Effect of essential fatty acid deficiency on maternal, placental, and fetal rat tissues.
Prolonged dietary deprivation is needed to produce essential fatty acid (EFA) deficiency. But lack of EFA also impairs reproductive function. Inclusion of small amounts of linoleic acid in the diet can overcome this difficulty; further, if large amounts of oleic acid are included in the diet, this competes with the utilization of 18:2 producing EFA deficiency. Using this approach, female rats were fed a fat-free diet containing 5% oleic acid w/w (with 2-3% 18:2) as the only source of fat for 4 months. They were mated and on the 21st day of gestation, the fatty acids of fetal tissues, placenta, maternal liver and plasma were analyzed and compared to controls on a stock diet. Fetuses from the experimental group were smaller and contained higher amounts of 18:1 and 20:3 omega 9 indicating EFA deficiency. The omega 6 fatty acids in the polar lipids of placenta of the EFA-deficient group were not significantly lower than the controls, in spite of lower concentrations in the maternal plasma, suggesting a unique capacity of the placenta to concentrate omega 6 fatty acids, which in turn may be utilized for prostaglandin synthesis needed for inducing labor and other vascular changes in the fetus.