碩士 / 國立屏東科技大學 / 水產養殖系所 / 99 / Cobia, Rachycentron canadium, is one of the most potential sea-cage farmed fish species in Taiwan. Recently, we find that the disease resistance of cobia fingerlings is low, resulting in low survival rate. The possible reason is probably due to the inbreeding depression that cause cobia early-maturing and growing up slowly. We want to solve this problem by using selected breeding method to improve the growth performance and disease resistance of cobia fingerlings. The purpose of this study is aimed to improve the growth performance, feed conversion ratio and disease resistance of progeny by crossbreeding between wild-caught cobia and long-term cultured inbred line （hybrid group）and inbreeding long-term cultured inbred cobia （inbred group）. Results show that the performances of hybrid group are better than inbred. The egg fertilization rate, mean egg diameter, post-hatching larvae deformity and fingerling feed conversion ratio（FCR）of hybrid and inbred groups were 68%, 1,356 ± 44μm, 5.67 ± 4%, 1.03 and 21.9%, 1,296 ± 51μm, 17.67 ± 10%, 1.31, respectively. The performances of larvae starvation and hypoxia tolerance tests in hybrid group are also better. In addition, the hybrid line performed higher resistance to Photobacterium damselae subsp. Piscicida. than inbred line. In conclusion, the study show that the quality of seeds obtained from the hybrid group is better than inbred group.
| Identifer | oai:union.ndltd.org:TW/099NPUS5086001 |
| Date | January 2010 |
| Creators | Shau - Wen Laio, 廖紹文 |
| Contributors | Yan - Horn Lee, Shinn - Pyng Yen, 李彥宏, 葉信平 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 63 |
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