Lactobacillus-fermented milk enhances postprandial muscle protein synthesis in Sprague-Dawley rats

This study aimed to investigate the effects of Lactobacillus-fermented milk on postprandial skeletal muscle protein synthesis (MPS) in rats. Within 4 h of administration, bulk and time-specific fractional MPS were measured using deuterium and the tracer D-5-phenylalanine, respectively. Both bulk and fractional MPS were higher for the group given fermented milk compared to the groups given skim or acidified milk (Bulk P = 0.08 and 0.06 vs. skim and acidified milk, respectively; Fractional: P < 0.01 vs. Skim and P = 0.06 vs. Acidified by two-way analysis of variance (ANOVA)). Treatment with a proton pump inhibitor (PPI), which was used to elucidate the impact of acidic pH, did not significantly affect fractional MPS, although PPI did decrease leucine absorption in the Fermented milk group. These results suggested that fermented milk enhanced postprandial MPS via pH-independent mechanisms.