Effect of feeding gilthead seabream ("Sparus aurata") with vegetable lipid sources on two potential inmunomodulator products : prostanoids and leptins

Abstract

Gilthead sea bream (Sparus aurata) were fed practical-type diets that contained different levels of substitution with a blend of linseed, rapeseed and palm oil (LO, RO, PO) for a 155 days periodo The major PUFA in total, neutral and polar lipids from plasma were related to the dietary lipid intake. Levels of n- 6 PUF A were highest while levels of n-3 PUF A were lower in fish fed vegetable oils compared with those fed fish oil. Fish fed blends of vegetable oils had significantly decreased 22:6n-3, 20:5n-3 and 20:4n-6 compared with fish oil fed fish in total, polar and neutral lipid classes. While fish vegetable oils had significantIy higher levels of 18:2n-6, 18:3n-3, 18:1n-9, 20:2n-2 and 20:3n-6. There was also higher levels of 20:3n-3 and 20:3n-4. There was a constant level of 20:4n-6/20:5n-3 in plasma phospholipids among the four treatment, and reduced level of 20:4n-6/20:3n-6 in fish fed vegetable oils due to the increased 20:3n-6 in polar lipid of plasma from those fish. There was a little difference between the composition on fatty acids PI from leucocytes and phospholipids from plasma, PI incorporated more C20 PUF A and maintained a constant, but higher, ARAIEPA ratio and t a very small or inexistent content on DHGLA in this phopholipids. Production of PGE2 in plasma was not different among the four treatment which may be explained by the constant eicosanoids precursor. PGE3 levels in plasma were different among the four treatments and was strongly correlated to EP A content in polar lipids, the highest value was enregistred in fish fed FO and the lowest in fish fed 100 % blend of vegetable oils. Plasma leptin was not different among the four treatments and correlate strongly with feed intake and conversion indexo.