Maternal body weight gain and fetus development of rats fed a moderately altered olive oil.

The present study examines whether the consumption of a moderately altered olive oil influenced body weight gain and food efficiency ratio of pregnant rats as well as placental and fetal development. Olive oil used for frying 15 times undergoes a relatively slight alteration involving a statistically significant increase in polar content (9.0+/-0.1 mg/100 mg oil vs 2.0+/-0.1 mg/100 mg oil; p < 0.001). The methyl ester content also increased (5.1+/-0.8 mg/100 mg oil vs 1.8+/-0.5 mg/100 mg oil; p < 0.02), while the linoleic acid and oleic acid contents decreased significantly (6.2+/-0.6% oil vs 7.2+/-0.2% oil and 75.8+/-0.6% vs 78.9+/-0.2%, respectively, both p < 0.05). Wistar rats were divided into four groups, two of which included pregnant rats (P1 and P2) and the other two, non-pregnant rats (NP1 and NP2). Groups NP1 and P1 received a diet containing 15% of fat as unused olive oil, while groups NP2 and P2 were fed a diet with a fat content of 15% as the olive oil used in 15 fryings. Pregnancy increased food intake, body weight, weight gain and food efficiency ratio (P1 vs NP1, and P2 vs NP1), while consumption of the used olive oil diet with respect to the unused oil diet did not alter food intake, body weight, weight gain and food efficiency ratio, placental weight, fetal weight and the number of fetuses in P2 rats with respect to P1 ones. These results suggest that in pregnant rats consumption of olive oil with a moderate level of alteration, as the only dietary fat source, exerts no detrimental effects on the mother weight gain or conceptus development.