT, GPT and total cholesterol contents in the plasma were not affected by the dietary additives. Composition of C20:4n-6 in the dorsal muscle of fish fed the Con diet was significantly higher than that of fish fed the other diets. The results of this study suggest that the dietary inclusion of garlic meal at 1% may improve feed utilization of growing flounder.

• Fisheries and Aquatic Sciences
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• v.20 no.9
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• pp.20.1-20.8
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• 2017

The objective of this study was to examine the effect of dietary supplementation of taurine for juvenile olive flounder (Paralichthys olivaceus) at low water temperature ($16.4{\pm}0.36^{\circ}C$). Fish meal (FM)-based diet was used as the control diet. Four other experimental diets were prepared by adding taurine to FM-based diet at 0.25, 0.50, 1.00, and 1. 50% (T1, T2, T3, and T4, respectively). Each experimental diet was fed to triplicate groups of fish (initial mean body weight, 19.5 g) for 10 weeks. At the end of the feeding trial, growth performance and feed utilization, hematological parameters, non-specific immune responses, whole-body proximate composition, and liver mRNA expression of insulin-like growth factor-1 (IGF-1) were investigated. Feed conversion ratio was significantly reduced while protein efficiency ratio was significantly increased in taurine-supplemented groups. Hematocrit and hemoglobin were also significantly increased while plasma cholesterol levels were decreased in taurine-supplemented groups than those in the control group. Nitroblue-tetrazolium, myeloperoxidase and lysozyme activities, and plasma immunoglobulin level were significantly increased by taurine supplementation. These results suggest that dietary taurine supplementation is effective in improving growth performances, feed utilization, and innate immunity of olive flounder in low water temperature season.

• Journal of Fisheries and Marine Sciences Education
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• v.23 no.3
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• pp.461-467
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• 2011

This experiment was conducted to determine the each level of a newly developed squid liver powder (SLP) as a dietary protein source replacing fish meal (FM) in juvenile flounder. A diet excluding SLP (FM diet) and a commercial diet were two control diets. Six experimental diets were formulated to replace FM with three types of SLP at 5 and 10% level, respectively (SLP-A5, SLP-A10, SLP-B5, SLP-B10, SLP-C5, SLP-C10). Prior to the start of a feeding trial, fish were fed the commercial diet for 1 week to adjust to the experimental conditions. Fish with average weight of $22.8{\pm}0.40g$ ($mean{\pm}SD$), were randomly distributed to each aquarium as groups of 20 fish and fed the experimental diets in triplicate at satiation for 8 weeks. After 8 weeks, weight gain and specific growth rate of fish fed SLP-C10 was lower than those of fish fed FM diet and SLP-B5. Meanwhile, no significant difference was observed in WG and SGR among fish fed diets excluding SLP-C10. Feed efficiency (FE) and protein efficiency ratio (PER) of fish fed each level of three types of SLP were not different from those of fish fed FM diet. However, fish fed SLP-C5 and SLP-C10 has lower FE and PER than those of fish fed a commercial diet, SLP-A5 and SLP-B5. Therefore, these results indicate clearly that dietary SLP-B could be a good protein source to develop inexpensive commercial diet in juvenile flounder.

• Fisheries and Aquatic Sciences
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• v.1 no.2
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• pp.227-231
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• 1998

The teleosts represent ancient real-bony vertebrates in phylogeny and resemble major genetic patterns to higher vertebrates. In the present study, we have defined the single family of insulin-like growth factors (IGFs) from flounder (Paralichthys olivaceus), compared to the prototype of IGFs observed in the Agnathan hagfish. In flounder, IGFs are clearly diverged into two major types including type I and II, and they are structurally similar by displaying a multidomain structure consisting of five functional regions as previously found in other vertebrates. However, flIGF-I appears to be more basic (pI 8.03) than the flIGF-II (pI 5.34) in the fully processed form for the B to D domain region. The flIGF-I seems to contain an evolutionary conserved Asn-linked glycosylation in E domain, which is not found in flIGF­II. The most interesting feature is that flIGF-II appeared to be structurally close to hagfish IGF in secondary structures, particularly in Band D domains. This could tell us an idea on the molecular divergence of IGFs from the Agnatha to teleosts during the vertebrate phylogeny. It also support, in part, a notion regarding on how IGF-II is appeared as more embryonic during development. Nonetheless, the biologically active B to D domain region of flIGF-II shows significant sequence homology of $65.6\%$ to flIGF-Is and contains the evolutionary conserved insulin-family signature, as well as a reserved recognition site (Lys) in D domain, necessary to generate proteolytic cleavage for E-peptide. A significant structural difference was found in E domain in which flIGF-I possesses two potential alternative splicing donor site at $Val^{17,\;24}$ of E domain. Therefore, it seems so far that IGF-I sorely produces spliced variants due to the spliced E-peptide moiety while IGF-II appears to be maintained in a single type during evolution. IGF-II, however, may be also possible to transcribe unidentified variants, depending on the physiological conditions of tissues in vertebrates in vivo.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.4
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• pp.351-361
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• 2018

