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BACKGROUND: The chicken body louse is an obligate ectoparasite of domestic chickens. Chicken body lice feed on feathers, and infestation with this louse is linked to decreases in egg production, hen weight, and feed conversion efficiency. However, it is unknown how chicken body lice impact egg-laying chickens in cage-free environments. Welfare and behavior metrics were collected from flocks of egg-laying chickens either infested with chicken body lice or left uninfested. METHODS: In two trials, two flocks of cage-free commercial egg-laying chickens were infested with chicken body lice or maintained as uninfested controls. At three timepoints, behavior and welfare of all chickens was measured. On-animal sensors were used to quantify pecking, preening, and dustbathing behavior. Other animal-based welfare metrics included recording comb wounds and skin lesions. RESULTS: Birds infested with chicken body lice exhibited significantly more preening behaviors than uninfested birds, even at low louse levels. Moderate or severe skin lesions were detected on birds that were moderately infested with chicken body lice while skin lesions were never detected on uninfested birds. CONCLUSIONS: The welfare of chickens was impacted by the chicken body louse, a chewing louse that primarily feather feeds. Evidence of skin lesions on infested birds suggests that lice may cause more damage to birds than previously thought, and further evaluation of louse economic damage is necessary.

Infectious bronchitis virus (IBV) induces severe economic losses in chicken farms due to the emergence of new variants leading to vaccine breaks. The studied IBV strains belong to Massachusetts (Mass), Canadian 4/91, and California (Cal) 1737 genotypes that are prevalent globally. This study was designed to compare the impact of these three IBV genotypes on primary and secondary lymphoid organs. For this purpose, one-week-old specific pathogen-free chickens were inoculated with Mass, Canadian 4/91, or Cal 1737 IBV variants, keeping a mock-infected control. We examined the IBV replication in primary and secondary lymphoid organs. The molecular, histopathological, and immunohistochemical examinations revealed significant differences in lesion scores and viral distribution in these immune organs. In addition, we observed B-cell depletion in the bursa of Fabricius and the spleen with a significant elevation of T cells in these organs. Further studies are required to determine the functional consequences of IBV replication in lymphoid organs.

Newcastle disease (ND), an economically important disease in poultry, is caused by virulent strains of the genetically diverse Orthoavulavirus javaense (OAVJ). Laboratories rely on quantitative real-time reverse transcription PCR (qRT-PCR) to detect OAVJ and differentiate between OAVJ pathotypes. This study demonstrates that a fusion cleavage site based molecular beacon with reverse transcription loop mediated isothermal amplification (MB-RT-LAMP) assay can detect and differentiate OAVJ pathotypes in a single assay. Data show that the assay can rapidly identify diverse OAVJ genotypes with sensitivity only one log-fold lower than the current fusion qRT-PCR assay (104 copies), exhibits a high degree of specificity for OAVJ, and the molecular beacon can differentiate mesogenic/velogenic sequences from lentogenic sequences. Further, data show that a two-minute rapid lysis protocol preceding MB-RT-LAMP can detect and differentiate OAVJ RNA from both spiked samples and oropharyngeal swabs without the need for RNA isolation. As the MB-RT-LAMP assay can rapidly detect and discriminate between lentogenic and mesogenic/velogenic sequences of OAVJ within one assay, without the need for RNA isolation, and is adaptable to existing veterinary diagnostic laboratory workflow without additional equipment, this assay could be a rapid primary screening tool before qRT-PCR based validation in resource limited settings. [ABSTRACT FROM AUTHOR]

