• Journal of Microbiology and Biotechnology
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• v.17 no.7
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• pp.1162-1168
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• 2007

Although widely used as a host for recombinant protein production, Escherichia coli is unsuitable for massive screening of recombinant clones, owing to its poor secretion of proteins. A vector system containing T4 holin and T7 lysozyme genes under the control of the ptsG promoter derivative that is inducible in the absence of glucose was developed for programmed cell lysis of E. coli. Because E. coli harboring the vector grows well in the presence of glucose, but is lysed upon glucose exhaustion, the activity of the foreign gene expressed in E. coli can be monitored easily without an additional step for cell disruption after the foreign gene is expressed sufficiently with an appropriate concentration of glucose. The effectiveness of the vector was demonstrated by efficient screening of the amylase gene from a Bacillus subtilis genomic library. This vector system is expected to provide a more efficient and economic screening of bioactive products from DNA libraries in large quantities.

• Food Science of Animal Resources
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• v.35 no.3
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• pp.398-405
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• 2015

Egg allergy has been shown to be the most common food allergy in children with atopic dermatitis. Allergic reactions to proteins derived from egg white (EW) are more common than those derived from egg yolk. Ovomucoid, ovalbumin, ovotransferrin, and lysozyme have been identified as major allergens in EW. This study was conducted to evaluate the effect of EW on immune modulation in an induced allergy mouse model. A total of 50 five-week-old BALB/c male mice were treated with trimellitic anhydride (TMA) for three weeks to induce allergy-like symptoms. The TMA-treated mice were rested for one week and then divided into five groups and fed 0, 10, 50, and 100 mg/d EW for four weeks. All EW consumption groups showed no significant increase or decrease in the populations of white blood cells; however, a significant increase in B-lymphocyte activity was observed in the fourth week. Furthermore, EW consumption did not influence serum immunoglobulin G and immunoglobulin E levels. Taken together, these data demonstrate that the consumption of EW by TMA-treated mice did not increase allergic parameters such as serum IgE level, but enhanced the lymphocyte activities against pathogens. Therefore, this study suggests that the consumption of EW promotes Th2 immune modulation, and EW could be an excellent candidate for maintaining health.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.3
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• pp.383-390
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• 2014

A 15-wk feeding trial was conducted to examine the supplemental effects of Barodon on growth performance, gastrointestinal histology, feed digestibility and innate immunity in olive founder. A basal commercial diet was used as a control and two other diets were prepared by spraying 0.1% or 0.2% of Barodon. Triplicate groups of fish (BW, 145 g) were fed one of the test diets to apparent satiation twice daily. At the end of the feeding trial, fish growth performance was not significantly affected by dietary treatments; however, feed utilization was significantly improved (linear and quadratic, p<0.05) by Barodon supplementation. Significantly higher (p<0.05) survival rates were obtained in fish fed Barodon containing diets. Hepatosomatic index increased significantly in Barodon treated groups. Also, the use of Barodon resulted in significant increase (linear and quadratic, p<0.05) of intestine length and number of goblet cells. Significantly higher (Quadratic, p<0.05) apparent digestibility coefficient of DM was obtained by supplementation of Barodon. Lysozyme and myeloperoxidase activities increased quadratically and linearly, respectively, in Barodon treated fish. Also, significantly higher (linear and quadratic, p<0.05) superoxide dismutase activity was found in Barodon fed fish. The findings in this study show that inclusion of Barodon in diets for olive flounder improves feed utilization and digestibility, and positively affects digestive tract histology and innate immunity.

• Fisheries and Aquatic Sciences
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• v.18 no.4
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• pp.367-372
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• 2015

