Immune parameters in two different laying hen strains during five production periods

During life, the number and function of immune cells change with potential consequences for immunocompetence an organism. In laying hens, studies have primarily focused on early development competence only few investigated systemic lymphatic distribution leukocyte subsets during adolescence egg-laying period. The present study determined various types in blood, spleen, cecal tonsils 10 Lohmann Brown-Classic LSL-Classic hens per wk life 9/10, 15/16, 23/24, 29/30, 59/60, encompassing important production as well developmental stages, by flow cytometry. Although traits differed between 2 hen strains, identical patterns age-related immunological changes were found. numbers all lymphocyte spleen blood γδ T increased from 9/10 to 15/16. This suggests ongoing release lymphocytes primary lymphoid tissues influx into due novel pathogen encounters adolescence. A strong decrease CTL increase innate within found 15/16 covering transition phase activity. Numbers peripheral splenic remained low period or even further decreased, example CD4 + cells. Functional assessments showed that vitro IFN-γ mitogen-stimulated splenocytes was lower 60. Taken together, activity seems alter system toward a more pronounced humoral response, probable thus productivity, health welfare hens.