Fish oil supplementation of maternal rats on an n-3 fatty acid-deficient diet prevents depletion of maternal brain regional docosahexaenoic acid levels and has a postpartum anxiolytic effect

Docosahexaenoic acid (DHA) and arachidonic acid (AA) are the major polyunsaturated fatty acids (PUFA) in the neuronal membrane. Most DHA and AA accumulation in the brain occurs during the perinatal period via placenta and milk. This study examined whether maternal brain levels of DHA and AA are depleted during pregnancy and lactation due to meeting the high demand of the developing nervous system in the offspring and evaluated the effects of the reproductive cycle on serotonin metabolism and of fish oil (FO) on postpartum anxiety. Pregnant rats were fed during pregnancy and lactation with a sunflower oil-based n-3 PUFA-deficient diet without or with FO supplementation, which provided 0.37% of the energy source as n-3 PUFA, and the age-matched virgin rats were fed the same diets for 41 days. In both sets of postpartum rats, decreased DHA levels compared to those in virgin females were seen in the hypothalamus, hippocampus, frontal cortex, cerebellum, olfactory bulb and retina, while AA depletion was seen only in the hypothalamus, hippocampus and frontal cortex. Serotonin levels were decreased and turnover increased in the brainstem and frontal cortex in postpartum rats compared to virgin rats. FO supplementation during pregnancy and lactation prevented the decrease in maternal brain regional DHA levels, inhibited monoamine oxidase-A activity in the brainstem and decreased anxiety-like behavior. We propose that the reproductive cycle depletes maternal brain DHA levels and modulates maternal brain serotonin metabolism to cause postpartum anxiety and suggest that FO supplementation may be beneficial for postpartum anxiety in women on an n-3 PUFA-deficient diet.