碩士 / 國立臺灣海洋大學 / 水產養殖學系 / 99 / Color is one of the price-determining factors for red striped snapper (Lutjanus erythropterus♀ x L. sebae♂). Carotenoid is the main pigment source in aquatic animals. Since fish cannot synthesize carotenoid de novo, they must rely on food supply to achieve the pigmentation. This study conducted two experiments. The first one studied the effects of various dietary sources of astaxanthin on the survival, growth, body astaxanthin content and antioxidant capacity of the fish. Two natural astaxanthin: red yeast Phaffia rhodozyma and red bacteria Paracoccus carotinifaciens and a synthetic astaxanthin were added to the diet at astaxanthin concentration of 100 mg/kg. Control diet did not add astaxanthin. Each diet was fed to 3 tanks of fish (stocking density 10 fish/200L, mean size 14.05 ± 0.51g) for 10 weeks. Overall mean weight gain was 71%. Treatments had no effect on growth. Treatments with natural astaxanthin added had a higher survival rate (86%) than the control group (67%). Based on total body astaxanthin content, red yeast had the best pigmentation, followed by red bacteria and synthetic astaxanthin. Control fish had the poorest pigmentation. Regardless of the source of astaxanthin, the fish stored mainly diester form astaxanthin on its skin. In terms of antioxidant capacity, fish in astaxanthin added groups had lower superoxide dismutase (SOD) activity and higher Glutathioine peroxidase (GPx) activity than fish in control group. There was no difference found in the antioxidant capacity among the astaxanthin added groups. The second experiment studied the effect of different sources of astaxanthin and background lightness on fish coloration. Diets used were the same as those in the first experiment. Background colors were black and white. Fish were transferred from rearing tank of orange color to black or white aquarium for two hours and then taken pictures. The pictures went through Digital Image Acquisition Processing technique to quantify the coloration parameters. Fish in astaxanthin added groups had better performance in skin coloration than control fish as indicated by redness, yellowness, chroma, hue and Entire Color Index, but not lightness. Among the three sources of astaxanthin, red yeast had the best performance in coloration, followed by red bacteria and synthetic astaxanthin. Fish exposed to white background had higher skin lightness than black background fish. Other than this, background lightness had no effects on coloration. Overall, the dietary astaxanthin can effectively improve the survival rate of red striped snapper, antioxidant capacity, enhance the skin color, and the background lightness can affect skin lightness. These findings can be relevant to color enhancement and concomitantly, price of the fish.
| Identifer | oai:union.ndltd.org:TW/099NTOU5086035 |
| Date | January 2011 |
| Creators | Yi-Jie Huang, 黃義傑 |
| Contributors | Yew-Hu CHien, 陳瑤湖 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 99 |
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