This study investigated the potential of collagenous protein fractions (CPFs) as functional foods. The specific CPFs studied were recovered from the roe of bastard halibut (BH), Paralichthys olivaceus; skipjack tuna (ST), Katsuwonus pelamis; and yellowfin tuna (YT), Thunnus albacares through the alkaline solubilization process at pH 11 and 12. The buffer capacity, water-holding capacity and solubility of CPFs with pH-shift treatment were significantly better at alkaline pH (10-12) than at acidic pH (2.0). At pH-shift treatment (pH 2 and 12), the foaming capacities of CPFs from ST and YT were improved compared to those of controls, but they were unstable compared to BH CPFs. The emulsifying activity index (EAI, $m^2/g$ protein) of CPFs (controls) was 16.0-21.1 for BH, 20.1-23.9 for ST and 9.3-13.7 for YT (P<0.05). CPFs adjusted to pH 12 showed improved EAI and YT CPFs showed significantly greater emulsifying ability than those from BH and ST. CPFs recovered from fish roe are not only protein sources but also have a wide range of food functionalities, confirming the high availability of fish sausage and surimi-based products as protein or reinforcing materials for functional foods and alternative raw materials.

• Journal of Fisheries and Marine Sciences Education
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• v.21 no.4
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• pp.562-567
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• 2009

This study was conducted to evaluate of improving extruded pellet (EP) for growth of juvenile flounder by comparing with raw fish-based moist pellet (MP) diet. Two replicate groups of 80 fish per each tank (initial weight of $36.0{\pm}1.2 g$) were fed one of the three EPs (EP1, EP2 and CEP) and (MP for 16 weeks. Survival was not significantly affected by experimental diets (P>0.05). Weight gain of fish fed the MP was not significantly different from that of fish fed the EP1 & EP2 (P>0.05), but that of fish fed CEP was significantly lower than that of fish fed MP (P<0.05). Specific growth rate of fish fed the CEP was significantly lower than those of fish fed EP1, EP2 and MP (P<0.05). Feed efficiency of fish fed the EP1 was significantly higher than those of fish fed CEP and MP (P<0.05), but not significantly different from those of fish fed EP2 (P>0.05). The Contents of crude protein and crude lipid in whole body were significantly different among all groups (P<0.05). Therefore, these results strongly suggest that EP1 & EP2 diets could be developed to replace MP diet for flounder without adverse effects on growth performance.

• Journal of Fisheries and Marine Sciences Education
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• v.21 no.4
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• pp.556-561
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• 2009

This study was conducted to evaluate the laboratory formulated extruded pellet (EP) for olive flounder Paralichthys olivaceus in the East Sea. Three replicate groups of 3,200 fish per each tank (initial weight of $28.1{\pm}0.2g$) were fed one of the two EPs (EP and CEP) and Moist pellet (MP) for 16 months in a commercial farm (Pohang, Korea). Survival was not significantly affected by experimental diets (P>0.05). Weight gain and specific growth rate of fish fed the EP were not significantly different from those of fish fed the MP, but that of fish fed CEP was significantly lower than that of fish fed EP and MP (P<0.05). Feed efficiency and protein efficiency ratio of fish fed the EP was significantly higher than those of fish fed MP (P<0.05), but not significantly different from those of fish fed CEP (P>0.05). The Contents of moisture, crude protein and crude lipid in the dorsal muscle were not significantly different among all groups (P>0.05). These results clearly indicated that the laboratory formulated extruded pellet used in this study can be developed to replace the moist pellet without affecting any growth performance of olive flounder in the commercial farm feeding trail.

