FEMALE ZEBRAFISH EXPOSED TO ENVIRONMENTAL DOSES OF TRIAZOPHOS ON PARENTA REPRODUCTION, OXIDATIVE STRESS AND EMBRYONIC DEVELOPMENT OF OFFSPRING

Triazophos is a widely used organophosphorus insecticide. The residual amount of triazophos detected in natural water may pose a potential threat to non-target aquatic organisms. This paper aims to investigate the toxic effect of triazophos on zebrafish. In this study, 3-month-old female zebrafish (Danio rerio) were continuously exposed to environmentally relevant concentrations of triazophos (10 µg/L) for 21d. Subsequently, natural spawning and fertilization were performed using healthy males, and the toxicity of triazophos on both the parental females and their offspring was assessed. The assessment included measurements of female fertility, oxidative stress in parent and offspring, as well as indicators of embryonic development in the offspring. The main results were as follows: after exposure to 10 µg/L triazophosphos, the spawning capacity of parental female fish increased significantly (P<0.05), moreover, it caused a significantly decrease in the activity of liver acetylcholinesterase (AChE) (P<0.05), an increase in malondialdehyde (MDA) content (P<0.05), and a significant enhancement in the activities of superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione S-transferase (GST) and carboxylesterase (CarE) (P<0.05). The embryo fertilization rate, fertilized egg diameter, embryo heart rate and body length of newly hatched larvae were significantly lower (P<0.05), while the malformation rate of larval fish was significantly higher (P<0.05). However, there was no significant difference in the hatching rate (P>0.05). The activity of AChE and SOD in larvae decreased although not significant (P>0.05), whereas the MDA content increased significantly (P<0.05). Furthermore, the activities of GPx and GST were significantly decreased (P<0.05), while CarE activity was significantly increased (P<0.05). The above findings suggest that exposure to environmental concentrations of triazophos can increase female zebrafish's fecundity, cause oxidative stress in the parenta and their offspring, and adversely affect the developmental process of the offspring embryos.