• Korean Journal of Fisheries and Aquatic Sciences
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• v.45 no.2
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• pp.146-153
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• 2012

This study examined the effect of formulated diets (composed of condensed freshwater $Chlorella$ or $Schizochytrium$ sp., $Crypthecodinium$ sp., and EPA oil sources derived from baker's yeast) on the population growth and fatty acid composition of the brackish water flea ($Diaphanosoma$ $celebensis$) to determine diet effectiveness for mass production. Results indicated that the highest maximum density, fecundity, and population specific growth rate (SGR) of the flea were observed using a diet of $Tetraselmis$ $suecica$ (control). However, results using condensed freshwater $Chlorella$ and the mixed treatment of $Schizochytrium$ sp.+$Crypthecodinium$ sp.+EPA oil did not significantly differ from the control treatment ($P$>0.05). Thus, $T.$ $suecica$ could be replaced with a combination diet of $Schizochytrium$ sp., $Crypthecodinium$ sp., and EPA oil in condensed freshwater $Chlorella$ without growth interruption of $D.$ $celebensis$. As the percentage of combination diet (mix of $Schizochytrium$ sp., $Crypthecodinium$ sp., and EPA oil) in condensed freshwater $Chlorella$ increased, the level of ARA, EPA, DHA, and n-3 HUFA in $D.$ $celebensis$ also increased. However, the population density of $D.$ $celebensis$ sharply decreased with the use of treated supplements C5M5 (CHL [50%] and $Crypthecodinium$ sp.+ $Schizochytrium$ sp. + EPA oil [MIX 50%]). The optimum proportions of CHL and MIX for $D.$ $celebensis$ within the mixture were 70% and 30%, respectively. Based on the results, the combination of $Schizochytrium$ sp., $Crypthecodinium$ sp., and EPA oil in condensed freshwater $Chlorella$ appears to be a stable and effective food source for mass production of $D.$ $celebensis$.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.3
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• pp.391-397
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• 2015

Two hundred and sixteen Institut de S$\acute{e}$lection Animale (ISA) brown layers (40 wks of age) were studied for 6 wks to examine the effect of microalgae powder (MAP) on egg production, egg quality, blood lipid profile, and fatty acid concentration of egg yolk. Dietary treatments were as follows: i) CON (basal diet), ii) 0.5% MAP (CON+0.5% Schizochytrium powder), and iii) 1.0% MAP (CON+1.0% Schizochytrium powder). From 44 to 46 wks, egg production was higher in 1.0% MAP treatment than in control treatment (linear, p = 0.034); however, there was no difference on the egg production from 40 to 43 wks (p>0.05). Serum triglyceride and total cholesterol were significantly reduced in the groups fed with MAP, compared to those in groups fed with control diets (Quadratic, p = 0.034 and p = 0.039, respectively). Inclusion of 0.5% MAP in the diet of layers improved egg yolk color, compared with hens fed with basal diet at 46 wks (quadratic, p = 0.044). Eggshell thickness was linearly increased in MAP-fed treatments at 46th wk (p<0.05). Concentration of yolk docosahexaenoic acid (DHA; C22:6n-3) was increased in treatment groups fed with MAP (linear, p<0.05). The n-6 fatty acids, n-6/n-3 fatty acid, and unsaturated fatty acid/saturated fatty acid were decreased in treatment groups fed with MAP (linear, p<0.05). These results suggest that MAP improved the egg production and egg quality, and may affect serum lipid metabolites in the layers. In addition, MAP increases yolk DHA levels, and deceases n-6/n-3 fatty acid ratio.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.2
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• pp.144-153
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• 2014

Both docosahexaenoic acid (DHA, 22:6n-3) and eicosapentaenoic acid (EPA, 20:5n-3) have attracted increasing attention since the first epidemiological report on the importance of n-3 essential fatty acids. Lipids in microbial cells play various biological roles and, consequently, much research has been carried out on their role in cell physiology. The lipid composition of microorganisms can exhibit considerable variations depending on environment. The effects of culture conditions, temperature (15, 20, 24, 28, 32 and $36^{\circ}C$), salinity (10, 20, 30, 40 and 50 psu), pH (pH5, 6, 7, 8 and 9), rotation speeds (50, 100, 150 and 200 rpm), carbon sources, nitrogen sources and C/N ratio on the production of docosahexaenoic acid, fatty-acid profiles, and acids secreted to the broth culture by the oleaginous microorganism, Schizochytrium mangrovei (KCTC 11117BP), were studied. Temperature (initially $28^{\circ}C$), salinity (20 psu), pH (pH7), rotation speeds (100 rpm), organism fatty acids, and secreted acids in the broth were varied during cultivation of S. mangrovei. At pH 7.0, S. mangrovei was able to accumulate lipids up to 40% of its biomass, with 13% (w/w) DHA content. The monosaccharides glucose and fructose, and yeast extract were suitable carbon and nitrogen sources, respectively. The primary omega-3 polyunsaturated fatty acid produced was docosahexaenoic acid.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.4
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• pp.339-344
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• 2011

