¹College of Animal Science and Veterinary Medicine, Henan Institute of Science and Technology, Xinxiang 453003, CHINA DOI : 10.9775/kvfd.2023.31166 This study was conducted to investigate the effect of Alfalfa polysaccharide (APS) on the growth performance and immune responses of broilers. A total of 400 1-day-old Avian broiler chicks were randomly divided into four treatment groups and administered intranasal with different levels of APS (0, 2.5, 5.0 or 10.0 mg/dose) on day 1 and day 14. Growth performance, phagocytic activity, T lymphocyte transformation, and serum antibody titers against the Newcastle disease virus (NDV) vaccine were examined. During the study period of 42 days, no significant differences were observed in food intake among treatment groups (P>0.05). The APS administered groups displayed a low FCR, especially the 2.5 mg groups (P<0.05). Broilers with 2.5 mg APS displayed a much higher phagocytic activity than the control group (P<0.05). At the same time, APS enhanced the T lymphocyte transformation in response to phytohaemagglutinin (PHA). The antibody titer to NDV was not influenced by APS on day 14, while it improved on day 28 and day 42, especially in the 2.5 mg group (P<0.05). And the above data suggest that APS could improve innate and cellular immune responses in broilers. Keywords : Alfalfa polysaccharide, Broilers, Diseases, Growth, Immunity