title: Biochemical and immunological responses of young turkeys to vaccination against Ornithobacterium rhinotraheale and different levels of dietary methionine.
abstract: The objective of this study was to verify the hypothesis that increasing levels of dietary methionine can stimulate the mechanisms of cell-mediated and humoral immunity in young turkeys. The blood and organs involved in cell-mediated and humoral immune responses were analyzed in 8-week-old turkeys that had been vaccinated against Ornithobacterium rhinotraheale (ORT) infection (on days 17 and 48). The birds were fed diets with a low (LM), medium (MM) and high (HM) methionine content (0.45 and 0.40%, 0.60 and 0.51%, 0.71 and 0.57% in weeks 1 - 4 and 5 - 8, respectively). Dietary methionine supplementation led to a significant increase in body weights of turkeys at 56 days of age, from 3532 g in group LM to 3720 g in group MM and 3760 g in group HM (p=0.001). A significant increase in vaccine-induced antibody titers against ORT was noted in group HM relative to group LM (p=0.006). Increasing levels of methionine had no significant effect on total serum IgG nor IgM levels and most serum biochemical parameters, TP, ALB, GLOB, GLU, AST, ALP, P and Ca. In comparison with group LM, group HM turkeys were characterized by a lower percentage of IgM⁺ B cell subpopulation in the blood and bursa of Fabricius. The percentages of CD4⁺ and CD8⁺ T cell subpopulations in the bursa of Fabricius in group HM were significantly different from those found in groups LM and MM. The highest percentages of CD4⁺ T cells and CD8⁺ T cells in the spleen were observed in groups LM (p<0.001) and HM (p=0.04), respectively. The differences were statistically significant relative to the remaining groups. Turkeys of group LM were characterized by a lower CD4⁺ T cell percentage in the thymus (p<0.001) and a lower CD8⁺ T cell percentage in the cecal tonsils (CTs) (p<0.01). Vaccination against ORT resulted in a significant increase in the percentage of CD4⁺CD8⁺ T cell subpopulation and a decrease in the percentage of CD8⁺ T cell subset in the spleen.
authors.forename: M
authors.initials: M
authors.lastname: Kubińska
authors.forename: B
authors.initials: B
authors.lastname: Tykałowski
authors.forename: A
authors.initials: A
authors.lastname: Koncicki
authors.forename: J
authors.initials: J
authors.lastname: Jankowski
mesh_terms: D000821:Animal Feed / Q000032:analysis; D000818:Animals; D001428:Bacterial Vaccines / Q000276:immunology*; D004032:Diet / Q000662:veterinary; D045826:Flavobacteriaceae Infections / Q000382:microbiology / Q000517:prevention & control / Q000662:veterinary*; D008715:Methionine / Q000008:administration & dosage / Q000494:pharmacology*; D045246:Ornithobacterium / Q000276:immunology*; D014422:Turkeys; D014611:Vaccination
chemical_list: D001428:Bacterial Vaccines; D008715:Methionine