Palmy R. Jesudhasan

Background: Staphylococcus aureus (SA) causes septicemia and arthritis, eventually resulting in substantial economic losses and health hazards in poultry. Lethal electron beam (eBeam) treatment kills bacteria while preserving surface epitopes. Methods: This study compared broiler chicken immune responses (local and systemic) after eBeam-killed (eB) or formalin-killed (FK) SA injections. The vaccine (sham) control was endotoxin-free PBS. This study contained six treatments (trt) with five chickens/trt, with vaccine trts divided into two groups, A and B. Group A received in ovo vaccine/sham treatments (phase 1) initially. At 34 d of age, the pulps of growing feathers (GFs) received intradermal (i.d.) injections of the respective trt to elicit booster and primary responses in groups A and B, respectively. Blood was collected to analyze leukocyte populations and plasma SA-specific antibody levels. Additionally, in phase 2, GFs were collected to assess leukocyte presence in GF pulps. Two-way ANOVA was conducted to test the effects of treatment, time, and their interactions, followed by Tukey’s HSD tests at p < 0.05 for statistical significance. Results: Early in phase 1, the eB group had increased SA-specific IgM, IgA, and total lymphocyte concentrations compared with FK. In phase 2, FK and eB i.d. vaccines increased total lymphocyte and T cell proportions in GF pulps compared with sham. In blood, the recall eB vaccination increased monocytes, B cells, CD8+ T cells, and total lymphocytes, while the recall FK vaccination increased heterophils (p < 0.05). Conclusions: Improved early protection at mucosal surfaces may be reflected by higher plasma levels of SA-specific IgM and IgA following in ovo eBeam-killed-SA vaccination. Additionally, both eB-SA and FK-SA vaccines stimulated robust local inflammatory responses dominated by lymphocytes in GF pulps.

Bacterial chondronecrosis with osteomyelitis (BCO) is a major cause of lameness in modern broiler chickens. It remains a persistent challenge in the broiler industry, resulting in substantial economic losses and serious animal health concerns. The pathogenesis of BCO involves rapid muscle growth, resulting in disproportionate body weight relative to skeletal maturity, thereby increasing mechanical stress and leading to microfractures and osteochondrotic clefts in the proximal growth plates of the femora and tibiae. Infection progresses via hematogenous dissemination and colonization of the leg bones by opportunistic pathogens, primarily Staphylococcus spp., Enterococcus spp., and Escherichia coli, originating from the gastrointestinal or respiratory tract, leading to chronic inflammation, ischemia, biofilm formation, and progressive bone necrosis. Control strategies, including selective breeding, enhanced management and production practices, nutritional interventions, and the administration of antimicrobial agents, offer partial mitigation but have failed to provide a permanent solution to BCO incidence. Vaccination is one of the most promising and targeted immunological approaches to enhance the host immune responses against bacterial pathogens. Electron beam (eBeam) inactivated vaccines represent a significant advancement among available vaccination strategies. This review leverages current knowledge of the etiology, pathophysiology, control measures, and the use of eBeam technology (EBT) in vaccine development to provide a scientifically grounded and innovative approach to controlling BCO-associated lameness in broiler chickens. This article also provides insights into future directions for integrated, antibiotic-free strategies to mitigate BCO and revenue losses, enhance broiler welfare, ensure consumer safety, and support the long-term sustainability of the global poultry industry.

With the projected increase in the global population to 10 billion by 2050, the global agricultural system is under immense strain to meet the growing demand for food while also ensuring sustainability and efficiency. Insects present a promising alternative to traditional feed sources, as they can transform low-quality ingredients such as organic food waste into high-quality protein feed. As insects are rich in protein, essential amino acids, and other nutrients that are beneficial for animal health and growth, they indeed offer a promising alternative to traditional feed sources. However, there are concerns regarding potential health risks associated with consuming insects, such as allergens or pathogens. This study focuses on addressing a key knowledge gap by evaluating the efficacy of electron beam (eBeam) technology, an FDA-approved nonthermal intervention for the microbial decontamination of insect-based feed products. For this study, Salmonella Infantis was experimentally inoculated into 4 different matrices, including houseflies, mosquitoes, cricket meal, and frass. The samples were then subjected to a range of eBeam doses to determine the matrix-specific thresholds for pathogen, specifically Salmonella, inactivation. Our results indicate that even though the eBeam dose varied by substrate, complete inactivation of Salmonella was achieved at doses ranging from 5 to 12.5 kGy based on the type of matrix. These results underscore the potential of eBeam technology as a scalable, nonthermal solution to enhance the microbial safety of insect-based feeds, and its adoption may significantly contribute to food safety and sustainability.

