ORIGINAL ABSTRACT

Glyphosate, a prevalent herbicide, has raised concerns due to its potential ecological impact, especially on aquatic ecosystems. While it is crucial for managing agricultural productivity, its inadvertent effects on non-target aquatic species like the red swamp crayfish, Procambarus clarkii, are not fully understood. In the present study, the neurotoxicity, oxidative stress, and immune suppression of glyphosate on P. clarkii were investigated. Sublethal glyphosate exposure (5, 10 and 20 mg/L) for 96 h was found to significantly decrease AChE activity in both brain and hepatopancreas, correlating with reduced foraging efficiency and increased turnover time. Oxidative stress was evident through increased lipid peroxidation (LPO) and malondialdehyde (MDA) levels and altered antioxidant enzyme activities such as superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx). In addition, the total antioxidative capacity (T-AOC) was inhibited at 10 and 20 mg/L of glyphosate exposure. Immune assays revealed a decrease in total hemocyte counts (THC) and suppression of key immune enzyme activities and transcriptional expressions at higher concentrations, suggesting compromised immune defenses. The findings demonstrate that glyphosate can induce considerable neurotoxic and immunotoxic effects in P. clarkii, disrupting essential physiological functions and behavior.