EFFECT OF FAT-FREE DIET ON FATTY-ACID UNSATURATION

The aim of this study was to investigate the effect of short-term fat-free protein-cabohydrate diet (protein, 11.94%; carbohydrate, 75.33%) on the change in the liver lipid fatty acid content. Male Fischer rats were fed fat-free during 14 days. The other group of animals was on a control diet (protein, 19.73%; carbohydrate, 64.82%; lipids, 3.67%). The two diets were isocaloric (15 kJ/g-1). The total lipids in the liver of rats on fat-free diet were observed to increase by 19%, as compared to 6% in rats on control diet. Fatty acids were determined by gas chromatography. After the fat-free diet, unsaturated fatty acids were found to be increased and the factor of desaturation, D(f), as assessed for C16 and C18 acids, was as follows: D(f)16 = 18.3 and D(f)18 = 40.7. Desaturation of total lipid fatty acids was a reflection of an increased proportion of triacylglycerol monoenoic acids and free fatty acids. Desaturation was not observed in the groups of polar lipids. Therefore, such a diet appeared to result exclusively in fatty acid desaturation at level of monoenoic acids of energy-relevant nonpolar liver lipids.