Impact of parenteral lipid emulsions on the metabolomic phenotype in preterm TPN‐fed piglets

Abstract

Lipids in parenteral nutrition provide essential fatty acids and are a major source of energy for hospitalized neonates. Intralipid (IL) is the only approved lipid emulsion in the U.S, but new generation emulsions include Omegaven (OV) and SMOFlipid (SL). There are no studies describing the metabolite profile in neonates comparing different type of lipid emulsions. Our aim was to perform metabolomic profiling of liver and muscle tissue in TPN‐fed piglets given different lipid emulsions. Preterm pigs were assigned to 4 groups (7–14 pigs/group; equal daily macronutrient intake with 5 g/kg lipid): PN+IL, PN+OV, PN+SL and an enteral group fed milk formula (EN). Plasma, muscle and liver tissue were collected after 14 d and subjected to analysis of fatty acid, amino acid and citric acid cycle metabolites by various HPLC and GC/MS methods. In liver tissue, acyl‐CoA species were most abundant for the dominant fatty acids in the respective lipid emulsions. Tissue free carnitine in EN pigs was 4‐fold higher than TPN groups and this resulted in a reduced liver, but not muscle acyl‐carnitine levels. The acyl‐CoA:acyl‐carnitine ratios were higher in liver than muscle tissue and also higher in all TPN groups vs EN. Among citric acid cycle intermediates, only citrate was higher in EN vs. all TPN groups. We conclude that metabolomic profiles revealed a carnitine deficiency in TPN groups that suggests impaired hepatic fatty acid oxidation.Grant Funding Source:USDA