Search Results (357)

Background: Salmonella is a major zoonotic foodborne pathogen. Conventional poultry vaccines may present limitations in terms of efficacy, safety, and practicality. Objectives: This study focuses on enhancing the immunogenicity and improving the safety of a novel oral vaccination employing inducible toxin–antitoxin (TA) systems, which lead to self-destruction of virulent Salmonella Enteritidis. Methods: A Hok/Sok (HS) TA system was designed to induce cell death upon absence of arabinose. Point mutations were introduced to the Hok toxin promoter to moderate toxin production. A combination of HS and CeaB/CeiB (CC) TA systems was designed to induce cell death both in low di-cation levels or anaerobic conditions. Survival of Salmonella-carrying TA systems was tested in culture and in the Raw264.7 macrophage cell line. One-day old chicks were inoculated with Salmonella carrying the TA system to evaluate bacterial persistence and induction of a protective immune response. Results: Attenuation of the Hok toxin promoter prolonged bacterial survival in vitro. Salmonella carrying the combined TA systems was eliminated completely both in vitro and in inoculated chickens, eliciting high levels of antibodies and conferring protection against challenge with wild-type Salmonella. Conclusions: These findings highlight the potential of the adaptable TA-based vaccination platform to generate safe and efficacious Salmonella vaccines for poultry, contributing to reduced transmission in the food chain. Full article

Background: The global dissemination of multidrug-resistant (MDR) Salmonella poses a persistent and serious threat to food safety systems. As a leading poultry-exporting country, Thailand requires a comprehensive understanding of how resistance plasmids spread among Salmonella populations within its chicken production chain. Methods: Between March 2023 and February 2024, 223 Salmonella isolates were collected from chicken slaughterhouses and markets in northeastern Thailand. From these, 19 representative MDR Salmonella enterica isolates, selected based on distinct spatiotemporal distributions, underwent whole-genome sequencing. Genomic analyses included sequence typing, core-genome phylogenetics, and screening for antimicrobial resistance genes. Plasmid replicons were identified, and functional annotation was performed using the COG database. Results: Phylogenetic analysis revealed 11 distinct sequence types within the population. Among these, ST1541 and ST50 showed clear evidence of clonal transmission across different production stages, with a notable clustering pattern observed during the winter season. All sequenced isolates exhibited an MDR phenotype. Plasmids were detected in 78.9% of isolates, with conjugative plasmids being the most frequent type (57.9%). The β-lactamase gene bla_TEM-60 was the most prevalent (78.9%) and showed a strong correlation (r ≥ 0.7) with resistance to both ampicillin and cefotaxime. Functional annotation further revealed an abundance of genes involved in carbohydrate and amino acid metabolism across all isolates. Conclusions: These findings indicate that MDR Salmonella dissemination is driven by two synergistic mechanisms: the clonal expansion of fit lineages and the horizontal transfer of conjugative plasmids harboring β-lactamase genes. We identified IncI-gamma-K1 and Col-related plasmids as key vectors in this process. This study advocates for targeted interventions, guided by a One Health approach, that specifically aim to disrupt plasmid transmission at critical control points, such as slaughterhouses, to curb the spread of antimicrobial resistance. Full article

The extensive use of sulfathiazole in poultry farming has raised growing concerns regarding its residues in poultry-derived products, posing risks to human health and food safety. To overcome the limitations of conventional detection methods and address the analytical challenges posed by inherent complexity of chicken blood matrix for the detection of sulfathiazole residues in chicken blood, a rapid and sensitive surface-enhanced Raman spectroscopy (SERS) method was developed for detecting sulfathiazole residues in chicken blood. Four colloidal substrates, i.e., gold colloid A, gold colloid B, gold colloid C, and silver colloids, were synthesized and evaluated for their SERS enhancement capabilities. Key parameters, including electrolyte type (NaCl solution), colloidal substrate type (gold colloid A), volume of gold colloid A (550 μL), volume of NaCl solution (60 μL), and adsorption time (14 min), were systematically optimized to maximize SERS intensities at 1157 cm⁻¹. Furthermore, a genetic algorithm-support vector regression (GA-SVR) model integrated with adaptive iteratively reweighted penalized least squares (air-PLS) and multiplicative scatter correction (MSC) preprocessing demonstrated superior predictive performance with a prediction set coefficient of determination (R²_p) value of 0.9278 and a root mean square error of prediction (RMSEP) of 3.1552. The proposed method demonstrated high specificity, minimal matrix interference, and robustness, making it suitable for reliable detection of sulfathiazole residues in chicken blood and compliant with global food safety requirements. Full article

