Alteration in the histology of gonads and hormone levels of fish Channa punctatus on exposure to 17-α ethynylestradiol

Abstract

It has been demonstrated that effluents discharged from sewage treatment facilities allow synthetic estrogens, widely employed in contraceptives and other pharmaceutical applications, to reach the aquatic environment. One of the most biologically active xenoestrogens in the aquatic environment is the synthetic hormone 17-α ethynylestradiol(EE2), raisingreproductive issues in the fish population. The present study chose Channa punctatus fish to study the effects of EE2 on gonad histology and the calculation of estrogen and testosterone levels. The experimental setting was separated into four groups, with Group I as control with 0 ng/L of EE2. The other three groups viz., Group II to IV, had 5 ng/L, 10 ng/L, and 20 ng/L concentrations of EE2, respectively, and samples were obtained after the durations of 7, 14, 21, and 28 days. The findings showed that as 17-α ethynylestradiol concentrations increased, testosterone levels decreased from 10.88±0.24 ng/dL to 4.91±0.24 ng/dL,while estrogen levels increased from 42.7±2.22 pg/mL to 120.18±4.54 pg/mL. The number percentage of primary growth oocytes, previtellogenic oocytes and vitellogenic oocytes in the histology of ovary decreased from 28.45±1.42 to 10.43±0.47; 16.22±0.81 to 3.15±0.16 and 14.81±0.89 to 2.14±0.11 respectively while in testis, the number percentage of spermatogonia, spermatocytes decreased from 21.4±0.86 to 15.1±0.68 and 97.1±3.88 to 54.2±3.25. In contrast, the percentage of mature spermatids increased from 20.8±0.94 to 40.2±2.41. Since synthetic estrogens adversely affect aquatic animals, especially fish, they should be treated properly before releasing them into the aquatic environment.