Comparative Study on Apparent Digestibility, Absorption and Distribution of Fatty Acids in Rats Fed Diets Containing either Beef Tallow or Plant Oils

The digestibility and absorption of dietary lipids depend on several factors including their fatty acid composition. In this study, apparent digestibility (AP) and the fatty acid profile of different dietary lipids, rich in saturated (SFA) and monoor polyunsaturated fatty acids (MUFA, PUFA), and also effects of some fatty acids especially stearic acid (18:0), was studied in rats. Twenty-four SD-male rats (7 weeks old) were raised for 6 weeks on 4 different diets containing 12% of beef tallow canola oil, olive oil or safflower oil. Patterns of distribution of different fatty acids in body tissues of rats was described. Rats raised with beef tallow, with high content of 18:0, showed significantly lower apparent digestibility compared to other diets with lower 18:0 content.(P,0.05). Stearic acid was one of the main fatty acid of fecal undigested fats. It can be concluded that poor digestibility of beef tallow is due to higher content of (18:0). Not significant cholesterolemic effect of beef tallow in spite of its high contents of palmitic acid was also attributed to its high content of stearic acid, which is considered to be an exceptional non-cholesterolemic and even cholesterol-lowering SFA.