碩士 / 國立臺灣海洋大學 / 水產養殖學系 / 95 / This thesis investigated the histopatholgy of Japanese eel （Anguilla japonica） injected by Aeromonas hydrophila and Edwardsiella tarda . After challenge with A. hydrophila, the moribund eels manifested redden abdomen or local pin-prick haemorrhages on body surface, protruded haemorrhaged anus. Some moribune eels exhibited abnormal dark green area on the abdomen site near liver which, if slightly pressed, emitted yellow-green fluid. Internally, enlarged liver, empty gut, congested intestine filling with yellow-green fluid were observed. After challenge with extracellular products（ECP）of A. hydrophila, the moribund eels exhibited redden abdomen and anus characterized by the presence of pin-prick haemorrhages, exophthalmia with bloodshot. Some moribund eels manifested ulcers on the injection site.
Histopathological observation revealed that all the moribund eels exhibited necrotic lesions in the liver, withering necrosis of renal tubules in the kidney, necrosis of splenic tissue developed into hollow cavity after bacterial challenge. All the essences of kidney, spleen and liver filled with bacterial cells. Similar histopathological observations were found in moribund eels after injection of ECP or those challenged with bacteria except the presence of bacterial cells in relative.
External signs of moribund eels challenged with bacterial cells of E. tarda were protruded anus, haemorrhaged abdomen fins and pim-prick haemorrhgaes near the base of pectoral fins. Internal examination revealed that the presence of swollen kidney and empty gut were the only two evident signs. No evident sign was observed externally or internally in moribund eels after injecting with ECP of E. tarda. Histopathological changes of moribund eels challenged with E. tarda on its ECP were similar with those challenged with A. hydrophila on its ECP.
Japanese eels were challenged with a same dose of A. hydrophila and E. tarda ( 106 CFU/g fish body weight), deathes were observed on the second and third day after challenge with A. hydrophila and E. tarda, respectively. The elevation of temperature could increase mortality rate in both bacterial challenge in Japanese eels. The results revealed that the ECP of A. hydrophila was more virulent than ECP of E. tarda in Japanese eels. Leading to presence of evident external and internal clinical signs.
| Identifer | oai:union.ndltd.org:TW/095NTOU5086051 |
| Date | January 2007 |
| Creators | Hsiao-Fang Nien, 粘曉芳 |
| Contributors | Kuo -Kau Lee, 李國誥 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 74 |
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