Impact of the quality of dietary fatty acids on metabolism and the composition of polar lipid classes in female gonads of Pecten maximus (L.)

The impact of dietary deficiency of the essential fatty acids 20:5(n-3), 22:6(n-3) and 20:4(n-6) was studied at the level of different polar lipid classes that constitute the membrane structure of female gonads of Pecten maximus by using three microalgal diets. After 11 weeks of conditioning of the broodstock, the relative percentages of polar lipid classes were very little, or not at all, influenced by the composition of the microalgae. On the other hand, the imprint of dietary fatty acid composition was reflected in the relative composition of fatty acids specific to some classes but not all of them. The dietary fatty acid composition thus clearly influenced that of phosphatidylcholine (PC), the plasmalogens and to a smaller extent the phosphatidylserine (PS) and phosphatidylethanolamine (non plasmalogen PE), but not of phosphatidylinositol (PI) and the glycolipid (GLY). The PI showed a very stable composition and was rich in 20:4(n-6) (>30%) irrespective of the diet. Likewise, the 22:6(n-3) content was consistently higher than 76% in the glycolipid. The maintenance of the specific fatty acid composition of these classes is probably a physiological necessity for gametogenesis and embryogenesis.