engleski

The influence of HVT FC 126 given by means of nebulization compared to parenteral vaccination on chickens immunocompetent cell transformation

Marek’s disease is a common lymphoproliferative disease of chickens, usually characterized by mononuclear cell infiltration of peripheral nerves and various other organs and tissues, including the iris and skin. A group of 70 newly-hatched chicks was vaccinated by means of nebulization and exposed for 60 seconds to the HVT FC 126 vaccine, while the other group of 70 chicks received the same vaccine by parenteral route (s.c.). The aim of this study was to compare the morphological patterns of the chicken’s lymphocytes in their peripheral blood, before and after vaccination by means of either nebulization or parenteral injection. Image analysis was performed using the SFORM software (VAMSTEC, Zagreb, Croatia). A total of 50 blood smears from vaccinated chickens (20 by means of nebulization and 30 by parenteral injection), with an average of 100 cells per smear, were analyzed. The results showed that the peripheral blood lymphocytes of chickens vaccinated by means of nebulization, compared with parenteral vaccinated, had significantly higher values for the majority of the measured variables: area, outline, minimum and maximum radius, length, breadth and convex area, on all days after vaccination, except on day 4, indicating the significantly higher metabolic activity of those cells. In lymphocytes of chickens vaccinated parenterally, only the nucleo-cytoplasmic ratio was higher. The results show that morphological patterns of immunocompetent cell transformation could be used to evaluate immune responses to vaccination and vaccine efficacy. We conclude that nebulization as a mode of vaccination against Marek’s disease stimulates the transformation of immunocompetent cells much earlier, thus shortening the time of immunosuppression and improving the immune response. This is of paramount importance for the practical application of Marek’s disease vaccine.

chickens; Marek's disease; nebulization; parenteral vaccination; lymphocyte morphometry

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