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

► Feeding diets containing HGSO or borage oil for 90 days had similar biologic effects. ► Metabolism of primary n−6 fatty acids in plasma and organ phospholipids was similar. ► No adverse effects were observed with HGSO fed at 1980 mg/kg bw/day and 2530 mg/kg bw/day. ► HGSO is biologically equivalent to borage oil, providing a safe alternative source of GLA in the diet.