Lymphatic absorption of docosahexaenoic acid given as monoglyceride, diglyceride, triglyceride, and ethyl ester in rats

Lymphatic absorption of docosahexaenoic acids (DHA) given as monoglyceride (MG), consisting of 1 (or 3)-species (91.4%), 2-species (4.2%) and diglyceride (DG) consisting of 1.3-species (70.8%), 1(or 3),2-species (28.6%), were investigated in comparison with that of triglyceride (TG) and ethyl ester (EE). Rats were infused with a lipid emulsion containing 200 mg of DHA-MG, DG, TG, or EE via a gastric cannula. Lymph was collected through the thoracic lymph duct at 2 h intervals for 10 h and at a single collection from 10 to 30 h. Physiological saline containing glucose was infused (2 mL/h) throughout the lymph collection. The overall recovery of DHA at 30 h after its infusion was significantly higher in the rank order DHA-MG>DG>TG=EE. Moreover, time-dependent changes in recovery rates from 2 to 10 h of DRA given as MG were significantly higher than those of the corresponding DG, TG, and EE. These results indicate that DHA-MG and DG are absorbed and transported more effectively than TG and EE forms under restricted water supply, even if they mainly consist of 1 (or 3)-species. Lymph lipids were mainly transported as TG, and a large amount of DHA was incorporated into a TG fraction in all fat types examined. Furthermore, the intramolecular distribution of DHA in lymph TG was similar in all groups.