Eu³⁺ is a fluorescent and paramagnetic ion whose emission intensity increases when chelated with enhancers such as tetracycline (TC). In this study, Eu³⁺ was conjugated with citric acid (CA) to form magnetic fluorescent probes capable of capturing trace TC from solutions. The probes were rapidly prepared (~2.25 min) and trapped TC within ~2.5 min under microwave heating. The method enabled sensitive detection of TC, oxytetracycline, and chlortetracycline with detection limits of ~3–7 nM by fluorescence spectroscopy. It was successfully applied to real food samples, including fresh chicken broth and commercial broth cubes, achieving high accuracy (93.7% and 96.6%). This dual-functional probe offers a rapid and sensitive approach for detecting TC residues in complex food matrices, demonstrating strong potential for food-safety monitoring. Full article

Veterinary drugs are widely present in animal manure and manure-based fertilizers, making their safety for use as soil amendments still ambiguous. This study investigated the concentrations of 17 typical veterinary drugs in animal manure and manure-based fertilizers from Shandong Province using solid-phase extraction coupled with high-performance liquid chromatography–tandem mass spectrometry and assessed their environmental risks to soil organisms based on risk quotient values. The established method demonstrated robust performance, with drug recovery rates ranging from 72.9% to 109%. Tetracyclines were identified as the most prevalent contaminants, with mean concentrations of 1522 μg/kg in animal manure and 144 μg/kg in manure-based fertilizers. Drug concentrations in manure-based fertilizers were generally lower than those in animal manure. Livestock manure contained higher drug concentrations compared to poultry manure. Influenced by farming practices, drug concentrations were higher in beef cattle manure than in dairy cattle manure, and higher in broiler manure than in layer manure. Manure-based fertilizers primarily derived their drug content from chicken, cattle, and sheep manure. Tetracyclines in swine and sheep manure posed high risks to soil organisms, while those in beef cattle manure and dairy cattle manure posed medium risks. In contrast, most drugs in manure-based fertilizers exhibited low risks. Comprehensive analysis of both concentration levels and ecological risks indicates that manure-based fertilizers represent a more feasible option for soil amendment. This study provides a theoretical foundation for better understanding the feasibility of applying animal manure and manure-based fertilizers to agricultural land. Full article

The extensive use of antibiotics in intensive farming weakens immunity and threatens food safety. Stevia isochlorogenic acid (SICA), a kind of dicaffeoylquinic acid derived from stevia residue, exhibits strong antioxidant activity. This study evaluated the ability of SICA to improve immune function in an immunosuppressed broiler model. SICA significantly increased the spleen, thymus, and bursa of Fabricius indices (p < 0.05), alleviated spleen damage, and elevated serum interleukin-2 (IL-2), IL-4, interferon-γ, IL-1β, tumor necrosis factor-α, immunoglobulins (IgA, IgM, IgG), and complement components C3 and C4 (p < 0.05). Isobaric tags for relative and absolute quantification-based proteomics indicated that SICA enhanced splenic immune function by activating cell adhesion molecules, phagosomes, and the intestinal immune network for IgA production pathways. Quantitative PCR analysis showed upregulation of mRNA and protein levels of B-cell receptor, major histocompatibility complex class II, protein tyrosine phosphatase receptor type C, and neutrophil cytosolic factor 2 (p67phox) and downregulation of C-C motif chemokine receptor 9. Molecular docking demonstrated the strongest binding affinity between SICA and p67phox. Overall, SICA effectively alleviated immunosuppression in broiler chickens and represents a promising natural alternative to antibiotic feed additives. Full article

