The mode of delivery of parenteral multivitamins influences nutrient handling in an animal model of total parenteral nutrition

Background: Very low birthweight preterm infants receive early total parenteral nutrition (TPN) to optimize protein balance. Adding multivitamins (MVP) to the lipid emulsion (MVP+LIP) rather than to the amino acid+dextrose moiety of TPN (AA+MVP) limits the effects of light exposure on lipid peroxidation and vitamin loss. Aim: Compare the effects of the mode of delivery of MVP on nutrient handling and indices of oxidant stress. Methods: Three-day old guinea pig pups were assigned to TPN containing MVP+amino acids+dextrose+heparin and electrolytes, with lipids provided separately (AA+MVP). Solutions were light exposed (LE, n=8) or light protected (LP, n=9). In a further group (n=7), MVP was co-administered with the lipid moiety and light exposed (LIP+MVP). Variables measured in urine (creatinine, nitrogen, vitamin C) and in liver (protein, glutathione, isoprostane, vitamins A, E, C) were compared by ANOVA. Results: Urinary nitrogen and vitamin C were higher (P<0.05) during LE, while hepatic levels of vitamin C were higher (P<0.05) with LIP+MVP. These results were not related to total peroxide levels in TPN or to markers of oxidant stress. Conclusion. Co-administration of MVP with lipid or light protected amino acids offers comparable beneficial effects on nitrogen and vitamin C metabolism.