Diet (n-3) polyunsaturated fatty acid content and parity affect liver and erythrocyte phospholipid fatty acid composition in female rats

The fatty acid composition of membrane phospholipids affects the physicochemical properties of the membrane and thus influences cell function. In this study, the effects of 1-4 sequential pregnancies on the phospholipid fatty acid compositions of the maternal liver and erythrocytes were determined in female rats fed diets containing alpha-linolenic acid (ALA), ALA and preformed docosahexaenoic acid (DHA; ALA+DHA), or minimal ALA (low ALA). Virgin females, fed the diets for commensurate durations, served as a control for reproduction. Liver and erythrocyte total phospholipid compositions were determined at weaning by TLC/GC. In both tissues, significant main effects of diet and reproductive status were detected for many fatty acids, but a significant interaction of diet, reproductive status, and duration of treatment (no. of reproductive cycles or equivalent time period for virgins) was detected only for DHA, 22:6(n-3). Primiparous dams fed the ALA and low ALA diet had decreased liver DHA content of 31% and 74%, respectively, compared with virgin females fed the ALA diet. Liver DHA did not decrease further after additional reproductive cycles. Liver DHA content was unchanged in parous dams fed the ALA+DHA diet, but virgin females fed this diet exhibited a 50% increase in liver DHA after 13 wk of treatment. Changes in erythrocyte DHA were of similar magnitude and time course to those observed in liver, suggesting that this tissue may serve as a marker for liver DHA status.