Effects of atrazine on the endocrinology and histoarchitecture of the testes in African Catfish, <I>Clarias gariepinus</I> (Burchell, 1822)

Abstract

Aquatic ecosystems often receive a wide spectrum of pollutants introduced directly or indirectly. The herbicide atrazine, an endocrine disrupting chemical (EDC), frequently contaminates potable water supplies and aquatic ecosystems. Studies suggest atrazine induced alterations in the neuroendocrine system along the hypothalamuspituitary-gonadal (HPG) axis. This study investigated the effects of atrazine (0, 2.5, 25, 250 and 500 μg l⁻¹ for 28 days of exposure) on testosterone (TST) and prolactin (PRL) levels, testes histology and seminiferous tubular morphometry of Clarias gariepinus juveniles. TST and PRL significantly decreased in all the 28 days atrazine exposed groups. Histologically, the testes showed vacuolated and sloughing of basal germinal epithelium in the treated groups. A high correlation between testicular biopsy score counts and results of seminiferous tubular morphometry was also observed. Findings from this study confirm that atrazine is an EDC in fish that alters reproductive dysfunction by targeting the HPG axis, as evidenced by its effects on the investigated reproductive hormones. Furthermore, atrazine disrupted the histoarchitectural components of the testes, which may interfere with spermatogenesis and therefore impair the reproductive functions of the fish.