Fatty acid regiodistribution analysis of divergent animal triacylglycerol samples - A possible approach for species differentiation

Possible species specificity was tested in storage lipids of red deer, moose, wild boar, extensively farmed pig, badger, rabbit and goose, by fatty acid positional distribution analysis of triacylglycerols (TAG) and 2-monoacylglycerols (2MAG). All species were proven to preferentially store monoenoic and n-6 polyenoic fatty acids in TAGs, and had higher chain length and unsaturation (except pigs) at the sn-2 position. More symmetric fatty acids were proven to acylate preferentially at the sn-2 position. In the native TAGs, the high abundance of odd-chain-length fatty acids was specific for the ruminants and rabbit. Ruminants had n-6/n-3 ratios close to 1, as was the badger, while all other species showed n-6 dominance. In 2MAGs, pigs had lower unsaturation, in a species-specific manner. The occurrence frequency of n-9 acids was lower at the sn-2 position only in pigs. The determination of the fatty acid positional distribution seems to be powerful in sample differentiation.