Physiological and metabolic disruption in Caiman latirostris induced by realistic pesticide mixtures used in Argentina

Abstract

Wild populations of Caiman latirostris in South America are increasingly exposed to complex mixtures of pesticides linked to intensive agricultural practices. These contaminants can disrupt key physiological processes, ultimately compromising survival and reproduction. In this study, yearling caimans were subjected to a 60-day sub-chronic exposure to four commercial pesticide formulations—glyphosate (GLY; 2%), 2,4-dichlorophenoxyacetic acid (2,4-D; 0.12%), imidacloprid (IMI; 0.2%), and chlorantraniliprole (CAP; 0.03%)—and to mixtures: M1 (GLY + 2,4-D), M2 (IMI + CAP), and M3 (M1 + M2), with a negative control for comparison. Biomarkers assessed included genotoxicity, lipid peroxidation (LPO), hematological and biochemical parameters, and body condition. Results revealed treatment-specific and mixture-dependent alterations across metabolic, oxidative, and genotoxic endpoints. The Integrated Biomarker Response (IBR) index further indicated that mixtures, particularly M2 and M3, elicited the most complex and amplified responses. These findings underscore the utility of multi-biomarker approaches for evaluating pesticide impacts in wildlife and highlight the vulnerability of crocodilians to environmentally relevant chemical mixtures.