三倍体雄性虹鳟(Oncorhynchus mykiss)生殖发育研究

以8~35月龄的三倍体雄性虹鳟为试材,同期二倍体为对照,研究了性腺发育和精子发生过程中组织结构、超微结构以及几种生殖激素含量的变化,以了解染色体多倍化对三倍体虹鳟精巢发育和精子发生的影响,探讨多倍体虹鳟的生殖机制。结果表明,三倍体虹鳟精巢能够发育成熟,但较二倍体发育迟缓,成熟精子量少,精子结构正常、大小不一;精子发生经历了精原细胞、初级精母细胞、次级精母细胞、精子细胞和精子5个阶段,各级生精细胞结构与二倍体相同,但体积较大,发生过程中有大量坏死细胞存在,精子变态期尤为明显;败育的生殖细胞被支持细胞所吞噬;生殖激素仅呈现一个生殖周期变化,与二倍体变化趋势相同但滞后。三倍体雄性虹鳟的生精细胞能够完成减数分裂,滞育于精子细胞阶段,由于非同源染色体不规则的联会,产生的精子绝大多数因含有多余的染色体片段成为非整倍体而败育,只有少数生精细胞能够正常发育成精子。

Research on reproduction and development of triploid male Oncorhynchus mykiss

In order to syudy the effect of chromatosome polyploidy on spermary development and spermatogenesis and reproductive mechanism of polyploid rainbow trout(Oncorhynchus mykiss),triploid male from 8 to 35 months were sampled as materials,diploid at the same stage as control,the system study was carried out on histological structure,ultrastructure and changes of several hormones during the stage of gonadal development and spermatogenesis.The results showed that spermary of triploid rainbow trout could develop to mature,but with an obvious delay in comparation to diploid at the same stage.Spermatozoa was not of the uniform size and the amounts of mature were small,but the structures were normal;spermatogenesis underwent five stages,which were spermatogonium,primary spermatocyte,secondary spermatocyte,spermatid and spermatozoa.The structure of each spermatogenic cell wasbasically the same to diploid,but the volume was bigger and accompanied with large amounts of cellularnecrosis,especially it was obvious at the stage of sperm metamorphosis;abortive germinal cells werephagocytized by sertoli cells;reproductive hormone in triploid male rainbow trout presented only one cycle change,and the trend was the same to diploid but the time was later.Spermatogenic cells of triploid male could finish meiosis,but were diapauses at the stage of spermatid,nonhomologous chromosome underwent irregular synapses and most of sperm produced were aneuploid and led China to abortion because of the existence of chromosome segments among them,so only a small number of spermatogenic cells could normally develop to spermatozoa.