Effects of β-glucan supplementation on lymphocyte proliferation, macrophage chemotaxis and specific immune responses in broilers

Immunomodulatory feed additives might offer alternatives to antimicrobial growth promoters in poultry production. This experiment was carried out to test the effect of beta-glucan supplementation on the growth performance and immune response in broilers. Total of 160 day-old broilers were randomly assigned to 4 treatment groups fed corn-soybean diets containing 0, 0.012, 0.025 or 0.05% of beta-glucan supplement in a 6 week feeding experiment. Growth performance, antibody titer against New Castle vaccine, lymphocyte blastogensis, and peritoneal macrophage chemotaxis activity of broilers were evaluated. Results showed that there were no significant differences in weight gain and feed efficiency among the treatments, and no differences in antibody titer was observed. Supplementation of beta-glucan did not elevate the lymphocyte blastogensis among treatments, following stimulation with different mitogens. However, supplementation with 0.025 and 0.05% beta-glucan enhanced the macrophage chemotaxis activity of broilers. These results suggest that beta-glucan may enhance some cell-mediated immune responses of chickens by modulate macrophages ability.