Interpretive Summary: CCK and GLP-1 release in response to proteinogenic amino acids using a small intestine ex vivo model in pigs

By: Maximiliano Müller, Elout Van Liefferinge, Marta Navarro, Elisabet Garcia-Puig, Alan Tilbrook, Robert van Barneveld, and Eugeni Roura

Understanding which dietary amino acids (AA) may impact the release of gut hormones involved in the modulation of feed intake, such as cholecystokinin (CCK) and glucagon-like peptide 1 (GLP-1), can help improve pig feed formulations. The series of studies presented assessed the effect of the 20 proteinogenic non-bound AA on the secretion of CCK and/or GLP-1 by duodenum, jejunum, and/or ileum samples from postweaning piglets. None of the AA tested stimulated the secretion of both CCK and GLP-1. Among the essential AA (EAA), Ile, Leu, Met, and Trp significantly stimulated GLP-1 from the ileum, while Phe stimulated CCK from the duodenum. Of the non-essential AA (NEAA), AA amides Gln and Asn caused the release of CCK, while Glu and Arg increased the release of GLP-1 from the ileum. The results suggest that both nonbound EAA and NEAA participate in appetite control via the release of gut peptides in pigs. Given that CCK was mainly released from duodenum samples (in the pre-enzymatic section of the small intestine), protein-bound AA could only influence CCK release through feedback mechanisms such as through the presence of GLP-1 receptors.

Read the full article in the Journal of Animal Science.