花䱻卵母细胞发育的组织学和超微结构观察

2015年7月至2017年10月在河南省驻马店宿鸭湖水库采集花?(Hemibarbus maculatus Bleeker)雌鱼样本190尾,体长7.12～32.21 cm,体重10.55～330.22 g,采用组织学和扫描电子显微镜技术观察了花?卵母细胞发育各时期的特征。结果表明,花?卵母细胞发育可分为5个时相,第I时相卵母细胞处于卵原细胞增殖阶段;第Ⅱ时相卵母细胞处于初级生长阶段,出现滤泡膜;第Ⅲ时相卵母细胞出现皮质液泡,细胞质膜之间形成放射带;第Ⅳ时相卵母细胞处于大生长后期,卵黄颗粒增多。电镜下观察发现放射带表面形成微孔状结构,核仁外排,可能与卵母细胞内营养物质积累有关;第Ⅴ时相卵母细胞中细胞核消失,卵母细胞发育为成熟卵子,与卵膜脱离,准备排卵。繁殖季节,花?卵巢成熟系数达到13.78%～17.04%。研究结果可为花?人工繁殖和育种工作提供参考。

Histological and ultrastructural study of oocyte development in the spotted steed, Hemibarbus maculatus

In this study, oocyte characteristics were observed during ovarian development of the spotted steed (Hemibarbus maculatus), sampled from 2015 to 2017, under light and scanning electron microscopy. A total of 190 fish were sampled, with body length between 7.12 cm and 32.21 cm and body weight between 10.55 g and 330.22 g. Our results showed that oocyte development can be divided into five distinct stages. Oocytes in phase I are considered to be in an oogonial proliferation stage. The second phase of oocyte development for the spotted steed is equivalent to the primary growth stage, and this oocyte development stage is characterized by the presence of a follicular layer. Stage III is marked by the appearance of cortical vacuoles, and the zona radiata (ZR) can be differentiated from the follicular layer. Stage IV oocytes enter the late growth stage, and the yolk granules increase. In electron micrographs, the pore-like structures of the ZR were clearly observed, which are believed to be related to nutrient accumulation. Stage V oocytes are characterized by mature oocytes and a completely degenerated nuclear membrane. Following ovulation, the space between the oocyte and ovary membrane is evident. During the reproductive season, the gonadosomatic index (GSI) ranged from 13.78% to 17.04%. The obtained data will consequently facilitate the artificial propagation and breeding of this commercially important species.