Background: Bacterial Chondronecrosis with Osteomyelitis (BCO) is a significant issue affecting the welfare and economy of the broiler industry, causing substantial revenue losses annually. This disease is frequently associated with Staphylococcus spp. and Enterococcus spp. infections and necrosis of leg and vertebral bones. The typical annual lameness incidence of approximately 3–5% may increase to 30% during outbreaks. Neither the etiology or pathogenesis of the disease has been comprehended, nor have effective preventative measures been identified. Electron beam (eBeam) technology is renowned for producing efficient whole-cell vaccines by preventing bacterial multiplication through irreversible DNA shredding while preserving the integrity of membrane proteins (immunogenic epitopes). This study aims to reduce BCO-induced lameness in broiler chickens via in ovo immunization using eBeam-inactivated multi-strain Staphylococcus. Methods: A total 1080 birds were assigned to four vaccination groups: eBeam-inactivated, formalin-inactivated, combination of eBeam- and formalin-inactivated, and sham (vehicle). The birds were directly exposed to aerosolized, natural BCO challenge until 56 days of age. Results: Birds vaccinated with the eBeam-inactivated Staphylococcus vaccine showed a significant reduction (>50%) in daily cumulative lameness compared to other groups and a decrease in Staphylococcus colonization was observed in the leg joints of treated birds. Conclusions: the eBeam-inactivated Staphylococcus vaccine successfully prevented BCO lameness in broiler chickens.

Bacterial Chondronecrosis with Osteomyelitis (BCO) is a significant issue affecting the animal welfare and economy of the commercial broiler industry, resulting in revenue losses of hundreds of millions of dollars annually. This metabolic disease is frequently associated with Staphylococcus spp. and Enterococcus spp. infections and necrosis of leg and vertebral bones. The typical annual lameness incidence of approximately 3-5% may increase to 30% during outbreaks. Neither the complete etiology and pathogenesis of the disease has been fully understood, nor have effective, commercially available measures of total prevention been identified. Electron beam (eBeam) technology is renowned for producing efficient whole-cell vaccines by preventing bacterial multiplication through irreversible DNA shredding while preserving the integrity of membrane proteins (immunogenic epitopes). This study aims to reduce BCO-induced lameness in broiler chickens via in ovo immunization using an eBeam-inactivated multi-strain Staphylococcus vaccine. 1080 birds were assigned to four vaccination groups: eBeam-inactivated, formalin-inactivated, combination of eBeam and formalin-inactivated, and sham (vehicle). Birds were directly exposed to aerosolized, natural BCO challenge until 56 days of age. Birds vaccinated with the eBeam-inactivated Staphylococcus vaccine showed significant reduction (>50%) in daily cumulative lameness compared to other groups and a decrease of Staphylococcus colonization in the leg-joints of treated birds.

Bacterial chondronecrosis with osteomyelitis (BCO) is caused by several bacteria, including Salmonella, Staphylococcus spp., Escherichia coli, Enterococcus spp., and Mycoplasma spp., and BCO is a significant animal health and welfare issue in broiler production, causing 1–2% of bird condemnation at marketing age and resulting in annual losses of tens of millions of dollars. This study evaluated the efficacy of a probiotic program alone and combined with a multivalent electron beam (eBeam)-inactivated vaccine in reducing BCO lameness. The probiotic program included an Enterococcus faecium spray (E. faecium 669, at 2 × 10⁹ CFU/bird) at hatch and a triple-strain Bacillus-based product (B. subtilis 597, B. subtilis 600, and B. amyloliquefaciens 516 at 1 × 10⁹ CFU/bird/day) in drinking water from day 1 to day 56. An aerosol transmission challenge model simulated commercial bacterial exposure. Birds were divided into five groups: a positive control (PC) group (T1) and a negative control (NC) group (T2) receiving no treatment and three treatment groups receiving the probiotic program (T3), the multivalent vaccine (T4), or both the probiotic program and the multivalent vaccine (T5). Data analyzed via ANOVA (p < 0.05) showed T3, T4, and T5 had significantly lower lameness (43.7%, 40.3%, and 40.7%) than T2 (71.0%) and T1 (83.0%). T5 resulted in reductions comparable to T4, indicating no significant synergistic effect. These findings show that probiotics alone or with a vaccine effectively mitigate BCO lameness, enhance broiler welfare, and reduce economic losses.

This review provides an overview of electron beam (eBeam) technology and its applications across a wide variety of disciplines. More importantly, it discusses this technology’s advantages and its benefits in developing inactivated vaccines. eBeam technology is currently being used all around the world for a variety of industrial applications, extending from food pasteurization to the cross-linking of polymers in the wire and cable industries. It is a successful emerging alternative for developing vaccines against bacterial, protozoan, and viral pathogens. This review includes a descriptive account of the mechanism of action of eBeam and how this technology achieves the complete inactivation of pathogens while retaining the integrity of their surface epitopes. This unique advantage is crucial for the production of efficacious vaccines. This review provides a detailed account of the usage of eBeam technology for developing vaccines to protect a multitude of hosts against a wide range of pathogens. eBeam-inactivated vaccines are advantageous over live vaccines, RNA/subunit vaccines, and chemically inactivated vaccines mainly due to the complete inactivation of pathogens, and the presence of intact, highly antigenic epitopes. To conclude, this article descriptively highlights eBeam technology’s advantages over other means of vaccine development.