The interaction between lysyl-lysine and arginine in the neonatal Yucatan miniature pig small intestine

Abstract

Using an in situ intestinal perfusion model in sow-fed neonatal piglets, our objectives were to determine whether the lysyl-lysine enhanced arginine absorption led to a functional benefit of greater mucosal protein synthesis, and whether it was mediated through the mTOR pathway. Three segments of piglet’s small intestine were isolated, and were continuously perfused with: arginine, arginine + lysyl-lysine, or arginine + L-lysine. At 90 min, buffers containing the same amino acids plus phenylalanine were initiated for 30 min to measure mucosal protein synthesis. Six additional piglets underwent the identical protocol, but one hour before the intestinal perfusion, rapamycin was delivered intravenously. Co-perfusing arginine with lysyl-lysine resulted in greater arginine uptake, and higher mucosal protein synthesis. Moreover, both protein synthesis and the phosphorylation of mTOR were inhibited by rapamycin. Thus, lysyl-lysine led to a greater mucosal protein synthesis, which was likely mediated through enhanced arginine absorption.