Recovery of Behavioral Impairments in F1 Offspring of Zebrafish ( <i>Danio rerio</i> ) Induced by Parental Imidacloprid Exposure Linked to Attenuation of Disruptions in Visual and Circadian Systems

The intergenerational effects on behavior following parental imidacloprid (IMI) exposure were detected in zebrafish F1 offspring at different stages. At 4 dpf, F1 larvae exhibited detectable IMI residues, accompanied by significant behavioral impairments, altered expression levels of opsin and circadian rhythm genes, and reduced levels of retinol-related metabolites. At 2 and 4 months, no statistical variations were detected in the behavioral end points and the levels of retinol-related metabolites. The changes in the mRNA/protein levels of opsins and circadian rhythm were reduced in the number and/or the tested time points. The reduction in changes in gene/protein expression and metabolites might partially explain the recovery of behavioral abnormalities, which occurred concurrently with the elimination of IMI and the development of zebrafish F1 offspring. These results emphasize that circadian photoentrainment orchestrates diverse behaviors, highlight the importance of critical developmental windows in toxicology, and suggest the potential resilience of zebrafish to recover from parental exposure.