• Ocean and Polar Research
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• v.36 no.2
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• pp.199-208
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• 2014

Copepods are a major food source for marine fish larvae in nature. Many studies on copepods culture have been conducted to develop a new live food for the seedling production of marine fish larvae. But fish farmers still depend on rotifer and Artemia nauplii. This study was carried out to find suitable copepods as live food for the larvae in hatchery. Eight species of copepods (1 calanoid, 2 cyclpoid, 5 harpacticoid) that were fed Isochrysis galbana were examined in terms of the size of nauplii, fecundity, amino acids, and fatty acids contents. These species were divided into small (nauplii length 46-86 ${\mu}m$) and large (nauplii length 120-188 ${\mu}m$) size group. Nitokra spinipes in the small group and Tigriopus japonicus in the large group showed the highest fecundity with 151.1 and 139.6 nauplii production per gravid female, respectively. With regard to nutrients, essential amino acids were the highest with 21.2% in cyclopoid Paracyclopina nana in the small group and n-3 HUFA were the highest in calanoid Pseudodiaptomus inopinus (8.5 ${\mu}g/mg$) in the large group and P. nana (8.8 ${\mu}g/mg$). In terms of the size, fecundity, and nutritional value of copepods examined in this study, N. spinipes and P. nana seem to be suitable copepod species to develop as a new live food for small mouth fish larvae.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.4
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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.

• Journal of Life Science
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• v.12 no.4
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• pp.407-415
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• 2002

The survival of the early larvae of the freshwater crab, E. japonicus, fed on different diets at 22土1$^{\circ}C$ and 24$\pm$1% were studied in the laboratory. The larvae in the control (no feed) lived for 4 days (1~2 zoeal stages), and in the experimental container of non-living foods (egg Powder, soy bean Powder, Pellet Powder, millet Powder, and mussel meat), they were lived for 7~9 days (2~3 zoeal stages), When the larvae fed on phytoplankton (Chlorella ellipsoid., Skeletonema costatum. and Chaetoceros gracilis), they lived for 10, 18, and 19 days(3~5 zoeal stages), and fed on zooplankton (Artemianauplii and rotifer), they were reached to the juvenile stage in 24 and 25 days, respectivily. When the larvae fed on a mixed diets (see table 1). it was more effective than a single food diet, and the most effective diets included Chaetoceros gracilis, Artemia nauplii and rotifera, in which the larvae reached the juvenile stage in 22 days, and the survival was 73%.

• Journal of Aquaculture
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• v.1 no.1
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• pp.1-11
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• 1988

There are many problems to be solved for the establishment of more feasible and simplified method of seed production of marine fishes. One of the most important tasks in seed production is to clarify the feeding ecology of larvae and juveniles under. rearing conditions. In the present study, two groups of postlarvae-juveniles of the flounder, Paralichthys olivaceus were used. One ranging 11.38 to 17.08 mm in mean total length was fed with Artemia nauplii at two different water temperatures (19 to $21^{\circ}C$ and 24 to $25^{\circ}C$) and the other ranging 4.39 to 10.64 cm in mean total length was fed with prepared diet. Time required from the start of feeding to satiation was 45 to 55 minutes at 24 to $25^{\circ}C$ and nearly one hour at 19 to $21^{\circ}C$. Mean numbers of Artemia nauplii in digestive tract were 236 to 375 individuals per fish at 24 to $25^{\circ}C$. The amount of food remained in the intestine was $24.8\%$ of the total food in the digestive tract. In juveniles of 4.39 to 10.64 cm in mean total length, amount of prepared diet consumed at satiation was 0.04 to 0.46 g per fish. Digestive tract index in juveniles was rapidly decreased for 24 hours after satiation and kept nearly constant after 48 hours, showing that the time to completely digest the prepared diet in juveniles was estimated to be about 48 hours.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2001.10a
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• pp.249-250
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• 2001

