The effect of dietary fat on the glyceride structure of rat carcass fat

Carcass fats were obtained from weanling rats fed a complete diet for 8 weeks, which consisted of 2% cottonseed oil and 10% of the following fats: (1) corn oil; (2) the fatty acids of corn oil; (3) triricinolein; (4) ricinoleic acid; (5) the hydrogenated fatty acids of castor oil; and (6) commercial hydrogenated shortening. The fats were subjected to both pancreatic lipase and nonspecific hydrolysis; the resulting acids converted into methyl esters by conventional methods, and subjected to gas Chromatographie analysis. From these data, the positional distri‐bution of the component fatty acids, glyceride types, and isomeric forms were calculated. The results indicated a preferential placement of un‐saturated acids in the 2‐ position of the carcass triglycerides and that the carcass fat composition in terms of unsaturated (U) and saturated (S) fatty acid composition is not greatly influenced by the S and U compositions of the dietary fat. It was found that hydroxy acids or their tri‐esters are metabolized much the same as are normal triglycerides and exert no particular in‐fluence upon the fat structure of the rat. Some type of relationship between the dietary U and the U3 in the carcass fat appears to be present. The glycerides of the carcass fats examined here are essentially a random mixture of the major glyceride types, but the isomeric forms (SUS, S SU, USU and UUS) are a definite non‐random mixture.