Dimetridazole (DMZ) is a broad-spectrum anti-anaerobic and antiprotozoal drug extensively used for the control of blackhead disease in poultry (especially turkeys). The presence of DMZ and its metabolites in animal food poses potential risks to human health. In this study, we developed a high-performance liquid chromatography tandem mass spectrometry (HPLC/MS-MS) method for the precise detection of DMZ and its metabolite 2-hydroxymethyl-1-methyl-5-nitroimidazole (HMMNI). Our results demonstrate a strong linear relationship (r² > 0.99) between the concentrations of DMZ and HMMNI in tissues and egg within the range of 1~100 ng/g. The limits of detection (LOD) were determined to be 0.5 ng/g, with corresponding limits of quantification (LOQ) at 1.0 ng/g. Furthermore, average recoveries in tissues and egg fell within the range of 84.90% to 103.01%, with coefficients of variation below 15% for both intra-day and inter-day analyses. To investigate the residue elimination pattern of DMZ and HMMNI, diets containing 500 mg/kg DMZ were fed to healthy SanHuang chicken and Hy-line Gray laying hens for 10 consecutive days. The results indicated that the concentration of HMMNI consistently exceeded that of DMZ during the same period, in both broiler tissues and egg. Sebum showed the slowest elimination of DMZ and HMMNI, becoming undetectable after 168 h of withdrawal. In egg, residues of both substances peaked on the first day after drug withdrawal, followed by slow elimination with half-lives of 0.45 days for DMZ and 0.66 days for HMMNI. Based on these findings, WT1.4 software was used to calculate a withdrawal time of 11 days for broilers and an egg abandonment period of 14 days after withdrawal for laying hens, providing a scientific basis for the safe and rational use of DMZ in poultry farming. [ABSTRACT FROM AUTHOR]

Accurate and timely molecular diagnosis of respiratory diseases in chickens is essential for implementing effective control measures, preventing the spread of diseases within poultry flocks, minimizing economic loss, and guarding food security. Traditional molecular diagnostic methods like polymerase chain reaction (PCR) require expensive equipment and trained personnel, limiting their use to centralized labs with a significant delay between sample collection and results. Loop-mediated isothermal amplification (LAMP) of nucleic acids offers an attractive alternative for detecting respiratory viruses in broiler chickens with sensitivity comparable to that of PCR. LAMP's main advantages over PCR are its constant incubation temperature (∼65 °C), high amplification efficiency, and contaminant tolerance, which reduce equipment complexity, cost, and power consumption and enable instrument-free tests. This review highlights effective LAMP methods and variants that have been developed for detecting respiratory viruses in chickens at the point of need. [ABSTRACT FROM AUTHOR]

Marek's disease (MD) is a neoplastic disease that significantly affects the poultry industry. Long non-coding RNAs (lncRNAs) are crucial regulatory factors in various biological processes, including tumourigenesis. However, the involvement of novel lncRNAs in the course of MD virus (MDV) infection is still underexplored. Here, we present the first comprehensive characterization of differentially expressed lncRNAs in chicken spleen at different stages of MDV infection. A series of differentially expressed lncRNAs was identified at each stage of MDV infection through screening. Notably, our investigation revealed a novel lncRNA, lncRNA 803, which exhibited significant differential expression at different stages of MDV infection and was likely to be associated with the p53 pathway. Further analyses demonstrated that the overexpression of lncRNA 803 positively regulated the expression of p53 and TP53BP1 in DF-1 cells, leading to the inhibition of apoptosis. This is the first study to focus on the lncRNA expression profiles in chicken spleens during MDV pathogenesis. Our findings highlight the potential role of the p53-related novel lncRNA 803 in MD pathogenesis and provide valuable insights for decoding the molecular mechanism of MD pathogenesis involving non-coding RNA. RESEARCH HIGHLIGHTS Differentially expressed lncRNAs in spleens of chickens infected with Marek's disease virus at different stages were identified for the first time. The effects of novel lncRNA 803 on p53 pathway and apoptosis of DF-1 cells were reported for the first time. [ABSTRACT FROM AUTHOR]

Mycoplasma gallisepticum (MG) and Mycoplasma synoviae (MS) are the primary agents responsible for mycoplasma disease in poultry. MG has been identified as a significant cause of chronic respiratory disease in chickens, while MS has been linked to the development of tenosynovitis, joint swelling and other symptoms in chickens, leading to considerable economic losses for the poultry industry. Unfortunately, there is no specific drug for treatment and vaccination is the most important way to control the disease. There are some different types of vaccines, including live vaccines, inactivated vaccines, sub-unit vaccines and vector vaccines. This paper provides a comprehensive review of the development of vaccines for MG and MS. [ABSTRACT FROM AUTHOR]

