The Digestion and Absorption of Fat in Dog and Man

Abstract

Small amounts of endogenous lipid of fairly constant composition were recovered from all parts of the small intestine of dogs fed fat-free test meals. When cottonseed oil was fed, the composition of lipid recovered from the small intestine of dogs killed after three hours closely resembled that reported by others during the first one to two hours of the hydrolysis of triolein in vitro. The composition of lipid recovered from jejunal fistula dogs fed cottonseed oil was similar to that reported by others as being produced during the first one-fourth to one-half hour of the hydrolysis of triolein in vitro. Fat recovered from fistula dogs fed diglycerides was very similar in composition to that produced during the first one-half hour of the hydrolysis of diolein in vitro. Fat may be hydrolyzed, therefore, in much the same manner in vivo as in vitro. Hydrolysis of monoglycerides fed to dogs was very rapid in the duodenum. The proportion of diglycerides and triglycerides was greatly increased in the intestine, suggesting that synthesis and hydrolysis occur simultaneously. Gastric lipolysis of cottonseed oil and monoglycerides in the dog was slight, while butterfat was somewhat more digested in the stomach of humans. The composition of lipid recovered from the small intestine of man fed butterfat triglycerides was very similar to that found in the small gut of dogs fed cottonseed oil.