165 Research Article EVALUATION OF DIFFERENT ROUTES OF VACCINATION BY CLONE VACCINE ON HUMORAL ANTIBODY RESPONSE Moin Khodayari, Adel Feizi * Received 15 September 2017, revised 16 November 2017 ABSTRACT: Prevention of Newcastle disease in broiler birds is a priority for successful poultry industry. The present study evaluates the immune response to Clone 30 live vaccine alone and in combination with inactivated vaccine administrated by different routes in broiler chickens. To evaluate the various route of vaccination and inactivated vaccines on antibody response, Clone vaccine was administered in different routes such as eye drop, spray, and drinking water with or without inactivated vaccine. Hemagglutination inhibition (HI) and enzyme-linked immunosorbent assay (ELISA) methods was used to assess the antibody response. Results indicated significant difference among different groups and the antibody titer showed highest in eye drop with inactivated vaccine group in both the tests at 42 th. day. Key words: Newcastle disease, Vaccination route, Clone 30 vaccine, Inactivated vaccine, Antibody titer. INTRODUCTION Newcastle disease (ND) is a highly contagious and wide spread viral disease of the avian species causing severe economic losses in domestic poultry, especially in chickens (Al-Garib et al. 2003). ND is one of the most important diseases of poultry Globally ND remains as a major barrier to international trade in poultry and poultry products (Balachandran et al. 2014). Researchers indicated that the ND has most economical impact on the world than other viral disease (Alexander et al. 2008). Despite the advances in vaccines and vaccination programs in control of ND, the disease remains a major constraint in industrial poultry production worldwide (Alexander et al. 2012). Various factors influence the outcomes of a vaccination programs in broiler industry, such as efficacy of the vaccine strain, the inhibitory effects of maternal and residual active immunity, the ability of the vaccine virus in antibody production, and secondary reactions that were due to vaccine strain or unsuitable route of vaccination (Lim 2014). An advantage of the live vaccines is that they can be administered at large scale. The method more popular for administration is by supply in the drinking water, although aerosols and eye-drop methods are utilized (Landman et al. 2017).For success in ND prevention, it is necessary to compare the available vaccine strains and efficient methods of application (Cardenas Garcia et al. 2014). It was reported that the vaccination with live vaccines based on less virulent strains sometimes cause disease and growth retardation; therefore mostly the least or avirulent strain of the virus was use for live vaccination of poultry. Although this strategy reduces the vaccination reaction, but sometimes vaccination could not effective in preventing infection and transmission of virus to other birds (Burridge et al. 1975, Kapczynski and King 2005, Senne et al. 2004). Currently mesogenic, lentogenic and a pathogenic enteric types of vaccine in use in worldwide (Swayne et al. 2013), but in Iran only lentogenic (includes: Hitchner B1, VG/GA, Cloned La Sota and La Sota) and a pathogenic enteric types (includes: PHY.LMV.42 and Ulster 2C) are used in ND prevention programs. Vaccination of broiler chicken flocks against ND usually carried out by non-virulent live virus administered by spray or eye-drop or via drinking water. The various ways of administration usually produce considerable variation in the antibody responses of vaccinated birds, which causes variation in the levels of protection of broilers against the disease (Senne et al. 2004, Landman et al. 2017). It has been reported that simultaneous vaccination with live and killed ND vaccines resulted in better antibody response and protection (Lima et al. 2004). Following parenteral vaccination by an inactivated vaccine, the immune response is mostly humoral and is generally protective (Alexander et al. 2008). But the types Department of Clinical Science, Tabriz Branch, Islamic Azad University, Tabriz, Iran. Corresponding author. e - mail: adelfeiziiaut@gmail.com Explor Anim Med Res, Vol.7, Issue - 2, 2017, p. 165-169