Color and fluorescence spectrometry were evaluated as rapid, objective tools for verifying the cleanliness of poultry-processing food-contacting surfaces contaminated with a model chicken solution across six common materials. Both techniques detected chicken residues at dilutions several orders of magnitude below human visual and olfactory thresholds, with stainless steel and blue plastic yielding the largest color differences between clean and contaminated states and fluorescence measurements remaining highly sensitive on all tested surfaces. Representative limits of detection were on the order of 1:50–1:100 dilution of chicken residue for color measurements on most surfaces and approximately 1:50 for fluorescence measurements, compared with human detection thresholds of approximately 1:50. Cleaning chemicals routinely used in poultry plants did not measurably reduce detection performance, and a simple machine learning classifier further improved separation of clean versus contaminated readings. These findings indicate that compact color and fluorescence instruments can provide fast, quantitative pre-sanitation checks that strengthen SSOP verification and reduce reliance on subjective human inspection in poultry processing facilities. Full article

Bioaerosols are a major source of airborne microbial contamination in intensive poultry production systems. Their concentration and community structure can profoundly influence animal health, public health, and the overall safety of the farming environment. However, the dynamic characteristics of bacterial aerosols in enclosed poultry houses during winter remain insufficiently studied. Using Taihang chickens as a model, this study investigated three key production stages—brooding (15 days), growing (60 days), and laying (150 days)—under winter cage-rearing conditions. A six-stage Andersen sampler was employed alongside culture-dependent enumeration and 16S rRNA high-throughput sequencing to analyze variations in bacterial aerosol concentration, particle size distribution, and community succession patterns. The results revealed a significant increase in the concentration of culturable airborne bacteria with bird age, rising from 8.98 × 10³ colony-forming unit (CFU)/m³ to 2.89 × 10⁴ CFU/m³ (p < 0.001). The particle size distribution progressively shifted from larger, settleable particles (≥4.7 μm) toward smaller, respirable particles (<4.7 μm). Microbial sequencing indicated a continuous increase in bacterial alpha diversity across the three stages (Chao1 and Shannon indices, p < 0.05), while beta diversity exhibited stage-specific clustering, reflecting clear differences in community assembly. The composition of dominant bacterial genera transitioned from potentially pathogenic taxa such as Acinetobacter and Corynebacterium during the brooding stage to a greater abundance of beneficial genera, including Bacteroides, Lactobacillus, and Ruminococcus, in later stages. This shift suggests a potential ecological link between aerosolized bacterial communities and host development, possibly related to the aerosolization of gut microbiota. Notably, several zoonotic bacterial species were detected in the poultry house air, indicating potential public health and occupational exposure risks under winter confinement conditions. This study is the first to elucidate the ecological succession patterns of airborne bacterial aerosols in Taihang chicken houses across different growth stages during winter. The findings provide a scientific basis for optimizing winter ventilation strategies, implementing stage-specific environmental controls, and reducing pathogen transmission and occupational hazards. Full article

Bacterial Chondronecrosis with Osteomyelitis (BCO) lameness is an infection of opportunistic bacteria in the structural skeletal bones impacting multiple animal species, particularly poultry species. BCO lameness results in significant financial losses to industrial poultry production and increases the risk of foodborne illnesses, posing a major threat to consumers’ food safety. As BCO lameness is an inherent risk of fast body weight gain in poultry species, especially broiler chickens, abundant studies have been conducted in broilers and turkeys. Nevertheless, BCO lameness incidence in ducks remains elusive. Thus, this is the first survey investigating the prevalence of BCO lameness cases in ducks. The survey was conducted in commercial duck farms in Indonesia, the fourth biggest duck-producing country globally. Two hundred birds from four commercial duck farms in Mojokerto, East Java, Indonesia, were necropsied to examine their lameness lesions in the femoral head and proximal tibia. Of the 44% birds showing BCO lameness lesions, 3% were evidently clinically lame birds, particularly exhibiting limping gait. Femoral head separation (FHS) and tibial head necrosis (THN) are the most frequently observed lesions in ducks, representing a mild-to-moderate BCO lameness state. Based on the results of this study, intervention measures to boost the immune system and skeletal bone integrity of ducks are urgently required. Full article

