Pyridaben exposure triggers osmotic and oxidative imbalance causing morphologic deformities in Daphnia magna

Pyridaben, a non-systemic insecticide and acaricide, poses a threat to aquatic organisms in regions far removed from agricultural areas due to atmospheric transport. This study aims to investigate subchronic (0.20-0.80 TU) in vivo (7 d) and in vitro biochemical effects of PDB at environmentally relevant concentrations on a non-target organism Daphnia magna. The integrated biomarker response index (IBR) approach was also employed to identify the global trend in biological responses to PDB. The SOD-CAT system was significantly upregulated, whereas Ca²⁺-ATPase activity and total protein levels decreased in correlation with morphometric traits following in vivo exposure to PDB. Additionally, glutathione metabolism parameters and SOD activity declined, and Ca²⁺-ATPase inhibition was observed after in vitro treatment. Overall, the reduced IBR values confirmed greater PDB toxicity at all tested concentrations under both experimental conditions, indicating that PDB elicited biological responses in D. magna even at its lowest concentration. These findings suggest that impairments in antioxidant and osmoregulatory systems were associated with dysmorphic changes in D. magna in response to PDB-induced toxicity. Further research is required to explore additional molecular mechanisms beyond the biochemical responses, in order to integrate multi-dimensional data under oxidative stress induced by PDB.