The effect of different Newcastle disease live vaccines and vaccination schedules on the immune response and performance of broiler chickens serologically positive to Mycoplasmas

Abstract

This study was conducted to investigate the efficacy of the Newcastle disease (ND) live vaccines from different commercial sources used in different programs for vaccination of chicks having maternal antibodies against Mycoplasma infection. The immune response was estimated using HI and challenge tests. The effect on the chicken performance was estimated by the detection of the body weight gain. The role of vaccines in stimulating respiratory bacterial stress was pointed out by the lesion scores.Birds vaccinated with live vaccines from source (2) showed higher HI titers than those vaccinated with vaccine from source (1) and birds received the 2 nd vaccination from heterologous source showed lower titers than those received from homologous source. Results of the challenge test indicated that birds vaccinated with live ND vaccines from one source and those vaccinated with Hitchner B1 at 33-days of age instead of La Sota showed 100% protection rate as compared with 95 % followed by vaccination with heterologous La Sota. Birds received Hitchner B1 of vaccine source (1) showed only 85% protection rate. All vaccinated chicken groups showed feed conversion rates lower than the non-vaccinated control one. Groups received Hitchner B 1 as a 3 rd dose of the vaccine showed higher rates than those vaccinated with La Sota.Results of the lesion score for chronic respiratory disease (CRD) in vaccinated groups with different regimes revealed that birds received ND vaccinal strains from source (1) having higher scores than those received ND vaccines from the 2nd source. Administration of Hitchner B1 vaccine at 33-days of age showed lower scores. Hitchner B1 can be recommended in vaccination of chickens derived from Mycoplasma infected hens. ef Su -Beni Veterinary Medical Journal

Preparation of mucosal nanoparticles and polymer-based inactivated vaccine for Newcastle disease and H9N2 AI viruses

“…Velogenic NDV caused economic losses among commercial chicken in Egypt [ 13 ]. Researchers in vaccines production gave more concerns to develop vaccines that induce protective immunity to prevent and control the virus evolution in poultry flocks [ 14 ]. The antigenic diversity of the NDVs isolated from 52 breeders and broiler flocks in Egypt [ 15 ], and the genetic resistance of the NDVs in the Egyptian native breeds has been reported [ 16 ].…”