Multidimensional gas chromatographic techniques applied to the analysis of lipids from wild-caught and farmed marine species

Comprehensive two-dimensional gas chromatography-mass spectrometry was exploited for the obtainment of fatty acid fingerprints in fish and molluscs from South Italy. Scope of the lipidomic investigation was to highlight differences in the fatty acid profiles of samples fromaquaculture and from the wild.Thefish speciesunder investigationwere Sparus aurata andDicentrarchus labrax, typically cultivated in Italy and commonly found in the fish market. Another aim was to find a correlation between the diet fed to fish and the expression of specific fatty acids in muscle composition. Beyond fish, two species of bivalves were analyzed to assess their lipidomic composition: Mytilus galloprovincialis (mussels) and Venerupis aurea var. laeta (clams). Both species originated fromtwo salt lakes in South Italy.GCGC–MS analysis showed that omega-3 fatty acids were naturallymore concentrated in wild fish,whereas their presence in cultivated fish was lower and in favor of omega-6 and oleic acids, as an evident consequence of food supplementation. Bivalves reported a consistentamount ofPUFA, although presenting some differences in thequality of fatty acids.As an additional parameter of investigation, the content of mercury was determined in all the samples by means of a DirectMercury Analyzer, based on Atomic Absorption Spectroscopy. Wild fish reported a level of mercury that was ten times higher than in aquafarmed fish, and the maximum amount tolerated by the EC regulation. On the contrary, the level of mercury in molluscs was in general very low, particularly when compared with samples from other Italian sites of collection.