Subcutaneous and intramuscular lipid traits as tools for classifying Iberian pigs as a function of their feeding background.

The present work was aimed to study the feasibility of classifying Iberian pigs fattened with two different diets, acorns and grass (AG) and oleic acid enriched concentrate (HO), by means of comparing the fatty acid profile and the content of different compounds of the unsaponifiable lipid fraction (neophytadiene and α- and γ-tocopherol) of subcutaneous (SCF) and intramuscular (IMF) fat of Biceps femoris and Semimembranosus muscles. The proportions of palmitic (C16:0), stearic (C18:0) and linoleic (C18:2 n-6) acids of the three studied tissues did not show a consistent behaviour as influenced by the feeding. The proportion of oleic acid (C18:1 n-9) was significantly affected by the diet in SCF and IMF of Semimembranosus muscle but not in IMF of B. femoris. Some minor fatty acids, such as arachidonic (C20:4 n-6) and linolenic (C18:3 n-3) acids, showed the best ability for the classification of the animals according to their feeding background and the obtained values showed significant differences caused by the diet in the three studied tissues. Neophytadiene and γ-tocopherol contents were statistically higher in AG than in HO pigs, while there were not differences in the α-tocopherol levels between experimental groups. Thus, it seems that procedures based on the quantification of arachidonic (C20:4 n-6) and linoleic (C18:3 n-3) acids as well as neophytadiene and γ-tocopherol levels would be useful to differentiate Iberian pigs fattened outdoors on acorns and grass from those fed MUFA enriched diets.