Superior Efficacy of Apathogenic Genotype I (V4) over Lentogenic Genotype II (LaSota) Live Vaccines against Newcastle Disease Virus Genotype VII.1.1 in Pathogen-Associated Molecular Pattern-H9N2 Vaccinated Broiler Chickens

A comparison of the efficacy of apathogenic genotype I (V4) and lentogenic genotype II (LaSota) strains of live Newcastle disease virus (NDV) vaccines was performed following vaccination with pathogen-associated molecular pattern (PAMP) H9N2 avian influenza vaccine and challenge with velogenic NDV genotype VII.1.1 (vNDV-VII.1.1). Eight groups (Gs) of day-old chicks were used (n = 25). Groups 1–4 received a single dose of PAMP-H9N2 subcutaneously, while Gs (1, 5) and (2, 6) received eye drops of V4 and LaSota, respectively, as two doses. All Gs, except for 4 and 8, were intramuscularly challenged with vNDV-VII.1.1 at 28 days of age. No signs were detected in Gs 1, 5, 4, and 8. The mortality rates were 0% in Gs 1, 4, 5, and 8; 40% in G2; 46.66% in G6; and 100% in Gs 3 and 7. Lesions were recorded as minimal in Gs 1 and 5, but mild to moderate in Gs 2 and 6. The lowest significant viral shedding was detected in Gs 1, 2, and 5. In conclusion, two successive vaccinations of broilers with a live V4 NDV vaccine provided higher protection against vNDV-VII.1.1 challenge than LaSota. PAMP-H9N2 with live NDV vaccines induced more protection than the live vaccine alone

Comparative Evaluation of HVT-IBD Vector, Immune Complex, and Live IBD Vaccines against vvIBDV in Commercial Broiler Chickens with High Maternally Derived Antibodies

Infectious bursal disease (IBD) causes increased mortality and severe immunosuppression in commercial chickens. Currently, vaccination mainly used to control IBD. In this study, Group A (n = 30) received the HVT-IBD vector vaccine (Vaxxitek®) s/c and Group B (n = 30) received the immune complex vaccine (Bursa-Plex®) s/c at 1 day of age. Group C (n = 30) received a single dose of intermediate plus vaccine (228E) through the eye-drop route at 14 days of age. Group D (n = 30) was vaccinated twice with the intermediate vaccine (D78) at 12 and 22 days of age by eye-drop. Group E (n = 30) had the same treatment as group D along with the IBD killed vaccine (Nobilis G®) at 5 days of age. The PC (n = 20) and NC (n = 20) groups were non IBD vaccinated birds either challenged or not with vvIBDV, respectively; 20 chicks from each group were challenged with vvIBDV at 4 weeks of age. Based on clinical signs, postmortem gross lesions, histopathological changes, mortality rate, feed conversion rate, serology, bursal and spleen indices, the HVT-IBD vector vaccine administered was found to be safer and provided better protection against the vvIBDV challenge. The use of a killed IBD vaccine at an earlier age in broilers strengthened the protection induced by double doses of intermediate vaccines in broilers with high maternally derived antibodies against the vvIBDV challenge

The Simultaneous Administration of a Probiotic or Prebiotic with Live Salmonella Vaccine Improves Growth Performance and Reduces Fecal Shedding of the Bacterium in Salmonella-Challenged Broilers

Salmonellosis is one of the most important bacterial diseases in poultry, causing heavy economic losses, increased mortality and reduced production. The aim of this study was the comparative efficacy of a commercial probiotic and/or prebiotic with a live attenuated Salmonella Enteritidis (SE) vaccine on the protection of broiler chickens from SE challenge. The efficacy of probiotic or prebiotic products, as well as a live Salmonella Enteritidis (SE) vaccine at the 7th day of age, administered via drinking water, were evaluated for clinical protection and effects on growth performance of broiler chickens experimentally challenged with SE at the 28th day of age. The use of probiotic or prebiotic simultaneously with the live Salmonella vaccine can diminish the negative effect of live vaccine growth performance, reducing mortality rate, fecal shedding, and re-isolation of SE from liver, spleen, heart and cecum. The use of probiotic or prebiotic simultaneously with the application of the live Salmonella vaccine is a good practice to diminish the negative effect of the harmful bacteria and improve the growth performance of broilers. Thus, further studies may be carried out with layers and breeders