LigiLactobacillus saerimneri (L. sae) has shown considerable promise as a probiotic in recent years, particularly in poultry production. Comprehensive evaluation of its genetic functions, safety profile, and immunogenicity is essential prior to practical application. Our previous study demonstrated that the chicken-derived strain L. sae M-11 colonizes effectively and exhibits a favorable safety profile at adequate dosages. In this study, we further evaluated the potential of L. sae M-11 by analyzing its genetic basis for intestinal adaptation, metabolic features, safety risks, and suitability as a delivery vector. Comparative genomic analysis revealed that L. sae has evolved distinctive genetic features and functional specialization that may facilitate host adaptation. Genomic stability assessments and virulence factor screening confirmed that L. sae M-11 poses no substantial health risks. Furthermore, based on transmembrane protein predictions, the LPQTGE-motif protein was identified as a cell wall anchor in genetically engineered L. sae M-11 using immunoelectron microscopy. Notably, this delivery system selectively activated peripheral blood monocyte-derived dendritic cells (PB-MoDCs) in vitro, as evidenced by the up-regulation of maturation markers (CD83, CD80), pro-inflammatory cytokines (IL-1β, IL-6), Th1-associated IL-12, and the chemokine CXCLi1. However, it exhibited a limited antigen presentation capacity, indicated by low expression levels of CD40, MHCII, DEC205, TNF-α, and IFN-γ. The prospects and challenges associated with the application of L. sae M-11 have been discussed. Overall, these findings support the potential development of L. sae M-11 as a microbial cell factory and mucosal delivery vector. Full article

Regulatory agencies worldwide have implemented stringent measures to monitor and reduce Salmonella contamination in poultry products. Rapid quantitative detection methods enable producers to identify contamination early, implement corrective actions, and enhance food safety. This study aimed to develop and optimize a surface plasmon resonance (SPR) biosensor for the quantitative detection of Salmonella Typhimurium in ground chicken. The sensor surface was functionalized with a well-characterized monoclonal antibody specific to Salmonella flagellin, and an SPR workflow was established for quantitative analysis. Ground chicken samples were inoculated with four S. Typhimurium strains at contamination levels ranging from −0.5 to 3.5 Log CFU/g and enriched at 42 °C for 10 or 12 h prior to SPR analysis. Contamination levels were confirmed using the Most Probable Number (MPN) method. Linear regression analysis indicated that optimal quantification was achieved after 10 h of enrichment (R² ≥ 0.86), whereas extended enrichment (12 h) did not improve performance. The limit of quantification (LOQ) was below 1 CFU/g. A strong positive correlation (R² ≥ 0.85) was observed between SPR and MPN results, demonstrating consistency between the two methods. These findings highlight SPR as a rapid, reliable, and cost-effective alternative to conventional methods for Salmonella quantification. By delivering accurate results within a single day, SPR enhances testing efficiency and supports the production of safer poultry products, thereby reducing public health risks associated with Salmonella contamination. Full article

Infectious Bursal Disease (IBD) is an immunosuppressive viral disease caused by the Infectious Bursal Disease Virus (IBDV). It primarily affects young chickens, targeting the bursa of Fabricius, and poses significant economic threats to the poultry industry. To date, in addition to strict biosecurity measures, large-scale immunization is the optimal strategy and effective method to prevent and control IBDV infection. The emergence of new variant strains has made it more urgent to develop new vaccination strategies against IBD. Over the past few decades, many high-quality vaccines have been available on the market for the control of IBD, which can provide solid protection against the infections and diseases caused by classic IBDV to very virulent IBDV that had been continuously evolving and were endemic worldwide. However, viruses are not static. As they continue to circulate and evolve in the fields, novel antigenic variant viruses have been emerged in the last few years, and vaccines need to keep up with their pace. Collectively, this review summarizes the strategic evolution of IBDV vaccines from traditional methods to cutting-edge molecular platforms, providing promising strategies for developing the next-generation vaccines with higher safety, efficacy, and the ability to keep pace with the antigenic drift in IBDV. Full article

