• Journal of Aquaculture
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• v.19 no.4
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• pp.299-304
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• 2006

This study was conducted to investigate the effects of protein and lipid levels of extruded pellet on growth and body composition of juvenile flounder. Six extruded dry pellets were formulated to contain two protein levels (50 and 55%) and three lipid levels (8, 12 and 15%). Triplicate groups of fish (initial mean weight 21 g) were hand-fed to apparent satiation two times a day for 9 weeks. Survival, weight gain and daily feed intake were not significantly affected by dietary protein and lipid levels. Feed efficiency and protein efficiency ratio were significantly (P<0.001) affected by dietary lipid level, and tended to increase as dietary lipid level increased. Feed efficiency ratio of fish fed the 55% protein diet with 15% lipid was not significantly different from that of fish fed the 50% protein diet with 15% lipid, but significantly (P<0.05) higher than that of fish fed the other diets. Protein efficiency ratio of fish fed the 55% protein diet with 15% lipid was significantly (P<0.05) higher than that of fish fed the 50% protein diet with 8% lipid and 55% protein diets with $8{\sim}12%$ lipids. The contents of moisture, crude protein and lipid in the liver was significantly (P<0.01) affected by dietary lipid level. The results of this study indicate that an increase in lipid level at 50-55% protein in extruded pellet can improve feed efficiency for juvenile flounder.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.2
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• pp.93-99
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• 1986

A longline is made of many snoods with baited hooks which are connected to mainline at constant intervals. Hauling the mainline, removing the unused baits and the hooked fish, and the arrangement of hooks are dependent on mainly manual labour as compared with mechanized other fishing gear in fishing operation. The mechanization for longline operation is needed in order to eliminate the manual handling and to shorten the labour time. The magnetic hook splitting apparatus which consists of the hook separator and the guide leading to storage magazine rail was devised for the mechanization of hauling operation. The experiments were carried out in order to measure the splitting rate of hooks in accordance with the hauling speed of mainline and magnetic flux density of splitting apparatus from February to November, 1985. The splitting rate was $94\%$ for the Alaska pollack (Theragra chalcogramma) hook and $96\%$ for the halibut (Paralichthys olivaceus) hook at the hauling speed 24 m/min and magnetic flux density 482 gauss. The unsplitting of hooks was caused by entangling snood in the mainline and low magnetic flux density. The rate is greater the faster hauling speed and the lower magnetic flux density, with an average of about $6\%$, The magnetic flux density needed to hook splitting becomes increased with the increasing hauling speed. When the practical hauling speed is from 20 to 35m/min, the magnetic flux density is needed from 400 to 850 gauss.

• Journal of fish pathology
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• v.20 no.2
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• pp.99-108
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• 2007

Vibrio harveyi, one of the major causal agent of vibriosis, affects a diverse range of marine vertebrates and invertebrates over a wide geographical area. The organism is synonymous with Vibrio carchariae, which is also known as a fish pathogen. The aims of this study were to investigate the characteristics of the pathogenic non-luminous V. harveyi and the luminous V. harveyi. And V. harveyi isolates were examined the pathogenicity to the black rockfish, Sebastes schlegeli. Both strains of V. harveyi showed haemolytic activity, and the survival rate of non-luminous V. harveyi FR 2 was higher than other strains in the skin, gut mucus and fresh serum of olive flounder, Paralichthys olivaceus and black rockfish, Sebastes schlegeli, respectively. The virulence of non-luminous V. harveyi FR 2 was higher than that of luminous V. harveyi VIB 391 in the intraperitoneally infected black rockfish. In conclusion, the present study revealed that the pathogenicity of V. harveyi FR 2 isolated from marine fish was higher than that of V. harveyi VIB 391 isolated from shrimp for black rockfish. It was suggested that the pathogenicity of V. harveyi on the black rockfish was related with bacterial luminescense.

