Buprofezin induces exoskeletal defects in the whiteleg shrimp Litopenaeus vannamei: From mechanical properties to molecular mechanisms

Buprofezin (BPFN), an insecticide that inhibits arthropod chitin synthesis, is widely applied in agriculture and increasingly detected in aquatic environments. Given the evolutionary conservation of chitin biosynthesis pathways, its potential impacts on non-target crustaceans remain poorly understood. In this study, we investigated the effects of environmentally relevant BPFN concentrations on the exoskeletal properties of the whiteleg shrimp Litopenaeus vannamei . Nanoindentation revealed significant reductions in exoskeletal stiffness and hardness following BPFN exposure. Consistently, chitin and total calcium content decreased, accompanied by reduced mineral density and cuticular volume as shown by histology and micro-CT imaging. These structural impairments were closely associated with altered patterns of molt-related physiological and biochemical indicators, including changes in glycogen storage, chitinase activity, carbonic anhydrase activity, and Ca 2 + dynamics, and metabolites annotated to steroid-related pathways. Integrated transcriptomic and metabolomic analyses further revealed that BPFN markedly suppressed amino sugar and nucleotide sugar metabolism, downregulating key enzymes required for chitin precursor generation. BPFN also interfered with ECM-receptor interactions and ER-associated protein processing, disrupting cuticular protein assembly, and perturbed TGF-β/BMP signaling pathways critical for calcium carbonate deposition. Correlation analyses linked these molecular disturbances with defects in chitin synthesis, matrix organization, and biomineralization. In summary, our findings demonstrate that BPFN exposure compromised the structural integrity and mechanical performance of L. vannamei exoskeleton by impairing chitin synthesis and recycling, disturbing cuticular protein processing, weakening calcium carbonate mineralization, and disrupting molt-associated physiological processes.