Modulatory effects of two levels of dietary Alliums on immune response and certain immunological variables, following immunization, in White Leghorn chickens.

This study aimed at investigating the effects of dietary Allium sativum (garlic, G) and Allium cepa (onion, O) on immune functions in White Leghorn chicken. One-week-old chicks, were fed diets without (control) or with Alliums (GL and OL, 10 g or GH and OH, 30 g/kg diet). Chickens were immunized with Newcastle disease virus (NDV), sheep red blood cells (SRBC) and Brucella abortus (BA). Antibodies, lymphocyte proliferation, and ratios of CD4(+) , CD8(+) and CD4⁻ CD8⁻ lymphocytes were investigated. Histology and weights of the spleen, thymus and bursa (BF), and white blood cell (WBC) counts were studied as well. Alliums at 10 g/kg diet enhanced anti-NDV, anti-SRBC and anti-BA antibody productions, whereas 30 g/kg diet had less stimulatory effects. Histology of the lymphoid organs and proliferation of peripheral blood lymphocytes (PBL) were not influenced. However, splenocyte and thymocyte proliferations were augmented with garlic. Flow cytometry analysis showed reduction in CD4(+) and increase in CD4⁻ CD8⁻ lymphocyte ratios in GH and OH groups. Garlic-supplemented chickens had heavier spleen and thymus, and higher WBC counts, whereas BF weight increased with both Alliums at 30 g/kg diet. These results suggest that dietary Alliums have a potential to enhance the immune functions in White Leghorn chickens.