Avian leukosis viruses (ALVs) include a group of avian retroviruses primarily associated with neoplastic diseases in poultry, commonly referred to as avian leukosis. Belonging to different subgroups based on their envelope properties, ALV subgroups A, B, and J (ALV-A, ALV-B, and ALV-J) are the most widespread in poultry populations. Early identification and removal of virus-shedding birds from infected flocks are essential for the ALVs' eradication. Therefore, the development of rapid, accurate, simple-to-use, and cost effective on-site diagnostic methods for the detection of ALV subgroups is very important. Cas13a, an RNA-guided RNA endonuclease that cleaves target single-stranded RNA, also exhibits non-specific endonuclease activity on any bystander RNA in close proximity. The distinct trans-cleavage activity of Cas13 has been exploited in the molecular diagnosis of multiple pathogens including several viruses. Here, we describe the development and application of a highly sensitive Cas13a-based molecular test for the specific detection of proviral DNA of ALV-A, B, and J subgroups. Prokaryotically expressed LwaCas13a, purified through ion exchange and size-exclusion chromatography, was combined with recombinase polymerase amplification (RPA) and T7 transcription to establish the SHERLOCK (specific high-sensitivity enzymatic reporter unlocking) molecular detection system for the detection of proviral DNA of ALV-A/B/J subgroups. This novel method that needs less sample input with a short turnaround time is based on isothermal detection at 37 °C with a color-based lateral flow readout. The detection limit of the assay for ALV-A/B/J subgroups was 50 copies with no cross reactivity with ALV-C/D/E subgroups and other avian oncogenic viruses such as reticuloendotheliosis virus (REV) and Marek's disease virus (MDV). The development and evaluation of a highly sensitive and specific visual method of detection of ALV-A/B/J nucleic acids using CRISPR-Cas13a described here will help in ALV detection in eradication programs. [ABSTRACT FROM AUTHOR]

Dr. Benjamin S. Pomeroy was a highly respected veterinarian who specialized in poultry production and the control of poultry diseases. He obtained his veterinary degree from Iowa State University and went on to earn a Master of Science and a PhD from Cornell University and the University of Minnesota, respectively. Dr. Pomeroy's research focused on poultry diseases, particularly salmonellosis, and he played a significant role in the development of disease control programs. He also contributed to the establishment of veterinary specialization in avian pathology and was involved in the founding of important professional organizations. Dr. Pomeroy's expertise and contributions to the field of veterinary medicine were widely recognized and he continues to inspire others in the field. [Extracted from the article]

Live coccidiosis vaccines have mainly been used to reduce Eimeria species infection, which is considered the most economically important disease in the poultry industry. Evaluation data on vaccine effectiveness through large-scale field experiments are lacking, especially in broilers. Thus, the effectiveness of a commercial coccidiosis vaccine was evaluated in approximately 900,000 chicks reared on three open-broiler farms where coccidiosis is prevalent. The vaccine's effectiveness after vaccination of 1-day-old chicks was monitored using three parameters (lesion score, fecal oocyst shedding, and production index, PI) in nine trials performed three times on each farm. Lesion scores were confirmed in three different areas of the intestine because the vaccine contained four Eimeria species. The average lesion scores were 0.36 to 0.64 in the duodenal region, 0.30 to 0.39 in the jejuno-ileal region, and 0.18 to 0.39 in the cecal region. The average fecal oocyst shedding rate ranged from 19,766 to 100,100 oocysts per gram, showing large variations depending on farms and buildings within the farm. Compared with the PI of the previous 9–10 trials on each farm, the PI increased by 2.45 to 23.55. Because of the potential for perturbation of the fecal microbiota by live coccidiosis vaccines, the fecal microbiota was investigated using 16S rRNA microbial profiling. Although the β-diversity was significantly different in distribution and relative abundance among farms (PERMANOVA, pseudo-F = 4.863, p = 0.009), a Kyoto Encyclopedia of Genes and Genomes pathway analysis found no significant bacterial invasion of the epithelial cell pathway across farms. This large-scale field trial of a live Eimeria vaccine indicates that coccidiosis vaccines can have meaningful effects on the poultry industry and could be used as an alternative to the prophylactic use of anticoccidial drugs under field conditions. [ABSTRACT FROM AUTHOR]

