SummaryThe optimum distance and duration of ultraviolet (UV) irradiation for the complete inactivation of African catfishClarias gariepinusegg nucleus was investigated in this study. The UV light was suspended above the unfertilized eggs at four distances (5, 10, 20 and 30 cm) and for five durations (1, 2, 3, 4 and 5 min). Then, the irradiated eggs were activated with sperm from diploidC. gariepinusand cold shocked at 5°C for 5 min just moments before cell cleavage. Ploidy analysis was performed using karyotype chromosome counting. The results obtained suggested that the further the distance, the better the hatchability rate, however prolonged duration seemed to significantly reduced hatchability. All treatments with surviving progenies at the end of the study showed evidence of successfully diploid gynogen (2n = 56) induction at different percentages. However, the optimal protocol that gave a moderately high hatchability/survival rate and completely induced gynogens was exposure of the eggs to UV irradiation at 20 cm for 1 min. It was concluded that the distance and duration of UV irradiation affects gynogenetic induction in African catfishC. gariepinus.

中文翻译：

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紫外线照射鲢鱼 (Burchell, 1822) 卵产生雄激素的优化

总结非洲鲶鱼完全灭活的紫外线（UV）照射的最佳距离和持续时间鲇鱼本研究对卵核进行了研究。紫外光在未受精卵上方悬浮四个距离（5、10、20 和 30 厘米）和五个持续时间（1、2、3、4 和 5 分钟）。然后，用来自二倍体的精子激活辐照过的卵子C. gariepinus并在细胞分裂前立即在 5°C 下冷激 5 分钟。使用核型染色体计数进行倍性分析。获得的结果表明，距离越远，孵化率越高，但持续时间延长似乎会显着降低孵化率。在研究结束时，所有存活后代的治疗都显示了以不同百分比成功诱导二倍体雌激素 (2n = 56) 的证据。然而，提供中等高孵化率/存活率和完全诱导雌激素的最佳方案是将卵暴露在 20 厘米的紫外线照射下 1 分钟。得出的结论是，紫外线照射的距离和持续时间会影响非洲鲶的雌核发育诱导C. gariepinus.