碩士 / 東吳大學 / 微生物學系 / 98 / Laminarin is one kind of β-glucan. The non-specific immunity of aquatic animals could be enhanced by laminarin through conjugating wuth β-glucan-bind protein(BPG), such as the phagocytosis, prophenoloxidase (proPO) activity and the immunol genes expression in hemocytes of prawns. This study detected the immunol activity in hemocytes and investigated the change of bacterial flora in the hepatopancreas of Macrobrachium rosenbergii by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) after orally treated with laminarin. We anticipated to know whether a selective growth stimulation of indigenous bacterial changes in hepatopancreas is connected to the increasing defense ability of prawns by orally treated with laminarin. Prawns were treated with different concentrations (0, 20, 30, 40 μg/prawn) for 15 days. During experiment period, the shrimps’ conditions were observed on days 0, 3, 5, 10 and 15, both the raito of PO activities in hemocytes and the change of the bacterial flora in hepatopancreas observed in PCR-DGGE by two primers (V3 and V1~V3) designed from 16S rDNA were detected at the same time.
Except the dead prawns in 30μg-treated group were found on day 10, prawns in control group (without feeding) and two other groups(20μg and 40μg-treated groups) either died or infected with muscle necrosis on day 5. According to the ratios of PO activities in hemocytes detected during experiment period, the ratios of day 10 (0.53, 0.61, 0.58) were all higher than those on day 5 (0.15, 0.25, 0.31) for 1.8 to 3.5 times, which belong to control group, 20μg and 40μg -treated groups respectively. On the other hands, the ratios of PO activities was increased steadily after treatment, and the ratio on day 10 (0.40) was 1.1 time to day 5 (0.35).
The effects of bacterial flora in hepatopancreas after orally treating with laminarin at the same day but different concentrations were analyzed by PCR-DGGE with the SPSS and the Phoretix 1D software. The results showed that the change tendency of bacterial flora resulted from V3 and V1~V3 were similar, and the change of bacterial flora was most obviously in 30μg-treated group. The 55 bands collected from both DGGE samples by two primers of 30μg-treated group were sequenced. Similar results were analyzed from both samples. They were belonged to 8 genus, including Aerococcus, Enterococcus, Mesoplasma, Lactobacillus, Klebsiella , Cronobacer. Deinococcus, and Macrococcus. Lactobacillus plantarum was appeared in the hepatopancreas of prawns after treating with laminarin accompanied the disappearance of Enterococcus sp., Enterococcus faecalis and Citrobacter freundii. Along with the laminarin feeding time increase, the bacterial speciece diversity (H') drop gradually from 2.5 to 1.7 in hepatopancreas of prawns.
Analyzed with the survival of prawns, the ratios of PO activities and the change of bacterial flora in hepatopancreas, the ratios of PO activities of prawns could be enhanced steadily by orally treated with laminarin in 10 days. There was a relationship between the delayed of infection and death of prawns, and the disappearance of the opportunity pathogens (Enterococcus sp. and Citrobacter freundii) in hepatopancreas on day 3.
| Identifer | oai:union.ndltd.org:TW/098SCU05381004 |
| Date | January 2010 |
| Creators | Dong-jong Liu, 呂東榮 |
| Contributors | Hung-hung Sung, 宋宏紅 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 126 |
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