Newcastle disease (ND) is among the most important poultry diseases worldwide. It is the major threat to poultry production in Africa and causes major economic losses for both local and commercial chickens. To date, half of ND class II genotypes have been reported in Africa (I, IV, V, VI, VII, XI, XIII, XIV, XVII, XVIII, and XXI). The information on the circulating NDV genotypes is still scarce despite the endemic nature of ND in most countries on the African continent.A total of 659 oro-cloacal swabs were collected from local chickens in Mawenzi live bird market located in Morogoro, Tanzania, between June 2020 and May 2021. Newcastle disease virus was detected by using reverse transcription real-time polymerase chain reaction (RT-qPCR) and conventional PCR followed by sequencing of PCR products. The prevalence of NDV in the surveilled live bird markets was 23.5%. Sequencing and phylogenetic analysis revealed the presence of sub-genotype VII.2. The detected sub-genotype VII.2 has phylogenetic links to Zambian NDV strains implying a Southeast dissemination of the virus, considering that it was first detected in Mozambique. This study underscores the need of active NDV surveillance to determine the distribution of this NDV genotype in the country and monitor its spread and contribution to the emergence of new ND viruses.

Infectious bursal disease (IBD) is one of the dangerous diseases of poultry that affects the bursa of Fabricius, which is an important organ of the bird’s immune system. IBD virus is resistant to many drugs, making its control difficult. Vaccination of IBD is in practice for a long time worldwide to control IBD, but secondary issues like vaccine failure and lower efficacy lead to their reduced use in the field. Multiple medicines are currently used, but the phytochemicals have emerged as promising agents for controlling IBD. The drugs to be developed should possess direct antiviral properties by targeting viral entry mechanisms, enhancing the host immune response, and inhibiting viral protein synthesis. Phytochemicals have potential to contribute to food security by minimizing the possibility of disease outbreaks and ensuring that consumers worldwide obtain healthy poultry products. It has been now claimed that direct and indirect activities of phytochemicals can be effective in the control of IBDV. Although available evidence suggest that the phytochemicals can contribute in controlling occurrence IBDV, there is a definite need of focused studies to gain more insight and develop rational strategies for their practical use. This review highlights the disease caused by IBDV, inhibition of viral replication, boosting the immune system, disruption of viral membrane, and important phytochemicals showing antiviral activities against IBDV. [ABSTRACT FROM AUTHOR]

Campylobacter is a leading cause of food-borne gastroenteritis worldwide, linked to the consumption of contaminated poultry meat. Targeting this pathogen at source, vaccines for poultry can provide short-term caecal reductions in Campylobacter numbers in the chicken intestine. However, this approach is unlikely to reduce Campylobacter in the food chain or human incidence. This is likely as vaccines typically target only a subset of the high genomic strain diversity circulating among chicken flocks, and rapid evolution diminishes vaccine efficacy over time. To address this, we used a genomic approach to develop a whole-cell autogenous vaccine targeting isolates harbouring genes linked to survival outside of the host. We hyper-immunised a whole major UK breeder farm to passively target offspring colonisation using maternally-derived antibody. Monitoring progeny, broiler flocks revealed a near-complete shift in the post-vaccination Campylobacter population with an ~50% reduction in isolates harbouring extra-intestinal survival genes and a significant reduction of Campylobacter cells surviving on the surface of meat. Based on these findings, we developed a logistic regression model that predicted that vaccine efficacy could be extended to target 65% of a population of clinically relevant strains. Immuno-manipulation of poultry microbiomes towards less harmful commensal isolates by competitive exclusion, has major potential for reducing pathogens in the food production chain. [ABSTRACT FROM AUTHOR]

