• Journal of Aquaculture
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• v.18 no.2
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• pp.115-121
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• 2005

This study was performed to investigate the formation and mass production of resting eggs by freshwater rotifer, Brachionus calyciflorus as influenced by different aeration supplements and exchange intervals of culture water in 15-L culture vessels and 500 L culture tanks. The maximum densities and mixis rates of the rotifers were not different between experimental group exposed to air or oxygen supplements. However, the fertilization rate and formation of resting eggs of the rotifers in the air-supplemented group were significantly higher than those in the oxygen supplemented group. In the experiment concerning exchange interval of culture water, the maximum density of the rotifers and formation of resting eggs in the batch culture were significantly higher than those in the semi-continuous culture with exchange of water every day. The formation of resting eggs per Chlorella dry weight was highest in the semi-continuous culture with exchange of water every day. The resting eggs of rotifers were produced at a density of $51.8{\sim}57.9{\times}10^6$ eggs in 500-L culture tanks. In this study, the batch culture with air is an effective method for mass production of resting eggs by the freshwater rotifer, B. calyciflorus, and the efficiency of mass production of resting eggs by this rotifer was similar to that of the seawater rotifers, B. plicatilis and B. rotundiformis.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.6
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• pp.798-802
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• 1999

This study was performed to compare the effect of enrichement of rotifer and Artemia fed marine bacteria (Erythrobacter sp. S$\pi$-1) with those fed the different diets-(Super Selco, $\omega$-yeast and marine Chlorella) on the slime flounder larvae, Microstomus achne. Because the ratio of docosahexaenoic acid (DHA) to fatty acids in rotifer (dry weight $\%$) fed on Super Selco and ESP-SR including Erythrobacter sp. S$\pi$-1 was higher than that in rotifer fed marine Chlorella, the growth of the slime larvae fed the former showed better than the latter. And the ratio of DHA and highly unsaturated fatty acid (n-3 HUFA) to fatty acids in Artemia (dry weight $\%$) enriched by ESP-A including Erythrobacter sp. S$\pi$-1 were also higher than those in Artemia enriched by others or Artemia without enrichment. Larvae fed on Artemia enriched by ESP-A showed better growth and survival rate than those fed on Artemia enriched by others or Artemia without enrichment. With regard to dietary value of Erythrobacter sp. S$\pi$-1, its use could improve the quality of the live foods for the slime flounder larvae.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.3
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• pp.319-328
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• 1997

To develop a beneficial microbial feed for the cultivation of rotifer, Brachionus plicatilis, an aerobic photosynthetic bacterium, Erythrobacter sp. $S\;\pi-I$ was isolated from marine structure at Haeundae beach in Pusan, Korea. Feeding effects of Erythrobacter sp. $S\;\pi-I$ on the growth of rotifer were analyzed comparing to other feeds such as PSB (purple nonsulfur bacteria), Chlorella sp. and baker's yeast. Erythrobacter sp. $S\;\pi-I$ contained more linoleic acid $(C_{18:3\omega3})$ and oleic acid $(C_{18:1\omega9})$ and amino acids than PSB (purple nonsulfur bacteria), Chlorella sp. and baker's yeast. The rotifer fed on Erythrobacter sp. $S\;\pi-I$ showed better effects than those fed on other feeds in the individual growth, size and weight. Also, the rotifer especially contained more eicosapentaenoic acid $(C_{20:5\omega3})$ and docosahexaenoic acid $(C_{22:6\omega3})$ in case of Erythrobacter sp. $S\;\pi-I$ feeding than the other feeds. In case of the feed of PSB and baker's yeast docosahexaenoic acid $(C_{22:6\omega3})$ did not show. In amino acid analysis, the rotifer fed on Erthrobacter sp, $S\;\pi-I$ showed more amino acid content comparing to those fed on other diets. Especially, arginine, isoleucine, histidine, lysine, methionine, phenylalanine, threonine, which are essential amino acid for fish growth, showed high contents. These results suggested that the aerobic photosynthetic bacterium, Erythrobacter sp. $S\;\pi-I$ would be a beneficial microbial teed for the cultivation of rotifer.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.3
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• pp.225-229
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• 2000

