Humoral immunological response in broilers vaccinated against newcastle disease and supplemented with dietary zinc and vitamin E

The humoral immune response of broilers fed diets supplemented with Zinc (Zn) (0, 40, and 400mg/kg) and vitamin E (0, 12, and 120mg/kg), separately or combined, was evaluated. A completely randomized design was used according to a 3x3 factorial arrangement, with nine treatments and four repetitions per treatment. Sexed birds (n=1440) were distributed in 36 boxes with 40 chicks each and reared until 41 days of age. Vaccination against Newcastle Disease (ND) was performed when birds were 14 days old. ELISA and HI tests were used to assess antibody levels before vaccination and at 28, 35 and 41 days of age. The results were analyzed using Proc Mixed from SAS. The interaction between the highest dietary levels of Zn and vitamin E resulted in higher antibody levels in ELISA at 14, 28, 35 and 41 days of age. Increasing levels of Zn and vitamin E supplemented separately in the diets provided greater levels of hemagglutinating antibodies in HI at 14, 28, 35 and 41 days old. The interaction between the highest levels of Zn and vitamin E resulted in greater antibody levels at 41 days of age