碩士 / 國立高雄海洋科技大學 / 水產養殖研究所 / 101 / In this study, various Weissella sp. strains isolated from fish gut were first tested their antimicrobial activity against the pathogen Streptococcus iniae by using the paper disk agar diffusion assay.The results showed that Weissella cibaria 981025mfic2, 981101spic2 and Weissella paramesenteroides 981213mfia1, 981213spi1 have higher antimicrobial activity. Therefore the four Weissella sp. strains were added into the feed to investigate their effects on the the growth, immune response and resistance against S. iniae in larvae and juvenile giant seaperch (Lates calcarifer) . After providing the feed containing 108 cfu g-1 of four Weissella sp. strains respectively for 14 days, we measured the growth rate of the giant seaperchlarvae and juveniles, evaluated the immune response of the giant seaperch juvenile, the survival rate of juvenile after intraperitoneal injection of S. iniae .The results showed that after 14 days feeding with Weissella sp. 981025mfic2, 981101spic2 containing feed, the growth rate of giant seaperch larvae feed was significant higher than the control growth (p <0.05). All the juveniles fed with Weissella sp. containing feed for 14 days had higher growth rate and the 981213spi1group especially had significant difference (p<0.05). The results of immune response evaluation demonstrated that the juvenile fed with Weissella sp. containing feed for 14 days had higher respiratory burst activity and lysozyme activity than those in the control group. For the respiratory burst activity assay, of the juvenile in 981213spi1 group had significant higher activity (p <0.05) and for the lysozyme activity assay, the juvenile in 981025mfic2 and 981213spi1 groups had significant differences (p <0.05). Seven days post intraperitoneal injection with S. iniae 103 CFU/fish, the experimental group 981025mfic2, 981101spic2, 981213mfia1 and 981213spi1 had higher survival rate, 50, 55, 55, 60% respectively, than the control group (40%). The results of bacterial count in the intestine of the experimental juvenile showed that after 14 days feeding with the Weissella sp. containing feed, the total number of bacteria in each experimental group were 4.61x105, 3.75x105, 7.30x106, 8.38x105 CFU/ml respectively and in the control group was7.79x105 CFU/ml. The lactic acid bacteria count using MRS agar in each experimental group were 4.12x104, 7.28x103, 5.73x104 CFU/ml and 4.64x104 CFU/ml respectively and no lactic acid bacteria was detected in the control group. However, the number of lactic acid bacteria in each experimental groups were gradually decreased after stopping Weissella sp. containing feed. Some giant seaperch juvenile didn’t contain lactic acid bacteria in the intestine after 4 or 5 days stopping Weissella sp. containing feed. In conculsion, feed containing W. cibaria (981025mfic2, 981101spic2) and W. paramesenteroides (981213mfia1, 981213spi1) can enhance the growth of Lates calcarifer larvae, and juveniles. Increase the respiratory burst and lysozyme activity in the juvenile and reducing the mortality after infected by S. iniae. However, these experimental bacteria cannot maintained in the intestine of giant seaperch for long time. It need to be supplemented with these intestinal lactic acid bacteria for maintaining a constant amount.
| Identifer | oai:union.ndltd.org:TW/101NKIM0086002 |
| Date | January 2013 |
| Creators | Cai,Min-Siou, 蔡旻修 |
| Contributors | Chang,Poh-Shing, 張朴性 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 92 |
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