This study was performed to investigate production and hatching rate of the resting egg of freshwater rotifer, Brachionus calyciflorus fed the 5 different diets (ESP, freshwater Chlorella, baker's yeast, the mixture off$70{\%}\;ESP\;and\;30{\%}$freshwater Chlorelia, and the mixture of $30{\%}$ baker's yeast and $70{\%}$ freshwater Chlorella). The highest productions of resting eggs were 123.3 egg/ml and 126.7 egg/ml in the mixture of $70{\%}$ ESP and $30{\%}$ freshwater Chlorella, and the mixture of $30{\%}$ baker's yeast and $30{\%}$ and $70{\%}$ freshwater Chlorella, respectively, which were significantly better than ESP, freshwater Chlorella or baker's yeast alone (P<0.05). Hatching rate of the resting eggs from rotifer fed the mixture of $70{\%} ESP\;and\;30{\%}$ freshwater Chlorella was the highest, $71.9{\%}$ although this value was not significantly different compared with the mixture of $30{\%}$ baker's yeast and $70{\%}$ freshwater Chlorella, and freshwater Chlorella (P^lt;9.05). The results showed that the mixture of baker's yeast or ESP with the freshwater Chlorella seemed to be the best feeding regime for the production and hatching rate of resting egg of freshwater rotifer.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.3
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• pp.351-358
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• 2016

The aim of this study was to verify the performance of Teleaulax amphioxeia as prey for Brachionus plicatilis and for the larvae of the bivalves (Pacific oyster Crassostrea gigas and Manila clam Ruditapes philippinarum) to select the best of five T. amphioxeia strains. The five strains of T. amphioxeia were collected from the coasts of Korea, purecultured and then fed to the rotifer and bivalve larvae. The density and fecundity rate of the rotifer fed on strain 01 were the highest. The instantaneous growth rate of the rotifer fed strain 08-2 was the highest. The maximum density and fecundity rate of the rotifer fed strain 08-2 were significantly higher than those fed Chlorella ellipsoidea, while instantaneous growth rate showed the opposite pattern. Survival rates of the Manila clam larvae fed each strain of Teleaulax showed no significant difference between strains. Survival rates of the Pacific oyster fed Teleaulax were significantly higher than those fed Chaetoceros sp., but lower than those fed I. galbana. This study indicates that strain 08-2 showed better growth for B. plicatilis and better survival for the bivalve larvae than did the other strains, and that T. amphioxeia can also be used as a prey organism for rotifers or bivalve larvae.

• Journal of Fisheries and Marine Sciences Education
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• v.28 no.2
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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 $0.05mg/10^4rotifers$.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.11
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• pp.682-687
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• 2018

This study investigated the food value of Paracyclopina nana for flounder Paralichthys olivaceus larvae in two feeding stages, rotifer (for 12 days) and Artemia (for 16 days). In the rotifer feeding stage, survival and growth of flounder larvae in the only P. nana (nauplii) feeding experiment were higher than in the only rotifer feeding experiment on 12 DAH (days after hatching). In the Artemia feeding stage, the growth of flounder larvae in the only P. nana (C4-adult) feeding experiment and mixture feeding experiment (P. nana+Artemia) were higher than in other experiments on 30 DAH, but the survival of flounder larvae did not differ significantly among experiments. The n-3 HUFA contents of nauplius and C4-adult were 4.0% and 5.4%, respectively. Overall the results of this study indicate that the brackish water cyclopoid copepod, P. nana, is an effective live food organism for larval seedling production of marine fish.

