Abstract

CHARCA P, Silvia et al. Evaluation of three avian infectious laryngotracheitis vaccination programmes using two commercial vectorized vaccines in broilers. Rev. investig. vet. Perú [online]. 2015, vol.26, n.4, pp.621-629. ISSN 1609-9117.  http://dx.doi.org/10.15381/rivep.v26i4.11204.

The aim of this study was to evaluate the protection of three immunization programmes against infectious laryngotracheitis (ILT) in broilers using two recombinant commercial vaccines. Atotal of288 1-day-old Ross-308-linemalebirdsweredistributed in four experimental groups of 72 animals with three replicates of 24 birds per group. Group A was subcutaneously vaccinated at 1 day of age with a commercial recombinant fowlpox virus (FPV)-vectored vaccine expressing ILT virus (ILTV) glycoprotein B gene; Group B was vaccinated at day 14 of age with an inactivated vaccine by subcutaneous route and with the vaccine of Group A but applied via wing-web puncture; Group C was subcutaneously vaccinated at 1 day of age with HVT recombinant commercial vaccine expressing genes encoding for ILTV glycoproteins I and D; and Group D remained unvaccinated. All birds werechallenged with ILTVpathogenicstrain with 10⁷DIE₅₀at35daysofage. Unvaccinated chicks showed higher degree of respiratory signs on day 6 post challenge than the vaccinated ones (p<0.05). Microscopic lesions varied between groups, but group C presented a faster recovery (p<0.05). Production parameters (body weight, feed conversion index, and European productive efficiency index) showed no significant difference between groups. The best protection against ILT was obtained in birds vaccinated with the HVT recombinant vaccine; however, no difference in productive performance was found between treatments.

Keywords : laryngotracheitis; vaccination; recombinant.

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