Arginine and vitamin E improve the antibody responses to infectious bursal disease virus (IBDV) and sheep red blood cells in broiler chickens.

1. Dietary arginine (ARG) and vitamin E (VE) have been shown to improve immune responses in broiler chickens, but their combined effects have not been well documented. The objective of this study was to evaluate the combined effects of dietary ARG and VE on antibody responses to sheep red blood cell (SRBC, agglutination assay) inoculation in 13-d-old chicks, and antibody titres (ELISA) to infectious bursal disease virus (IBDV) before and after vaccination of 20-d-old chicks. 2. One-day-old broiler chicks were fed diets with normal (NARG, 12 g/kg of feed) or high (HARG, 22 g/kg of feed) inclusion rates of ARG, and three rates of VE (40, 80, or 200 mg/kg of feed; 40 mg being the supplement used in commercial diets) in a factorial arrangement. 3. Antibody titres to SRBC at 5, 8, and 12 d after inoculation were higher in chicks fed on the HARG diet than in those on NARG, and in chickens on VE80 compared with those on VE200 at 5, 8, and 12 d after inoculation. Antibody titres to the IBDV 2 days before and 19 d after vaccination were higher in chickens on HARG compared with those on NARG, and in chicks on VE80 compared to those on VE40 but similar to those on VE200. Conversely, 5 d after vaccination titres against IBDV were higher in chicks on NARG than in those on HARG, and in chickens on VE40 compared with those on VE80, yet similar to those on VE200. 4. These results show that diets with high ARG and high VE (80 mg/kg) improved the humoral-mediated immune response of broilers to IBDV and SRBC, suggesting it could be a strategy to improve vaccination protection and resistance to diseases.

Arginine and vitamin E modulate the subpopulations of T lymphocytes in broiler chickens.

We examined the effects of vitamin E (VE) and Arg on the subpopulations of T lymphocytes in peripheral blood after an infectious bursal disease virus vaccination (20 d old, n = 54). Broiler chickens were fed diets with normal levels of Arg (NARG, 1.2%) or high levels of Arg (HARG, 2.2%) and 3 levels of VE (40, 80, or 200 IU/kg of feed) in a factorial arrangement of treatments. The percentages of CD4+ and CD8+ cells 9 d after vaccination were not different in birds fed the HARG or NARG feed, but they were higher in birds fed the VE80 diet than in birds fed the VE40 diet. Birds fed the VE200 feed had similar levels of CD4+ and CD8+ cells as birds fed the VE40 diet. However, 19 d after vaccination, the percentage of CD4+ cells was higher in birds fed the HARG (43.93 +/- 1.05) diet than in birds fed the NARG diet (41.14 +/- 1.05) and in birds fed the VE80 and VE200 (44.1 +/- 1.28 and 44.42 +/- 1.28, respectively) diets compared with birds fed the VE40 diet (39.04 +/- 1.28). On the other hand, the percentage of CD8+ cells was highest in birds fed the HARG-VE80 feed compared with all the other Arg and VE combinations. The percentages of CD3+ cells and BU-1+ cells were higher in birds fed the HARG (81.35 +/- 1.46 and 22.3 +/- 0.89, respectively) diet than in birds fed the NARG diets (77.82 +/- 1.46 and 18.93 +/- 0.89, respectively). Birds fed the VE40 had a higher amount of BU-1+ (24.35 +/- 1.073) but lower amounts of CD3+ cells (75.76 +/- 1.76) than birds fed the VE80 (18.46 +/- 1.073 and 81.67 +/- 1.76) and VE200 (19.03 +/- 1.073 and 81.19 +/- 1.76, respectively). Neither Arg nor VE had an effect on the CD4+:CD8+ cell ratio and on the percentage of immature (CD4+CD8+) T lymphocytes 9 d after vaccination. These results suggest that Arg and VE have complimentary effects on cellular and humoral immune function and may enhance the resistance of broilers to infectious diseases.