Absorption of triglycerides with defined or random structure by rats with biliary and pancreatic diversion

Fat absorption may be compromised by pancreatic or bile insufficiency, resulting in low uptake of essential fatty acid and energy. Using a rat model of malabsorption, we examined the absorption of defined triglycerides with medium-chain fatty acids (MCFA) in the sn-1,3 positions and essential fatty acids in the sn-2 position (MLM) compared to other fats. The thoracic duct was cannulated for collection of lymph, and the common bile and pancreatic duct was cannulated to divert both the pancreatic juice and bile. The rats were given a single bolus of triglyceride as a taurocholate emulsion. Fat absorption was measured from collected lymph samples. The triglycerides administered were a defined triglyceride, MLM [mainly (8:0/10:0)-(18:2n-6)-(8:0/10:0)], a similar triglyceride subjected to chemical randomization, a mixture of medium-chain triglycerides and soybean oil, and soybean oil, respectively. The first three triglycerides had approximately 36 wt% linoleic acid (18:2n-6) content. Administration of defined triglyceride was followed by significantly higher lymphatic level (wt%) of 18:2n-6 (P < 0.01) as well as a relative enhancement in mol% of 18:2n-6 (P < 0.05) compared to the other triglycerides. Lymphatic absorption of MCFA was similar in the three first groups but not as efficient as for long-chain fatty acids. Our results indicate that defined triglycerides thus may provide a means to increase absorption of essential fatty acids in fat malabsorption, such as that seen in cystic fibrosis, or for pre-term infants.