Postprandial Amino Acid Kinetics of Milk Protein Mixtures are Affected by Composition, But Not Denaturation, in Neonatal Piglets

Rebecca J Welch-Jernigan; Evan Abrahamse; Barbara Stoll; O'Brian Smith; Peter A Wierenga; Bert J M van de Heijning; Ingrid B Renes; Douglas G Burrin

doi:10.1093/cdn/nzy102

Postprandial Amino Acid Kinetics of Milk Protein Mixtures are Affected by Composition, But Not Denaturation, in Neonatal Piglets

Curr Dev Nutr. 2018 Dec 19;3(4):nzy102. doi: 10.1093/cdn/nzy102. eCollection 2019 Apr.

Authors

Rebecca J Welch-Jernigan¹, Evan Abrahamse^{2

3}, Barbara Stoll⁴, O'Brian Smith⁴, Peter A Wierenga³, Bert J M van de Heijning², Ingrid B Renes^{2

5}, Douglas G Burrin^{1

4}

Affiliations

¹ Center for Comparative Medicine, Baylor College of Medicine, Houston, TX.
² Danone Nutricia Research, Utrecht, the Netherlands.
³ Laboratory of Food Chemistry, Wageningen University, Wageningen, the Netherlands.
⁴ USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX.
⁵ Department of Pediatrics, Emma Children's Hospital AMC, Amsterdam, the Netherlands.

Abstract

Background: Multiple studies have indicated that formula-fed infants show a different growth trajectory compared with breastfed infants. The observed growth rates are suggested to be linked to higher postprandial levels of branched chain amino acids (BCAAs) and insulin related to differences in protein quality.

Objective: We evaluated the effects of milk protein denaturation and milk protein composition on postprandial plasma and hormone concentrations.

Methods: Neonatal piglets were bolus-fed randomly, in an incomplete crossover design, 2 of 3 milk protein solutions: native whey protein isolate (NWPI), denatured whey protein isolate (DWPI), or protein base ingredient, comprising whey and casein (PBI). Postprandial plasma amino acids (AAs), insulin, glucagon-like peptide 1, glucose, and paracetamol concentrations were assayed. Plasma responses were fitted with a model of first-order absorption with linear elimination.

Results: DWPI (91% denatured protein) compared with NWPI (91% native protein) showed lower essential amino acids (EAAs) (∼10%) and BCAA (13-19%) concentrations in the first 30-60 min. However, total amino acid (TAA) concentration per time-point and area under the curve (AUC), as well as EAA and BCAA AUC were not different. PBI induced a ∼30% lower postprandial insulin spike than NWPI, yet plasma TAA concentration at several time-points and AUC was higher in PBI than in NWPI. The TAA rate constant for absorption (k _a) was twofold higher in PBI than in NWPI. Plasma BCAA levels from 60 to 180 min and AUC were higher in PBI than in NWPI. Plasma EAA concentrations and AUCs in PBI and NWPI were not different.

Conclusions: Denaturation of WPI had a minimal effect on postprandial plasma AA concentration. The differences between PBI and NWPI were partly explained by the difference in AA composition, but more likely differences in protein digestion and absorption kinetics. We conclude that modifying protein composition, but not denaturation, of milk protein solutions impacts the postprandial amino acid availability in neonatal piglets.

Keywords: amino acids; human milk; infant formula; insulin; neonatal piglets; whey protein.