2003 Fiscal Year Final Research Report Summary
Studies on control of the microbial communities on the surface of the biological filter system for prevention of diseases of fish in aquaculture.
| Project/Area Number |
14560165
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
General fisheries
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| Research Institution | University of Miyazaki |
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Principal Investigator |
MAEDA Masachika Univ. Miyazaki, Faculty of Agriculture, Professor, 農学部, 教授 (10343782)
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| Co-Investigator(Kenkyū-buntansha) |
YOSHIDA Terutoyo Univ. Miyazaki, Faculty of Agriculture, Associate Professor, 農学部, 助教授 (20240294)
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| Project Period (FY) |
2002 – 2003
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| Keywords | Biological control / Virucidal bacteria / Vibrio-static bacteria / Disease prevention / Aquaculture / Risks on the table / 無投薬養殖 / 安全、安心養殖魚 |
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| Research Abstract |
The occurrence of bacteria which repressed the grown of Vibrio anguillarum and Edwardsiella tarda and also Infectious Haematopoietic Necrosis Virus at the same time was investigated in aquaculture water where spotted parrotfish, flat fish and eel were reared in the closed circulation water system, respectively.
Bacteria were collected from the surface of the glass slides which were set in aquaculture water for 5 days, and also from the surface of the substrate of the bio-filter system which was set for the removal of suspended matter of water and also the purification of water. The bacterial numbers on the glass slide increase from 1 × 10^4 cells/cm^2 and 3.5 × 10^5 cells/cm^2 on the first day to 1.2 × 10^6 cells/cm^2 and 3 × 10^6 cells/cm^2 on the fifth day by the methods of plate count and microscopically direct count, respectively, in water rearing spotted parrotfish. Bacterial numbers in water rearing spotted parrotfish fluctuated between 6 × 10^4cells/ml and 2 × 10^5cells/ml by the plate count, and between 1.2 × 10^6 cells/ml and 2.2× 10^6 cells/cm^2 the direct count, respectively
Among 22 bacteria isolated from the surface of bio-filter substrates and water, 13 strains were showed the vibrio-static activities in which Pseudomonas spp. and Vibrio spp., although based on the tentative identification, expressed the higher activity than other isolates. Among these vibrio-static microbes, only 2 strains repressed the growth of Edwardsiella tarda.
The bacterial strains which showed the strong vibrio-static activity also possessed the anti-viral activities in which three strains had high repressive activities against viral growth in the fish cell culture.
When several viruses were infected to the above fish, the survival of fish was much higher when the artificial feeds containing the above useful bacteria were adopted than using the feeds without bacteria.
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Research Products
(6 results)