Multiparameter flow cytometry is a routine method in immunological studies incorporated in biomedical, veterinary, agricultural, and wildlife research and routinely used in veterinary clinical laboratories. Its use in the diagnostics of poultry diseases is still limited, but due to the continuous expansion of reagents and cost reductions, this may change in the near future. Although the structure and function of the avian immune system show commonalities with mammals, at the molecular level, there is often low homology across species. The cross-reactivity of mammalian immunological reagents is therefore low, but nevertheless, the list of reagents to study chicken immune cells is increasing. Recent improvement in multicolor antibody panels for chicken cells has resulted in more detailed analysis by flow cytometry and has allowed the discovery of novel leukocyte cell subpopulations. In this article, we present an overview of the reagents and guidance needed to perform multicolor flow cytometry using chicken samples and common pitfalls to avoid. [ABSTRACT FROM AUTHOR]

Avian coccidiosis, a parasitic disease prevalent in poultry, is caused by Eimeria species and leads to significant economic losses. The use of attenuated live oocyst vaccines has been adopted as an alternative to the use of anticoccidial drugs. However, the accurate detection and differentiation of vaccine strains from virulent ones remain challenging. Therefore, this study presents a novel TaqMan polymerase chain reaction (PCR) detection method that offers enhanced sensitivity, specificity, and reproducibility compared with traditional PCR techniques. Through whole-genome resequencing and bioinformatics analysis, we identified a molecular marker gene, Em_marker6, with a unique 21-base pair deletion specific to the Eimeria maxima attenuated vaccine strain. Optimized primers and probes targeting this marker enabled rapid quantification cycle value achievement and high fluorescence intensity. The standard curve's slope of -3.540 and correlation coefficient of 0.9971 confirmed precise quantification capabilities. The TaqMan PCR method detected as few as 30 plasmid DNA copies and 50 oocysts per reaction, outperforming traditional PCR techniques by an order of magnitude. No cross-reactivity was observed with other E. maxima wide-type strains or common intestinal pathogens, ensuring the exclusive detection of the E. maxima EMPY vaccine strain. Weekly testing over 3 weeks demonstrated minimal variability, indicating robust consistency in the method's application. Testing on 61 clinical samples revealed a 57.38% positivity rate for E. maxima species and 13.11% for the vaccine strain. The Em_marker6 gene exhibited genetic stability across multiple generations, confirming the detection method's robust stability for the attenuated E. maxima vaccine strain. This study significantly advances the field of avian coccidiosis research and control by providing a valuable tool for monitoring vaccine purity and preventing inadvertent infections in vaccinated flocks, aligning with global efforts to curb antibiotic use in animal feed. [ABSTRACT FROM AUTHOR]

Simple Summary: Simple Summary: The prevention of the spread of poultry diseases within and among farms largely depends on the adoption of good biosecurity practices. Through the process of profiling European poultry producers, we were able to identify the particular aspects that influence the adoption of biosecurity practices. The results suggest a wide and varied attitude towards biosecurity in the poultry farming community. Generally, most producers appear to be aware of the risks associated with poor biosecurity and the outcomes of carrying out or not carrying out certain practices. Yet, compared with producers of laying hens or parent breeding stock, meat poultry producers (broiler, turkeys, and ducks) appear to have more blocking components with regard to biosecurity. The education level had a positive effect on perception about biosecurity. Poultry producers are not a homogeneous group, and to change their attitudes and actions, approaches must consider the producers' mindset and need to be tailored to the specific needs of the producers. Poultry producers' attitudes towards biosecurity practices were assessed by using the ADKAR® (Awareness, Desire, Knowledge, Ability, and Reinforcement) behavioral change model. Conventional poultry producers (n = 155) from different production types including broilers (n = 35), layers (n = 22), breeders (n = 24), turkeys (n = 19), ducks (n = 23), free-range broilers (n = 11), free-range layers (n = 11), and hatcheries (n = 10) from seven European countries were scored for each ADKAR element (1 = total absence to 5 = perfect fulfilment). Each country performed selected interventions (e.g., coaching, participatory meetings, etc.) to improve biosecurity compliance. After the interventions, significant change was observed in three of the four attitude elements. The overall mean scores ( x ¯ ± SD) obtained during the initial assessment (n = 130) were 4.2 ± 0.6 for Awareness, 4.1 ± 0.7 for Desire, 3.8 ± 0.8 for Knowledge, and 4.0 ± 0.7 for Ability, whereas after intervention, the scores were A = 4.3 ± 0.6, D = 4.2 ± 0.7, K = 4.1 ± 0.7, and Ab = 4.1 ± 0.7. The Reinforcement component was only evaluated after the change and obtained a score of 3.7 ± 0.7 on average. Identifying the elements influencing poultry producers and their behavior related to farm management decisions was useful in guiding our educational interventions to effectively change their behavior. [ABSTRACT FROM AUTHOR]

