Diagnostic value of integrated immunohematological indices as markers of chronic stress in laying hens

Abstract

The study of stress in the conditions of industrial technologies of keeping laying hens and determining the level of technological stressors influence on the physiological state of poultry is a necessary condition for the development of new methods of stress prevention in choosing the best ways to keep them. The aim of the study was to determine the informativeness of integrated immunohematological indices for the diagnosis of stress-induced disorders in laying hens under the influence of technological stressors of varying intensity. Chronic technological stress was modeled by long-term keeping of laying hens at high planting density. The intensity of the stressor was determined by increasing the density of laying hens. Integral immunohematological indices were determined on the basis of an extended general blood test. It has been found that in laying hens, which due to prolonged exposure to high density were in a state of chronic stress, there is a high level of endogenous intoxication and impaired immunological reactivity, as evidenced by increased Leukocyte shift index, Immunoreactivity index, Leukocyte to erythrocyte sedimentation rate ratio, lymphocyte to monocyte ratio, heterophil to monocyte ratio. It is shown that under chronic stress in laying hens there is activation of the cellular part of the immune system, active adaptive response of white blood, as well as the predominance of delayed-type reactions over immediate-type hypersensitivity, as indicated decrease in lymphocyte-granulocyte index, general index, lymphocytic index and lymphocyte to eosinophil ratio. Thus, integrated immunohematological indices are promising markers for the diagnosis of chronic stress in laying hens.