• 한국식품과학회지
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• 제49권4호
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• pp.390-395
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• 2017

Mixed A, Chlorella vulgaris, Nannochloropsis oculata, Chaetoceros calcitrans 등 4종류의 미세조류로부터 99.9% 에탄올로 추출한 성분의 항균활성을 검증하기 위해 그람음성세균 2종(E. coli, S. Typhimurium)과 그람양성세균 2종(S. aureus, B. cereus)에 대하여 paper disk diffusion assay, MIC, MBC를 측정하였다. 4종류의 미세조류 추출물은 공시균주에 대하여 0.62-1.66 mg/mL의 MIC를 나타내었으며, C. vulgaris 추출물이 4종의 공시균주에 대한 MIC가 0.62 mg/mL로 가장 강한 항균활성을 나타내었으며, MBC 또한 C. vulgaris 에탄올 추출물이 E. coli에 대해 2.50 mg/mL, S. aureus, B. cereus와 S. Typhimurium에 대해서는 4.16-5.00 mg/mL로 가장 강한 항균활성을 나타내었다. 항균활성이 가장 강한 C. vulgaris 에탄올 추출물의 성분을 분석한 결과, 함량이 가장 많은 성분은 9,12-octadecadienoic acid (linoelaidic acid, peak 5, 7)로 38.8%이었으며, 그 다음이 2-Hexadecen-1-o1, 3,7,11,15-tetramethyl (phytol, peak 2,6)로 30.0%이었다. Octadecadienoic acid는 일명 linoelaidic acid로 탄소수 18개의 고도불포화지방산이며, 두 번째로 함량이 많은 Phytol은 클로로필을 구성하는 불포화 제1급 알코올의 일종으로서(엽록소의 구성 성분) 병원성 대장균 및 황색포도상구균에 항균활성을 나타낸다는 보고로 볼 때, 이 2가지 성분이 항균활성의 주성분인 것으로 사료된다.

• 한국양식학회지
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• 제21권3호
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• pp.167-171
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• 2008

원생동물 섬모충의 한 종인 Euplotes는 해산어 종묘생산시설의 로티퍼 대량배양수조에서 혼재생물로서 매우 자주 관찰된다. 그들은 로티퍼에게 먹이로 첨가되는 농축 상태의 먹이(미세조류)를 중간에서 가로채어 빠른 속도로 증식하면서 로티퍼의 증식을 방해한다. 더불어 이때 형성된 배양수조내의 세균상은 로티퍼의 전멸을 초래하기도 한다.

• 한국수산과학회지
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• 제42권1호
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• pp.56-62
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• 2009

Feeding regimens was investigated for the growth and survival rate of juvenile Maroon clownfish (Premnas biaculeatus) in order to establish a seed production technique for this fish. Three types of feeding regimens were used, and growth and survival were highest under the following regimen: rotifer from day 0, Artemia from day 4, copepod from day 9 and artificial food from day 15, respectively (P<0.05). The average body lengths of the larvae were $6.76{\pm}0.55\;mm$, $7.63{\pm}0.50\;mm$ and $7.33{\pm}0.43\;mm$ in the Nannochloropsis oculata, Isochrysis galbana and control treatments conducted with 3 larvae/L, respectively (P<0.05). There were significant differences in larval growth between the treatments and controls conducted with 6 larvae/L and 9 larvae/L, respectively (P<0.05) but there was no significant difference between the N. oculata and I. galbana treatments (P>0.05). There were no significant differences in larval growth between the treatments at densities of 3-9 larvae/L (P>0.05). At highest density level, the larvae reared in I. galbana had the highest survival rate whereas survival was lowest in the control.

• Journal of Plant Biotechnology
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• 제44권4호
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• pp.462-471
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• 2017

Thiamine pyrophosphate (TPP), the active form of thiamine is a cofactor for enzymes involved in central metabolism pathways. However, it is also known to have a role as a stress signaling molecule in response to environmental changes. Anabaena sp. and N. oculata are microorganisms which are abundantly found in Malaysia's freshwater and marine ecosystem. However, not much studies have been done especially in regards to thiamine biosynthesis. This work aimed to amplify of gene transcripts coding for thiamine biosynthesis enzymes besides looking at the expression of thiamine biosynthesis genes upon stress application. Various stress inducers were applied to the cultures and RNA was extracted at different time points. The first two genes, ThiC and ThiG/Thi4 encoding enzymes of the pyrimidine and thiazole branch respectively in the thiamine biosynthesis pathway were identified and amplified. The expression of the genes were analysed via RT-PCR and the intensity of bands were analysed using ImageJ software. The results showed up to 4-fold increase in the expression of ThiC and ThiG gene transcript as compared to control sample in Anabaena sp. ThiC gene in N. oculata showed an expression of 6-fold higher as compared to control sample. In conclusion, stresses induced the expression of the gene coding for one of the most important enzymes in thiamine biosynthesis pathway. This is an agreement with the hypothesis that overexpression of thiamine is crucial in assisting plants to combat abiotic stresses.