Simple Summary: Necrotic enteritis caused by Clostridium perfringens (CP) is an important disease for the poultry industry. It leads to decreased growth and production performance in chickens. Bacillus amyloliquefaciens SC06 (BaSC06) is known to play a role in preventing damage from the bacterial infection. However, whether CP could affect brain function and behavior and whether BaSC06 has a preventive role in infected animals are not yet reported. Thus, the aim of this study was to investigate whether BaSC06 has a preventative effect on broiler chickens infected by CP. Our results showed that CP is associated with a reduction in stress and fear-related behaviors and causes pathological damage to the pia and cortex of the brain, as well as inhibiting the expression of genes related to stress, while the treatment of BaSC06 alleviates these adverse effects. Poultry studies conducted on Clostridium perfringens (CP) mainly focus on the effects of intestinal health and productive performance. Notably, the probiotic Bacillus amyloliquefaciens SC06 (BaSC06) is known to play a role in preventing bacterial infection. However, whether CP could induce the changes in brain function and behaviors and whether BaSC06 could play roles in these parameters is yet to be reported. The aim of this study was to evaluate the effects of BaSC06 on stress-related behaviors and gene expression, as well as the brain morphology and mRNA sequence of the hypothalamus in broiler chickens. A total of 288 one-day-old chicks were randomly divided into four groups: (1) a control group with no treatment administered or infection; (2) birds treated with the BaSC06 group; (3) a CP group; and (4) a BaSC06 plus CP (Ba_CP) group. The results showed that stress and fear-related behaviors were significantly induced by a CP infection and decreased due to the treatment of BaSC06. CP infection caused pathological damage to the pia and cortex of the brain, while BaSC06 showed a protective effect. CP significantly inhibited hypothalamic GABA and promoted HTR1A gene expression, while BaSC06 promoted GABA and decreased HTR1A gene expression. The different genes were nearly found between the comparisons of control vs. Ba group and Ba vs. CP group, while there were a great number of different genes between the comparisons of control vs. Ba_CP as well as CP vs. Ba_CP. Several different gene expression pathways were found that were related to disease, energy metabolism, and nervous system development. Our results will help to promote poultry welfare and health, as well as provide insights into probiotics to replace antibiotics and reduce resistance in the chicken industry. [ABSTRACT FROM AUTHOR]

