EFFECT OF MATERNAL DIETARY ARACHIDONIC OR LINOLEIC-ACID ON RAT PUP FATTY-ACID PROFILES

Rapidly growing neonatal mammals accrete relatively large quantities o f long chain (greater than or equal to C-20) polyunsaturated fatty aci ds (LCP) in membrane phospholipids. We have examined accumulation of o mega 6 LCP in suckling neonatal rat pups during the first 14 d of life when their dams received essential fatty acids in the form of triglyc erides containing linoleic acid or arachidonic acid. Dietary levels of these fatty acids were either 1 or 5% of total dietary fatty acids. T he fatty acid profile of pup stomach contents (composed solely of the dams' milk) and plasma lipids, as well as liver and brain phospholipid s, were determined, Stomach linoleic and arachidonic acid levels refle cted the diet of the dams. Pup plasma and liver arachidonic acid level s increased progressively from the group receiving 1% linoleic acid to 5% linoleic acid and from 1% arachidonic acid to 5% arachidonic acid. Interestingly, brain phosphatidylethanolamine and phosphatidylcholine arachidonic acid levels were more stable than plasma or liver levels. These results suggest that the brain may be capable of either selecti ve transport of omega 6 LCP or chain elongation/desaturation of linole ic acid. These data indicate that care must be exercised when adding L CP to infant formula since widely divergent accretion rates of arachid onic acid may occur in various tissues.