Does commercial indoxacarb pose ecotoxicological consequences? Employing a multi-marker approach in the model species Theba pisana

Indoxacarb is one of the most extensively used oxadiazine insecticides worldwide, but it may exert detrimental effects on ecosystems, population dynamics, and health. Due to the lack of knowledge on the ecotoxicity of indoxacarb, it is still challenging to assess whether this insecticide poses an ecotoxicological impact on terrestrial environments. Therefore, our study aims to provide novel data on the toxic effects of 28-day dietary exposure to commercial grade indoxacarb at two environmentally relevant concentrations, 0.02 µg/mL and tenfold (0.2 µg/mL) on the model species, Theba pisana. Their effects were studied using a multiple biomarker approach by evaluating physiological, biochemical, and histopathological responses. After 28 days of treatment, indoxacarb at both concentrations significantly reduced the food intake and growth of the treated snails. Also, it caused decreases in lipid peroxidation (LPO) levels after 7 and 14 days of exposure, whereas an opposite effect occurred after 21 and 28 days. All treated snails were found to exhibit a lower content of glutathione (GSH) after all times of exposure. Moreover, catalase (CAT), glutathione-S-transferase (GST), and glutathione peroxidase (GPx) activities, as well as protein content (PC), were elevated in the treated snails after all time intervals. Post exposure to both realistic indoxacarb concentrations, changes in acetylcholinesterase (AChE) activity between a decrease and an increase were observed. Furthermore, indoxacarb caused histo-architectural changes in the hepatopancreas of T. pisana. Our results demonstrate that, at environmentally relevant concentrations, indoxacarb poses negative consequences for T. pisana, indicating its ecotoxicological impacts.