Baseline Immune Cell Composition in Broiler Spleen is Altered by Probiotic Supplementation

Probiotics are supplemented in poultry diets to support beneficial intestinal microbial community members. The alteration of the microbiota due to probiotic supplementation is shown to improve host health, but the underlying changes to immune cell populations have not been well-described in poultry. The objective of this study was to examine the effects of probiotics at two different dietary inclusion levels on the immune cell populations in spleens of unchallenged broiler chickens. Probiotic supplementation did not impact overall percentages of leukocytes, but did alter the composition of cells making up leukocyte subpopulations (P ≤ 0.05). Additional research is needed to evaluate how these changes to immune cell populations translate to a modulated immune response under challenge conditions.