Consejo Superior de Investigaciones Científicas (CSIC), Instituto de Acuicultura de Torre de la Sal (IATS), 12595 Ribera de Cabanes, Castellón, Spain.
J Fish Biol. 2009 Dec;75(10):2657-69. doi: 10.1111/j.1095-8649.2009.02458.x.
This paper reports on an evaluation of growth, gonadal development and reproductive endocrinology of older triploid (3n) European sea bass Dicentrarchus labrax in comparison with their diploid (2n) counterparts throughout their fifth and seventh annual cycle of life. While older triploids retained impaired reproductive endocrinology, a sexually related dimorphic growth was observed with 3n females attaining the largest sizes. Comparisons of some body indexes showed that 3n females had a significantly lower hepato-somatic index (I(H)) than 2n females but a significantly higher viscero-somatic index (I(F)). In contrast, both male and female triploids showed significantly lower gonado-somatic index (I(G)) than diploids. Accordingly, diploids produced mature gametes but triploids did not, demonstrating that despite the longer time given to triploids for gonadal development, they could not reproduce. Furthermore, older triploids had lower levels of plasma sex steroids (testosterone, T; 11-ketotestosterone, 11-KT and oestradiol-17beta, E(2)) and luteinizing hormone (LH) than their 2n counterparts with 3n females showing drastic effects of triploidization on their reproductive endocrinology. Vitellogenin (VTG) was undetectable in 3n females. Gonadal content of steroid hormones and Sparus aurata-type gonadotropin-releasing hormone (sbGnRH) in the brain and pituitary were also lower in triploids compared with diploids. These results suggest that older 3n D. labrax retain functional sterility in both sexes, and 3n females might reach larger sizes than 3n males and their 2n counterparts in this species.
本文报道了三倍体（3n）欧洲鲈鱼（Dicentrarchus labrax）在其第五和第七个生活年周期中生长、性腺发育和生殖内分泌的评估结果，并与二倍体（2n）进行了比较。尽管老年三倍体保留了受损的生殖内分泌功能，但观察到了一种与性相关的二态生长，3n 雌性达到了最大体型。一些身体指数的比较表明，3n 雌性的肝体比（I(H)）显著低于 2n 雌性，但脂体比（I(F)）显著高于 2n 雌性。相比之下，雄性和雌性三倍体的性腺体比（I(G)）均显著低于二倍体。因此，二倍体产生成熟的配子，而三倍体则不能，表明尽管三倍体有更长的时间进行性腺发育，但它们无法繁殖。此外，老年三倍体的血浆性激素（睾酮、T；11-酮睾酮、11-KT 和雌二醇-17β、E(2)）和促黄体生成激素（LH）水平低于其 2n 对应物，3n 雌性的生殖内分泌受到三倍体化的严重影响。3n 雌性的卵黄蛋白原（VTG）无法检测到。三倍体的脑和垂体中的类固醇激素和 Sparus aurata 型促性腺激素释放激素（sbGnRH）的性腺含量也低于二倍体。这些结果表明，老年 3n D. labrax 在两性中均保持功能性不育，并且 3n 雌性在该物种中可能比 3n 雄性和其 2n 对应物达到更大的体型。
