ASSESSMENT OF THE EFFICIENCY OF USING SPECIES-SPECIFIC INTERFERON-α TO REDUCE POST-VACCINATION STRESS IN BROILER CHICKENS

The aim of our work was to assess the efficiency of using species-specific interferon-α to reduce a post-vaccination stress in Cobb-500 cross broiler chickens against chicken infectious bronchitis. To determine the intensity of the stress reaction of the bird's body, the Krebs index was calculated. The level of intoxication in the body of broiler chickens upon vaccine administration was determined by the leukocyte index. An indicator of the acute stage of the stress reaction was also calculated –the blood cell index; lymphocytic granulocyte index and immunoreactivity index by D. O. Ivanov. The results obtained during the study showed that vaccination caused a stress syndrome in the birds. The use of interferon-α for the prevention of vaccine stress helped alleviate the load on the immune system, which confirms the decrease, relative to the control of the leukocyte Krebs indices, the leukocyte intoxication index, and the blood cell index. The increase in the indices of immunoreactivity and the lymphocytic-granulocyte index indicates that the use of interferon-α contributed to the activation of lymphopoiesis and a decrease in the degree of tension of the cellular component of immunity.