Post‐feeding serum metabolic responses to extensively hydrolyzed whey (WPH) or native whey concentrate (WPC) in rats

Abstract

The purpose of this study was to compare how feeding extensively hydrolyzed whey protein (WPH) versus its native whey protein concentrate (WPC) in 8‐h fasted rats transiently affects serum metabolic profiles. Male rats (~300 g) were fed an isonitrogenous amounts of WPH or WPC and sacrificed 15 min‐, 30 min‐and 60 min post‐gavage for serum extraction. Rats fasted for 8–9 h were used as controls (CTL). Serum biochemicals were detected using GC/MS and LC/MS/MS. 333 serum metabolites were detected amongst all groups. Both WPH and WPC increased several amino acids (1.2–2.8‐fold), branched chain amino acids (BCAAs, 1.2–1.7‐fold), and serum peptides (1.1–2.7‐fold) over the 60 min time course compared to CTL rats (p < 0.05). However, WPH feeding rapidly (at 15‐min post) increased select amino acids (including BCAAs) and peptides compared to WPC and CTL feedings (p < 0.05). WPH and WPC led to increases in numerous free fatty acids (FFAs) over the post‐feeding time course compared to CTL rats (up to 6‐fold increases, p < 0.05). However, WPH feeding uniquely resulted in a 30‐min post‐feeding elevation in numerous FFAs compared to WPC feeding (p < 0.05), which may be due the WPH‐induced increase in circulating epinephrine compared to CTL and WPC (p < 0.05). These data provide a unique postprandial time‐course perspective as to how WPH versus WPC feedings affect circulating biochemicals.Supported by Bionutritional Research Group