• 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.36 no.6
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• pp.606-613
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• 2003

This study investigated the effects of food type (condensed freshwater Chlorella, dried Chlorella, dried Spirulina, dried Schizochytrium, baker's yeast and $\omega-yeast$) and amount, and supplementation of vitamin $B_{12}$ on the growth of freshwater rotifer (Brachionus calyciflorus) in high density culture. Growth of rotifers fed condensed freshwater Chlorella was the highest and its density ranged $7.65-8.14{\times}10^3\;inds./mL.$ The primary lipid acids of rotifers fed condensed freshwater Chloyella were linoleic and linolenic, and their amount ($\%$ of total fatty acids) were $48.8\%\;and\;26.8\%,$ respectively. This suggests that condensed freshwater Chlorella would be an effective diet for high quality and quantity rotifers, which in turn serve as live food for freshwater fish larvae. Growth rate of rotifers with Chlorella supplementation increased as amount of supplementation increased up to 1.5 and 2.5 mg at 28 and $32^{\circ}C$, respectively. However, undissolved ammonia toxicity and packing volume of Chlorella in culture medium, reached the optimal conditions for the stable and effective cultivation of rotifers when amount of condensed freshwater Chlorella was 1.5 mg in dry weight per 1,000 rotifers at $28^{\circ}C\;and\;32^{\circ}C$ Growth of rotifers in condensed freshwater Chlorella with vitamin $B_{12}$ supplementation was significantly higher than that of rotifers without supplementation. However, no significant difference was found among the different concentrations of vitamin $B_{12}.$ Therefore, vitamin $B_{12}$ could improve the growth of rotifers (B. calyciflorus).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.3
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• pp.280-283
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• 1999

The experiment was carried out in a 10 $\ell$ vessel in order to evaluate the growth and nutritional quality of rotifer, Brachienus rotundiformis fed by different diets (Freshwater Chlorella, Marine Chlorella and $\omega$-yeast) for the high density cultivation. The maximum densities for the rotifer fed on the marine Chlorella, freshwater Chlorella and $\omega$-yeast were $10,900\~12,400,\;9,190\~10,600$ and 2,390$\~$2,750 inds./ml, respectively. Therefore, the maximum densities for the rotifer fed on the marine Chlorella and freshwater Chlorella were higher than that for rotifer fed on the $\omega$-yeast The essential n-3 highly unsaturated fatty acid in rotifer fed on the marine Chlorella was $8.71\%$ which was slightly lower than that in rotifer fed on the $\omega$-yeast, $9.14\%$, while it was higher than that in the rotifer fed on freshwater Chlorella, $4.45\%$. This result indicated that marine Chlorella could be appropriate diet for the high density cultivation of rotifer.

• Journal of Aquaculture
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• v.1 no.2
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• pp.135-143
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• 1988

Rotifers became an important live food for fish larvae, especially for marine fishes, and Chlorella has been used as a very useful food for the mass culture of rotifer. However, not many tests for suitable Chorella species for the mass culture of rotifer were done and many of Chlorella sp. have been used without consideration of species for this purpose. There-fore, two species of marine Chlorella and four species of freshwater Chlorella were tested to select suitable species for the mass culture of a rotifer, Brachionus plicatilis. These Chlorella species were cultured in five different culture media; f/2, Erdschreiber, Complesal for marine species and S$\cdot$K, Wai and Complesal for freshwater species. Proximate analyses were done to see the protein, lipid and ash contents of a marine species, C. ellipsoidea and a freshwater species, C. vulgaris. Amino acids content of these species were also tested. C. ellipsoidea and C. vulgaris showed better growth than the other species. For marine Chlorella sp., f/2 media was better than Erdschreiber and Complesal. But for the freshwater species, Complesal showed the best result in growth. By the proximate analyses, C. ellipsoidea has higher lipid contents whereas C. vulgaris has higher protein and ash. In the analysis of amino acid of Chlorella, it was remarkable that freshwater Chlorella, C. vulgaris, has high content of $NH_3$ comparing with marine Chlorella, C, ellipsoidea. According to the above results, C. vulgaris seems have higher possibilities for mass culture of rotifer but further studies are needed.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.2
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• pp.93-97
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• 2000

This study was carried out to investigate the effect of rotifer fed the different diets in high density culture on larval flounder Paralichthys olivaceus. Potifer was enriched with enrichment supplements, Marine ${\alpha}\;and\;{\omega}-yeast$ for 6 hours after being cultured with freshwater Chlorella for 18 hours during high density culture before it was fed to larval flounder. And rotifer was culutured with marine Chlorella and freshwater Chlorella for 24 hours during semi-continuous high density culture before it was fed to larval flounder. Culture tanks(21 working volum) set for rotifer culture in a water bath($28{\circ}C$) were continuously supplied with oxygen gas. The content of n-3 HUFA to fatty acids in rotifer(dry weight ${\%}$) enriched with Marine ${\alpha}$ for 6 hours and cultures with marine Chlorella for 24 hours were higher than that in rotifer enriched with ${\omega}-yeast$ for 6 hours or cultured with freshwater Chlorella for 24 hours. The growth and survival rates of larval flounder fed on rotifer enriched with Marine ${\alpha}$ for 6 hours and cultured with marine Chlorella for 24 hours were higher than those of larval flounder fed on rotifer enriched with ${\omega}-yeast$ for 6 hours or cultured with freshwater Chlorella for 24 hours. And the content of n-3 HUFA of larval flounder fed on rotifer enriched with Marine ${\alpha}$ for 6 hours was higher than that of larval flounder fed on other rotifers, The results from this study indicated that rotifer culture with marine Chiorelia would be suitable for the high density culture and effective diet for the growth of larval flounder.

