Table 1 Summary of the role of amino acids in GALT and the intestine

• Oxidative substrate for immune cells and IECs

• Precursor for glutamate/GSH

• Intestinal growth, structure and function (young animals and disease states)

• Supports proliferative rates and reduces apoptosis of IECs

• Protects against E.coli/LPS-induced damage to intestinal structure and barrier function

• Lowers inflammatory and increases immunoregulatory cytokine production

• Improves the proliferative responses of IELs and MLN cells

• Intestinal IgA levels

• Increases lymphocyte numbers in PP, lamina propria and IELs

• Oxidative substrate for immune cells and IECs

• Precursor for GSH and other amino acids (i.e. arginine)

• Intestinal growth, structure and function

• Acts as Immunotransmitter between dendritic cells and T-cells*

• Facilitates T-cell proliferation and Th1 and proinflammatory cytokine production

• Precursor for NO and glutamate in IECs and immune cells

• Intestinal growth, structure and function

• Supports microvasculature of intestinal mucosa

• Increases expression of HSP70 to protect intestinal mucosa

• Protects against E.coli/LPS-induced damage to intestinal structure and barrier function

• Facilitates neutrophil and macrophage killing through iNOS-mediated NO production

• Increases intestinal IgA levels

• Lowers inflammatory cytokine levels in intestine

• Increases T-lymphocytes in lamina propria, PPs, intraepithelial spaces

• Precursor for GSH, taurine and cysteine

• Reduces intestinal oxidative stress

• Intestinal structure

• Increases goblet cells and proliferating crypt cells

• Protects against DSS-induced intestinal damage (colitis model) by lowering inflammation, crypt damage and intestinal permeability.

• Mucin synthesis

• Intestinal structure and function

• Intestinal IgA levels