Grant: Discovery Grants Program - Individual

Dietary protein is taken up by absorptive cells in the small intestine after the digestive process breaks it down into free amino acids and small protein fragments called peptides. Free amino acids are absorbed from the digestive tract by specific amino acid transport systems, whereas thousands of types of small peptides are absorbed by one transporter called PepT1. In situations when the gut is injured, such as when piglets are weaned from the sow to chow diets, or during gastro-intestinal infections, there is evidence that the absorption of dietary protein as peptides is preserved, while capacity to absorb single amino acids declines. One of the objectives of this research program is to investigate whether there are any interactions between the absorption of peptides and free amino acids. In a previous study, we showed that the presence of a specific peptide in the intestine enhanced the uptake of a nutritionally important amino acid. We intend to further study other amino acids and dipeptides to more clearly describe the relationship at the site of absorption. Describing interactions between amino acids and peptides is becoming increasingly important as pig-rearing practices are moving towards lowering the total amount of protein in the diets, but adding back essential free amino acids to maintain optimal growth. Low crude protein diets reduce the negative environmental impact of pig manure in large production facilities and also help to avoid diarrhea in young pigs; however, interactions between free amino acids or between free amino acids and peptides at the site of intestinal absorption has not been well studied and may have significant impact on protein utilization in the growing pig.