Beta-cypermethrin, a type II synthetic pyrethroid insecticide, is widely used in pest control. Several studies have demonstrated that beta-cypermethrin can affect the reproductive system of mammals. However, there is still a scarcity of information about the reproductive toxicity to fish induced by beta-cypermethrin and its molecular mechanism. Therefore, this study was conducted to address this scientific question, in which the adult zebrafish were exposed to 0 (blank control), 0 (acetone solvent control), 0.1, 0.5, and 2.5 μg/L of beta-cypermethrin for 21 days. A decrease in cumulative egg production of zebrafish was observed, indicating that beta-cypermethrin had a negative impact on reproductive capacity of zebrafish. Regarding the histomorphological analysis of gonads, the delay of gonadal development was observed after exposure for 21 days. In addition, significant changes in plasma 17β-estradiol (E2) and testosterone (T) were found in zebrafish. Further exploration showed that the transcription levels of hypothalamic-pituitary-gonadal (HPG) axis-related genes were remarkably changed, which corresponded well with the alterations of hormone levels. These results demonstrated that beta-cypermethrin might have an adverse effect on the reproduction system of zebrafish through delaying gonadal development, disturbing sex hormone secretion, and affecting HPG axis gene expression. This study suggests that beta-cypermethrin poses a potential threat to the reproduction of fish populations, and the toxicity assessment of beta-cypermethrin plays a vital role in the environmental risk assessment of pesticides.

β-氯氰菊酯是一种II类合成拟除虫菊酯杀虫剂，已广泛用于害虫防治。多项研究表明，β-氯氰菊酯可以影响哺乳动物的生殖系统。但是，关于β-氯氰菊酯对鱼类的生殖毒性及其分子机制的信息仍然匮乏。因此，进行这项研究是为了解决这个科学问题，即成年斑马鱼暴露于0（空白对照），0（丙酮溶剂对照），0.1、0.5和2.5μg/ Lβ-氯氰菊酯21天。观察到斑马鱼的产卵量减少，这表明β-氯氰菊酯对斑马鱼的繁殖能力有负面影响。关于性腺的组织形态学分析，暴露21天后观察到性腺发育延迟。在斑马鱼中发现了β-雌二醇（E2）和睾丸激素（T）。进一步的研究表明，下丘脑-垂体-性腺（HPG）轴相关基因的转录水平发生了显着变化，这与激素水平的变化非常吻合。这些结果表明，β-氯氰菊酯可能通过延迟性腺发育，干扰性激素分泌和影响HPG轴基因表达而对斑马鱼的繁殖系统产生不利影响。这项研究表明，β-氯氰菊酯对鱼类种群的繁殖构成潜在威胁，β-氯氰菊酯的毒性评估在农药的环境风险评估中起着至关重要的作用。