2005 Fiscal Year Final Research Report Summary
Effects of dietary free radicals on the pathology and bio-defensive functions in fishes
| Project/Area Number |
15380135
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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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 | Nagasaki University |
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Principal Investigator |
YOSHIKOSHI Kazuma Nagasaki University, Faculty of Fisheries, Professor, 水産学部, 教授 (00039728)
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| Co-Investigator(Kenkyū-buntansha) |
KANAI Kinya Nagasaki University, Faculty of Fisheries, Professor, 水産学部, 教授 (40145222)
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| Project Period (FY) |
2003 – 2005
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| Keywords | juvenile kelp grouper / juvenile striped jack / young yellowtail / lipid peroxides / digestive organ / pathology / bio-defensive functions / feeding rate |
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| Research Abstract |
Effects of dietary free radicals on the pathology and defense functions of fishes were examined using juvenile kelp grouper, juvenile striped jack and young yellowtail. Major results obtained are as follows.
(1) Satiation feeding of a commercially-sold dry pellet feed caused marked decrease of ingestion rate in kelp grouper, while no appreciable decrease of ingestion rate was found in striped jack and yellowtail.
(2) Satiation feeding of a commercially-sold dry pellet feed caused the depression of growth and mortality in kelp grouper, while no appreciable change in growth and mortality was found in striped jack and yellowtail.
(3) Light and electron microscopy revealed that oral administration of oxidized oil (methyl linoleate) injured the cell membrane and membranous organelles of the hepatocytes and enterocytes in yellowtail and resulted in necrosis of these cells.
(4) Oral administration of oxidized oil (methyl linoleate) with dry pellet feed decreased agglutination titers and bactericidal activity in the neutrophils of yellowtail at a concentration that no growth depression was observed.
These results suggest that dietary free radicals are closely associated with pathogenesis in fishes by injuring the digestive and other organs and decreasing bio-defensive functions. It was also suggested that commercially-sold dry pellet feed containing lipid peroxides might decrease bio-defensive functions and causes mortality at higher feeding rates.
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