尼罗罗非鱼♀×萨罗罗非鱼♂人工杂交卵子、精子形态观察

Morphological observation on eggs, sperms in artificial hybridization of Oreochromis niloticus ♀×Sarotherodon melanotheron♂

采集尼罗罗非鱼♀×萨罗罗非鱼6杂交中人工挤压亲鱼腹部获得的卵子、精子.用光学显微镜和解剖镜对卵子形态进行观察、拍照,比较分析不同成熟阶段卵子形状、卵径、表面色泽及卵黄颗粒积累特征,结果表明,未成熟卵细胞呈椭圆形,表层布满细长血管;成熟卵细胞呈梨形,卵径0.5～1.6 mm,外层有透明卵膜,充满金黄色卵黄颗粒;过成熟卵细胞形状极不规则,卵黄颗粒开始液化.用扫描电镜对精子外形特征进行观察,发现正常精子由头部、中片及尾部组成,头部呈长锥状,长径1.82（±0.35）μm,宽径1.41（±0.34）μm;中片近圆柱形、较短,长径0.74（±0.08）μm,宽径0.16 （±0.06）μm;尾部极长,为16.42（±0.35）μm,单鞭毛结构;同时,还观察到短尾、双头、双尾3种异常类型.研究结果可为罗非鱼人工杂交技术改进提供一定基础依据.

Eggs of female Oreochromis niloticus and sperms of male Sarotherodon melanotheron ♂were collected by abdominal squeezing of the broodstocks. The egg shape, size, color and accumulation of yolk granules at different matured stages were analyzed by optical microscope and dissecting microscope techniques, the result showed that the immatured eggs were oval-shaped and covered with small blood vessel; the matured eggs were pear-shaped, eggs diameter were 0.5-1.6 mm, they were coated with a transparent egg membrane and filled with large amounts of golden yellow yolk granules; the over-matured eggs had irregular shape, with some liquefied yolk granules. The sperms were observed by scanning electron microscopy technique, normal sperms were composed with head, middle and tail piece, the head was a elongated cone, long diameter was 1.82（±.35）μm, wide diameter was 1.41（±0.34）μm; the middle film was short and cylindrical, long diameter was 0.74（±0.08）μm, wide diameter was 0.16（±0.06）μm; the tail, single flagellum structured, was extremely long, was 16.42（±0.35）μm. Three types of abnormal sperm including short-tailed, double headed and two-tailed, were also observed. The results could provide some basic dates to improve tilapia artificial hybridization techniques.