Abstract: In this study, in order to investigate the metabolic pathway of semicarbazide, a metabolite of nitrofurazone, in crustacean aquatic products, the accumulation of nitrofurazone and its metabolites in Procambarus clarkii was evaluated at different time points, and the metabolomics characteristics of semicarbazide were analyzed by ultra-high performance liquid chromatography-quadrupole/electrostatic field orbitrap high resolution mass spectrometry (UPLC-Q-Exactive-MS). Meanwhile, substances that may be related to semicarbazide production in the metabolic pathway were examined through in vitro simulation test. The results showed that the semicarbazide content in the muscle tissue of P. clarkii increased with increasing nitrofurazone stress period, while the nitrofurazone content initially increased, then decreased and finally increased again. Metabolomics demonstrated that a total of 39 differential metabolites were annotated in samples treated with nitrofurazone for 24 h compared to 4 h, of which 22 metabolites were up-regulated while the remaining 17 were down-regulated. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis suggested that nitrofurazone exposure could affect pathways associated with taurine and hypotaurine metabolism, arginine biosynthesis, alanine, aspartate and glutamate metabolism, and D-glutamine and D-glutamate metabolism. Validation tests confirmed that taurine, arginine, alanine and glutamine might be crucial in the metabolic pathway of semicarbazide.

Key words: nitrofurazone; semicarbazide; metabolomics; metabolite changes; in vivo simulation