Influence of Dietary Fat on Triglyceride Structure in the Rat

Abstract

The structure of the triglycerides of adipose, liver and kidney tissues of rats fed a fat-free diet and diets supplemented with corn oil, lard and menhaden oil was investigated. The triglyceride composition of the tissues had no direct relationship to that of the dietary fat. Quantitative differences in the triglyceride composition of the tissues were produced by the different dietary fats as related to their fatty acid compositions. Differences between the triglyceride composition of the tissues in each group were indicated by the pattern of the distribution of the fatty acids. Such differences were especially apparent in the animals fed menhaden oil, as evidenced by high concentrations of triglycerides containing polyunsaturated fatty acids in the liver and kidney tissues when compared with the epididymal fat pads. Structural analysis of the triglycerides of all tissues indicated that a competitive interrelationship existed for the β-position, increasing, in order, with palmitic, oleic and linoleic acids. The higher polyunsaturated fatty acids of menhaden oil did not take precedence over other fatty acids for the β-position. The effect of switching the diets containing the different fatty supplements indicated that the normal turnover of lipid in the rat was a gradual process requiring at least 6 months.