• Journal of Environmental Science International
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• v.24 no.12
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• pp.1591-1600
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• 2015

The response of the freshwater microalga, Chlorella vulgaris, to heavy metal stress was examined based on chlorophyll fluorescence analysis to assess the toxic effects of heavy metals in freshwater ecosystems. When toxic effects were analyzed using regular chlorophyll fluorescence analysis, photosystem II activity($F_v/F_m$) decreased significantly when exposed to $Cu^{2+}$ and $Hg^{2+}$ for 12 h, and decreased in the order of $Hg^{2+}>Cu^{2+}>Cd^{2+}>Ni^{2+}$ when exposed for 24h. The effective photochemical quantum yield(${\phi}{\prime}_{PSII}$), chlorophyll fluorescence decrease ratio($R_{Fd}$), minimal fluorescence yield($F_o$), and non-photochemical quenching(NPQ), but not photochemical quenching(qP), responded sensitively to $Hg^{2+}$, $Cu^{2+}$, and $Cd^{2+}$. These results suggest that $F_v/F_m$, as well as ${\phi}{\prime}_{PSII}$, $R_{Fd}$, $F_o$, and NPQ could be used to assess the effects of heavy metal ions in freshwater ecosystems. However, because many types of heavy metal ions and toxic compounds co-occur under natural conditions, it is difficult to assess heavy metal toxicity in freshwater ecosystems. When Chlorella was exposed to heavy metal ions for 12 or 24h, $F_v/F_m$ and maximal fluorescence yield($F_m$) changed in response to $Hg^{2+}$ and $Cu^{2+}$ based on image analysis. However, assessing quantitatively the toxic effects of several heavy metal ions is challenging.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.37 no.1
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• pp.7-12
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• 2004

This study investigated the possibility of salinity acclimation of freshwater rotifers (Brachionus calyciflorus) as live food for sweetfish (Plecoglossus altivelis) larvae, and also examined the optimal salinity for the growth of sweetfish. Freshwater rotifers cultured in 0 and 4 PSU and seawater rotifers (B. rotundiformis) cultured in 33 PSU were supplied to the larvae with four kinds of enrichment material (condensed freshwater Chlorella, $\omega-yeast,$ baker's yeast, Super Selco) and larval growth at 4 PSU was examined. Growth of the freshwater rotifers positively increased from 0 PSU to 6 PSU, but decreased when over 8 PSU was reached. Growth and survival of the sweet fish larvae reared in 0 PSU were significantly lower than those reared in either 4 PSU or 33 PSU. This indicated that the freshwater rotifers (B. calyciflorus) could be used as live food for sweetfish larvae reared in 4 PSU. The body weight of sweetfish larvae fed on freshwater rotifers enriched with Super Selco was the highest at 0.163 mg, but there was no significant difference in survival and body length of the fish fed with the other enrichment materials. The content of n-3 HUFA of the sweetfish larvae fed on the freshwater rotifers enriched with Super Selco and the condensed freshwater Chlorella was higher than that enriched with $\omega-yeast$ and baker's yeast. These results indicated that B. calyciflorus cultured with the condensed freshwater Chlorella could be used for the sweetfish larvae without enrichment, and the most efficient enrichment material for B. calyciflorus is Super Selco.

• Journal of Aquaculture
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• v.13 no.2
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• pp.147-152
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• 2000

To reduce the production cost of the rotifer, different combinations of Chlorella and Baker's yeast were used to mass culture of Brachionus calyciflorus. Rotifer density tended to decrease abruptly at 100% Chlorella-feeding, when unionized ammonia level ranged from 14.1 to 29.6 ppm and DO level from 0.2 to 0.3 ppm. Hence DO level > 0.3 ppm and unionized ammonia level < 14 ppm should be maintained. Production cost of the rotifer was the highest, when a combination of 100 % Chlorella was chosen as food source, but it was about 1.8 times less, when a combination of 70 % Chlorella and 30% yeast was used as food source. However, the highest rotifer density remained almost at the same level, when either of the combination was chosen as food source. A combination of 70 % Chlorella and 30 % yeast is recommended for maximum production of the rotifer at the lowest feed cost.

• The Plant Pathology Journal
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• v.34 no.6
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• pp.567-574
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• 2018

This study was conducted to investigate the efficacy of freshwater alga, Chlorella fusca on the improvement of growth and qualities in organic spinach and Chinese chives farm. The average height of Chinese chives treated with the chlorella was 3.7 cm smaller than that of the untreated. The leaf width and fresh weight of Chinese chives treated with the chlorella was 0.5 mm wider and 30.3 g heavier than that of the untreated. The commercialization and yield of Chinese chives treated with the chlorella was 11.9% and 18.3%, respectively higher than that of the untreated. Also, the disease severity of gray mold disease of Chinese chives treated with the chlorella was reduced by more than 24.2% when compared with the untreated. The thickness and number of spinach leaves treated with chlorella was 27.9% and 41.8%, respectively higher than that of the untreated. The fresh weight and yield of the spinach treated with the chlorella was 63.6% and 31.5%, respectively higher than that of the untreated. Moreover, the mineral content of K, Ca, Mg, P, Fe, and Mn were recorded higher in the spinach treated with chlorella compared with that of untreated. The results indicated that the freshwater alga, Chlorella fusca is efficient and economical biostimulant in improving plant growth and quality of Chinese chives and spinach in organic farm.

• 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 $D.$ $celebensis$.