Electron beam inactivated multi-strain Staphylococcus vaccine effectively controls broiler chicken BCO lameness

Authors: PERERA, RUVINDU - University Of Arkansas; DO, ANH - University Of Arkansas; ALHARBI, KHAWLA - University Of Arkansas; ASNAYANTI, ANDI - University Of Arkansas; LARBI, MANEL - University Of Arkansas; ANTHNEY, AMANDA - University Of Arkansas; ASSUMPCAO, ANNA - University Of Arkansas; Jesudhasan, Palmy; Arsi, Komala; PHILLIPS, GEETHA - University Of Arkansas; KALAPALA, TANMAIE - University Of Arkansas; SANTAMARIA, JOSSIE - University Of Arkansas; PILLAI, SURESH - Texas A&M Agrilife; Donoghue, Ann; ALRUBAYA, ADNAN - University Of Arkansas

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 9/17/2024
Publication Date: 9/26/2024
Citation: Perera, R., Do, A., Alharbi, K.S., Asnayanti, A., Larbi, M.B., Anthney, A.P., Assumpcao, A., Jesudhasan, P., Arsi, K., Phillips, G., Kalapala, T., Santamaria, J., Pillai, S., Donoghue, A.M., Alrubaya, A. 2024. Electron beam inactivated multi-strain Staphylococcus vaccine effectively controls broiler chicken BCO lameness. Abstract. Arkansas Association for Food Prevention, September 24-26, 2024.

Interpretive Summary: Broiler chicken lameness caused by Bacterial Chondronecrosis with Osteomyelitis (BCO) was first reported in 1972 and is presently amongst the top-most economic and animal welfare issues faced by the poultry industry. BCO lameness results hundreds of millions of dollars in lost revenue annually in the United States and worldwide due to bird condemnation at the marketing age. BCO is caused by multiple opportunistic bacterial pathogens in the respiratory and gastro-intestinal (GI) tracts. The regular lameness rate in broiler chickens varies from 3% up to 15%, resulting in mortality rates ranging from 5% to 10%. In the early 2010s, 12.5 billion broiler chickens were estimated to experience leg-related disorders worldwide. Considering the broiler production value of $50.4 billion of the United States in 2022, the current estimate of the regular economic loss in chicken meat production due to lameness in the US ranges from $900 million to $1.8 billion. Therefore, the aforementioned impact on the poultry industry added to the absence of efficacious mitigatory measures, vehemently necessitates the development of a successful commercial vaccine for the control of BCO lameness worldwide. We developed and tested an eBeam-killed Staphylococcus vaccine and tested the vaccine safety in vitro. In addition, we conducted an in-vivo field studies at the University of Arkansas Poultry Research Farm to test the efficacy of the vaccine. Based on the results, eBeam-killed vaccines developed against Staphylococcus species reduces lameness in broiler chickens by >50%. Currently, there are no commercial vaccines available, and the 50% reduction of BCO-induced lameness would be an excellent benefit for the poultry industry.

Technical Abstract: Bacterial Chondronecrosis with Osteomyelitis (BCO) is a significant issue affecting the commercial broiler industry, which results in average annual revenue losses of tens of millions of dollars due to condemnation at marketing age. This is commonly associated with necrosis of the leg bones (femur and tibia) of chicken and is generally driven by Staphylococcus sp. infection, which is one of the main pathogens causing the disease. The average annual lameness incidence is between 3-5% but may increase over 25% in outbreaks. Currently, there is no approved effective vaccine to control BCO lameness. Electron beam (eBeam) technology is widely used in food preservation as it prevents microbial activity and multiplication by irreversibly shredding microbial DNA. Meanwhile, microbes would retain the outer membrane proteins (epitopes) necessary for immune response, so eBeam is used in whole-cell vaccine development. Our objective was to evaluate the efficiency of an eBeam-treated multi-strain Staphylococcus vaccine to reduce BCO lameness. A total of 1080 chicks were immunized in ovo with four vaccination (treatment) groups: eBeam-treated, Formalin-treated, a combination of the above vaccine types, and sham (carrier). They were directly exposed to natural BCO causative pathogens using our aerosol hybrid induction model of 2 wire-floor pens of 60 birds at the front end of the facility, which acted as the source of infection from the day of hatch via aerosol until day 56. Each treatment had four pens of 60 birds. Daily cumulative lameness was recorded from day 21, and clinically lame birds were euthanized to visualize the progression of bone necrosis due to BCO lameness. On the final day, the BCO lesions of birds were swabbed onto media plates, and the isolated bacterial cultures were identified (via DNA extraction, PCR amplification for the 16S rDNA V1-V5 region, and sequencing). Only the eBeam vaccine significantly reduced daily cumulative lameness by >50% and prevented Staphylococcus colonization in the bones of treated birds. Therefore, this vaccine is beneficial for the welfare of broilers and the sustainability of the broiler industry.