碩士 / 國立屏東科技大學 / 水產養殖系所 / 101 / Cobia (Rachycentron canadum) is one of potential candidates for sea-cage culture species in Taiwan. Recently, due to the inbreeding depression of cobia, the quality of seeds is decreasing, including biological characteristics, deformity, growth rate, etc. We want to solve these problems by using selected breeding method to improve the quality of cobia seeds. In this study, the cobia outbred breeders are ready to propagate for increasing the genetic diversity and quality of seeds. In addition, we use the feeds which contain Estradiol (E2) and Methyltestosterone (MT) in different dose (2 mg kg-1, 10 mg kg-1) to control the sex of cobia. Results showed that the performances of outbred were better than inbred, including egg fertilization rate, hatching rate, egg diameter, yolk-sac larval deformity, 25 days post-hatched larval deformity, larval starvation and larval growth rate. From histological analysis, the gonadal sex differentiation time of cobia larvae is between 84 to 98 days post hatching (dph). Oral administration of sex steroids can promote cobia gonadal differentiation. The feminization rates of 2 mg and 10 mg estradiol are 79.3±6.1 % and 87.7±10 %, respectively. The masculinization of 2 mg and 10 mg methyltestosterone both are 75 %. In conclusion, the study show that outbred cobia progeny is better than inbred’s and sex steroids can control cobia gender effectively. These results will be applied to cobia aquaculture.
| Identifer | oai:union.ndltd.org:TW/101NPUS5086006 |
| Date | January 2013 |
| Creators | Hsiang-En Wu, 吳祥恩 |
| Contributors | Yan-Horn Lee, Mei-Chen Tseng, 李彥宏 博士, 曾美珍 博士 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 65 |
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