Effect of deltamethrin on the physiological response of Mudskipper (Apocryptes bato)

Abstract

The extensive use of agrochemicals and industrial effluents that contain toxic substances pollutes water bodies and damages aquatic ecosystems. This study focused to investigate the sublethal toxicity of deltamethrin (DM) on a Mudskipper species (Apocryptes bato) highlighting its physiological, hematological, and biochemical consequences. After 48 hours, the lethal concentration (LC50) of DM was found to be 42.2 ppm. Significant disruptions in growth performance, including decreased weight gain, specific growth rate, and feed conversion efficiency, as well as an increased feed conversion ratio, were caused by sublethal exposure at concentrations of 4.25 ppm (10% of LC50) and 8.50 ppm (20% of LC50). Under pesticide stress, hematological parameters determines including hemoglobin, cholesterol, and red blood cell count showed notable decreases, whereas glucose levels increased rapidly. Decreases in serum albumin, globulin, total protein, and ion (Na⁺ and Cl⁻) concentrations were found due to deltamethrin exposure. Additionally, fish exposed to DM had higher erythrocytic morphological alterations, including both cellular (twin, tear-drop shaped cell, elongated, fusion, echinocytic) and nuclear abnormalities (nuclear degeneration, karyopyknosis, notched nuclei and micronuclei). These results demonstrate how susceptible mudskippers are to exposure to deltamethrin, even at sublethal levels, and how the pesticide can interfere with essential physiological and metabolic functions. The study's assessed characteristics are reliable signals for assessing pesticide toxicity in aquatic environments, indicating the necessity of appropriate pesticide application regulations to protect aquatic ecosystems. This study demonstrates that, even at sublethal doses, deltamethrin poses serious ecological risks to aquatic ecosystems by significantly altering hematological, physiological, and ion concentration parameters.