Effects of Dietary Supplementation of Vitamin E on Growth Performance and Immune System of Broiler Chickens

Abstract

As a potent antioxidant, Vitamin E may lessen the potentially harmful consequences of such oxidative stress to protect broilers against immune-pathological damage. Broiler chicken growth and viability are enhanced by Vitamin E supplementation. The present study aimed to investigate the effects of Vitamin E dietary supplementation on broiler chickens’ growth performance and health status. A total of 48 one-day-old Ross chicks were randomly divided into two groups of control and treatment (supplementation of Vitamin E at a dose of 300 mg/kg diet) with three replicates per group. The study included an equal number of Ross breed chicks and Vitamin E dosage in two trials on two different dates (January and March, 2022). In both trials, the obtained results indicated no significant changes in weight gain in the control and treatment groups. In both trials, there were no significant differences in the spleen weight of the control and treated groups; however, from day 1 to 28 of the second trial, the bursa of Fabricius was heavier in the treated group than in the control group. Additionally, Vitamin E had no significant effects on the mitogenic responses to phytohemagglutinin (PHA) and Concanavalin A (Con A). Dosages of 20 and 10 µl for both PHA and Con A did not significantly affect the rate of pure lymphocyte proliferation in chicks fed 300 mg Vitamin E /kg feed. Cell-mediated immunity did not differ significantly between the two trials. The percentages of CD4, CD8, Bu1, and MHCII molecules in the spleen and cecal tonsil of the chicks that received Vitamin E 300 mg/kg feed did not change significantly. The antibody titers against infectious bronchitis and infectious bursal disease vaccines showed no significant differences. On day 42, there was a trend toward an increase in antibody titer in the case of the Newcastle disease vaccine. In conclusion, 300 mg/kg of Vitamin E added to the diet did not improve growth performance and immunity in broiler chicks. Keywords: Broiler chicken, Growth performance, Immune system, Vitamin E