Utilization of docosahexaenoic acid from intravenous egg yolk phospholipid

Docosahexaenoic acid (DHA, 22:6n-3) is provided directly to human premature infants during parenteral nutrition from the egg yolk fraction of an intravenous fat emulsion. This study aimed to determine whether the high egg yolk phospholipid content of Intralipid 10% (IL 10%, Pharmacia, Uppsala, Sweden) relative to the standard emulsion Intralipid 20% (IL 20%, Pharmacia) could be a strategy to increase the delivery of DHA to the developing brain. Male, Large White piglets were randomly selected from sows 3 d after birth. Piglets were assigned to receive a 9-d continuous intravenous infusion commencing 5 d after birth of either Intralipid (IL) 10%, IL 20%, or Lipofundin S 20% (LFS; B. Braun, Melsungen, Germany). There were four piglets in each treatment group. IL 10% provides twice as much DHA as IL 20%, while LFS provides no DHA. Protein and other nutrients were provided enterally using a low-fat milk formula. After 9 d, animals were killed, and the fatty acid compositions of blood, liver, and cerebral cortex were analyzed. IL 10% infusion approximately doubled the amount of plasma phospholipid DHA (microg/mL of plasma) in comparison to IL 20%. However, red blood cells, liver, and cerebral cortex phospholipid DHA levels were indistinguishable between these two groups. LFS was associated with reduced levels of DHA in plasma, red blood cell and liver phospholipids in comparison to IL 20%. We conclude that infusion of additional phospholipid is an ineffective strategy for increasing DHA delivery to piglet tissues. This may be due to the formation of inert phospholipid particles in plasma. The data do not support the concept of using IL 10% as a means of providing additional DHA to premature human infants.