High levels of dietary arachidonic acid triglyceride exhibit no subchronic toxicity in rats

Arachidonic acid (AA), an n-6 long-chain polyunsaturated fatty acid (LC-PUFA), serves an important role in the body as a structural fatty acid of many tissues including neurological tissues. It is also a precursor of the n-6 class of eicosanoids and is the most abundant n-6 LC-PUFA found in human breast milk. We have optimized the production of a microfungal 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 the oil. Two groups of control animals received either untreated standard 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 weight, food consumption, clinical chemistry, hematology parameters, neurobehavioral assessments, and macroscopic as well as microscopic postmortem evaluations were performed. Tissue fatty acid analyses indicated that the AA levels in the brain, heart, and liver of the high-dose ARASCO(R)-fed animals increased by 8, 59, and 76%, respectively, indicating that the AA in the oil was readily incorporated into tissue lipids. In spite of this high elevation in tissue AA levels, no developmental, histopathological, or neuropathological differences were seen in the animals administered ARASCO(R) compared with the vehicle control animals. Being highly enriched in AA, ARASCO(R) offers the means to study the effect of this fatty acid in experimental settings and in human metabolic studies.