الفهرس 
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Abstract
The suitability and efficacy of prophylactic immunization of broilers at 2 weeks of age against infectious laryngotracheitis (ILT) through the drinking water route compared with eye—DROP application was investigated. A commercial ocular type of ILT vaccine was used for comparison and was applied ror drinking water vaccination in double the vaccine dose (2x1027 E1D50/bird) required for eye—DROP application. The criteria used for judgernent involved vaccine reactions, humoral and cell—mediated immune responses, together with resistance to intratracheal challenge with Eli)50! bird of the virulent W ybridge strain of ILT virus. The conventional agar—gel precipitin (AGP) and serum neutralization (SN) tests were used to demonstrate humoral antibody response to vaccination, and the leukocyto migration inhibition (LMT) test on pripheral bleed loukocytes as an in vitro correlate of cell—mediated immune response. For the latter, a 1% crude vaccine antigen containing l0 E1D50/ml was used f or simplicity reasons after pilot studies.
Results obtained from the present work are sum— marized in the following points