Microstructure of oogenesis in Sinibrama taeniatus

In order to explore the law of oogenesis of Sinibrama taeniatus and provide instruction for artificial reproduction, we observed and described the microscopic structure of its oogenesis process that was divided into five phases: phase of oogonium (Phase I), phase of single-layer follicular cell (Phase II), phase of yolk vesicle (Phase III), phase of yolk filled (Phase IV) and phase of mature oocyte (Phase V). Results of paraffin section reveals that oogonium could be distinguished as two types according to their microscopic characteristics (oogonium at early stage and mitosis). Meanwhile, the early primary oocyte was devided into Phase II, and several small nucleolus appeared at the edge of the nuclear membrane, which was regarded as the sign of beginning of little growth period. Yolk vesicles appeared in Phase III and the yolk began to accumulate and mainly existed in the form of yolk granule when the yolk vesicles increased to 3−5 layers. After entering Phase IV, the yolk deposited into yolk platelet, and the yolk vesicles were squeezed to the perivitelline area and formed cortical vesicles. After the oocyte was mature, the area of cortical vesicles exhibited as lumps or particulates, and was dyed orange by hematoxylin-eosin staining.