Pathomorphological changes in the bursal sac of chickens vaccinated against Newcastle disease using adjuvants

The article presents the results of a study of pathomorphological changes in the bursal sac of chickens vaccinated against Newcastle disease. The experiment was carried out in the conditions of Sabinsky IPS LLC in the Sabinsky district of the Republic of Tatarstan during the period of raising chickens of the Lomann LSL cross. For research, 60 chickens of 8 weeks of age were taken, which were divided into 4 groups of 15 chickens in each. The birds of the first group were immunized with a once inactivated emulsified vaccine against Newcastle disease with the addition of squalene in the form of emulsion at a dose of 0.5 cm3. The second group was inactivated by the emulsified vaccine against Newcastle disease containing Montanide ISA-71VG adjuvant. The third group was immunized with a vaccine against Newcastle disease without adjuvant, and the remaining 15 chickens were intact. The vaccine in various embodiments was administered to the chickens in a volume of 0.5 cm3 subcutaneously in the dorsal surface of the middle part of the neck. Slaughter of experimental birds of groups 1, 2, 3, and 4 was carried out on the 7th, 14th, and 21st days after vaccination, 6 animals for each study period. Pieces of the bursal sac were preserved in a 10% solution of neutral formalin. After dehydration and compaction of the taken material, the prepared histological sections with a thickness of 8 μm were stained with hematoxylin and eosin and examined under a microscope. Studies of involutional changes in the microstructure of the bursal sac of chickens showed its dependence not only on hereditary mechanisms, but also on additional antigenic stimulation. It has been established that the vaccine against Newcastle disease has reactogenic and immunogenic qualities. In this connection, the most pronounced involutional processes were noted in the bursal sac in chickens of the 3rd group, and the maximum immunogenic qualities of the vaccine preparation were manifested in the structure of the bursal sac in chickens of the 2nd and especially the 1st group. The lowest level of alterative changes in the bursal sac was observed in birds of the 4th group. Involutional processes in these birds were determined by hereditary factors, while the chickens of the remaining groups noted the incidental nature of the manifestation of involution.