LYMPHATIC FATTY-ACIDS FROM RATS FED HUMAN-MILK AND FORMULA SUPPLEMENTED WITH FISH-OIL

Absorption of long-chain polyunsaturated fatty acids from human milk a nd formula supplemented with fish oil was studied to determine if the distribution route into lymphatic triacylglycerol (TAG) and phospholip id (PL) varies with the dietary source. Rats were intraduodenally infu sed with human milk or formula containing graded amounts of fish oil ( 0, 0.5, or 1.0 g/100 mL), and the mesenteric lymph was collected. Arac hidonic acid (20:4n-6) levels in lymphatic TAC and PL were highest fro m animals fed human milk. In the animals infused with formula containi ng fish oil, as the amount of eicosapentaenoic acid (EPA, 20:5n-3) inf used increased, there was essentially an equal increase in EPA associa ted with both lymphatic TAG and PL. Animals intraduodenally infused wi th human milk or formula without fish oil had only minor levels (less than 1%) of EPA in the lymph. in the fish oil-treated animals, as the amount of docosahexaenoic acid (DHA, 22:6n-3) infused increased, there was a 16-fold increase in DHA associated with lymphatic TAG, but only a 3-fold increase in DHA associated with lymphatic PL. The highest le vel of DHA in rats infused with human milk was observed in lymphatic P L. Hence, fish oil can be added to formula as a source of long-chain p olyunsaturated fatty acids, but the distribution of fatty acids into l ymphatic TAG and pL is not the same as that observed with human milk.