Postprandial. serum triacylglycerols and oxidative stress in mice after consumption of fish oil, soy oil or olive oil: Possible role for paraoxonase-1 triacylglycerol lipase-like activity

Objective: Postprandial triacylglycerols and oxidative stress responses are influenced by the type of fat consumed. We investigated the effect of individual unsaturated fatty acids or oils (fish; soy, or olive) on postprandial triglyceridemia response in association with serum resistance to oxidation and paraoxonase-1 (PON1) activity. Methods: Balb/C mice were supplemented with phosphate buffered saline.(control), docosahexaenoic acid (omega-3), linoleic acid (omega-6), or oleic acid (omega-9; 500 mu g/300 mu L of phosphate buffered saline) and with fish, soy, or olive oil (300 mu L); blood samples were collected 2 h after feeding. Results: Serum triacylglycerol and oxidative stress responses increased after intake of all unsaturated fatty acids and oil supplements. However, ingestion of fish oil or its major fatty acid, docosahexaenoic acid, induced the most remarkable increase in postprandial serum triacylglycerols and in the susceptibility of serum to in vitro oxidation. Serum PON1 activity was decreased by 24% after fish oil ingestion. The increase in postprandial serum susceptibility to oxidation was lower after soy oil supplementation to PON1-transgenic mice in comparison with Balb/C mice, showing that PON1 attenuates the postprandial serum oxidative response. In parallel, in PON1-transgenic mice, a decreased postprandial triacylglycerol response was noted, suggesting PON1 involvement in triacylglycerol metabolism. PON1 exhibited a triacylglycerol lipase-like activity on chylomicrons. Conclusion: PON1 attenuates the postprandial oxidative stress response, and this could have resulted from PON1 lipase-like activity on chylomicron triacylglycerols. (c) 2006 Elsevier Inc. All rights reserved.