The Influence of β‐Glucan on Immune Responses in Broiler Chicks

Abstract

Beta‐1,3/1,6‐glucan (β‐glucan) was tested as a possible immunomodulator. Chicken macrophages from a macrophage cell line MQ‐NCSU and from abdominal exudate of broiler chickens were exposed to various concentrations of β‐glucan in vitro. In addition, day‐old broiler chicks were fed a diet containing 0, 20, and 40 mg/kg β‐glucan in the starter and 0, 20, and 20 mg/kg in the grower diet. Several baseline immune parameters were examined following such exposures. The results showed that β‐glucan exposure increased nitrite and interleukin‐1 (IL‐1) production as well as induced macrophage to proliferate in culture. However, IL‐6 production was not affected. Dietary β‐glucan supplementation increased the macrophage phagocytic activity, anti‐sheep red blood cells antibody response post‐boost, as well as the PHA‐P‐mediated lymphoproliferative response measured as a toe‐web swelling. The percentage of CD4⁺, CD8⁺, and CD4⁺/CD8⁺ double positive lymphocytes in the intestinal intraepithelial leukocytes was increased in β‐glucan supplemented chicks. Furthermore, the primary and secondary lymphoid organs such as bursa of Fabricius, thymus and spleen were larger in β‐glucan‐supplemented chicks as compared to the chicks on basal diet. The findings of these studies which showed that β‐glucan improves several base‐line immune responses in the chicken imply that β‐glucan can be used as a possible immunomodulator in food animals such as the chicken.

Key Words :

• β‐glucan
• Immune functions
• Chicken