Clinical Relevancy Statement

Commercial enteral nutrition formulas with immunonutri-tion, such as arginine, n-3 polyunsaturated fatty acids, and glutamine, are widely used in critical care for enhancement of the immune system. The application of chronic exogenous arginine is currently not warranted as a supplement in paren-teral nutrition for peritonitic patients who develop arginine deficiency and impaired immune function. The findings of our study showed that a pharmacological dose of parenteral arginine (>6 % of total calories) might not be of benefit for the immunity of peripheral blood cells and splenocytes in sub-acute peritonitic rats, even though the synthesis of ornithine, a precursor of polyamine that has the ability to increase DNA, RNA, and protein synthesis in lymphocytes, was increased