SUMMARY Infectious laryngotracheitis (ILT) is a very serious worldwide respiratory disease of poultry, with many countries reporting ILT infections over the last decade. However, few reports are available regarding ILT disease prevalence in poultry in Turkey. Accordingly, the present study investigated ILT infection in Turkish broiler flocks between 2018 and 2022. Circulating ILT strains were characterized by sequence and phylogenetic analysis of two fragments of the infected-cell protein 4 gene. ILT virus (ILTV) was confirmed by quantitative PCR in 8 of the 21 flocks examined. As in other diseases, co-infections with other respiratory pathogens in confirmed ILT cases may worsen the symptoms and prolong the disease course. The present study confirmed co-infections with infectious bronchitis virus (13/21 tested flocks and 5/8 ILTV-positive flocks), indicating the importance of these pathogens in the occurrence of ILT infections. RESUMEN Circulación y caracterización molecular del virus de la laringotraqueítis infecciosa en bandadas de aves de corral con trastornos respiratorios en Turquía, 2018–2022. La laringotraqueítis infecciosa (ILT) es una enfermedad respiratoria muy seria de la industria avícola en todo el mundo y muchos países han notificado infecciones por esta enfermedad durante la última década. Sin embargo, hay pocos informes disponibles sobre la prevalencia de laringotraqueítis infecciosa en la avicultura de Turquía. En consecuencia, el presente estudio investigó la infección por laringotraqueítis infecciosa en parvadas de pollos de engorde en Turquía entre los años 2018 y 2022. Las cepas de laringotraqueítis infecciosa circulantes se caracterizaron mediante análisis de secuencias y filogenéticos de dos fragmentos del gene de la proteína 4 de las células infectadas. El virus ILT (ILTV) se confirmó mediante PCR cuantitativa en ocho de las 21 parvadas examinadas. Como ocurre con otras enfermedades, las coinfecciones con otros patógenos respiratorios en casos confirmados de laringotraqueítis infecciosa pueden complicar los signos clínicos y prolongar el curso de la enfermedad. El presente estudio confirmó coinfecciones con el virus de la bronquitis infecciosa (en 13/21 parvadas analizadas y en 5/8 parvadas positivas para laringotraqueítis infecciosa), lo que indica la importancia de estos patógenos en la aparición de infecciones por la laringotraqueítis infecciosa. [ABSTRACT FROM AUTHOR]

Newcastle disease (ND) is a significant infectious disease in poultry, causing substantial economic losses in developing countries. To control ND, chickens must be vaccinated multiple times a year. In order to develop an improved vaccine that provides long-term protection, the F gene from genotype VII NDV was inserted into the herpesvirus of turkey (HVT) vaccine virus using CRISPR/Cas9-mediated NHEJ repair and Cre/LoxP technology. The immunogenicity and protective efficacy of the resulting recombinant vaccines were evaluated through antibody assays and virus challenge experiments. Two recombinant vaccines, rHVT-005/006-F and rHVT-US2-F, were generated, both exhibiting growth rates comparable with those of HVT in vitro and consistently expressing the F protein. One-day-old specific pathogen-free (SPF) chickens immunized with 2000 PFU/bird of either rHVT-005/006-F or rHVT-US2-F developed robust humoral immunity and were completely protected against challenge with the NDV F48E8 strain at 4 weeks post-vaccination (wpv). Furthermore, a single dose of these vaccines provided sustained protection for at least 52 wpv. Our study identifies rHVT-005/006-F and rHVT-US2-F as promising ND vaccine candidates, offering long-term protection with a single administration. Moreover, HVT-005/006 demonstrates promise for accommodating additional foreign genes, facilitating the construction of multiplex vaccines. [ABSTRACT FROM AUTHOR]

Recently, herpesvirus of turkeys (HVT), which was initially employed as a vaccine against Marek's disease (MD), has been shown to be a highly effective viral vector for producing recombinant vaccines that can simultaneously express the protective antigens of multiple poultry diseases. Prior to the development of commercial HVT-vectored dual-insert vaccines, the majority of HVT-vectored vaccines in use only contained a single foreign gene and were often generated using time-consuming and inefficient traditional recombination methods. The development of multivalent HVT-vectored vaccines that induce simultaneous protection against several avian diseases is of great value. In particular, efficacy interference between individual recombinant HVT vaccines can be avoided. Herein, we demonstrated the use of CRISPR/Cas9 gene editing technology for the insertion of an IBDV (G2d) VP2 expression cassette into the UL45/46 region of the recombinant rHVT-HA viral genome to generate the dual insert rHVTVP2- HA recombinant vaccine. The efficacy of this recombinant virus was also evaluated in specific pathogen-free (SPF) chickens. PCR and sequencing results showed that the recombinant virus rHVT-VP2-HA was successfully constructed. Vaccination with rHVT-VP2-HA produced high levels of specific antibodies against IBDV (G2d) and H9N2/Y280. rHVT-VP2-HA can provide 100% protection against challenges with IBDV (G2d) and H9N2/Y280. These results demonstrate that rHVT-VP2-HA is a safe and highly efficacious vaccine for the simultaneous control of IBDV (G2d) and H9N2/Y280. [ABSTRACT FROM AUTHOR]

