碩士 / 國立海洋大學 / 水產養殖學系 / 91 / This study investigated and screened the inhibitory effects of extracts from Rhei rhizome, Scutellaria baicalensis, Gintiana scabra, Paeonia suffruticosa and Macrocarpinm officinale against pathogenic bacteria isolated from diseased fish and shellfish. From the results of in vitro tests, the application of Rhei rhizome (rhubarb) exhibited higher inhibitory effects against all the 11 strains of bacteria tested including Aeromonas hydrophila (2 strains), Vibrio harveyi (2 strains), V. alginolyticus (4 strains), V. carchariae (2 strains) and Photobacterium damselae subsp. piscicida (1 strain) than the other 4 Chinese medicines. Therefore, the differences of inhibition against V. harveyi from extraction of Rhei rhizome at room temperature or by heating in water, minimum inhibitory concentration and separation of inhibitory components were further studied. Different amount of the crude rhubarb was added in feeds and fed the white shrimp by different methods. The white shrimps were then challenged with lethal dosage of V. harveyi. The NBT (superoxide anion radical) and pro-PO activities (prophenoloxi- dase system) in hemolymph were tested together with the measurements of protein concentration for plasma and coagulogen. Appropriate amount of the crude rhubarb and feeding recipe were tried to find the control measure for V. harveyi infection in white shrimp.
Crude rhubarb exhibited lowest inhibitory concentration than the others extracted by solvent with MIC values ranging from 5 to 20 mg/ml. The inhibitory effects of extracts obtained at room temperature were better than that obtained by heating and methanol was the best solvent for extraction with MIC values ranging from 6.25 to 50 mg/ml. Thin-layer chromatogra- phy was used to screen suitable solvent system for the separation of anti- bacterial components. The use of both acetone : chloroform (15:30) and hexanes : ethylacetate (30:20) solvent systems could separate antibacterial components comparable to the standards of aloe-emodin, emodin and rhein.
The growth rates of white shrimp fed with food containing crude rhubarb ranging from 50 to 500 mg/kg were not affected. Of that, the shrimp fed with food containing 100 mg/kg crude rhubarb for one week survived against lethal challenge of V. harveyi at a dose of 2×106cfu/g body weight. The interrupted form of feeding was better than continued form in the shrimp fed with food containing 100 mg/kg crude rhubarb against the bacterial challenge. The NBT and pro-PO activities in hemolymph and protein concentrations for plasma and cogulogen of the shrimp fed with food containing 100 and 200 mg/kg crude rhubarb were higher than that of the other groups.
The results reveal that crude rhubarb can inhibit the growth of patho- genic bacteria from fish and shellfish. The addition of appropriate amount of crude rhubarb (100 mg/kg feed) in feed can protect the shrimp against lethal challenge of V. harveyi in a short period. Hence, crud rhubarb is suggested to be a promising fishery drug and is worthy of further investi- gation.
| Identifer | oai:union.ndltd.org:TW/091NTOU0086040 |
| Date | January 2003 |
| Creators | ChunRu Yang, 楊淳如 |
| Contributors | Lee, Kuo-kau, 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 | 0 |
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