Effects of Grazor (Glufosinate-Ammonium) Herbicide on the Behavioural Responses and Serum Biochemical Parameters in Nile Tilapia (Oreochromis niloticus)

The indiscriminate application of herbicides in agriculture for weed control and to improve agricultural productivity has led to significant contamination of aquatic ecosystems, resulting in physiological dysfunction in aquatic biota including fish. This study investigated the acute and sub-lethal effects of Grazor, a glufosinate-based herbicide, on the behavioural and biochemical parameters of Nile tilapia (Oreochromis niloticus). For the acute toxicity test, fish were exposed to 0.30, 0.60, 1.20, 2.40, and 4.80 mL/L of the herbicide for 96 h and to 0.07, 0.15, and 0.29 mL/L for 28 days to determine the effects of the herbicide on the biochemical parameters of the fish, and were withdrawn 24 h after exposure. The 96-h LC50 of the Grazor herbicide in the fish was estimated at 1.17 mL/L. The exposure led to behavioural abnormalities including hyperactivity, surface orientation, stress, restlessness, temporary calmness, and mortality, in comparison with the control group. Biochemical analysis revealed significant increases in alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), creatinine, and urea levels at higher concentrations. Total protein levels decreased relative to the control, while albumin and globulin levels showed no consistent pattern. Exposure to acute and sublethal concentrations of Grazor herbicide can cause behavioural disturbances and biochemical dysfunction in O. niloticus. Care should be taken when handling and applying this herbicide to avoid the adverse effects it may cause in aquatic organisms including fish.