Absorption and Metabolism of Dietary Triglycerides in Germfree and Conventional Rats

Although it is well-known that the physiology, morphology and biochemistry of the germfree animal differs in many respects from its conventionally reared counterpart, these studies were initiated to investigate the effect of the absence of the intestinal microflora on the absorption and metabolism of triglycerides derived from dietary corn oil. Germfree and conventional male rats were trained to consume a semipurified diet within a 1.5-hour period daily. Fasting plasma triglycerides were elevated significantly in the germfree animals. Analysis of the fatty acid composition of the fasting plasma triglycerides showed a higher percentage of linoleic acid in the germfree group. Postprandial plasma triglyceride analysis indicated a faster rate of clearance of the absorbed triglyceride by the germfree rat but did not indicate any apparent difference in the rate of absorption of the dietary triglyceride. Fasting plasma glucose levels were found to be elevated in the germfree animals. Glucose tolerance tests showed that the germfree rats clear glucose from the plasma more slowly than conventional rats. Immunoassay of plasma insulin obtained during the glucose tolerance testing indicated a delayed and decreased insulin secretion by the germfree rats.