• Journal of fish pathology
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• v.33 no.1
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• pp.83-89
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• 2020

In the study, we investigated the effect of Taurine-F^TM, which is a commercially available fishery nutritional supplements complex, on anti-hepatotoxicity stressed with thioacetamide (TAA) and innate immune responses in olive flounder. To investigate the change in liver toxicity, firstly, TAA (30 ppm/100 g of fish) was intraperitoneally (i.p.) administered 12 hr after the intramuscular (i.m.) injection of Taurine-F^TM (0.02 ml/100 g of fish)(Taurine/TAA). Secondly, Taurine-F^TM was i.m. injected 24 hr after the administration of TAA (TAA/Taurine). Finally, TAA was administered simultaneously with Taurine-F^TM (TAA+Taurine). All blood samples were collected 24 hr after injection. GOT level in group Taurine/TAA appeared similar to the control, whereas group TAA/Taurine and TAA+Taurine showed significantly increased (p<0.05) levels compared to the control. In GPT level, group Taurine/TAA and TAA/Taurine showed elevated levels compared to the control, whereas no significant difference was observed between group TAA+Taurine and the control. Serum ACH₅₀ activity was significantly (p<0.05) augmented 24 hr after Taurine-F^TM injection compared to the control group, whereas no significant increase was observed 48 hr after Taurine-F^TM injection. On the other hand, serum lysozyme activity elevated in an acute stressed condition appeared significantly down-regulated 24 and 48 hr after Taurine-F^TM injection compared to the control. In conclusion, i.m. injected Taurine-F^TM augmented flounder serum complement activity and decreased a possible handling stress resulting in reducing a serum lysozyme activity and recovering hepatotoxicity. Thus, it is assumed that i.m. injection of Taurine-F^TM mixed with antibiotics or available vaccines could be utilized as an anti-hepatotoxic recipe in fish culture industry.

• Korean Journal of Environmental Biology
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• v.21 no.1
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• pp.18-25
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• 2003

Effects of tributyltin chloride (TBTC) in vitro on mixed function oxygenase (MFO) system on liver microsome of eight marine fish species were investigated. To determine the effects on MFO system, cytochrome P45O (CYP) and cytochrome b5 con-tents, activities of two reductases (NADH-cytochrome b5 reductase and NADPH-cy-tochrome P450 reductase) and four dealkylation enzymes (EROD, PROD, MROD and ECOD) were measured in fish microsoms exposed to TBTC for 20 min. The WP content was reduced to 10% of the control group in 6 out of 8 species exposed to TBTC, whereas there was no significant change in the cytochrome bs content. the response of NAD(P)H dependant reductases depended on fish species. The dealkylation enzyme activities in microsome were also apparently inhibited by TBTC. The degree of inhibition was different among fish species and four enzymes. The EROD activities in eight species were decreased to the range of 1∼65% of control group.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.3
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• pp.215-223
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• 2009

This study was conducted to investigate the effect of diets supplemented with different levels (0, 2.5, 5.0, and 7.5%) of yuza (Citrus junas Sieb ex Tanaka) on nutritional composition of olive flounder. Four groups of fish (242.2$\pm$14.2 g) were fed to apparent satiation twice daily for 4 months. There were no significant differences in proximate composition among the treatment groups (P<0.05). Vitamin C content in flounder muscle was higher in the yuza-added groups than in the control group, and the content among the treatment groups increased as amount of yuza added to diets increased (P<0.05). Of the eight organic acids in flounder muscle, lactic acid was predominant, followed by oxalic acid, succinic-acid, tartaric acid, and acetic acid. Flounders fed 2.5% yuza diet had the highest lactic acid content of all treatments. Four sugars were found in all groups and glucose was the major sugar. Glucose and ribose were detected as the highest sugars in the 2.5% treatment, while maltose and galactose were the dominant sugars in the 5.0% treatment. The abundant fatty acids in fed flounders were 22:6n-3 (DHA), 16:0, and l8:1n-9, which were composed of over 60% of total fatty acids. The control and the 7.5% treatment group had higher 22:6n-3 (DHA) content than the other groups. Major amino acids in samples were glutamic acid, aspartic acid, lysine, leucine, valine, arginine, and alanine. The 2.5% yuza treatment had the highest content of total amino acids and essential amino acids. There were little differences in the free amino acid compositions among the treatments. However, taurine was the predominant amino acid and made up over 47% of total free amino acids. The 2.5% added yuza group contained higher amount of sweet amino acids such as alanine, serine, proline, glycine than the other groups. The addition of yuza to diet of olive flounder had no or little effect on the nutritional components of olive flounder except for vitamin C. However, the 2.5% yuza added group had the highest nutritional values of the treatment groups.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.3
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• pp.262-267
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• 2009