We investigated the effects of dietary supplementation of two types (powder or liquid) of propolis on innate immunity and disease resistance of olive flounder Paralichthys olivaceus against Edwerdsiella tarda. A total of 600 fish averaging 30 g were randomly distributed into 24 tanks in groups of 25. Three tanks were assigned to each of eight experimental diets: 0 (Control), 0.25, 0.5, 0.75 and 1 % propolis in powder form and 0.25, 0.5 and 1 % propolis in liquid form (PP0.25, PP0.5, PP0.75, PP1, LP0.25, LP0.5 and LP1, respectively). Fish were fed each experimental diet twice daily for four weeks to apparent satiation. At the end of the feeding trial, lysozyme and myeloperoxidase activities and total immunoglobulin level were significantly higher in fish fed the PP1 and LP0.5 diets compared to those fed the control diet. The PP1 diet was also associated with a significant increase in anti-protease activity compared to the control diet. After challenge with E. tarda, fish fed the LP0.5 diet showed numerically higher survival compared to the other groups. This study indicates that non-specific immune responses of olive flounder can be enhanced by dietary supplementation with powder and liquid forms of propolis, and that the optimal level would be 1% in powder form or 0.5% in liquid form. It seemed that growth performance and feed utilization are not affected by the propolis supplementation in diets for olive flounder.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.1
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• pp.15-24
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• 2017

This study examined the effects of dietary supplementation with citrus by-product (CBP) on the growth, feed utilization, innate immunity, and histology of the gills and intestine of juvenile olive flounder Paralichthys olivaceus during low water temperature season. A vitamin C-free basal diet was regarded as a control and five other diets were formulated that contained 30 and 300 mg of L-ascorbyl-2-polyphosphate (LAPP) or CBP as vitamin C equivalents/kg diet, or the antibiotic oxytetracycline (OTC) (designated as control, LAPP30, LAPP300, CBP30, CBP300, and OTC, respectively). Olive flounder (initial body weight $44.6{\pm}0.32g$) were fed the six experimental diets to apparent satiation for 9 weeks. Growth and feed utilization were significantly higher in CBP30 than in the control and LAPP groups. The lysozyme activity was significantly higher in CBP30 than in LAPP300. Enterocyte height was significantly higher in CBP30 than in the control. The number of goblet cells was increased significantly with LAPP30, LAPP300, and CBP30. These results demonstrate that CBP can reduce or replace vitamin C and antibiotic in the diet of olive flounder during the low-water-temperature season. The optimal CBP supplementation level seems to be approximately 1%, which is equivalent to 30 ppm vitamin C/kg in the fish diet.

• Fisheries and Aquatic Sciences
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• v.23 no.5
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• pp.12.1-12.8
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• 2020

Background: An 8-week feeding trial was designed to evaluate the potential of yellow mealworm (MW; Tenebrio molitor) as a locally available nutrient-rich feedstuff for rainbow trout fry (Oncorhynchus mykiss). Methods: Triplicate groups of fish (mean ± SE; 1.11 ± 0.01 g) were assigned to each of the five isonitrogenous and isocaloric practical diets containing graded level of a full fat MW (0, 7, 14, 21, and 28%) at the expense of fish meal (designated as MW0, MW7, MW14, MW21, and MW28, respectively). Results: Fish growth performance in terms of weight gain and specific growth rate significantly increased with increasing dietary MW level up to 14% and then declined when dietary MW levels further increased to 28%. Significantly higher protein efficiency ratio and lower feed conversion ratio were found in fish fed with diets containing MW compared to fish fed the control MW0. Myeloperoxidase activity was significantly higher in fish fed MW7 diet compared to fish fed the MW0 diet. Fish fed the MW14 and MW28 diets had significantly higher lysozyme activities than those fed the MW0 diet. Conclusions: Overall, the efficacy of MW as promising alternative to fish meal in practical diets for rainbow trout fry has been proved not only in relation to growth rates and feed utilization, but also from the viewpoint of immunopotentiation effects.

• Fisheries and Aquatic Sciences
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• v.23 no.8
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• pp.22.1-22.8
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• 2020

