Effect of Beta-Carotene Supplementation on the Serum Oxidative Stress Biomarker and Antibody Titer against Live Bovine Respiratory Syncytial Virus Vaccination in Japanese Black Calves.

The purpose of this study was to determine the effect of vaccination and beta-carotene supplementation on blood oxidative stress and antibody response in calves. Thirty Japanese Black calves were randomly assigned to two groups. Fifteen calves received 20 mg of beta-carotene supplemented into their daily provided rations from 2 to 8 weeks of age (BC group), and the other 15 calves did not receive the daily beta-carotene supplement (control group). All calves received a commercially available modified live bovine respiratory syncytial (RS) virus vaccine at 4 and 8 weeks of age. Blood samples were taken at 2, 4, 8, and 12 weeks of age. At 4 weeks of age, the concentration of reactive oxygen metabolites within serum were significantly lower in the BC group than the concentrations measured in the control group. Also at 4 weeks of age, the concentration of biological antioxidant capacity within serum was significantly higher in the BC group than the concentrations measured in the control group. Both groups showed a gradual decrease of antibody titers to live bovine RS virus in the samples taken from 2 to 12 weeks of age. These results confirmed that beta-carotene supplementation decreased oxidative stress. However, beta-carotene supplementation did not affect the antibody response to live bovine RS virus vaccination, perhaps due to the presence of the maternal antibody.