Diets rich in saturated, monounsaturated and polyunsaturated fatty acids differently affect plasma lipids, platelet and arterial wall eicosanoids in rabbits

New Zealand male rabbits, on a moderate dietary fat intake (10.2% w/w) received, as the major dietary lipid, butter, olive oil and corn oil, respectively, for a period of 8 weeks. At the end of the dietary treatment, plasma total cholesterol was significantly decreased in the corn oil group, compared to butter, whereas the olive oil-consuming rabbits had an intermediate cholesterolemia; the corn oil and olive oil groups had significantly elevated high-density lipoprotein (HDL) cholesterolemia, compared to the butter group. Maximal platelet aggregability, with collagen and arachidonic acid, did not appear to differ in the three treatment groups. Thromboxane B₂ release in the sera of treated rabbits was slightly higher after corn oil administration. The arterial release of prostacyclin (PGI₂), tested by perfusing platelet-rich plasma through the aorta of donor rabbits, was lowest in the corn oil group. Corn oil is the most effective dietary fat in reducing cholesterolemia, but it may also reduce PGI₂ release from arteries. Butter has the most unfavorable effect on lipidemia and HDL-cholesterol, whereas dietary olive oil shows an intermediate lipid-lowering activity but preserves arterial PGI₂ production.