• 한국수산과학회지
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• 제49권4호
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• pp.467-473
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• 2016

Several of our recent studies have focused on mass production of the marine Cladoceran Diaphanosoma celebensis, which can serve as a feed substitute for Artemia nauplii in the culture of larval marine fish. We compared the growth and survival rates of tiger puffer Takifugu rubripes fed D. celebensis with those fed Artemia. The group fed D. celebensis showed an increase in growth from 0.10 g to 1.78 g, while the group fed enriched Artemia had a growth from 0.10 g to 0.92 g. The survival rate of fish fed D. celebensis was 86.7% while that of fish fed enriched Artemia was 51.1%, indicating that the former group was superior to the latter both in growth and survival rate. Fatty acid analysis revealed that D. celebensis fed Nannochloropsis oculata and Schizochytrium sp. had an eicosapentaenoic acid (EPA) content of 16.42% and a docosahexaenoic acid (DHA) content of 3.93%. Meanwhile, juvenile tiger puffer fed D. celebensis had an EPA content of 9.12% and a DHA content of 10.69%. Juvenile tiger puffer fed D. celebensis had a similar n-3 highly unsaturated fatty acid content to that of tiger puffer fed enriched Artemia which had an EPA content of 5.82% and a DHA content of 15.90%, indicating that no additional enrichment was required.

• 수산해양교육연구
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• 제28권2호
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• pp.315-322
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• 2016

This study determined the optimum microalgae species and concentration for growth of small rotifer Proales similis, in community cultures by feeding it several different foods. Four single trials (Tetraselmis suecica, TET; Isochrysis galbana, ISO; Nannochloropsis oculata, NAN; freshwater Chlorella vulgaris, CHL) were conducted at 5 psu and $25^{\circ}C$. The maximum density and specific growth rate (SRG) were highest for rotifer fed CHL reaching 1,075 individuals (inds.)/mL and 0.83 respectively. By contrast, other foods of ISO, NAN and TET resulted in poor growth rates and maximum density. In the freshwater C. vulgaris experiments examining a range of 0.05 to $8.8mg/10^4rotifers$, the growth of rotifer tended to decrease with the amount of supplement. The maximum density and SGR of females was highest at 910 inds./mL and 0.55 respectively, at $0.05mg/10^4rotifers$. These results suggest that the best microalgae species for the culture of P. similis is freshwater C. vulgaris and the optimum concentration is $0.05mg/10^4rotifers$.

• Fisheries and Aquatic Sciences
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• 제26권8호
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• pp.470-481
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• 2023

Algal overgrowth in shrimp culture ponds can affect the quality of the aquatic environment, thereby adversely affecting the shrimp and causing economic losses. The objective of this study was to evaluate the variation in phytoplankton composition in intensive shrimp ponds in Bac Lieu province, Vietnam. Phytoplankton samples were collected in three black tiger shrimp (Penaeus monodon) ponds and three whiteleg shrimp (Litopenaeus vannamei) ponds. The collected data were analyzed using SPSS and canonical correlation analysis softwares. In total, 75 species of phytoplankton were recorded in black tiger shrimp ponds and 64 species in whiteleg shrimp ponds. Diatoms had the highest species diversity with 29-30 species (39%-47%), followed by green algae with 9-19 species (14%-25%); species numbers of other phyla varied from 5-12 (8%-16%). The total number of phytoplankton species throughout the study varied from 34-50 species. Algal density was relatively high and ranged from 497,091-2,229,500 ind./L and 1,301,134-2,237,758 ind./L in black tiger shrimp and whiteleg shrimp ponds, respectively. The diatom density tended to increase during the final stage of the production cycle in black tiger shrimp ponds. Blue-green algae and dinoflagellates also increased in abundance at the end of the cycle, which can affect shrimp growth. Diatoms were significantly positively correlated with pH, salinity, total ammonia nitrogen, and nitrate (NO₃^-) concentrations (p < 0.05). Blue-green algae and dinoflagellates were positively correlated with salinity, phosphate (PO₄^3-), and NO₃^-. Algal species diversity was lower in the whiteleg shrimp ponds than in the black tiger shrimp ponds. Several dominant algal genera were recorded in the shrimp ponds, including Nannochloropsis, Gyrosigma, Chaetoceros, Alexandrium, and Microcystis. The results of this study provide basic data for further investigations, and they contribute to the management of algae in brackish-water shrimp ponds.

