https://scholars.lib.ntu.edu.tw/handle/123456789/142563
Title: | The profiles of serum estradiol-17β and testosterone levels during silvering of the wild Japanese eel Anguilla japonica | Authors: | Han YS Liao IC Tzeng WN Huang YS Yu JYL |
Keywords: | Japanese eel Anguilla japonica, silvering, sex steroid, estradiol-17β, testosterone, gonadal development, morphology, radioimmunoassay | Issue Date: | 2003 | Journal Issue: | 4 | Start page/Pages: | 911-918 | Source: | Comparative Biochemistry and Physiology A | Abstract: | To understand the changes of serum levels of sex steroids in the wild Japanese eel Anguilla japonica during silvering process, eels collected from the Kaoping River of Taiwan from Aug 2000 through Jun 2001 were examined. The maturational stages of the female eels before and during silvering were divided into four stages: juvenile, sub-adult, pre-silver and silver stages based on skin coloration and oocyte diameter. The male eels were investigated only in the silver stage. Radioimmunoassays were employed to measure serum levels of estradiol-17β (E2) and testosterone (T). The mean liver weight of the female eels increased significantly during silvering, but the mean hepatosomatic index remained rather constant. On the contrast, both mean ovarian weight and gonadosomatic index increased significantly during silvering process. The mean serum concentrations of E2 in the females increased significantly during silvering (p < 0.05). The serum E2 levels were undetectable in silver males. The mean serum T concentrations increased significantly in females (p < 0.05) during silvering, with lowest mean values in the juvenile stage and highest mean value in the silver stage. The mean serum T level in the silver males was significantly lower than the silver females (p < 0.05). In conclusion, both serum E2 and T concentrations increased with ovarian development of the wild Japanese eels during silvering, while serum E2 was undetectable in the silver male eels. The findings support that androgen, but not estrogen, is likely an important factor for silvering process of the eels in both sexes. |
URI: | http://ntur.lib.ntu.edu.tw//handle/246246/64344 |
Appears in Collections: | 漁業科學研究所 |
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