The effects of long-term estradiol-17β treatment on the growth and physiology of female triploid brook trout (Salvelinus fontinalis)
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- 作者：Schafhauser-Smith ; D. ; Benfey ; T.J.
- 关键词：Estradiol-17β ; ; Gonadal development ; Hematocrit ; Hemoglobin ; Salmonid ; Testosterone ; Triploidy ; Vitellogenin
- 刊名：General and Comparative Endocrinology
- 出版年：2003
- 出版时间：March, 2003
- 年：2003
- 卷：131
- 期：1
- 页码：9-20
- 全文大小：445 K
文摘
Triploid female fish show impaired gonadal development, which results in the production of only a few oocytes relative to diploids. The rate of maturation of these few oocytes in much slower relative to those of diploids and is attributed to an insufficient estradiol-17β (E2) stimulus. Female triploid brook trout, aged 2+, were fed E2 for seven months (i.e., July 1998 to February 1999) in an attempt to increase plasma E2 comparable to diploid levels and thereby accelerate rates of oocyte growth. Compared to triploids fed a normal diet (i.e., control-triploids), the administration of 30mgE2/kg feed to triploids (i.e., E2-treated-triploids) led to the development of secondary sex characteristics, a significant reduction in hematocrit and total blood hemoglobin level, a decrease in plasma testosterone and no weight gain. Plasma vitellogenin was significantly higher in E2-treated-triploids than in control-triploids and diploids at every month except October 1999. Although greater than in the control-triploids, plasma E2 for the E2-treated-triploids did not attain the high levels shown by the diploids during the months of peak vitellogenesis (i.e., September and October). Following maturation and spawning of diploids, sacrificed E2-treated and control-triploids showed no differences in ovarian development or liver size. The E2 dose for the treated-triploids was increased to 80mgE2/kg feed for approximately seven more weeks in a further attempt to increase plasma E2, with no success. It is suggested that the low plasma E2 of the treated-triploids was the result of a high metabolic clearance rate.