Agriculturally relevant pesticide exposure scenario induces early-life lipid metabolism disruption and physiological stress in Caiman latirostris.

Pesticide use in extensive agriculture generates complex exposures for wildlife, however, early-life effects in reptiles remain underexplored. In this study, we evaluated whether embryonic exposure at manufacturer-recommended concentration for field use: glyphosate (GLY at 1 and 2%), 2,4-D (at 0.06 and 0.12%), chlorantraniliprole (CAP at 0.015 and 0.03%), imidacloprid (IMI at 0.1 at 0.2%) and three mixtures at the lowest concentrations (M1: GLY+2,4-D; M2: CAP + IMI; M3: M1+M2) disrupt lipid metabolism, lipoperoxidation and corticosterone levels in Caiman latirostris hatchlings. Hatching success declined under 2,4-D 0.06%, CAP 0.03%, and IMI 0.2%. Residual yolk showed alterations in polyunsaturated fatty acids, together with yolk-cholesterol and α-tocopherol depletion, particularly under CAP 0.03% and in the complex mixtures M1, M2, and M3. Changes in plasma lipid profiles, hepatic aminotransferase activities as well as alteration of NADPH-producing gene expression in blood were observed in M2 and M3. Higher lipoperoxidation levels were observed at the highest concentration across single compounds and in M1 and M3; whereas corticosterone increased in 2,4-D 0.12%. These findings demonstrate that early life stages of caimans are highly sensitive to these xenobiotics, affecting lipid metabolism and associated physiological processes. Moreover, mixtures induced stronger and more complex responses than single compounds, leading to metabolic disruption during early development. Our findings highlight the importance of evaluating realistic agrochemical mixtures to better assess their ecological risk.