Effects of Δ5 polyunsaturated fatty acids of maritime pine ( Pinus pinaster ) seed oil on the fatty acid profile of the developing brain of rats

Conifer (pine) seeds are a potential source of dietary oils, but their safety and nutritional properties are not well established. Conifer seed oils differ from common edible vegetable oils in having a series of unusual polyunsaturated fatty acids (PUFA) with a polymethylene‐interrupted (PMI) double bond system and a double bond at the Δ5 position. A rat study was conducted to assess whether Δ5 PMI‐PUFA of conifer seeds could alter the levels of n−6 and n−3 long‐chain polyunsaturated fatty acids (LC‐PUFA) in mothers' milk and the developing brain of fetuses and pups. Feeding maritime pine ( Pinus pinaster ) seed oil (MPO) diet with a Δ5 PMI‐PUFA content of 1.4 g/100 g throughout pregnancy and lactation resulted in a large incorporation of Δ5 PMI‐PUFA in mothers' milk (5.1±0.5% of total fatty acids). The fetus (17 d old) and pup (22 d) brains, however, accumulated very little (0.6 and 0.4% of total fatty acids, respectively) Δ5 PMI‐PUFA. Mother's milk and pup's brain of the MPO group contained normal levels of 20∶4n−6, 22∶4n−6, and 20∶5n−3 compared to a reference group of rats fed a fat blend of sunflower, high‐oleic sunflower, and canola oils. The level of 22∶6n−3, however, was slightly but significantly ( P <0.05) higher in milk and pup brain of the MPO group. These results show that Δ5 PMI‐PUFA of MPO exert no negative effect on the levels of n−6 and n−3 LC‐PUFA in rat brain during its early development.