Soybean Oil Supplementation Improves Growth and Prevents Docosapentaenoic Acid (22: 5n–6) Accumulation in Tissues of Rats Fed on Palm Oil Diet

Effects of soybean oil supplementation as a source of linoleic and α-linolenic acids in a palm oil diet on growth and docosapentaenoic acid (22: 5n–6) levels in tissue lipids in male Sprague–Dawley rats were studied. The rats fed for two months with the diets containing soybean oil (10–50%) in palm oil showed significantly higher weight gain than that in rats fed a diet containing only palm oil as a fat source. The highest weight gain was observed in rats fed 50% soybean oil blended in palm oil. Such performance was also better than those observed in rats received diets containing soybean oil alone or canola oil alone. Addition of soybean oil to the palm oil diet prevented 22: 5n–6 accumulation in plasma, red blood cells, liver, heart, and retinal lipids with a compensative increase of docosahexaenoic acid (22:6n–3). Poly-unsaturated fatty acid profiles of brain were not affected by the addition of soybean oil. Changes in arachidonic acid contents in organs were not observed. The results indicated that soybean oil supplementation increases the weight gain and prevents the accumulation of 22: 5n–6 in the tissues which were observed in the rats fed a diet containing palm oil alone.