Fatty acid profile of muscles, liver and mesenteric fat in wild and reared perch (Perca fluviatilis L.)

This study addressed determinations of the fatty acid profile of muscle, liver and mesenteric fat in European perch originating from natural aquifers and from intensive rearing in a closed circuit on an artificial feed mixture. The qualitative composition of fatty acids was identical in both groups of perch, except for 16:4 acid identified exclusively in the reared perch. The study demonstrated equal concentrations of saturated (SFA) and unsaturated (UFA) fatty acids in muscles, liver and mesenteric fat of both groups of perch. The wild fish, however, were characterised by lower concentrations of monoenoic (MUFA) and higher concentrations of polyenoic (PUFA) fatty acids. Analyses also demonstrated similar contents of n -3 PUFA in muscles and their diversified concentrations in liver and mesenteric fat (higher in the wild fish), as well as a higher content of n -6 PUFA in all samples. The lower content of MUFA in the wild perch was mainly due to lower concentrations of cis18:1 n -9 and 20:1 n -9, whereas the higher content of n -3 PUFA was due to a higher concentration of DHA, and the higher content of n -6 PUFA was due to a higher concentration of arachidonic acid (AA). The biggest differences between wild and reared perch were detected for AA. The wild and reared perch were also found to differ in the n -3/n -6 ratio (higher in the reared fish) and to have similar values for atherogenic index (AI) (except for liver and mesenteric fat) and thrombogenicity index (TI). A comparative analysis of the fatty acid profile of diets and fish demonstrated that the contents of docosahexaenoic (DHA) and n -3 PUFA in the wild and reared fish were higher than those determined in natural feed and artificial feed mixture, whereas concentrations of AA and n -6 PUFA were consistent with those assayed in both diets. It suggests that perch displayed a capability for bioconversion of long-chain highly unsaturated fatty acids, especially of DHA, from their dietary precursors.