Zinc is essential to the body; however, in high concentrations, it can be toxic. In this study, the protective effect of garlic (Allium sativum) against the toxic effect of zinc on the testicular tissues of goldfish (Carassius auratus) was assessed. Seventy-five healthy fish were allocated into 5 equal groups: control group, untreated; group 1, exposed to zinc sulfate (Merck, Germany) at dose of 3 mg/L; groups 2, 3, and 4 were also exposed to zinc sulfate in the same concentration as group 1 but their diet was supplemented with garlic (A. sativum) at 0.5, 1, and 2.5% of daily diet, respectively. After 45 days, 8 fish from each group were randomly selected, testicular tissue taken, and assessed histologically. Severe histopathologic lesions were seen in groups 1 and 2 and to lesser extents in groups 3 and 4 as garlic concentration increased. This showed that goldfish testicular tissue is sensitive to zinc toxicity and that garlic can reduce zinc accumulation in tissues, indicating that antioxidant compounds from garlic might act as chelators for zinc, allowing its excretion from the body.
