Aromatase inhibitor induces sex reversal in the protogynous hermaphroditic rice field eel (Monopterus albus)
Aromatase inhibitor induces sex reversal in the protogynous hermaphroditic rice field eel (Monopterus albus)
复制标题
芳香酶抑制剂诱导先熟雌雄同体稻田鳗鱼（Monopterus albus）的性逆转
DOI：
10.1016/j.aquaculture.2022.737960
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发表时间：
2022-01-29
期刊：
影响因子：
4.5
通讯作者：
Hu, Wei
中科院分区：
文献类型：
--
作者：
Jiang, Yinjun;Luo, Hongrui;Hu, Wei
黄鳝（Monopterus albus）是一种雌雄同体的鱼类，在东亚作为一种水产养殖品种进行商业化养殖。人工养殖黄鳝需要大量的成年雌、雄鳗，但黄鳝发育为雄鳗需要经历较长的雌、间性阶段，导致生产实践中功能性雄鳗短缺。本研究开发了一种人工方法，通过口服芳香化酶抑制剂（AI，来曲唑：300毫克/公斤饲料）在幼鱼生产功能的男性。经处理的鱼的性腺部分的组织学分析揭示了初级卵巢到成熟睾丸的过渡。在AI处理的初始阶段，2月龄的黄鳝都是雌性。AI给药导致体内17 β-雌二醇水平显著降低，睾酮和11-酮睾酮水平升高。细胞增殖发生在性腺上皮的外层，卵母细胞退化的卵巢。AI处理120天后，卵巢完全转化为睾丸。性逆转的鱼在停止药物治疗后保持雄性并产生功能性精子。值得注意的是，人工性别逆转的男性的生殖力没有显着不同的野生型男性。定量PCR分析显示，cyp 19 a1 a的表达下降，而雌激素受体esr 1，esr 2a和esr 2b的mRNA水平在AI处理过程中显着增加。此外，foxl 2的表达下调，而dmrt 1，amh，和sox 9上调，在鱼的性腺管理AI。本研究揭示了内源性雌激素的合成在黄鳝性别转变中起着关键作用，雌激素不足时卵巢会向睾丸转化。这种人工诱导的性别转换在黄鳝育种中具有重要的应用价值。
The rice field eel (Monopterus albus) is a protogynous hermaphroditic fish reared commercially as an aquaculture species in East Asia. Artificial breeding of rice field eels requires an abundance of adult females and males; however, the eels need to undergo a long period of female and intersexual stages before they develop into males, which results in a shortage of functional males in production practice. This study developed an artificial method for producing functional males through the oral administration of an aromatase inhibitor (AI, letrozole: 300 mg/ kg feed) in juvenile fish. Histological analysis of gonadal sections of treated fish revealed the transition of primary ovaries to mature testes. During the initial period of the AI treatment, 2-month-old rice field eels were exclusively female. AI administration resulted in a significant reduction in 17 beta -estradiol levels and increase in testosterone and 11-ketotestosterone levels in vivo. Cell proliferation occurred in the outer layer of the gonadal epithelium, and oocytes degenerated in the ovaries. After 120 days of AI treatment, the ovaries were completely converted to testes. The sexually reversed fish maintained the male sex and produced functional sperm after cessation of drug treatment. Notably, artificially sex-reversed males' fecundity did not differ significantly from wild-type males. Quantitative PCR analysis revealed that the expression of cyp19a1a decreased, whereas the mRNA levels of estrogen receptors esr1, esr2a, and esr2b increased significantly during AI treatment. Moreover, the expression of foxl2 was downregulated, whereas dmrt1, amh, and sox9 were upregulated in the gonads of fish administered AI. This study revealed that endogenous estrogen synthesis plays a key role in the sex change of rice field eels, with ovaries undergoing a reversal to testes in response to estrogen insufficiency. Such artificially induced sex conversion will be of considerable value in breeding rice field eels.Superscript/Subscript Available