Continuous Parenteral and Enteral Nutrition Induces Metabolic Dysfunction in Neonatal Pigs

Abstract

Background We previously showed that parenteral nutrition (PN) compared with formula feeding results in hepatic insulin resistance and steatosis in neonatal pigs. The current aim was to test whether the route of feeding (intravenous [IV] vs enteral) rather than other feeding modalities (diet, pattern) had contributed to the outcome. Methods Neonatal pigs were fed enterally or parenterally for 14 days with 1 of 4 feeding modalities as follows: (1) enteral polymeric formula intermittently (FORM), (2) enteral elemental diet (ED) intermittently (IEN), (3) enteral ED continuously (CEN), and (4) parenteral ED continuously (PN). Subgroups of pigs underwent IV glucose tolerance tests (IVGTT) and hyperinsulinemic-euglycemic clamps (CLAMP). Following CLAMP, pigs were euthanized and tissues collected for further analysis. Results Insulin secretion during IVGTT was significantly higher and glucose infusion rates during CLAMP were lower in CEN and PN than in FORM and IEN. Endogenous glucose production rate was suppressed to zero in all groups during CLAMP. In the fed state, plasma glucose-dependent insulinotropic polypeptide (GIP), glucagon-like peptide (GLP)–1, and GLP-2 were different between feeding modalities. Insulin receptor phosphorylation in liver and muscle was decreased in IEN, CEN, and PN compared with FORM. Liver weight was highest in PN. Steatosis and myeloperoxidase (MPO) activity tended to be highest in PN and CEN. Enterally fed groups had higher plasma GLP-2 and jejunum weight compared with PN. Conclusions PN and enteral nutrition (EN) when given continuously as an elemental diet reduces insulin sensitivity and the secretion of key gut incretins. The intermittent vs continuous pattern of EN produced the optimal effect on metabolic function.

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New generation lipid emulsions prevent PNALD in chronic parenterally fed preterm pigs

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De novo synthesis is the main source of ornithine for citrulline production in neonatal pigs

“…Newborn (Յ1-day-old), crossbred female pigs (n ϭ 6), obtained from the Texas Department of Criminal Justice (Huntsville, TX), were transported to the animal facility of the Children's Nutrition Research Center (Houston, TX). Upon arrival (day 1), piglets were implanted with Silastic catheters in the jugular vein and stomach and a Tygon catheter in the carotid artery as previously described (30). After surgery, piglets were placed in individual cages in a heated room (ϳ30°C) and fed every 3 h at 50% of their requirement for 24 h. Their respective dietary intake was increased gradually to 100% within the next 3 days.…”