Diet (n-3) polyunsaturated fatty acid content and parity interact to alter maternal rat brain phospholipid fatty acid composition

Abstract

Low tissue levels of (n-3) polyunsaturated fatty acids (PUFAs), particularly docosahexaenoic acid [DHA, 22:6(n-3)], are implicated in postpartum depression. The effects of 1-4 sequential reproductive cycles on maternal brain phospholipid fatty acid composition were determined in female rats fed diets containing alpha-linolenic acid (ALA), containing ALA and pre-formed DHA (ALA+DHA), or lacking ALA (low-ALA). Virgin females, fed the diets for commensurate durations served as a control for reproduction. Whole-brain total phospholipid composition was determined at weaning by TLC/GC. A single reproductive cycle on the low-ALA diet decreased brain DHA content by 18% compared to ALA primiparas (P < 0.05), accompanied by incorporation of docosapentaenoic acid ((n-6) DPA, 22:5(n-6)) to 280% of ALA primiparas (P < 0.05). DHA was not further decreased after subsequent cycles; however, there was an additional increase in (n-6) DPA after the second cycle (P < 0.05). Brain DHA of virgin females fed the low-ALA diet for 27 wk decreased 15% (P < 0.05), but was accompanied by a more modest increase in (n-6) DPA than in parous low-ALA dams (P < 0.05). Virgin females and parous dams fed the diet containing ALA+DHA exhibited only minor changes in brain fatty acid composition. These observations demonstrate that brain DHA content of adult animals is vulnerable to depletion under dietary conditions that supply inadequate (n-3) PUFAs, that this effect is augmented by the physiological demands of pregnancy and lactation, and that maternal diet and parity interact to affect maternal brain PUFA status.