EFFECTS OF MATERNAL DIETARY N-3 AND N-6 FATTY-ACIDS (PRE-DELTA-6 AND POST-DELTA-6 DESATURATION) ON TISSUE GLYCEROPHOSPHOLIPID FATTY-ACID COMPOSITIONS IN DAMS AND SUCKLING MICE

The present study examined the effects of supplementation of either 18 :3n-3 or a mixture of its post-Delta 6-desaturation metabolites, 20:5n -3/22:6n-3, in combination with either 18:2n-6 or its immediate Delta 6-desaturation product, 18:3n-6, in the maternal diet (n-3 to n-6 rati o at 0.25) on brain, liver, heart, and kidney glycerophospholipid fatt y acid composition in dams (B6D2F(1) mice) and their 12-day-old suckli ng pups. As expected, n-3 and n-6 fatty acids competed for incorporati on into tissue glycerophospholipids in both darns and their suckling p ups. Feeding a 20:5n-3/22:6n-3 as compared with an 18:3n-3 rich diet i ncreased the tissue levels of 20:5n-3 and 22:5n-3, whereas it decrease d those of 20:3n-6 and 20:4n-6. Replacing 18:2n-6 with 18:3n-6 in the maternal diet increased significantly the levels of 18:3n-6, 20:3n-6, and 20:4n-6, whereas it reduced those of 20:5n-3. However, the effects of maternal dietary fats on tissue fatty acid compositions in pups we re qualitatively similar to but quantitatively smaller than those in d ams. The discrepancy might be due to differences in the composition of fatty acids taken up and synthesized by the dams and that transferred to the pups.