Two 15-week feeding trials were conducted to investigate feeding rate and feeding frequency for growth of sub-adult flounder in suboptimal water temperature ($12^{\circ}C$). In the first experiment, duplicated groups of fish (initial mean weight of 279 g) were fed a extruded pellet once a day at the different feeding rates of 0.1, 0.15, 0.2, 0.3% body weight per day (BW/d), and satiation (0.32% BW/d). Weight gain and feed efficiency were increased significantly (P<0.05) with increase in feeding rates from 0.1 to 0.3% BW/d, but there were no significant differences in weight gain and feed efficiency of fish fed the diet between 0.3% BW/d and to satiation. Crude protein content of dorsal muscle of fish fed the 0.1% BW/d diet was significantly (P<0.05) lower than that of the other groups. In the second experiment, duplicated groups of fish (initial mean weight of 281 g) were fed to apparent satiation with a extruded pellet at three different feeding frequencies (one meal every two days, one meal a day and two meals a day). Weight gain, feed efficiency and condition factor of fish fed one meal every two days were significantly (P<0.05) lower than those of fish fed one meal and two meals a day, but there were no significant differences in weight gain, feed efficiency and condition factor of fish fed between one meal and two meals a day. Based on the results of this study, optimum feeding frequency is one meal a day with satiation feeding for growth and feed efficiency of sub-adult flounder (270-350 g) in suboptimal water temperature ($12^{\circ}C$).

• 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.

• Fisheries and Aquatic Sciences
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• v.12 no.2
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• pp.104-110
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• 2009

Feeding trials were performed at two different water temperatures (summer and winter seasons) to identify suitable protein and lipid (energy) levels to be used in formulating extruded pellets for olive flounder. Experiments were conducted to determine the effects of protein and lipid levels in extruded pellets on the growth and body composition of the flounder in both feeding trials. Six experimental diets were prepared containing three protein levels (46%, 51%, and 56%) and two lipid levels (10% and 17%). In the first experiment, during the summer season ($22{\pm}2.2^{\circ}C$), a triplicate group of fish (initial weight, 114 g) were fed to satiation one of the six diets for 11 weeks. The highest weight gain was observed in fish fed the 56/17 (% protein/% lipid) diet, but this weight gain was not significantly different from that of fish fed the other diets, except for those fed the 46/10 diet. The feed efficiency and protein efficiency ratio of fish fed the 17% lipid diets were higher than those of fish fed the 10% lipid diets at each protein level. In the second experiment, during the winter season ($13{\pm}1.5^{\circ}C$), a triplicate group of fish (initial weight, 107 g) were fed to satiation one of the six diets for 9 weeks. Weight gain was not significantly different among all groups. The feed efficiency and protein efficiency ratio tended to increase with increasing dietary lipid level at each protein level. The whole-body crude lipid content of the of fish fed the 17% lipid diets was significantly higher than that of fish fed the 10% lipid diets at each protein level in both feeding trials. Based on the data obtained in this study, the inclusion of dietary protein at a level of 46% appears to be sufficient to support optimal growth, and increasing the dietary lipid level from 10% to 17% had no beneficial effects on the growth and feed utilization of olive flounder (110-300 g), except for fish fed a 56% protein diet in the summer season.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.5
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• pp.506-519
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• 2017

This study evaluated the protein recovery and functional properties and biological activity of boiled and steamed process water (BPW and SPW, respectively) generated from the preparation of concentrated roe of bastard halibut (BH; Paralichthys olivaceus), skipjack tuna (ST; Katsuwonus pelamis), and yellowfin tuna (YT; Thunnus albacares) using the cook-dry process. The protein loss from the water extracts (EXT) of 100 g of roe protein was 15.05-19.71% and was significantly (P<0.05) higher than that of BPW (5.47-10.34%) and SPW (3.88-8.18%). The foam capacity of BPW (166-203%) and SPW (15-194%) was better than that of EXT. The emulsifying activity index of the original samples was lower than those ($15.40-107.86m^2/g$) of diluted protein samples. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and the reducing power of BPW and SPW were stronger than those of EXT. The 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid ($ABTS^+$) radical scavenging activity of EXT (0.028-0.045mg/mL) was significantly higher those of BPW and SPW. The angiotensin I-converting enzyme (ACE) inhibitory activity of SPW was the highest for BH (1.04 mg/mL), followed by YT and ST. The predominant amino acids in SPW were Glu, Ala, Leu, and His. These results demonstrate that processing water containing diluted organic components, including protein, can be consumed directly by humans as a functional reinforcing material after appropriate concentration processes.