Laboratory of Ecotoxicology, University of Le Havre, BP 540, 76058, Le Havre, France.
Centre for Environmental Research, School of Life Sciences, University of Sussex, Falmer, Brighton, BN1 9QG, UK.
Fish Physiol Biochem. 2010 Sep;36(3):767-777. doi: 10.1007/s10695-009-9351-5. Epub 2009 Aug 13.
Fish reproduction is subjected to worrying trends in many aquatic environments. In this study, we report the absence of histological and biochemical alterations in fish sampled in a low contaminated site (characterised by the absence of detectable oestrogenic activity and mutagenicity in sediment extracts). A total of 474 roach (Rutilus rutilus) were monthly sampled during 18 months, and no intersex fish were recorded after careful histological examination, thus indicating that the incidence of this phenomenon may be very low under natural conditions. Furthermore, mean male plasma vitellogenin concentration was 24 ng ml(-1) and was only slightly elevated during the spawning period (up to 120 ng ml(-1)) indicating that these low values may be characteristic of a low contaminated site. Of the male roach, 45.3% were sampled, a sex-ratio that did not significantly deviated from the expected 1:1 ratio between male and female. Results also showed that natural conditions can greatly affect the reproductive cycle of roach. Gametogenesis showed a biphasic pattern with first gonad maturation between September and December and a final maturation occurring at the end of winter/early spring. Under decreasing temperatures, particularly below 6 degrees C, gametogenesis was stopped or even regressed with secondary oocytes becoming rare under histological observation. Conversely, elevated temperatures during the winter lead to an earlier gonad maturation.
在许多水生环境中，鱼类繁殖受到令人担忧的趋势的影响。在这项研究中，我们报告了在低污染地区（沉积物提取物中无检测到雌激素活性和致突变性）采集的鱼类没有组织学和生化变化。在 18 个月的时间里，每月对 474 条鲈鱼（Rutilus rutilus）进行采样，经过仔细的组织学检查，没有记录到雌雄同体的鱼类，这表明在自然条件下，这种现象的发生率可能非常低。此外，雄性血浆卵黄蛋白原的平均浓度为 24ng/ml，仅在产卵期略有升高（最高可达 120ng/ml），这表明这些低值可能是低污染地区的特征。在雄性鲈鱼中，有 45.3%被采样，性别比例与预期的 1:1 雄性和雌性比例没有显著偏差。研究结果还表明，自然条件会极大地影响鲈鱼的生殖周期。配子发生呈双相模式，第一次性腺成熟发生在 9 月至 12 月，最后一次成熟发生在冬季/早春结束时。随着温度的降低，特别是低于 6°C 时，配子发生停止，甚至退化，组织学观察到次级卵母细胞变得罕见。相反，冬季高温会导致性腺更早成熟。
