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Nutrients 2018, 10(5), 636;

Growth Responses of Preterm Pigs Fed Formulas with Different Protein Levels and Supplemented with Leucine or β-Hydroxyl β-Methylbutyrate

School of Health Studies, University of Memphis, Memphis, TN 38152, USA
College of Nursing, University of Tennessee Health Sciences Center, Memphis, TN 38163, USA
Biological Sciences, University of Memphis, Memphis, TN 38152, USA
Author to whom correspondence should be addressed.
Received: 31 March 2018 / Revised: 9 May 2018 / Accepted: 16 May 2018 / Published: 18 May 2018
(This article belongs to the Special Issue Early Life Nutrition: From Nutrients to Systems)
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Growth after preterm birth is an important determinant of long-term outcomes. Yet, many preterm infants suffer ex utero growth retardation. We evaluated effects of leucine and the metabolite, β-hydroxy β-methylbutyrate (HMB) on growth of preterm pigs, a previously-validated translational model for preterm infants. After 48 h of parenteral nutrition preterm pigs were fed for 6 to 7 days isocaloric formulas with different levels of protein (50 or 100 g/L) with leucine (10 g/L, 76 mM) or HMB (at 1.1 g/L, 4 mM) added to stimulate protein synthesis or with alanine (6.8 g/L; 76 mM) as the control. Rates of growth of pigs fed the low protein formula with alanine (3.4 ± 0.2% gain per day) or leucine (3.7 ± 0.2) exceeded that of pigs fed the high protein formula (2.8 ± 0.2, p = 0.02 for comparison with both low protein formulas; p = 0.01 compared with low protein + leucine). Supplementing the high protein formula with leucine or HMB did not increase growth relative to alanine (2.72 ± 0.20, 2.74 ± 0.27, and 2.52 ± 0.20, respectively). Small pigs (<700 g birth weight) grew slower during parenteral nutrition and had a more pronounced response to leucine. Females fed the high protein formulas grew faster than males, and particularly for small pigs (p < 0.05). Blood urea nitrogen values were lower for pigs fed the low versus the high protein formulas (p < 0.05). Leucine and HMB improved growth of preterm pigs fed low, but not high protein formulas, even after controlling for birth weight and sex, which independently correlated with growth rates. They offer an option to improve growth without increasing the amino acid load, with its attendant metabolic disadvantages. View Full-Text
Keywords: prematurity; preterm infant; growth; leucine; β-hydroxy β-methylbutyrate; formula prematurity; preterm infant; growth; leucine; β-hydroxy β-methylbutyrate; formula

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Buddington, R.K.; Howard, S.C.; Lee, H.W.; Buddington, K.K. Growth Responses of Preterm Pigs Fed Formulas with Different Protein Levels and Supplemented with Leucine or β-Hydroxyl β-Methylbutyrate. Nutrients 2018, 10, 636.

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