Assessment of the Efficiency of Applying Methisoprinol and Vaccination of Turkeys against the Haemorrhagic Enteritis Virus Using in Ovo Methods

The aim of the research was to determine the efficiency of in ovo immunisation of turkeys against the haemorrhagic enteritis virus, while simultaneously applying a synthetic immunomodulator – methisoprinol – by the same route of administration. Dindoral SPF vaccine, in a dose of 0.1 ml of the solution prepared ex tempore after dissolving the vaccine in 100 ml of water for injection, and methisoprinol in a dose of 5 mg per egg, were administered in ovo on the 26 d of incubation. The control groups consisted of turkeys hatched from eggs into which only the methisoprinol or the vaccine was administered, as well as birds hatched from eggs that were not interfered with. The susceptibility of turkeys to HE virus infection was determined on the basis of the presence of HE antibodies in serum, the evaluation of a splenic index, and attempts to register the virus presence in the spleen 120 h after the control infections. The research proved the effectiveness of immunising turkeys against the haemorrhagic enteritis virus by administering Dindoral SPF vaccine in ovo. It was also demonstrated that the simultaneous application of methisoprinol, showing an antiviral effect, and the vaccine inhibited the development of post vaccinal immunity against this virus.