Dietary Glutamine Supplementation Enhances Weaned Pigs Mitogen-Induced Lymphocyte Proliferation

Two experiments involving 92 crossbred, 21 day old weaned pigs were used to evaluate the effect of glutamine supplement in a dietary or culture medium on lymphocyte proliferation. In Exp. 1, 88 pigs were fed diets supplemented with 0, 0.5, 1.0, or 1.5% glutamine for 28 days. Lymphocytes were prepared from peripheral blood mononuclear cells (PBMC), ileal Peyer's patches (PP), the mesenteric lymph node (MLN), and the spleen in each dietary supplement group on days 7, 14, or 28 postweaning. Lymphocytes were cultured at $37^{\circ}C$ for 72 h in a RPMI-1640 medium with or without mitogen-stimulated, and pulsed with 3Hthymidine for an additional 18 h. The stimulation index of PBMC proliferation in 1.0% dietary glutamine supplement group and both of the MLN and splenocytes proliferation in 1.5% dietary glutamine supplement group was significantly (p<0.05) increased at 14 days postweaning. In Exp. 2, four weaned pigs were fed a basal diet for 14 days. The 3H-thymidine incorporation of PBMC, PP, and MLN cells, incubated with 0.125 to 0.25 mM glutamine in culture medium were markedly enhanced with Con A-stimulated, however, the splenocyte proliferation was not affected in the addition of glutamine medium. These observations suggest that dietary glutamine supplement might enhance the lymphocyte proliferation of weaned pigs.