Gastrointestinal structural and functional responses of piglets to soy based infant formulas with varying isoflavone content as compared to cow milk based formula

Abstract

Currently, 25% of formula‐fed infants receive soy formulas (SF) that contain isoflavones (ISO), including genistein (GEN). We have shown that GEN added to cow‐milk formula (CMF) reduced intestinal (INT) proliferation in piglets. Herein, the hypothesis that SF differing in ISO content would differentially impact neonatal INT development was tested. Piglets were randomized to CMF, SF (25 mg ISO/L expressed as aglycone equivalents) or a low ISO formula (LSF; 1.1 mg ISO/L expressed as aglycone equivalents). INT samples were collected on day 2, 6, 12 and 21. Daily weight (wt) gain was similar in all groups. SF piglets had looser (p=0.005) stool consistency than LSF and CMF, but all were within a normal range. Intestinal length/kg body wt and jejunal mucosal wt/kg decreased (p<0.0001) over time, but were not affected by diet. Intestinal wt/kg was not affected by day or diet. Jejunal lactase and sucrase activities increased with age, but were unaffected by diet. Ussing Chamber analyses detected no differences in INT electrophysiology (barrier function, glucose and glutamine absorption or chloride secretion). Wt gain, INT growth, enzyme activity and nutrient transport in piglets fed SF or LSF was similar to CMF, suggesting that ISF within SF do not impact INT development. (Funded by Solae LLC and the USDA)