The Effect of the Level of Vitamin E Supplementation In the Diet on the Transportation Stress Response and Humoral Immune Response of Broiler Chickens Against Newcastle Disease Vaccination

Broiler chickens (Cobb) were reared from day old to 42 days of age to investigate the effects of different level of vitamin E (0, 100, 200, 300mg/kg diets) in diet on transportation stress response and humoral immune response against Newcastle disease vaccination. Sixty unisex commercial broilers were designed into 4 treatments with 3 replications (five broilers in each replication). All birds were vaccinated against Newcastle disease at day 10 and booster at day 22 intraocular to verify the antibody titers generated by different treatments. Heterophils/Lymphocytes (H/L) were counted to evaluate the transportation stress response of broilers against transportation period (0, 90, 180, 360 minutes) and growth performances were evaluated. Significantly better feed efficiency was noted with broiler chicks fed diet supplemented with 200 mg and 300 mg of vitamin E per kg diet on day 42 (P<0.05). The lower value of H/L ratio recorded in broiler chicks fed diet supplemented with 100mg, 200mg and 300mg of vitamin E suggested that dietary vitamin E alleviate the negative impact of accumulative stress on broiler chicks from loading, handling and transportation. On day 21 (11 days after vaccination), dietary supplementation of vitamin E 300mg/kg diet enhance the antibody production against Newcastle disease vaccination, but the persistency of serum antibody level is shorter. On day 42 (31 days after vaccination), the broiler chickens fed diet supplemented with 200mg of vitamin E responded the lowest antibody titer against Newcastle disease vaccination; suggesting that dietry supplementation of vitamin E 200mg/kg diet cause adverse effect in humoral immune response of broiler chickens.