Alterations in Steroid Sex Hormones (17β Estradiol and Testosterone) of Clarias gariepinus Exposed to Different Sub-lethal Concentrations of Cypermethrin

Abstract

The study focused on the alterations in steroid hormone levels of Clarias gariepinus. Fish were exposed to sub-lethal concentrations of cypermethrin over a 28 days period. A total of 200 sub-adults of C. gariepinus with a mean weight of 55.280 ± 6.281g were used throughout the study. Sub-adults of C. gariepinus were exposed to 0.00 ppm, 0.0125 ppm, 0.025 ppm, 0.100 ppm and 0.400 ppm of cypermethrin. The concentration of 17β-Estradiol and testosterone in C. gariepinus sub-adults exposed to 0.0125 ppm, 0.025 ppm, 0.100 ppm and 0.400 ppm of the toxicant for 7, 14, 21 and 28 days decreased significantly from the control, with increase in toxicant at p<0.05, except for 17β-Estradiol and testosterone in fish exposed to 0.0125 ppm of cypermethrin for 21 days and 7 days. The mean levels of estradiol decreased in 0.400 ppm group compared to the control; from 212.4 ± 3.156 pg/mL to 118.9 ± 9.682 pg/mL (Day 7); 210.5 ± 8.286 pg/mL to 90.70 ± 7.554 pg/mL (Day 14); 131.7 ± 5.652 pg/mL to 80.77 ± 6.882 pg/mL (Day 21) and 177.6 ± 12.25 pg/mL to 52.77 ± 11.08 pg/mL (Day 28). The mean levels of testosterone decreased in 0.400 ppm group compared to the control; from 2.367 ± 0.208 pg/mL to 0.823 ± 0.276 pg/mL (Day 7); 2.700 ± 0.200 pg/mL to 0.466 ± 0.152 pg/mL (Day 14); 3.200 ± 0.300 pg/mL to 0.300 ± 0.100 pg/mL (Day 21) and 2.933 ± 0.251 pg/mL to 0.366 ± 0.208 pg/mL (Day 28). Due to adverse alteration in 17β-Estradiol and testosterone concentration of the test fish, we recommend that the Government sensitizes the farmers properly on the proper use of pesticides and also enforce against an excess application of pesticides. More of similar studies should be funded to continue monitoring the effects of various pesticides on fishes and the aquatic eco-system at large.