Atrazine-Induced Intestinal Histopathology in Juvenile African catfish, Clarias gariepinus (Burchell, 1822)
摘要
Atrazine is a frequently detectable, persistent, and ubiquitous pesticide that could negatively impact the survival of aquatic life including fish. Therefore, understanding its likely impact on aquatic organisms is now a critical research priority. Juveniles of Clarias gariepinus were exposed to sub-lethal concentrations of atrazine in a controlled semi-renewal assay. The sub-chronic experiment lasted for 28 days using 2.5, 25, 250, and 500 µg L−1 of atrazine exposure. The study attempted to determine its impacts on tissues responsible for dietary intake, an area of study that is rarely investigated in water pollution research. The histopathological effects of atrazine were studied using a combination of both quantifiable and qualitative histomorphology-based health diagnostic tools. The pathological relevance of a lesion is dependent on the severity of its impact on organ function relative to the species survival. The control group showed normal structure, indicating no injury or alteration. Morphometric analysis of the intestine showed significant architectural alterations, including changes in cell number and morphology, observed only in 250 and 500 µg L−1 atrazine treatments with 25.00% and 89.58% of occurrence, respectively. Other alterations in this category that were observed only in the 500 µg L−1 treatment group are: completely damaged epithelium (91.67%), leakage of cells into the lumen (79.17%), advanced epithelial hyperplasia (79.17%), massive dis-epithelialization (66.67%), and completely degenerated tunica muscularis (95.83%). The results provide invaluable data for ecological risk assessments of atrazine and perhaps other current-use pesticides in freshwater environments.