Tissue cytokines in chickens from lines selected for high or low humoral antibody responses, given supplemental Limosilactobacillus reuteri and challenged with Histomonas meleagridis

Abstract

Histomonas meleagridis, a protozoan parasite, induces blackhead disease (histomoniasis) in poultry. During hatching, chicks from lines divergently selected for high (HAS) and low (LAS) antibody responses to sheep red blood cells were divided into two groups, each of HAS and LAS, and placed in pens with wood shavings as litter. Feed and water were allowed ad libitum. Half of the chicks from each line had Limosilactobacillus reuteri (L. reuteri) inoculated to their drinking water. On day 18, all chicks were given a transcloacal inoculation of 100,000 H. meleagridis cells. Then, 10 days later, they were euthanized, followed by collection of tissues from the brain, cecal tonsil, ceca, liver, thymus, and spleen for qPCR analyses of cytokines involved in immunological development. Changes in cytokine expressions were most numerous in the cecal tonsil, ceca, and liver. In the absence of a functional medication for control of histomoniasis, L. reuteri and/or its secretory product, reuterin, might serve, in some genetic populations, as a means to reduce the impact of histomoniasis in chickens. The data demonstrate that L. reuteri treatment had tissue specificity between the two genetic lines, in which the effects were targeted primarily toward the cecal tonsil, ceca, and liver, which are the primary tissue targets of the parasite (H. meleagridis), as well as the thymus and spleen. However, interactions among main effects reflect that responses to inflammatory markers observed in tissues for one genetic line may not be observed in another.

Growth of White Leghorn Chicken Immune Organs after Long-Term Divergent Selection for High or Low Antibody Response to Sheep Red Blood Cells

“…The HAS and LAS lines differ in their reproductive traits, body weight, and feed efficiency as well as in their resistance to infectious diseases, including Mycoplasma gallisepticum, Escherichia coli, Staphylococcus aureus, Eimeria tenella, Newcastle Disease, and Marek's Disease [3][4][5][6]. These genetic lines have also proven to be a model for genotypic and phenotypic studies to further the understanding of the intestinal microbiome, the MHC-B and MHC-Y complexes, the Usutu virus, and inflammation response to Histomonas meleagridis [7][8][9][10][11][12]. However, the effect of selection for high and low antibody response on growth and morphology, particularly of the immune organs, has not been recently analyzed.…”