A subchronic toxicity study was carried out to assess hepatic and renal functions of rats during oral exposure to glyphosate with zinc for the period of 8 weeks. Forty-eight Wistar rats used for the study were randomized into six groups of eight Wistar rats each, and each group had equal number of male and female Wistar rats. The Wistar rats administered with distilled water at 2 ml/kg body weight served as the control group (DW); others were administered with zinc at 50 mg/kg body weight (Z) group, glyphosate at 375 mg/kg body weight (G) group, a combination of zinc and glyphosate at 50 and 375 mg/kg body weight, respectively (Z + G), group, glyphosate at 14.4 mg/kg body weight (GC) group, and a combination of zinc and glyphosate at 50 and 14.4 mg/kg body weight, respectively (Z + GC), group. At the end of the study, blood samples were collected from each rats; from which, sera samples were obtained and assayed for total protein, albumin, alanine and aspartate aminotransferases, alkaline phosphatase, Na+, K+, Cl-, [Formula: see text], Ca2+, [Formula: see text], urea and creatinine using autoanalyzer, and globulin was calculated. The albumin concentration was significantly high (p < 0.05) in GC group compared to DW group, and this change was ameliorated following supplementation with zinc. The total protein and globulin concentrations did not differ significantly between the groups (p > 0.05), and the relative changes were ameliorated by supplementation with zinc. The alkaline phosphatase activity was relatively low in GC group; however, supplementation with zinc in Z + GC group made it to be significantly high (p < 0.05) compared to GC group. The alanine and aspartate aminotransferases in G and GC groups were relatively high compared to DW group, which were ameliorated by supplementation with zinc. The relatively low Ca2+ concentration in G and GC groups compared to DW were ameliorated in Z + G group, and it was significantly high in Z + GC group at p < 0.01 compared to DW, p < 0.001 compared to G and GC groups and p < 0.05 compared to Z + G group. There were only slight changes in the electrolytes concentrations (Na+, K+, Cl-, [Formula: see text] and [Formula: see text]), which were differentially ameliorated by zinc supplementation. The reasons for the various changes recorded were discussed. It was concluded that subchronic oral exposure to glyphosate caused both hepatic and renal functions toxicity in rats, which were ameliorated by zinc supplementation.
Keywords: Glyphosate; Hepatic; Renal; Serum biochemical; Subchronic; Zinc.