1. Investigación

To determine whether the composition of long-chain polyunsaturated fatty acids (PUFA) could be modified in the fetus by maternal dietary fatty acids, pregnant Sprague-Dawley rats were fed semi purified diets that differed only in the non-vitamin lipid component. The diets contained either 10 g palm, sunflower, olive or fish oil (FOD)/100 g diet. A total of 5-6 rats were studied in each group. At day 20 of gestation, corresponding to 1.5 days prior parturition, the fatty acids in maternal adipose tissue were closely related to the fatty acid composition in the corresponding diet. An important proportion of arachidonic acid (AA) appeared in maternal liver and plasma, although it was lower in the FOD than in the other groups. Except for saturated fatty acids, the proportion of individual fatty acids in the placenta correlated linearly with that in maternal plasma. Also, PUFA in fetal plasma and liver showed significant correlations with PUFA in maternal plasma. Again, AA showed the lowest proportion in the plasma and liver of the FOD group. Therefore, the maternal dietary fatty acid composition influences maternal and fetal plasma and tissue composition, and an increase in dietary co-3 fatty acids decreases the amount of AA in maternal and fetal tissues.

This study was designed to compare in rats the effects of dietary fish oil and olive oil during pregnancy and lactation on offspring development, fatty acid profile and vitamin E concentration. From d O of pregnancy, female Sprague-Dawley rats were divided into two groups that were fed purified diets that differed only in their nonvitamin lipid components. One diet contained 10 g fish oil/100 g diet (FOO), whereas the other contained 10 g olive oil/100 g diet (OOD). At d 20 of gestation, maternal adipose tissue fatty acid profile did not differ between rats fed the two diets, whereas both maternal and fetal plasma and liver arachidonic acid (AA) contents were proportionally lower and eicosapentaenoic (EPA) and docosahexaenoic (DHA) acid contents were higher in the FOD group than in the OOD group. a-Tocopherol concentration was lower in maternal and fetal plasma, liver and brain in the FOD group than in the OOD group. The postnatal increase in body weight and length was less and body and psychomotor maturation indices were delayed in pups from FOO-fed dams compared with those from OOD-fed dams. This difference was maintained when pups were cross-fostered at birth, with the delay in postnatal development present in the pups suckling dams fed FOD during lactation. At age 21 d, pups suckling dams fed FOD had lower AA and higher EPA and DHA concentrations in brain phospholipids. Although a-tocopherol in plasma and liver was lower in pups suckling dams fed FOD rather than OOD, brain a-tocopherol concentrations did not differ. Milk yield and milk a-tocopherol and AA concentrations were lower and EPA and DHA were higher in the milk of dams fed FOD compared with those fed OOD. Postnatal development indices and the proportion of plasma, liver and brain AA concentrations, although not plasma, liver and brain a-tocopherol concentrations, recovered to the values found in dams fed OOD when the FOD was supplemented with y-linolenic acid. However, postnatal development indices were not recovered when the FOD was supplemented with sufficient exogenous vitamin E to increase plasma and liver a-tocopherol concentrations above those in dams fed OOD. Thus, although feeding FOD during pregnancy and lactation decreases both a-tocopherol and AA concentrations, the latter deficiency rather than the former seems to be responsible for delayed postnatal development of rat pups.