Long-term excessive fluoride intake from food causes skeletal fluorosis, which manifests as bone sclerosis, deformation, joint dysfunction, and even disability. Mitophagy and ion homeostasis regulate bone function. This study investigated the role of melatonin (MLT) in mitigating this condition, given its known involvement in bone remodeling and the fact that fluoride impairs its synthesis in the pineal gland. Firstly, network pharmacology and molecular docking identified mitophagy as MLT’s key pathway against sodium fluoride (NaF)-induced osteosclerosis. Subsequently, a 400 mg/kg/day body weight NaF exposure model in chicken model with 25 mg/kg/day body weight MLT intervention were established in the current study. Fluoride exposure caused the disturbance of ion homeostasis, and the impairment of mitochondria and activation of PTEN-induced putative kinase1 (PINK1)/E3 ubiquitin ligase Park2 (Parkin)-mediated mitophagy in the bone. Importantly, these deleterious effects were significantly restored by MLT supplementation. In conclusion, NaF causes bone injury via ion homeostasis disruption, osteoblast mitochondrial damage, leading to excessive mitophagy. MLT inhibits fluoride-induced mitophagy through the calcium ion flow-mediated PINK1/Parkin pathway, mitigating bone damage. This study can not only ensure the safety of animal-derived food but also provide a theoretical basis for the prevention and treatment of fluorosis in humans and animals. Full article

As a core strategy for antibiotic replacement, probiotics have two advantages insofar as they enhance both animal productivity and pathogen suppression. In this study, we screened the intestines of antibiotic-naïve chickens for broad-spectrum antimicrobial lactic acid bacteria (LAB) with natural adaptability, based on the host–microbiota coevolution theory, and systematically evaluated their potential for development as poultry probiotics. We isolated a LAB strain, Lactiplantibacillus plantarum Y300, from traditional native free-range chickens, which showed strong inhibitory activity against avian pathogenic Salmonella, Escherichia coli, and Staphylococcus aureus. In vitro experiments indicated that the Lpb. plantarum strain Y300 had no hemolytic activity; excellent acid-producing ability;an outstanding tolerance to bile salts, low-pH environments, and simulated gastrointestinal fluids; a positive hydrophobic interaction with xylene, and good auto-aggregation characteristics. It also displayed a relatively high antioxidant capacity. Whole-genome sequencing revealed that the genome of Lpb. plantarum Y300 was approximately 3.05 mb, with a GC content of 44.74%. The main carbohydrate-active enzyme and bacteriocin genes were predicted in the Y300 genome, and no virulence genes or drug-resistance genes were detected. In summary, this study suggests that Lpb. plantarum Y300 has potential utility as a probiotic, and lays the theoretical foundation for the further development of microecological preparations of avian-sourced LAB. Full article

The detection of H5N1 highly pathogenic avian influenza virus (HPAIV) in lactating dairy cattle in the United States, with high viral titers in raw milk, has raised concerns about zoonotic transmission through unpasteurized milk and dairy products. While viral inactivation during pasteurization is documented, data on persistence in raw-milk cheeses remain limited. This study evaluated the survival of avian influenza viruses (AIVs), both low pathogenic (LPAIV, H1N1) and highly pathogenic (HPAIV, H5N1), during the production and ripening of Grana-type hard cheeses from raw cow’s milk. Experimental cheesemaking was carried out with milk artificially contaminated with A/duck/Italy/281904-2/06 (H1N1; 10^7.75 EID₅₀/mL) or A/duck/Italy/326224-2/22 (H5N1 clade 2.3.4.4b; 10^6.75 EID₅₀/mL). Cheeses were manufactured under Parmigiano-Reggiano standards and ripened 30 days at 5–6 °C. Viral detection in finished cheeses was performed using inoculation in specific-pathogen-free embryonated chicken eggs (SPF-ECEs), hemagglutination (HA) assay, and monoclonal antibody-based ELISA. No infectious virus was detected in cheese samples after two blind passages in SPF-ECEs. Both HA and ELISA tests were negative, indicating complete viral inactivation. These results demonstrate that Grana-type cheese processing, including cooking, acidification, and ripening, effectively inactivates LPAIV and HPAIV. Findings support the microbiological safety of raw-milk hard cheeses regarding AIV, contributing to risk assessment and food safety policies. Full article