요각류는n-3 HUFA의 함량이 풍부하여 동물먹이생물인 Artemia를 대체할 수 있는 먹이생물로서 이용 가능하다. 이러한 요각류를 먹이생물로 이용하기 위해서는 대량 배양이 성공적으로 이루어져야 한다. cyclopoid 요각류인 Paracyclopina nana는 부유성으로 성체의 크기가 500~60$\mu\textrm{m}$로서 Artmia nauplii(500$\mu\textrm{m}$)와 비슷하고, 요각류 Sinocalanus tenellus, Apocyclops royi, Tachidius triangularis, Nitoca lacustirs, Tigriopus sp.와 비교해서 개체 성장 및 군집성장에서 매우 높게 나타났다. (중략)

• Korean Journal of Fisheries and Aquatic Sciences
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• v.15 no.2
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• pp.161-170
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• 1982

A trial on the seed production of red sea-bream (Chrysophrys major) was made in Jejudo island at the southern end of Korea, from June, 1980 to August, 1981. Histological observation of the gonads indicated that the main spawning season was June to early July in Jejudo area. The newly-hatched fry were fed Brachionus sp. in the later stages Artemia nauplii, Tigriopus sp. and the minced fish flesh were given. Though during the winter season the water temperature in rearing tanks was decreased as low as $9.2^{\circ}C$, continuous feeding to the juveniles was carried out, showing body weight increase. This implies that winter rearing of juveniles in the near-shore facilities is feasible in the vicinity of Seogwipo area, in Jejudo. Feed coefficient of the juveniles (>23.2 g) was $4.16\sim4.77$ when fed the minced fish flesh.

• Ocean and Polar Research
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• v.45 no.2
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• pp.57-69
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• 2023

Growth responses along the gradient of water temperature, salinity, and light intensity and cytotoxicity against Artemia nauplii were explored using Ostreopsis sp. and Coolia canariensis strains, representing the two potentially toxic epiphytic dinoflagellate (EPD) species from Jeju coastal waters of Korea. Variation in maximum growth rate (GRmax) and maximum biomass yield (Ymax) along the environmental gradients was quite contrasting between the two strains, which appears to be reflected in the in situ abundance distribution of the corresponding genera. The more eurythermal characteristics of Ostreopsis sp. strain were in good agreement with the relative distribution of Ostreopsis spp. and Coolia spp. in 520 macroalgal samples collected from 6 stations. The more stenohaline C. canariensis strain was well matched by a markedly narrower range of salinities in the in situ distribution of Coolia spp. than the salinity range for Ostreopsis species. The differences in light adaptation between the high light-preferring Ostreopsis sp. strain and the more euryphotic C. canariensis strain were remarkably consistent with the distinct vertical profiles of Ostreopsis spp. and Coolia spp. abundance in the red alga Amphiroa sp. off Moom-seom. Cytotoxicity against Artemia nauplii in the Ostreopsis sp. preparation with 1000 cells ml^-1 was similar to that in C. canariensis preparation with 12000 cells ml^-1, which is noteworthy. Thus, the new potential cytotoxicity risks from C. canariensis along with the well-known toxic genus Ostreopsis may be introduced to Jeju coasts, which necessitates further exploration into the contrasting ecological niches occupied by EPD species in relation to their cytotoxicity.

• Journal of Aquaculture
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• v.17 no.2
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• pp.151-157
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• 2004

