Antioxidant protection by vanillin aldehyde against chronic pymetrozine-induced hepatic, renal, and DNA damage in African catfish.

Worldwide, aquatic ecosystems are increasingly threatened by the inappropriate overuse of insecticides, posing risks to aquatic life. There is a need for alternatives that are safe, economical, and environmentally friendly. Thus, the protective effects of dietary vanillin (VAN) against the detrimental consequences of long-term pymetrozine (PMZ) exposure in Clarias gariepinus (African catfish) are investigated in this study. To address this, fish were randomly assigned into four groups: control, VAN (10 mg/kg diet), PMZ (0.065 mg/L), and VAN + PMZ for two months, with 40 fish in each group. Chronic PMZ exposure significantly elevated the concentrations of alanine aminotransferase, aspartate aminotransferase, creatinine, glucose, cortisol, malondialdehyde, and 8-hydroxy-2’-deoxyguanosine by 131.44, 134.55, 564.28, 49.65, 76.00, 174.69, and 281.97%, respectively (P < 0.001), compared with the control. Conversely, total protein, albumin, globulin, total antioxidant capacity, and catalase activity decreased by 27.76, 32.73, 21.74, 58.20, and 60.41%, respectively (P < 0.001). Histological examination revealed that PMZ provoked a range of histopathological changes in the vital organs (liver, kidney, gills, and brain), including vacuolation, hydropic degeneration, and necrosis. Remarkably, VAN supplementation in the PMZ-exposed group significantly ameliorated these effects, reducing alanine aminotransferase (40.80%), aspartate aminotransferase (33.04%), creatinine (35.48%), glucose (22.70%), cortisol (18.39%), malondialdehyde (39.62%), and 8-hydroxy-2’-deoxyguanosine (26.18%) (P < 0.001). Moreover, it increased total protein, albumin, globulin, total antioxidant capacity, and catalase activity by 25.85, 34.67, 16.67, 404.08, and 364.86%, respectively (P < 0.001). Histological analyses of the VAN + PMZ group showed largely normal tissue architecture, with only mild hepatic cell degeneration, a few necrotic renal tubules, slight gill filament erosion, and occasional degenerated neurons. Dietary VAN also significantly reduced mortality from 37.50% (95% confidence interval: 24.20–53.00%) in the PMZ group to 12.50% (95% confidence interval: 5.50–26.10%) in the VAN + PMZ group (P = 0.018, Fisher’s exact test). In conclusion, dietary VAN demonstrates considerable potential in mitigating the adverse effects of PMZ on C. gariepinus. However, further field-based studies are warranted before recommending its application in aquaculture practice.