碩士 / 國立臺灣海洋大學 / 水產養殖學系 / 107 / White shrimp Litopenaeus vannamei, which natives to Central and South America region on the eastern coast of Pacific Ocean, has characteristics of rapid growth, strong disease resistance, high feed conversion rate, wide salt tolerance and relatively low farming threshold. The shrimp is one of an important global aquaculture species nowadays. In the past two decades, due to combination factors such as intensive farming, improper management of culture environment and antibiotics abuse, the shrimp aquaculture industry has been severely persecuted by pathogenic bacteria and viruses, resulting in a significant reduction in white shrimp production and a huge economic loss. In order to improve disease resistance of white shrimp, many studies of feed additives were developed to enhance the immune function of shrimp. Algae have been proven to have significant effects in promoting immunity and has great potential for development. The objective of this study is to investigate the effects of polysaccharides from native species of Caulerpa racemosa in Taiwan on non-specific immunity of white shrimp, and find out the best dosage of C. racemosa polysaccharides on shrimp diet, expecting to effectively enhance the immunity of white shrimp and industrial competitiveness.
C. racemosa is a seaweed that distributed widely in the ocean of subtropics and could be seen all year round in Hengchun Peninsula, Siao Liouciou, Penghu and the tidal zone reef in the northeast corner of Taiwan. The algae were taken from a commercial farm in Fangliao, Pingtung, Taiwan. After obtaining a large amount of fresh algae, the algae were extracted with hot water and then precipitated in alcohol to acquire algal polysaccharide crude extract. The extract was analyzed the polysaccharides composition, antioxidant activity and antioxidant content of algal polysaccharides. After mastering the initial antioxidant composition of algal polysaccharides, the test further co-cultured C. racemosa polysaccharides with white shrimp haemocytes to examine its MTS cell survival and in vitro immunity. The test was followed by adding the algal polysaccharides to the feed and feeding shrimp for 28 days to observe the effects of polysaccharides on the cellular immunity and antioxidant capacity of the white shrimp.
The results indicated that the reducing power, 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activity and 2,2’-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS+) scavenging activity of C. racemosa polysaccharides were IC50 = 44.76 ± 0.04 mg ml-1, IC50 = 12.22 ± 0.03 mg ml-1 and IC50 = 7.95 ± 0.03 mg ml-1, respectively. The polysaccharides composition was analyzed, it was found that there were three kinds of monosaccharide components, namely galactose, glucose and mannose. The proportions in the algal polysaccharides were 41.2, 30.5 and 28.3%, respectively. In the test of in vitro non-specific immunity of white shrimp haemocytes by C. racemosa polysaccharides, the production of superoxide anion (O2-) treated with 0.5, 1, 5, 10, 15, 20 mg ml-1 were 49.47 ± 1.32, 59.24 ± 2.51, 75.38 ± 5.98, 81.12 ± 3.93, 86.74 ± 3.27 and 79.53 ± 5.32 %, respectively, and were significantly different from the control group (p<0.05). Phenoloxidase activity (PO) treated with 5, 10, 15 and 20 mg ml-1 were 0.338 ± 0.017, 0.398 ± 0.071, 0.424 ± 0.029 and 0.374 ± 0.021, respectively, and significantly different from control group (p<0.05). Phagocytic rate (PR) treated with 5,15 and 20 mg ml-1 were 41.61 ± 3.89, 42.21 ± 2.34 and 46.15 ± 3.04 %, respectively, and were significantly different from control group (p<0.05).
In the test of dietary C. racemosa polysaccharides of white shrimp, at the dosage of 6 g kg-1, the production of O2-, PO, PR and phagocytic index (PI) were significantly increased (p＜0.05). The highest value was 108.81 ± 6.58 %, 0.287 ± 0.29, 50.86 ± 6.44 %, 1.5 ± 0.0981, respectively. In addition, at the dosage of 10 g kg-1, lipid peroxidation was 44.77 ± 3.81 nmol mg-1, which was significantly decreased (p＜0.05).
| Identifer | oai:union.ndltd.org:TW/107NTOU5086029 |
| Date | January 2019 |
| Creators | Ho, Yi-Tien, 何宜恬 |
| Contributors | Nan, Fan-Hua, Lee, Meng-Jou, 冉繁華, 李孟洲 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 83 |
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