| Project/Area Number |
12660171
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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 | HIROSHIMA UNIVERSITY |
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Principal Investigator |
NAKAI Toshihiro Hiroshima University, Faculty of Applied Biological Science, Associate Professor, 生物生産学部, 助教授 (60164117)
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| Co-Investigator(Kenkyū-buntansha) |
YOSHIDA Terutoyo Miyazaki University, Faculty of Agriculture, Associate Professor, 農学部, 助教授 (20240294)
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| Project Period (FY) |
2000 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2001: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 2000: ¥2,300,000 (Direct Cost: ¥2,300,000)
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| Keywords | Bacteriophage / Phage therapy / Biological control / Fish and shellfish / Bacterialdiseases / Ayu / Yellowtail / Oyster / 魚介類の細菌感染症 / 魚介類の細菌感染 / Pseudomonas plecoglossicida / Flavobacterium psychrophilum / Lactococcus garvieae / ファージ治療 / Plecoglossus altivelis |
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| Research Abstract |
Bacteriophages (phages) as specific pathogen-killers are expected as agents for controlling fish bacterial infections, but little attention has been paid for phage therapy and prophylaxis of bacterial infections of fish and shellfish. The present study was conducted to examine a possibility of phage-therapy in aquaculture and results are summarized as follows:
1. Lactococcus garvieae, the causative agent of streptococcal infection in cultured yellowtail Seriola quinqueradiata, consisted of a major phage type (phages : Siphoviridae). When experimentally infected fish with L. garvieae received intraperitoneally or orally administered anti-L. garvieae phages, fish showed significantly lower mortality compared with control fish without phage administrations
2. Pseudomonas plecoglossicida, the causative agent of bacterial hemorrhagic ascites in cultured ayu Pleooglossus altivelis consisted of a single phage type (phages : Myoviridae and Podoviridae). Oral administration of phage-impregnated feed to ayu increased resistance against experimental infection with P. plecoglossicida. When phage-therapy was evaluated under cohabitation conditions with fish which had been previously infected with P. plecogolssicida, phage-received fish showed significantly lower mortality than that of untreated control fish. Interestingly, phage-resistant variants of P. plecogolssicida exhibited no virulence to ayu. A field phage therapy reduced markedly mortalities of ayu due to P. plecogolssicida infection. Throughout the field therapy, neither phage-resistant P. plecogolssicida were detected from fish, nor phageneutrahzing antibodies were detected from fish.
3. Similar result was also obtained in phage-therapy experiments on Vibrio splendidus biovar II infection of larvae Japanese oyster Crassostrea gigas, though the phage type (phages : Podoviridae) of this pathogen was not single.
These results suggest that it may be possible to use phages to control the diseases in the aquaculture field.
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