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石斑鱼属雌雄同体雌性先成熟鱼类,低龄鱼卵巢先成熟,表现为雌性,高龄鱼才性转变为雄性。本实验通过持续跟踪取样,分析了人工养殖条件下斜带石斑鱼(Epinephelus coioides)在36月龄内的性腺发育过程,发现其性分化完成后,雌性卵巢在9月龄后开始发育。因此,采取投喂含有雄激素甲基睾酮(MT)饲料的方法,可以在石斑鱼卵巢发育之前,成功诱导8月龄的斜带石斑鱼幼鱼向雄性方向发育。结果表明,以MT 10mg/kg饲料的剂量投喂3个月能够有效诱导卵巢未发育的幼鱼往雄性方向发育;但停止投喂MT后,幼鱼精巢又开始出现退化,不会继续往雄性方向发展,而转变为雌性。以上结果表明,斜带石斑鱼性别决定和分化除了受遗传因子和内分泌调控外,还受到年龄、体型和群体、环境等因子的影响,人工投喂MT激素的作用并不能从根本上影响石斑鱼幼鱼的性腺发育的方向,只有在持续剂量的MT激素诱导下,石斑鱼幼鱼才能发育为成熟的雄鱼。
Grouper is a hermaphrodite female first mature fish, young fish ovary first mature, showing females, old fish males to males. In this experiment, the gonadal development of Epinephelus coioides under 36-month-old artificial breeding conditions was analyzed by continuous follow-up sampling. After ovariectomized, the ovary began to develop after 9 months of age. Therefore, adopting the method of feeding the feedstuff containing androgen methyltestosterone (MT) could successfully induce the juvenile grouper juveniles aged 8 months before the development of grouper ovary. The results showed that the feeding of MT at 10 mg / kg for 3 months could effectively induce undeveloped ovaries to develop in the male direction; however, after the MT was stopped, the testis of juvenile began to degenerate again and would not continue to males The direction of development, and into a female. The above results show that, in addition to the genetic factors and endocrine regulation, sex determination and differentiation of the grouper is affected by age, body size and population, environment and other factors. The effect of artificial feeding of MT hormone can not fundamentally affect the stone Grouper juvenile gonadal development direction, only the continued dose of MT hormone induced grouper juveniles to mature males.