Dietary L-argininemodulates immunosuppression in broilers inoculated with an intermediate strain of infectious bursa disease virus

BACKGROUNDThe effects of dietary l-arginine (Arg) on immunosuppression following infectious bursal disease virus (IBDV) inoculation in broiler chickens were evaluated. The design of this study was a 5 x 2 factorial arrangement (n = 5) with five Arg concentrations (starter: 9.9, 13.9, 17.6, 21.3 and 25.3 g kg(-1); grower-finisher: 9.5, 13.5, 17.1, 20.1 and 23.6 g kg(-1)) with or without IBDV inoculation (IBDV or saline inoculation at 14 days). Chickens were sampled at 2, 4 and 6 days post-inoculation (DPI) and 42 days of age. RESULTSThe IBDV inoculation decreased (P = 0.05) CD3(+), CD4(+), and CD8(+) T cell counts at 2 days post-inoculation (DPI) and monocyte counts at 6 DPI; and reduced (P < 0.05) bursal interleukin-1 (IL-1) mRNA expression at 2 DPI and serum IL-6 concentration at 4 DPI. Increasing Arg concentration increased (P < 0.05) CD4(+) and CD8(+) T cell counts at 2 DPI, linearly increased (P = 0.05) CD3(+) T cell counts in IBDV-inoculated groups and monocyte counts in control groups at 4 DPI; increased (P < 0.05) serum IL-6 concentration in IBDV-inoculated groups at 2 DPI; and increased (P < 0.05) serum anti-IBDV antibody titres at 42 days of age. CONCLUSIONVarying concentrations of Arg supplementation attenuated IBDV inoculation induced immunosuppression via modulating circulating T cell sub-populations. (c) 2014 Society of Chemical Industry