• Journal of Environmental Science International
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• v.20 no.11
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• pp.1383-1394
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• 2011

Environmental impacts of suspended solids (SS) released in coastal area by dredging, reclamation and construction can cause serious damages to coastal habitats and benthic organisms. Acute toxicity tests (4-7 days) were conducted to identify the relationship between SS concentration and mortality of three marine benthic species; benthic copepod (Tigriopus japonicus) adult, Pacific abalone (Haliotis discus hannai) spat, and olive flounder (Paralichthys olivaceus) fry. Benthic copepod was the most sensitive to SS followed by olive flounder fry and Pacific abalone spat, with an $LC_{50}$ (lethal concentration of 50% mortality) value of 61.0 mg/L and LOEC (lowest observed effective concentration) value of 31.3 mg/L for benthic copepod. LOEC and 7 day-$LC_{50}$ for Pacific abalone spat were 500.0 mg/L and 1887.7 mg/L, and those for olive flounder fry were 125.0 mg/L and 156.9 mg/L, respectively. The tolerance limits of the test species to SS revealed the various concentration ranges of SS, which reflects the physiology and ecology of the test species. These results are very valuable for the determination of SS concentration of effluents released into the coastal area by dredging, reclamation and construction etc. Also, sharp increase of SS can cause long-term damages to the benthic and sessile fauna by blanketing of benthic substratum. These experimental procedures for marine bioassay and acute toxicity results can be a useful guideline for practical management planning of SS discharge into coastal area.

• Journal of Aquaculture
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• v.10 no.1
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• pp.9-15
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• 1997

The pathogenic organisms occurred in cultured marine fishes in Kamak Bay were investigated from March to November in 1993. The samples were collected at 7 sampling stations once a month. Nine species of pathogenic organisms (Vibrio sp., Edwardsiella sp., Flexibacter sp., Streptococcus sp., Micrococcus sp., Caligus sp., Trichodina sp., Lymphocystis and Staphylococcus sp.) were identified as pathogenic organisms from four different species of fish (Sebastes schlegeli, Paralichthys olivaceus, lateolabrax japonicus and Pagrus major) collected in the study areas. Most of pathogenic organisms were found at over 20^{\circ}C$ of sea water temperature from June to October in 1993. On the test of drug sensitivity, Vibrio sp. (KS-9303) was sensitive to oxytetracycline and chloramphenicol ; Edwardsiella sp. (KP-9315) to oxytetracycline ; Flexibacter sp. (KP-9318) to oxytetracycline, chloramphenicol and oxolinic acid ; Streptococcus sp. (KP-9319) to erythromycin, chlorampheicol and oxytetracycline. However, all these 4 isolated bacteria were resistant to ampicilin, steptomycin, sulfamethoxazole and nitrofurazone.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.2
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• pp.277-284
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• 1999

To confirm the food quality of conventionally processed fish extracts, protein quality of boiled crucian carp(Carassius carassius) and bastard halibut(Paralichthys olivaceus) extracts and their residues were evaluated. For the both fish extracts, some of the essential amino acids were lowered significantly but two times more proline and glycine were detected in extracts than those in raw fish meats. Boiling(100oC, 5 hours) caused 1.8(crucian carp)~2.4(bastard halibut) times more total free amino acid contents in fish extracts as compared to those in original fish meats. Taurine, glutamic acid, proline, lysine, and ammonia were the predominant free amino acids released in fish extracts. In vitro digestibility of boiled fish extracts were lower at a level of 4~6% than those of raw fish meats. Fish extraction residue had a higher in vitro digestibility and had a 60% lower level of TI than that of original fish meats. 18(bastard halibut)~ 24%(crucian carp) of available lysine was reduced in boiled fish extracts but a remarkable variation was not noted between extracts and residues. PERs and NPRs of fish extracts were significantly lower than those of casein, while those values of extraction residue were slightly higher as compared to those of control(ANRC casein). In vivo apparent digestibility exhibited a similar trend to in vitro digestibility. Hematological properties in serum of rat fed with fish extracts and residue were not changed significantly but the serum cholesterol concentration were reduced in rats fed fish extraction residue comparing with those of control. These results suggest that body weight loss due to fish extracts may not affect physiological changes.