Use of elemental profiling and isotopic signatures to differentiate Pacific white shrimp (Litopenaeus vannamei) from freshwater and seawater culture areas

Shrimp samples from aquaculture ponds supplied with either freshwater (0.2-1.3 g L-1 salinity) or seawater (27.6-39.0 g L-1 salinity) were subjected to elemental profiling and to stable isotope analysis. Concentrations of 35 trace elements, including rare earth elements (REEs) were analyzed by ICP-MS, and the delta C-13 and delta N-15 concentrations were analyzed by IRMS in samples of peeled un-deveined (PUD) shrimp and in shrimp feed. Concentrations of 13 elements in pond water could be measured by ICP-MS. The analysis results showed that feeds offered to shrimp in freshwater and seawater did not differ in elemental concentrations (P < 0.01). Four elements (Li, Cr, Mn and Sr) were different (P < 0.05) between freshwater and seawater. The correlation between Cr in water and in shrimp was significant. Multivariate statistics including principal component analysis, stepwise discriminant analysis, canonical discriminant analysis and Kernel method demonstrated the validity of elemental profiling in distinguishing shrimp cultured in freshwater from those reared in seawater. The REEs such as Lu were more relevant to determining the provenance of shrimp than were Sr, Ba, Mn, As and delta N-15.