温度对鲫鱼性腺分化的影响

The Influence of Temperature on Sex Differentiation of Carassius auratus

鱼类的性腺分化受各种环境因素的影响,而温度的影响是重要因素之一。本文通过组织学方法观察了鲫鱼(Carassius auratus)原生殖细胞的迁移、生殖嵴形成和性腺分化,并探讨温度对性腺分化的影响。孵化后12～40d是鲫鱼性腺分化的敏感期。从第12d起,仔鱼分成7组,每组分别用下列7种水温中的一种培育28d:(16±1)℃、(20±1)℃、23～25℃、(27±1)℃、(30±1)℃、(32±1)℃、(34±1)℃。其中23～25℃组是对照组。结果显示,对照组幼鱼的雌雄比例大致是1∶1(1∶1.07)。(20±1)℃组的幼鱼雌雄比例也接近1∶1(1.09∶1)。在(27±1)℃组,雌性率上升,为55.3%(P<0.05)。在低温组(16±1)℃,雌雄比例是1∶1.45,雌性率达40.8%。然而,在高温组(30±1)℃、(32±1)℃、(34±1)℃中,雌雄比例分别是6.14∶1、2.51∶1和2.14∶1。其中(30±1)℃实验组的雌性率最高,达到86.0%(P<0.01),性腺分化趋向雌性化。研究提示,鲫鱼的性别分化属于温度依赖型。当前全球性气候变暖,以及各种环境因素所产生的温室效应,有可能对鲫鱼的性别平衡产生影响。

The gonadal differentiation in fishes is affected by many environmental factors, among which temperature is one of the most important factors. In this paper, migration of primordial germ cells （PGCs）, formation of genital ridge and gonadal differentiation were investigated using histological methods in Carassius auratus. Effects of different culturing water temperatures on the gonadal differentiation were also studied. Day 12 to day 40 was a sensitive period for the gonadal differentiation. From day 12 on, larvae were divided into 7 groups. Every group was cultured under one of seven temperatures for 28 days： 16±1℃, 20±1℃, 23-25℃, 27±1℃, 30±1℃ 32±1℃ and 34±1 ℃ . The control group was cultured at 23 - 25 ℃ . The results showed that larval sex ratio in the control group was approximately 1 ： 1 （female to male was 1 ： 1.07） . In the 20 ±1℃ group, the larval sex ratio was also close to 1 ： 1 （1.09 ： 1 ）. In the 27±1 ℃ group, female ratio increased and the female ratio could he as high as 55.3 % （ P 〈 0.05）. In lower temperature group 16 ±1℃, female to male was 1：1.45, and the female ratio reached 40.8%. However, in the higher temperature groups, the female to male ratios were 6.14： 1, 2.51 ： 1 and 2.14：1 when temperature was increased to 30 ±1℃ , 32±1℃ and 34 ±1 ℃, respectively. The female ratio in 30 ±1 ℃ group was the highest, reaching as high as 86.0% . The temperature of 30 ± 1℃ obviously induced feminization. These results suggest that sex determination in C. auratus is temperature-dependent sex determination （TSD）. Nowadays, the global temperature become warmer, and the changing environmental factors lead to greenhouse effect, which might skew the sex ratio of C. auratus.