• Fisheries and Aquatic Sciences
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• 제27권9호
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• pp.634-643
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• 2024

Silver pompano (Trachinotus blochii) is one of the major commodities of the aquaculture industry in Lampung. Silver pompano hatchery activities that still require natural feed, namely Brachionus sp. Brachionus plicatilis is a filter feeder that does not filter selectively all available feed, so an enrichment process is required so that natural feed reproduces with high nutritional content and is high in fatty acids (eicosapentaenoic acid [EPA] and decosahexaenoic acid [DHA]). This study aims to determine the best survival and growth of silver pompano larvae by feeding B. plicatilis enriched with EPA and DHA fatty acids derived from maggots black soldier fly (BSF). Five-day-old silver pompano larvae with a density of 20 larvae/tank in a 20 × 20 × 20 cm aquarium container. B. plicatilis was fed at a density of 13 ind/mL. Nannochloropsis salina was also given as additional feed at 300-400 cells/mL density. We gave B. plicatilis three times a day (05:00 am, 02:00 pm, and 9.00 pm) for 30 days of cultivation. The experimental treatments were A (no enrichment), B (100 ppm), C (300 ppm), D (500 ppm), and E (700 ppm). The conclusion of this study is the provision of EPA and DHA oil from maggot BSF with different doses of rotifer enrichment has a significant effect on the growth of silver pompano larvae. The results showed that the optimal dose of EPA and DHA oil was 300 ppm or 0.3 mL/L in treatment C with an average absolute length growth of 2.11 cm, and the survival rate reached 75%.

• 한국수산과학회지
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• 제33권1호
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• pp.66-69
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• 2000

이 연구에서는 로티퍼 B. rotundiformis의 대량 배양조에서 흔히 혼재가 관찰되는 코페포다 T japonicus가 배양을 목적으로 하고 있는 로티퍼 B. rotundiformis의 증식에 어떠한 영향을 미치는지 알아보았다. 실험에 사용한 로티퍼와 코페포다는 로티퍼의 대량 배양조에서 순수 분리 후 단일종 배양하던 것이다. 배앙 조건은 현장의 배양환경과 되도록 일치하도록 하였으며, 먹이는 $7{\times}10^5\;cells/ml$의 N. oculata를 급이하였다. B. rotundiformis의 배양조에 혼재된 T. japonicus는 C. rotundiformis를 단독 배양한 경우에 비하여 증식이 크게 억제되었고, 실험 종료일까지도 그 증식은 정체되는 양상을 보였다. 그러나, T. japonicus의 증식은 T. japonirus를 단독 배양한 경우에 비교하여 B. rotundiformis와 혼합 배양하여도 그 증식에는 큰 차이가 없었다. 또한, B. rotundiformis와 T japonicu의 혼합 배양에서 두 종간의 피포식 관계나 먹이 경쟁 관계와 같은 직접적인 상호 작용은 관찰할 수 없었다. 이 연구의 결과, 로티퍼 B. rotundiformis의 대량 배양조에서 혼재 생물로서 자주 관찰되는 코페포다 T. japonicus는 B. rotundiformis의 증식 저해요인으로서 작용하고 있음을 알 수 있었다.

• 한국양식학회지
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• 제11권1호
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• pp.99-103
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• 1998

rotifer의 배양조에 혼재된 Artemia가 rotifer의 증식에 미치는 영향을 검토하였다. 실험에는 Koshiki주의 rotifer, Brachionus rotundiformis와 미국 샌프란시스코의 Great Salt lake주의 Artemia sp.를 사용했다. 그리고 모든 실험은 염분을 22ppt, 배양 온도는 $25^{\circ}C.$, 먹이로서 N. oculata을 2일 간격으로 ml 당 $7{\times}10^5$ 세포씩 공급하면서, 50 ml의 비이커에 N. oculata 현탁액을 40ml씩 넣고, rotifer 20마리 그리고 Artemia는 3마리씩 각 수조에 수용하여 각 생물들을 단일종 배양한 경우와 혼합 배양한 경우의 증식을 비교하였다. rotifer와 Artemia 유생을 혼합 배양한 경우, 두 생물은 한정된 먹이 N. oculata 조건하에서 먹이 경쟁(food competition)을 하였다. 또한, rotifer의 대량 배양조에 Artemia 성체의 급속한 섭식 활동에 의해서 심각한 먹이 부족 현상을 일으켰다. 결국, Artemia 성체는 rotifer의 안정적인 생산을 크게 방해하는 rotifer 증식 억제 요인으로서 작용했다. 즉, rotifer을 안정적으로 생산하기 위해서는 종묘 생산 과정에서 유발될 수 있는 Artemia의 혼재가 일어나지 않도록 각별한 주의가 필요하다.