Background: High demand and low supply of fishmeal due to overexploitation of fisheries resources have resulted in a dramatic increase in the price of this ingredient. Olive flounder (Paralichthys olivaceus) commercial feed contains approximately 60% fishmeal and limited success has been achieved in identifying sustainable alternative protein sources for this species. Methods: An on-farm feeding trial was conducted to compare a basal diet containing 65% as the control (CONT) with two experimental diets replacing 10% of fishmeal by animal protein (AP₁₀) or 20% of fishmeal by animal and plant protein (APP₂₀). Sub-adult olive flounder averaging 327 ± 9.3 g (mean±SD) were fed one of the three diets in triplicate groups for 16 weeks. Results: Weight gain, specific growth rate, feed efficiency, protein efficiency ratio, and survival were not significantly different among fish fed all the experimental diets (P > 0.05). Also, non-specific immune responses (superoxide dismutase and lysozyme activity), serum biochemical parameters, and intestinal villi length were not significantly different among fish fed all the experimental diets (P > 0.05). Conclusions: Therefore, based on growth performance, non-specific immune responses, serum biochemical parameters, and intestinal histology, dietary animal and plant protein mixtures could replace up to 20% of fishmeal in the diet of sub-adult olive flounder.

• Journal of fish pathology
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• v.25 no.2
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• pp.67-76
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• 2012

Two bacteria strains were isolated from emaciated olive flounder (Paralichthys olivaceus) in aquafarm and were identificated as Vibrio harveyi (JV1) and Edwardsiella tarda (JE1), respectively. In the challenge experiments, we found 100% cumulative mortalities in all of olive flounder injected with JV1, JE1 or JV1+JE1 within eleven days after the injection. Two bacteria strains were reisolated from dead fish and were analyzed using the PCR method. In the physilogical analysis, the hematocrit, AST, ALT and cholesterol levels in experimental groups were increased significantly compared to those in control group, but the glucose, total protein and triglyceride levels were significantly decreased. Additionally, the lysozyme activity in the blood serum was decreased. The histopathological observations of the intestine showed that all groups had detachment and destruction of epithelial tissues except for the control group.

• Fisheries and Aquatic Sciences
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• v.16 no.3
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• pp.149-158
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• 2013

We demonstrate enhanced growth, innate immunity and protection against hydrogen peroxide ($H_2O_2$)-induced protein oxidation and cellular DNA damage in olive flounder Paralichthys olivaceus fed a chitosan-coated moist pallet (MP) diet. A chitosan-based biopolymer coated MP as the experimental diet and a non-coated MP (control) was fed to olive flounder fish. Growth, including the average weight gain (g/fish), weight gain (%) and feed intake (g) of the fish group fed a chitosan-coated MP diet increased significantly. The survival rate was reported as 100% throughout the experimental period. Immunological parameters indicated higher mucus lysozyme activity and significantly higher fish skin mucus total protein content was observed in fish fed the chitosan-coated MP diet compared to the control. A blood plasma analysis revealed attenuation of cellular DNA and protein oxidative damage caused by $H_2O_2$-induced oxidative stress in the fish fed the chitosan-coated MP diet compared to the control group. Moreover, blood serum biochemical analysis revealed health-promoting effects, including significantly higher hemoglobin and total cholesterol levels in the fish fed the chitosan-coated MP diet compared to the control group. In conclusion, growth, innate immunity and protection against oxidative stresses were improved by feeding of the chitosan-coated MP diet to olive flounder reared in aquaculture.

• Journal of Fisheries and Marine Sciences Education
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• v.22 no.4
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• pp.529-536
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• 2010

This study was conducted to effect of extruded pellets (EPs) and moist pellet (MP) diet on growth and fish health parameters in farm cultured olive flounder Paralichthys olivaceus. Two replicate groups of 2,600 fish per each tank (initial weight of $30.1{\pm}0.2$ g) were fed one of the three EPs (EP1, EP2 and CEP) and one MP for 13 months. In field feeding experiment conducted in commercial flounder farm, survival, growth (30-600 g) and condition factor of fish fed experimental EP1 and EP2 were comparable to those of fish fed MP, but considerably higher feed efficiency and protein efficiency ratio were observed in fish fed experimental EPs. Viable cell counts from diet and water from MP diet were considerably higher than those from EP diet, and lysozyme activity from EP diet was higher than that from MP diet. GOT and GPT of fish fed the EP diet were considerably lower than those from MP group, but total protein and glucose concentration of fish fed the EP groups were not significantly different from that of fish fed the MP. Therefore, these results strongly suggest that EP diets could be developed to replace MP diet without adverse effects on growth performance and to enhance the immunity and protective ability of olive flounder against fish disease such as Vibro, Edwardsiella and Strptococcus.