Lymphatic recovery of exogenous oleic acid in rats on long chain or specific structured triacylglycerol diets.

Specific structured triacylglycerols, MLM (M = medium-chain fatty acid, L = long-chain fatty acid), rapidly deliver energy and long-chain fatty acids to the body and are used for longer periods in human enteral feeding. In the present study rats were fed diets of 10 wt% MLM or LLL (L = oleic acid [18:1 n-9], M = caprylic acid [8:01) for 2 wk. Then lymph was collected 24 h following administration of a single bolus of 13C-labeled MLM or LLL. The total lymphatic recovery of exogenous 18:1 n-9 24 h after administration of a single bolus of MLM or LLL was similar in rats on the LLL diet (43% and 45%, respectively). However, the recovery of exogenous 18:1 n-9 was higher after a single bolus of MLM compared with a bolus of LLL in rats on the MLM diet (40% and 24%, respectively, P = 0.009). The recovery of lymphatic 18:1 n-9 of the LLL bolus tended to depend on the diet triacylglycerol structure and composition (P= 0.07). This study demonstrated that with a diet containing specific structured triacylglycerol, the lymphatic recovery of 18:1 n-9 after a single bolus of fat was dependent on the triacylglycerol structure of the bolus. This indicates that the lymphatic recovery of long-chain fatty acids from a single meal depends on the overall long-chain fatty acid composition of the habitual diet. This could have implications for enteral feeding for longer periods.