Abstract

The harmful effects of atrazine on fish have been well-documented. Consequently, it is imperative to explore alternative methods to safeguard the health of aquaculture species such as Clarias gariepinus. This study investigated the toxicological impacts of atrazine on Acetylcholinesterase (AChE) activities and the histological characteristics of the brain and the potential ameliorative effects of dietary supplementation of Vitamin C to atrazine toxicity. Four-week-old C. gariepinus juveniles were exposed to 0, 10, 20, and 30 µg/L of atrazine and 0.08g of vitamin C for twenty-eight days in a static renewal bioassay. Atrazine exposure significantly (p<0.05) inhibited the activities of AChE in the brain, ranging from 47.86 (control) to 32.39 U/L in the 30 µg/L treatment. Histopathological assessment of the brain showed the cerebrum with enlarged disorganized cells with vascular spaces around them and the appearance of blood congestion in the lowest treatment (10 µg/L). Dissociation of Purkinje’s cell layer from the granular cell layer was observed mostly at the 20 µg/L group, while severe cell infiltration occurred at 30 µg/L. Some unusual behaviors, such as heightened opercular rate, erratic swimming, mucous secretion, and air gulping, were observed across treatment groups in a dose-dependent pattern. These results indicate that the influence of atrazine might be linked to changes in the cholinergic system of the central nervous system, potentially impacting the observed behavioral trends. Dietary supplementation of fish feed with Vitamin C in this study has neuro-protective potential against atrazine-induced toxicity.