Comparison of growth, serum biochemistries and n−6 fatty acid metabolism in rats fed diets supplemented with high-gamma-linolenic acid safflower oil or borage oil for 90 days

Abstract

Recently, steps have been taken to further developments toward increasing gamma-linolenic acid (GLA) concentration and lowering costs in plant seed oils using transgenic technology. Through identification and expression of a fungal delta-6 desaturase gene in the high linoleic acid safflower plant, the seeds from this genetic transformation produce oil with >40% GLA (high GLA safflower oil (HGSO)). The aim of the study was to compare the effects of feeding HGSO to a generally recognized as safe source of GLA, borage oil, in a 90day safety study in rats. Weanling male and female Sprague–Dawley rats were fed a semi-synthetic, fat free, pelleted diet (AIN93G) supplemented with a 10% (wt/wt) oil blend containing HGSO or borage oil, with equivalent GLA levels. Results demonstrated that feeding diets containing HGSO or borage oil for 90days had similar biologic effects with regard to growth characteristics, body composition, behavior, organ weight and histology, and parameters of hematology and serum biochemistries in both sexes. Metabolism of the primary n−6 fatty acids in plasma and organ phospholipids was similar, despite minor changes in females. We conclude that HGSO is biologically equivalent to borage oil and provides a safe alternative source of GLA in the diet.