• Journal of Life Science
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• v.22 no.4
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• pp.486-491
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• 2012

Myostatin (MSTN), a member of the transforming growth factor (TGF)-beta family, is a potent negative regulator of skeletal muscle growth and maintenance. The MSTN prodomain inhibits MSTN biological activity. The rotifer Brachionus rotundiformis is an excellent primary live feed for fish larvae in aquaculture; however, it is not known whether the rotifer expresses MSTN and the MSTN prodomain along with its activity. The objective of this study was to examine the effects of recombinant MSTN prodomains. Individual cultures of the rotifer B. rotundiformis were carried out to determine the effect of recombinant MSTN prodomains (pMALc2x-poMSTNpro and pMALc2x-sMSTNpro) on the pre-reproductive phase, reproductive phase, post-reproductive phase, offspring, lifespan, fecundity, and male ratio. In addition, a population culture of the rotifer was performed to confirm the effects of pMALc2x-poMSTNpro and pMALc2x-sMSTNpro on population growth. The results showed that the rotifer treated with pMALc2x-pMSTNpro had a reduced pre-reproductive phase at higher concentrations (1, 2, and 4 ${\mu}g/ml$) compared to the non-treated control group. Moreover, the pMALc2xsMSTNpro treated rotifer effectively decreased the pre-reproductive phase at a lower concentration (0.25 ${\mu}g/ml$) compared to the pMALc2x-pMSTNpro treated and control group. Interestingly, pMALc2x-poMSTNpro and pMALc2x-sMSTNpro significantly increased the population of $B.$ $rotundiformis$.

• Journal of Aquaculture
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• v.21 no.1
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• pp.41-46
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• 2008

The purpose of the study was to suggest the optimal lipid enrichment conditions used digestive enzyme activity of rotifer changing due to water temperature and salinity. The high population growth appeared at the experiment temperature more than 28 degrees highly on the culture temperature(maximum 32 degrees, 1,453 individual/mL). The fecundity was low at high temperature, and the egg ratio was high at low temperature. Population growth of 10 and 15 ppt appeared in most highly, but the fecundity and the egg ratio were high most significantly appeared in natural seawater(32 psu). The digestive enzyme activity by the culture environment mainly showed high activity in natural seawater(amylase exclusion, 15 psu). However, the TAP activity by the water temperature showed highly at the more high temperature, but the amylase and the lipase appeared at low temperature. We carried out the lipid enrichment at 20 degrees and 26 degrees in a condition of the natural seawater. Total protein, the total essential amino acids differed not significantly. The methionine content that was essential amino acids, a total lipid content, unsaturated index of fatty acids, DHA and the DHA/EPA ratio were high significantly each in $20^{\circ}C$ enrichment trial. Therefore, we could suggest the $20^{\circ}C$ and natural seawater for the optimal lipid enrichment condition in aquaculture, because methionine contents, several indexes by the lipid, TG-lipase activity, fecundity and egg ratio are high.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.4
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• pp.692-697
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• 2016

This study examined the effects of salinity and medium used on the induction of sexual reproduction for the mass production of the resting eggs in the marine rotifer Brachionus rotundiformis for 9 days. After exposure to various salinities, the mixis rate in all treatments began to increase on the third day and decreased after the 4th or 5th day. The resting eggs appeared on the 4th day at 10‰, 15‰, 20‰, 25‰. In particular, the fertilization rates with 33.3% and 31.3% at 20‰ and 25‰ on day 6 were higher than those of the others, respectively. Mean mixis rate for 9 day at 0‰ and 20‰ were the highest with 25.3% and 20.2%, respectively, and the fertilization rate (14.0%) at 25‰ was the highest. In the medium experiment used, the mixis rate in all treatments were similar to the results of the salinity experiment. The resting eggs were only found at 0% and 25% of the used medium treatments. While there were no significant differences in the mean fertilization rate of all treatments, the mean mixis rate (22.3%) in the 25% treatment was higher than that of the control (0% treatment). As a result, salt stress was more effective than using the used medium to induce sexual reproduction in B. rotundiformis. The optimal salinity was considered to be 20-25‰, which caused a high mixis and fertilization rate in the rotifer. These results provide basic data for the mass production of rotifer resting eggs.