碩士 / 國立海洋大學 / 水產養殖學系 / 90 / Abstract
Four experiments were conducted to investigate the effects of lipid levels and sources on the weight gain and the chemical compositions and fatty acid compositions of muscle and liver of cobia, Rachycentron canadum. Six isonitrogenous purified diets（35%C.P.）including defatted casein for protein source contained graded lipid levels, 0、3、6、9、12 and 15%, in the form of mixture of 2:1 cod liver oil/corn oil in experiment 1. Cobia fed diets containing 6、9、12 and 15% lipid had significantly higher weight gain than those fed the other diets. Survival of all treatments were 100%. Based on percentage weight gain data using broken-line analysis, the optimal dietary lipid for cobia was found to be approximately 9.63%. Using defatted fish meal as protein source, six isonitrogenous purified diets （33%C.P.）with graded lipid levels, 0、3、6、9、12 and 15% were conducted in experiment 2. Cobia fed diets containing 6、9、12 and 15% lipid had significantly higher weight gain than those fed the other diets. Survival of cobia fed treatment diets were 80~100%. Based on percentage weight gain data using broken-line analysis, the optimal dietary lipid for cobia was found to be approximately 7.96%. The lipid content of muscle and liver of cobia increase with increasing dietary lipid in experiment 1 and 2. The neutral lipid of muscle and liver of cobia contained high levels of 16:0、16:1 and 18:1n-9 in experiment 1 and 2. The neutral lipid of muscle of experiment 1 and 2 were 6.7∼7.0% and 7.0∼9.7% 20:5n-3, respectively. The major fatty acids of polar lipid muscle and liver of cobia were main 16:0、18:0、18:1n-9 and 22:6n-3. The 20:5n-3 level of muscle in experiment 1 and 2 were 3.0∼6.7% and 5.8∼9.5%, respectively. The level of 20:4n-6 of neutral and polar lipid of muscle and liver were low in experiment 1and 2.
Seven isonitrogenous purified diets（43% C.P.）using defatted fish meal as protein source supplemented with 6%, cod liver oil, beef tallow, corn oil, soybean oil, olive oil, sesame oil and linseed oil were conducted in experiment 3. The cobia fed diet containing cod liver oil had significantly higher weight gain than other the treatments. The cobia fed diet containing corn oil and sesame oil had significantly the lowest weight gain. Survival of all treatments were 87~100%.
The dietary formula of experiment 4 was the same with that of the experiment 3 except for the defatted fish meal. In this experiment, the cobia fed diet containing olive oil or cod liver oil had no significant in weight gain but had significantly higher than others. The cobia fed diet containing soybean oil, corm oil, sesame oil and linseed oil had the significantly the lowest weight gain. Survival of cobia fed treatment diets were 93~100%. The fatty acid compositions of muscle of cobia fed treatment diets were changed with the fatty acid profile of the lipid sources in experiment 3 and 4. The cobia fed diet containing cod liver oil contained high levels of 20:4n-6、20:5n-3 and 22:6n-3. The cobia fed diet containing beef tallow contained high levels of 16:0 and 18:0. The cobia fed diet containing corn oil、soybean oil and sesame oil contained high levels of 18:2n-6. The cobia fed diet containing olive oil contained high levels of 18:1n-9. The cobia fed diet containing linseed oil contained high levels of 18:3n-3.
| Identifer | oai:union.ndltd.org:TW/090NTOU0086023 |
| Date | January 2002 |
| Creators | 楊文福 |
| Contributors | 沈士新 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 110 |
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