Porcine lactoferrin administration enhances peripheral lymphocyte proliferation and assists infectious bursal disease vaccination in native chickens

The purpose of this study was to investigate the effects of dietary supplementation with recombinant porcine lactoferrin (rPLF) produced by yeast culture on peripheral lymphocyte proliferation and serum antibody titers in chickens vaccinated against the infectious bursal disease (IBD) virus. Treatment groups were fed with rPLF powder in their diet (2.0%, w/w), and the IBD vaccine was administrated at 1 and 3 weeks of age. At 8, 12, and 16 weeks after vaccination, serum IBD antibody titers were measured via the micro-method and T cell proliferation rates were evaluated. In gene expression analyses, rPLF-treated chicken peripheral T lymphocytes were stimulated with concanavalin A (ConA) for 24 h. The mRNA expression levels of interleukin-2 (IL-2), interferon-γ (IFN-γ), interleukin-4 (IL-4), and interleukin-12 (IL-12) were determined using a semi-quantitative RT-PCR assay. The results revealed that the rPLF additive led to significant increases in serum IgG and IBD-specific antibody titers (P < 0.05). The rPLF administration significantly increased chicken intestinal villous lengths and also enhanced the expression of IFN-γ and IL-12 in chicken T lymphocytes. These data suggest that rPLF enhances cell-mediated immunity and augment the ability of IBD vaccination to benefit chicken industry in disease resistance.