The Effects and Interaction of Vitamin A and Zinc Food Supplements on Humoral Immune Response of Broilers to V₄-UPM (NDV) Vaccination

The antibody response of broilers to V4-UPM vaccine fed diets supplemented with zinc (Zn) (0, 50, and 500 mg kg-1) and Vitamin A (0, 15 and 150 mg kg-1), separately or combined was evaluated. A completely randomized design was used according to a 3x3 factorial arrangement with nine treatments and four replicates per treatment. Birds were reared until 56 days old. Haemagglutaination Inhibition (HI) test was used to assess antibody levels before vaccination and at 35, 42, 49 and 56 days of age. The results were analyzed using SPSS package. The interaction between Zn and Vitamin A resulted in higher antibody levels in Group 6 at 35, 42, 49, and 56 days of age. However, interaction between the highest levels of Zn (500 mg kg-1) and Vitamin A (150 mg kg-1) resulted in lower antibody production in the broiler birds. The control (Group 5) showed the least level of humoral immune response. Combined Zn and Vitamin A supplementation improved antibody response to Newcastle disease virus.