We investigated the effects of enrichment with oil or bacteria on the fatty acid composition of rotifers and Artemia as live prey. One enrichment(oil source) was mainly composed of squid Todarodes pacificus liver oil; the other(photosynthetic-bacterial source) was primarily made up of Schizochytrium sp. The enrichments were intended to enhance the nutritional value of the live prey, such as their EPA, DHA and n-3 HUFA contents. The lipid content as EPA and DHA of rotifers was higher when enriched with the oil source rather than the photosynthetic-bacterial source. The DHA content of Artemia nauplii after enrichment differed significantly, depending on the type of enrichment used(P<0.05). When the Artemia nauplii were enriched with the oil source, the DHA content was increased to 16.8%, whereas it increased only to 1.1% when enriched with the photosynthetic-bacterial source. These results indicate that selection of the enrichment is important for Artemia nauplii but not for rotifers.

• Korean Journal of Poultry Science
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• v.35 no.3
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• pp.255-265
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• 2008

The objective of this study was to evaluate the docosahexaenoic acid(DHA) levels of meats and eggs from chickens which were fed fermented soybean meal(FSM) by marine microalgae(Schizochytrium mangrovei MM103). The diets contained different amounts of FSM at 0, 3, 5 and 10%. DHA content of carcass was increased with dietary FSM. DHA amounts in the breast meat were higher in the 10% FSM diet(2.21%) than the 5%(1.65%) and 3%(1.18%) FSM, and similar results were observed in the leg meat(10% FSM: 2.21%; 5% FSM: 1.65%; and 3% FSM: 1.18%, respectively) and in eggs(10% FSM: 2.02%; 5% FSM: 1.22%; and 3% FSM: 0.73%). The level of n-3 polyunsaturated fatty acids such as DHA(22:6n-3) in the FSM treatment was significantly higher than those of the other groups(P<0.05). The results demonstrated that FSM by marine microalgae could be used to enhance DHA amounts in chicken meats and eggs.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.1
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• pp.31-38
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• 2014

Docosahexaenoic acid (DHA, 22:6n-3) and ecosapentaenoic acid (20:5n-3) have attracted increasing attention since the first epidemiological report on the importance of n-3 essential fatty acids. It is thought that DHA has important functions in brain and retinal tissues. Thraustochytrids, a group of marine protists, are capable of heterotrophic growth, and are potential omega-3 producers for industrial use, especially the members of the Schizochytrium and Thraustochytrium genera. The aims of this work were to isolate, identify and screen thraustochytrids from 17 different locations. Twenty-three isolates were screened for biomass, total fatty acid (TFA) and DHA content. Analysis of the fatty acid methyl esters revealed four distinct clusters biomass ranged from $8.68-9.36gL^{-1}$, and lipid and DHA contents ranged from $3.11-4.10gL^{-1}$ and $1.05-1.93gL^{-1}$ biomass, respectively. B-12 isolates were screened for biomass ($9.36gL^{-1}$), TFA ($4.10gL^{-1}$) and DHA (47.01%, w/w) content. C-6 isolates were also screened for biomass ($8.92gL^{-1}$), TFA ($3.30gL^{-1}$) and DHA (49.41%, w/w) content. The 18S rRNA gene sequencing results identified Schizochytrium mangrovei as B-12 and Crypthecodium cohnii as C-6.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.2
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• pp.154-160
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• 2016

Several our studies have focused recently on the mass production of the freshwater Cladoceran Moina macrocopa which can substitute Artemia nauplii for the culture of larval marin fish. A 6 weeks experiment was conducted to investigate the effects of enrichment on the fatty acid composition of Moina macrocopa through feeding Schizochytrium sp. containing highly unsaturated fatty acids and to study the impacts of n-3-HUFA enriched Moina on improving survival rate and fatty acid compostion of larval rockfish Sebastes schlegeli. After feeding for 6 weeks, the Moina-fed fry resulted in a higher survival rate of 99.2% compared to the Artemia-fed fry 12.8%. In addition, the Moina-fed fry had the fast growth rate 45.6mm compare to the Artemia-fed fry 25.7 mm at the end of the experiment. The Moina-fed fry showed significantly higher level of 16.47% DHA than their Artemia-fed fry counterparts of the level of 3.97% with respect to DHA. PL, the cell membrane components in living food organisms, constituted 63.8% of the Moina, which was significantly higher than in the 40.1% of the Artemia. The present study indicate that Moina macrocopa can be used as Artemia substitute and improving the survival rate rockfish larvae through enchriment Schizochytrium sp.

