1989 Fiscal Year Final Research Report Summary
Study on Environmental Control for Prevention against Sudden Population Decrease in Mass Production of the Rotifer Brachionus plicatilis.
| Project/Area Number |
62860024
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| Research Category |
Grant-in-Aid for Developmental Scientific Research
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| Allocation Type | Single-year Grants |
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| Research Field |
General fisheries
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| Research Institution | FACULTY OF FISHERIES, NAGASAKI UNIVERSITY |
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Principal Investigator |
HIRAYAMA Kazutsugu FACULTY OF FISHERIES, NAGASAKI UNIVERSITY. PROFESSOR., 水産学部, 教授 (80039718)
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| Co-Investigator(Kenkyū-buntansha) |
MAEDA Masachika OCEAN INSTITUTE, UNIVERSITY OF TOKYO. ASSOCIATE., 海洋研究所, 助手 (40107454)
HINO Akinori FACULTY OF AGRICULTURE, UNIVERSITY OF TOKYO. ASSOCIATE PROFESSOR., 農学部, 助教授 (90012012)
IMADA Katsumi MARINE BIOTECHNOLOGY INSTITUTE Co. Ltd. VICE DIRECTOR., 副所長
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| Project Period (FY) |
1987 – 1989
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| Keywords | Detritus food chain / Vitamin producing bacteria / Baker's yeast / Brachionus plicatilis / Freshwater Chlorella / Protozoa / Control of bacteria flora / Seedling |
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| Research Abstract |
The rotifer Brachionus plicatilis was found to have requirements for vitamin C and cholesterol when evaluated using basic food suspension composed of baker's yeast and other essential vitamins. Two strains of marine yeasts were found to have higher food value for the rotifer than baker's yeast. Freshwater Chlorella enriched with vitamin B_<12> showed the food value which could match that of marine Chlorella. Stable mass production of the rotifer was achieved by the supply of the freshwater Chlorella enriched with vitamin B_<12>.
Bacteria in a rotifer pond are proved to be important as an energy source and a supplier of essential vitamins. On the contrary, the venomous bacteria were found in mass culture pond of the rotifer which introduce sudden mass mortality. The rotifer culture was improved to attain extremely high density when bacterial flora was controlled by adding some useful bacteria periodically to the pond.
Most of ciliated protozoa occurred in the culture water of the rotifer were identified as Uronema and Euplotes. These ciliates nurtured the certain bacterial flora, which repressed the growth of the rotifer. These ciliates could be removed by installing the substratum in the culture water of the rotifer where the protozoa tended to attach. Using Artemia at the growth stage of more than the 10th instar, protizoa were also removed by its feeding. The growth of flagellated protozoa which seriously fed on marine Chlorella could be repressed by adding NaCl at the final concentration more than 3 % in water.
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