Protective Role of Vitamin C and Thyme Extract (Thymus vulgaris) on Chromium-Induced Toxicity in Catfish (Clarias gariepinus)

Background and Objective: Chromium toxicity in aquatic environment may occur through industrial pollutions. The impact of its toxicity may represent health hazards for aquatic environments and public health. Therefore, Clarias gariepinus were used to investigate the chromium toxicity and assess the ameliorative effect of thyme and vitamin C. Materials and Methods: A total of 90 fish were divided into sixequal groups (n = 15). Group 1 (control negative) was fed on basal diet without chromium in water. Group 2 (control positive) was fed on basal diet with Potassium Dichromate (PD) at dose 3.6 mg L^–1 dissolved in water. Group 3 was fed on diet with vitamin C at dose 200 mg kg^–1 of diet without PD in water. Group 4 was fed on vitamin C diet with PD in water. Group 5 was fed on diet supplemented with Thyme extract at dose 10 g kg^–1 dry food without PD in water. Group 6 was fed on thyme diet with PC in water. The experiment was done for a period of 30 days. Analyses of blood, antioxidant in tissues, micronucleus test, chromium tissue residues, comet assay and histopathology were done. Results: There was a significant decrease (p<0.001) in RBCs count, Hb content, PCV% and WBCs count with significant increase (p<0.001) in liver and kidney function. There were increased activities of SOD, CAT, GSH and MDA and chromium tissue residues. DNA damage and histopathological changes occurred in groups with chromium when compared to control negative group. Vitamin C and thyme extract decreased the toxic effect of chromium and improved biochemical parameters, with reduction of chromium residues in gills and muscles. Conclusion: Therefore, vitamin C and thyme extract can be used as ameliorative factors against chromium toxicity in aquaculture.