• Mycobiology
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• v.30 no.2
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• pp.76-81
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• 2002

Aquatic fungi from four brackish water lakes; Edku, Burullus and Manzala lakes which are located at the northern region of Egypt and Qarun lake that located in El-Fayoum city are reported in this manuscript. Twenty-nine fungal species which belong to 19 genera of aquatic fungi were recovered from water samples collected from the studied lakes. The most frequently isolated fungal species were Chytridium conferrop, Allomyces throughout and Rhizoclosmatium globosum. Thraustochytrium amoeboidum and Leptolegniella exoosporus have a moderately occurrence frequency. The maximum fungal count of recovered aquatic fungi was recorded in Burrullus lake followed by EdKu, Manzala and Qarun lakes. This study was extended to test the ability of six selected aquatic fungi(Brevilegniella keratinophila, Blastocladiella cystogena, Chytridium conferrop, Entophlyctis variabilis, Schizochytrium mangrovei and Thraustochytrium rosin), to uptake the radionuclide from their culture medium as a step to biologically treat the waste water or solution with radio-cesium and radio-cobalt. Fifty seven of Cs-137 and 35% of Co-60 could be removed from liquid waste by the selected aquatic fungi.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.10a
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• pp.141.2-141
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• 2003

고도불포화지방산 중 EPA(eicosapentaenoic acid)와 DHA(docosahexaenoic acid)는 여러 가지 생리활성 효과를 나타내는 것으로 알려져 있으며, 최근 관심이 주목되고 있다. 본 실험에서는 특히 DHA의 함량이 높은 해양미생물, 즉 조류(microalgae)인 Schizochytrium sp.에서 얻어진 DHA powder로부터 두 가지 방법으로 유지를 추출한 뒤 그 성질을 비교.분석하였다. 먼저, 8$0^{\circ}C$, soxhlet extractor로부터 6시간 동안 추출하고, 55$^{\circ}C$, shaking water bath로부터 같은 시간 동안 추출한 결과, 각각 25.5, 24.0%의 수율을 나타내었다. GC에 의한 지방산 조성 분석 결과, soxhlet extractor에서 추출한 경우, palmitic acid, DHA가 각각 30.98, 30.04 mol%로 주요 지방산인 것으로 나타났으며, shaking water bath에서 추출된 유지는 그 함량이 각각 31.44, 34.78 mol%를 나타내었다. 또한 pancreatic lipase에 의한 가수분해를 통해 sn-2 위치의 지방산 조성 분석 결과, DHA가 sn-2 위치에 주로 함유되어있는 것으로 조사되었다. 한편, HPLC-ELSD system을 이용하여 중성지방의 구성 성분을 분석 결과, 유지의 99%이상이 TAG(triacylglycerol) 형태로 이루어져 있었으며, 소량의 MAG(monoacylglycerol) 존재를 확인할 수 있었다.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.7
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• pp.973-978
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• 2017

Objective: The aim of this study was to investigate the effects of simultaneous supplementation of laying hens with alpha-linolenic acid (ALA) resources (flax, perilla, and Eucommia ulmoides [E. ulmoides] seeds) and eicosapentaenoic acid/docosahexaenoic acid (EPA/DHA) resources (Schizochytrium sp.) on egg quality and n-3 polyunsaturated fatty acids (PUFA) profile. Methods: Dietary treatments were as follows: i) diet C (control diet); ii) diet F (diet C+10% flaxseeds); iii) diet P, (diet C+10% perilla seeds); iv) diet E (diet C+10% E. ulmoides seeds); v) diet A (diet C+1.5% microalage); vi) diet AF (diet C+10% flaxseeds+1.5% microalage); vii) diet AP (diet C+10% perilla seeds+1.5% microalgae); viii) diet AE (diet C+10% E. ulmoides seeds+ 1.5% microalage). Results: Egg weight, yolk weight and production ratio were not significantly affected by either algae or in combination with seeds (p>0.05). No significant difference was observed in ALA and DHA concentration in eggs between flaxseed, perila, and E. ulmodies seeds supplementation alone (p>0.05). N-3 PUFA in eggs was slightly improved by microalgae supplementation. The best supplementation, a combination of microalgae and perilla seeds, elevated (p<0.05) ALA from 19.7 to 202.5 mg/egg and EPA+DHA from 27.5 to 159.7 mg/egg. Highest n-3 PUFA enrichment (379.6 mg/yolk) was observed with supplementation of a combination of perilla seed and microalgae (362.2 mg/yolk), followed by a combination of flaxseed and microalgae (348.4 mg/yolk). The ALA, EPA, and DHA content obtained with a combination of microalgae and seeds surpassed the total sum of that obtained with microalgae or ALA-seeds alone. Conclusion: It is feasible to enrich eggs with n-3 PUFAs by perilla or E. ulmodies seeds instead of flaxseeds. Simultaneous supplementation of microalgae and seeds helped improve the transfer from EPA and docosapentaenoic acid into DHA.