Total lipids of olive pomace (OP), olive pomace diet (OP diet), fish oil
diet (FO diet) and fish filets of farmed gilthead sea bream (fish fed
with FO diet and OP diet respectively) were extracted and separated into
polar (TPL) and neutral (TNL) lipids. All samples were assessed for
their in vitro activity against washed rabbit platelets aggregation
induced by platelet activating factor (PAF) and they were further
analyzed by electrospray-mass spectrometry. The high levels of palmitic
(16:0), oleic (18:1 cis ω − 9), linoleic (18:2 ω − 6) and
docosapentaenoic acid (DPA 22:5 ω − 3) contained in both OP and FO diets
are reflected to the gilthead sea breams fed with the individual diet
respectively, while the gilthead sea bream fed with FO diet displays a
decrease in DPA. All samples contained various glycerophospholipids
species. Two PE species were identified in OP, OP diet and fish fed with
OP diet and not in FO diet, while that might be an indication that
these substances are likely to be the key polar phospholipids that have
the ability to be in vitro PAF inhibitors, i.e. inhibit the formation of
atherosclerotic plaques in blood arteries.