Evaluation of commercially available aroA delated gene E. coli O78 vaccine in commercial broiler chickens under Middle East simulating field conditions

Abstract

The broiler industry in the Middle East (ME) faces many challenges related to bacterial infections, including M. gallisepticum, M. synoviae, E. coli, and other gram-negative bacteria, exacerbated by various errors in the brooding process. Antibiotics use in the first three days of life, such as Linco-Spectin 100 SP, tilmicosin, enrofloxacin, tylosin, colistin, and doxycycline, is the trend in the market to control such challenges. This study aimed to evaluate the efficacy of the newly introduced aroA E. coli vaccine (Poulvac E. coli) and its ability to reduce over-reliance on the heavy use of antibiotics in the ME. The study was conducted on 160 broiler chicks, divided into eight even groups. Each group was treated differently in terms of antibiotic therapy and ages at the time of Poulvac E. coli administration and the challenge of virulent avian pathogenic E. coli (APEC), serotype O78. Spray application of Poulvac E. coli at seven days of age plus Linco-Spectin 100 SP during the first three days provided the best results for zero mortality after challenge with APEC, while Poulvac E. coli at seven days with enrofloxacin during the early three days resulted in 10% mortality. Poulvac E. coli hatchery vaccination protected birds against mortality but reduced body weight gain compared to the 7-day group vaccinated with Linco-Spectin 100 SP during the first three days. Poulvac E. coli given on day one or day seven did not affect the immune response to concurrent respiratory viral vaccines and, in some cases, improved response. This study shows that Poulvac E. coli at seven days of age, together with Linco-Spectin 100 during the first three days, has produced the best results in terms of protection and performance in the ME high presence of avian pathogenic E. coli field challenge.

A systematic review and meta-analysis on the efficacy of vaccination against colibacillosis in broiler production

“…The findings regarding heterologous protection were not consistent among studies with some showing effectiveness against certain strains [54,60], but not others [56,57,60]. The efficacy of the vaccine against homologous challenge was enhanced by supplementation of probiotics Enterococcus faecalis [58] and pre-treatment with Lincospectin improved the vaccine's response [61]. However, the immune response elicited by the live attenuated vaccine was reported to be interfered by the prior application of ceftiofur sodium antibiotic in layer PLOS ONE The crp deletion mutant vaccine was efficacious to reduce mortality and bacterial colonization after homologous challenge but was not effective against heterologous challenge (O125).…”

A Comprehensive Review on Bacterial Vaccines Combating Antimicrobial Resistance in Poultry

“…Lozica et al [ 81 ] reported that an autonomous E. coli vaccine significantly reduced morbidity and mortality and increased egg production in poultry. Several studies showed that an E. coli vaccine, Poulvac® (Zoetis, Parsippany, NJ, USA) effectively worked against the avian pathogenic E. coli in poultry [ 82 , 83 , 84 , 85 , 86 , 87 ].…”

A live attenuated vaccine to prevent severe neonatal Escherichia coli K1 infections

“…Infections) 26 , 27 . Furthermore, it has also been reported that an E. coli O78 vaccine attenuated by deletion of the aro A gene was efficacious against avian diseases 28 . One of the main reason aroA is a good mutated background for vaccine strains is that it makes strains auxotrophic for aromatic amino acids and so cannot replicate properly in certain niches in the host 26 , 29 , 30 .…”