Two hundred, five-week old chickens were divided into six equal groups (30 chicks/group) and vaccinated with different live NDV vaccines in Nigella sativa oil. The vaccinated birds were bled at one-week interval post-vaccination over six weeks and the collected sera were tested by the HI test. Half of each group was challenged 21-days post-vaccination by intramuscular route of inoculation with 2X105EID50 of the velogenic viscerotropic Newcastle disease virus (VVNDV). Birds were observed for 15 days post-challenge for any clinical signs of Newcastle disease. Deaths within this period were subjected to post mortem examination. The remaining birds in each group were observed after challenge till 42-days post-vaccination.

In this study, two methods for determination of formalin amount were applied on samples of inactivated vaccines representing local or foreign companies. The first method; matching method was conducted by using phenyl hydrazine while in the other method is; spectrophotometry phloroglucinol was used. Spectrophotometrical method was found more sensitive and more accurate than the matching one. At the same time, the spectrophotometry method could be used for determination of formalin in all inactivated vaccines either bacterial or viral vaccines.

The efficacy of four infectious bursal disease virus (IBDV) vaccines including intermediate (D78) and intermediate plus (228E, IBD-Blen and Bursa-Vac+) were compared in priming vaccination of 10 days commercial old male layer chicks. There were different parameters were measured for testing these vaccines including; the immunogenic efficacy, the effect on performance, organ (bursa, spleen, and proventriculus) body weight index as well as histopathological examination of bursa, spleen, proventriculus and thymus. Chick was received a dose of 102 EID50 from one IBDV vaccine out of 228E, IBD-Blen or Bursa-Vac+, while D78 dose was 104 EID50. The results cleared out that all the tested vaccines passed through the maternal derived antibodies 2480.133 + 156.3. All vaccines stimulate antibody formation as measured by ELISA test. The used vaccines not affect markedly body weight and feed intake, as there were no significant differences between the control group and the vaccinated ones in the mean body weight and the feed conversion rate. Furthermore, the bursa: body weight index of vaccinated groups were generally less than those of control one at all intervals, while the spleen and proventriculus: spleen: body weight index of vaccinated groups was higher than control on at the end of the observation period. The used vaccines induced histopathological changes in bursa, spleen , proventriculus and thymus glands. These results indicated that all tested vaccine are of value in vaccination of commercial chicks from vaccinated breeders

In a trial for comparison between the efficiency of single fowl pox (FP) vaccination and the efficiency of each combined FP and Avian encephalomyelitis (AE) vaccination and simultaneous vaccination with FP and Reo and with FP and Chicken anemia virus (CAV) vaccines our conclusion was that there is no antagonistic reaction between FP virus strain and each AE, Reo and CA viruses strains. In addition, humoral immune response against AE virus strain in case of combined AE+FP vaccination is markedly potent than that in case of single AE vaccination, more over the value of average EID50 of AE virus strain in several batches of combined AE+FP vaccines is significantly higher at P > 0.05 than that in several batches of single AE vaccines. On the other hand, immune response against FP virus strain and Reo virus strain in case of simultaneous vaccination with FP and Reo vaccines is higher than that in case of single FP vaccination and single Reo vaccination. Consequently, it is advisable to use combined live attenuated AE+FP vaccine instead of vaccination with single FP and AE separately. Also, application of simultaneous vaccination with FP and Reo vaccines is advisable as it is proved to be more beneficial than vaccination with each vaccine separately specially in case of that FP vaccine of low potency.

Merthiolate (Thiomersal) is known to be used as antimicrobial agent in inactivated vaccines without affecting vaccine potency. The present work investigated the effect of thiomersal contents in ND, AI and IBD inactivated vaccines on liver and kidney functions of vaccinated birds. The histopathological effect and the withdrawal time of such mercurial product from vaccinated chicken muscles were also investigated. Results revealed that residual thiomersal contents in ND, AI and IBD were 0.03; 0.02 and 0.03mg/ml respectively. Liver and kidney function parameters showed significant increases in serum activities of alanine aminotransferase (ALT) and serum aspartate aminotransferase (AST) up to the 4th week post vaccination. Serum urea was significantly decreased on the 3rd week in vaccinated birds compared to control ones. Significant increase in serum creatinine in vaccinated chickens was recorded on the 5th week post vaccination. Liver and kidney functions’ parameters remain high allover the experimental period (8 weeks). The histopathological examination of liver specimens revealed degeneration of hepatic cells and congestion of the central vein with inflammatory cell infiltration and congestion of blood vessels as well as coagulative necrosis. The spleen of vaccinated chickens showed depletion of lymphocytes while lungs showed thickening of the alveolar. Mercury contents in muscle were 0.72, 0.52; 0.046 and 0.00 mg/kg on the 1st, 2nd, 3rd and 4th week post last vaccination that considered safe to the consumer. It is recommended that vaccinated poultry with inactivated vaccines containing thiomersal should not be slaughtered before at least 4 weeks and it is preferable to use combined inactivated vaccines to reduce the thiomersal contents as possible.