Effects of supplementing selected fatty acids on fatty acid incorporation (17 days) , and progeny production (14 days) in Artemia franciscana (Great Salt Lake, USA) were studied. To compare with the control four diets, which differed in fatty acid composition alone contain Dunalieia tertiolecta and an emulsion either rich in OA (oleic acid, 18: 1 n-9), ARA (arachidonic acid, 20:4n-6), EPA (eicosapentaenoic acid,20:5n-3), or DHA (docosahexaenoic acid, 22:6n-3). Each of these emulsions was supplemented at a ratio of 20 % of the daily dose of D. tertiolecta (% algal dry weight). The initial OA and ARA values were 33.5 and 1.7 mg/g DW of freshly-hatched nauplii, respectively. After 11 days of feeding, these values increased to 38.8 and 7.6 mg/g DW in Artemia receiving the fatty acid sup-plement rich in each of the respective fatty acids. After 14 days, the levels were almost doubled, reaching 62.8 and 13.4 mg/g respectively. On EPA supplementation, its level after 11 days of feeding was 14.3 and 17.3 mg/g in male and female, respectively and was 16.0 and 23.1 mg/g in the male and female after 14 days, respectively. The EPA accumulated more in the body (39.1 mg/g) than in ovisac (16.9 mg/g). In the DHA supplementation group also, DHA levels after 11 days of feeding were 3.1 and 5.5 mg/g in male and female, respectively. After 14 days, the DHA level continued to increase in male. but slightly decreased to 4.6 mg/g in female. It was not richer in ovisac (2.6 mg/g) than in the remaining body of female (4.6 mg/g). In conclusion, fatty acids supplied by a lipid emulsion as a supplement to the algal diet are well incorporated in the adult Artemia. Apart from being an extra source of energy, these emulsions may function as source of HUFA which may play an essential role for growth and progeny production (fecundity) of Artemia.

• Mycobiology
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• v.37 no.1
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• pp.31-36
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• 2009

A phytochemical study on the flower of Calotropis gigantea (Linn.) using silica gel column chromatography and preparative thin layer chromatography, led to the first time isolation of Di-(2-ethylhexyl) phthalate (compound 1) and anhydrosophoradiol-3-acetate (compound 2). The structures of these compounds were confirmed by spectroscopic analyses (IR, HRTOFMS and NMR). The antibacterial and antifungal activities of ethyl acetate extract, compound 1 and compound 2 were measured using the disc diffusion method. Ethyl acetate extract and compound 1 presented better results than compound 2. The minimum inhibitory concentrations (MICs) of the extract and compounds were found to be in the range of $16{\sim}128{\mu}g/ml$. The cytotoxicity ($LC_{50}$) against brine shrimp nauplii (Artemia salina) were also evaluated and found to be 14.61 ${\mu}g/ml$ for ethyl acetate, 9.19 ${\mu}g/ml$ for compound 1 and 15.55 ${\mu}g/ml$ for compound 2.

• Korean Journal of Ichthyology
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• v.21 no.3
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• pp.149-157
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• 2009

Larvae and juveniles of the filefish Thamnaconus modestus were reared for 64 days after hatching (DAH) in order to determine the activity of four enzymes (trypsin, pepsin-like enzyme, lipase, amylase) during ontogeny. Larvae were fed on rotifer Brachionus plicatilis from 2 to 26 DAH, Artemia nauplii from 10 to 64 DAH, and then gradually changed to pelleted feed from 40 DAH. Temperature was kept between $21.5{\sim}24.2^{\circ}C$ Activity of trypsin and lipase was found in larvae 4 DAH ($6.0{\pm}1.4unit$) and 6 DAH ($4.5{\pm}1.4unit$), respectively. The evolution of activity in both enzymes showed a profile marked by drastic increases between late larval and early juvenile stages. Pepsin-like enzyme activity was found at 10 DAH and drastically increased from 28 DAH, corresponding with the early juvenile stage of T. modestus. Interestingly, developmental changes in the pepsin-like enzyme activity coincided well with increases in the number of gastric glands. Amylase activity was found at 10 DAH and was maintained at a low level up to 28 DAH, followed by a drastic increase from 28 DAH to 40 DAH. It might be concluded that a drastic increase in trypsin and pepsin-like enzyme activities, and a corresponding increase in the number of gastric glands reflects a higher somatic growth of T. modestus during the early juvenile period.