Effect of sub-lethal toxicity of diazinon on steroid detoxification and quality of sexual production in male goldfish breeders (Carassius auratus)

Determination of the sub-lethal effects of diazinon toxin carried out on steroidogenesis and quality of sexual production in male goldfish breeders. For this purpose, fish were first exposed to different lethal concentrations of diazinon toxin (9, 10, 11, 12.5, 15 and 20 mg/L) and LC50 values were analyzed for 96 h using probit software.  The amount of LC50 was 11.4 in 96 hours and fish were assorted according to 0, 0.25, 0.50 and 0.75 percent of LC50 in 96 hours and were put there for 2 months. At the end of the experiment, the level of sex hormones and the quality of sexual production were studied in male broodstock. The results showed that diazinon toxin significantly reduced testosterone and 17-β-estradiol levels in the 0.50 and 0.75 mg/L treatments compared to the control (p<0.05). There was no significant difference in some sperm quality parameters such as sperm volume, sperm density and spermatocrit between the control and 0.25 treatment. By increasing the concentration of diazinon toxin (from 0.25 to 0.75 %), the duration of sperm motility decreased significantly. The percentage of motile sperm in the control treatment was higher than other treatment and it was decreased with increasing diazinon toxin concentration. The Gonadosomatic Index in the control treatment was significantly higher than the other treatments (p<0.05) and showed a decreasing trend with increasing toxicity. In conclusion, diazinon toxin in the aquatic environment, even at sub-lethal concentrations, causes undesirable changes in the sex steroid indices and quality of male gonads in goldfish.