Impact of Sub-Lethal Atrazine Exposure on Haematology, Serum Biochemistry, And Muscular Accumulation on Juveniles of Clarias Gariepinus and Its Hybrid with Heterobranchus Longifilis

Okpala-Ezennia KP, Nlewadim AA and Ikeogu CF

Published on: 2024-03-28

Abstract

Toxicology studies on aquatic animals such as fish are of great importance for the evaluation of various hazardous effects of toxicants, even at sub-lethal concentrations. This study investigated the chronic toxicity of atrazine herbicide on juveniles of Clarias gariepinus and hybrids (male Clarias gariepinus X female Heterobranchus longifilis) of mean weight 7.60±0.10g and mean standard length 3.51±0.13cm who were exposed to sub-lethal doses of 0.6, 1.3, and 2.5 mg/L of atrazine and a control (0.00 mg/L) for 84 days. Results from the study indicated that the values of packed cell volume, hemoglobin, and red blood cell count decreased in a dose-dependent manner, with the lowest values of (27.00±3.00), (10.03±0.56), and (2.78±5.78) recorded, respectively, in the hybrid juveniles exposed to the highest atrazine concentration (2.5 ml). While total white blood cell count and lymphocytes increased in a dose-dependent manner, with highest values of 2.65±0.50 and (82.33±0.58) recorded, respectively, in the hybrid juveniles exposed to the highest atrazine concentration. The highest value of neutrophils (29.67±0.57) was recorded in the control group of hybrids, while the least value (17.67±0.58) was recorded in the hybrid with the highest concentration of atrazine exposure. Serum biochemical analysis showed a significant difference (P<0.05) between the control and exposed groups for both species. Aspartate amino transferase (AST) and Alanine amino transferase (ALT), cholesterol, serum glucose, and low-density lipoproteins increased significantly, with highest values of 27.33±0.58, 21.00±1.00, 135.4±0.25, 45.67±0.58, and 71.43±0.06, respectively, in hybrids exposed to the highest concentration. There was a significant decrease in serum protein and high-density lipoproteins (HDL), with the least values of 2.00±0.01 and 64.36±0.12 found, respectively, in the hybrid with the highest atrazine exposure. Atrazine accumulation on the muscle tissue was found to be highest (5.76±0.04) in hybrid species exposed to 2.5 mL of atrazine concentration. Results of the sub-lethal toxicity test showed that atrazine was toxic to both species in a dose-dependent manner. The data collected from this study will contribute to the baseline behavioral, hematological, and biochemical parameters used in monitoring the health status of Clarid fish species in the aquaculture sector.