Arachidonic acid (AA), an n-6 long-chain polyunsaturated fatty acid (L
C-PUFA), serves an important role in the body as a structural fatty ac
id of many tissues including neurological tissues. It is also a precur
sor of the n-6 class of eicosanoids and is the most abundant n-6 LC-PU
FA found in human breast milk. We have optimized the production of a m
icrofungal source of a triglyceride oil (ARASCO(R)) which is enriched
in AA to about 40% by weight. To establish the safety of this oil as a
food, we evaluated the effect of ARASCO(R) in Sprague-Dawley rats (20
/sex/group) gavaged at dose levels of 1.0 and 2.5 g/kg/d for a period
of 90 d, paying special attention to any potential neurotoxicity of th
e oil. Two groups of control animals received either untreated standar
d laboratory diet (untreated control) or the same diet and vehicle oil
at the same dose volume administered to the treated animals (vehicle
control). Physical observations, ophthalmoscopic examinations, body we
ight, food consumption, clinical chemistry, hematology parameters, neu
robehavioral assessments, and macroscopic as well as microscopic postm
ortem evaluations were performed. Tissue fatty acid analyses indicated
that the AA levels in the brain, heart, and liver of the high-dose AR
ASCO(R)-fed animals increased by 8, 59, and 76%, respectively, indicat
ing that the AA in the oil was readily incorporated into tissue lipids
. In spite of this high elevation in tissue AA levels, no developmenta
l, histopathological, or neuropathological differences were seen in th
e animals administered ARASCO(R) compared with the vehicle control ani
mals. Being highly enriched in AA, ARASCO(R) offers the means to study
the effect of this fatty acid in experimental settings and in human m
etabolic studies.