Study of the correlation dependence of serum cytokines of broiler chickens on poultry density

The findings of biochemical studies of blood serum of broiler chickens kept in crowded floor conditions are discussed. The stocking density of chickens kept on the floor depended on the age of the birds. Up to ten-day age, the stocking density for broiler chickens of all groups was the same - 30 birds per 1 square meter of floor area. Later, starting from the age of 11 days, the stocking density per 1 square meter in the trial group was increased by 30% of that index in the control group. The following cytokine profile indices were detected in the blood serum of broilers: interleukin 1β (IL-1β), interleukin 6 (IL-6), tumor necrosis factor (TNF), interleukin 4 (IL-4), interleukin 10 (IL-10), and transforming growth factor β1 (TGF β1). Overcrowding of broiler chickens during floor housing leads to activation of the blood serum cytokine profile. The obtained data underwent statistical processing in the form of calculations of the correlation dependence of the indices of the cytokine profile of the blood serum of broilers regarding various parameters of the housing area. The cytokine ratio during the observation period of 42 days was overestimated in favor of proinflammatory interleukins IL-1β, IL-6 and tumor necrosis factor TNF. The levels of anti-inflammatory cytokines decreased to minimum values by the 42nd day of the study. Statistical processing was performed by using F-test. It was found that the levels of interleukins IL-1β and IL-6 in broiler chickens do not depend on the poultry density. The poultry density has a significant effect on the tumor necrosis factor, interleukins IL-4 and IL-10, and transforming growth factor β1. The findings of biochemical studies on the cytokine profile of broiler chickens are important diagnostic markers of stress response and the development of a protective and adaptive response in poultry.