Gumboro disease is a viral poultry disease that causes immune suppression on the infected birds leading to poor production, mortality, and exposure to secondary infections, hence a major threat in the poultry industry worldwide. A mathematical model of the transmission dynamics of Gumboro disease is developed in this paper having four compartments of chicken population and one compartment of Gumboro pathogen population. The basic reproduction number R og is derived, and the dynamical behaviors of both the disease-free equilibrium (DFE) and endemic equilibrium are analyzed using the ordinary differential equation theory. From the analysis, we found that the system exhibits an asymptotic stable DFE whenever R og < 1 and an asymptotic stable EE whenever R og > 1. The numerical simulation to verify the theoretical results was carried out using MATLAB ode45 solver, and the results were found to be consistent with the theoretical findings. [ABSTRACT FROM AUTHOR]

The botanical insecticide market is growing because of limitations placed on the use of certain synthetic chemical insecticides. In this sense, the lesser mealworm Alphitobius diaperius (Coleoptera: Tenebrionidae) is the main poultry pest. The insect causes weight loss and damage to the digestive system of poultry, and it is a vector and reservoir of pathogens. Consequently, this study explored the following hypotheses: (i) essential oils (EOs) derived from Mentha spp. are toxic to A. diaperius; (ii) these EOs are compatible with Beauveria bassiana, the natural enemy of the poultry pest, that parasite A. diaperinus; (iii) these EOs also exhibit activity against bacteria that are pathogenic to poultry. In topical applications and ingestion tests, EOs from Mentha arvensis, Mentha spicata, and Mentha piperita were toxic to A. diaperinus. Chromatographic analyses revealed that menthol is the predominant compound in M. arvensis and M. piperita, whereas carvone is the major compound in M. spicata. Both (−)- and (+)-menthol, along with (−)- and (+)-carvone, underwent testing with A. diaperinus. Nevertheless, their activity was not as potent as those of the EOs, suggesting a possible synergistic and/or additive effect. The EOs did not have any adverse effects on the conidial germination, vegetative growth, or conidia production per colony of the entomopathogenic fungus B. bassiana. Consequently, these EOs are compatible with this natural enemy. The EO extracted from M. spicata exhibited significant toxicity against Staphylococcus aureus (ATCC 25923), whereas the remaining EOs displayed moderate toxicity against this bacterium. The EOs derived from Mentha spp., as assessed in this study, hold promise for the development of botanical insecticides tailored for the control of A. diaperinus. These insecticides are selective in favor of the natural enemy B. bassiana and can also serve as effective sanitizers, thanks to their antibacterial properties. [ABSTRACT FROM AUTHOR]

An accurate understanding of the ecology and complexity of the poultry respiratory microbiota is of utmost importance for elucidating the roles of commensal or pathogenic microorganisms in the respiratory tract, as well as their associations with health or disease outcomes in poultry. This comprehensive review delves into the intricate aspects of the poultry respiratory microbiota, focusing on its colonization patterns, composition, and impact on poultry health. Firstly, an updated overview of the current knowledge concerning the composition of the microbiota in the respiratory tract of poultry is provided, as well as the factors that influence the dynamics of community structure and diversity. Additionally, the significant role that the poultry respiratory microbiota plays in economically relevant respiratory pathobiologies that affect poultry is explored. In addition, the challenges encountered when studying the poultry respiratory microbiota are addressed, including the dynamic nature of microbial communities, site-specific variations, the need for standardized protocols, the appropriate sequencing technologies, and the limitations associated with sampling methodology. Furthermore, emerging evidence that suggests bidirectional communication between the gut and respiratory microbiota in poultry is described, where disturbances in one microbiota can impact the other. Understanding this intricate cross talk holds the potential to provide valuable insights for enhancing poultry health and disease control. It becomes evident that gaining a comprehensive understanding of the multifaceted roles of the poultry respiratory microbiota, as presented in this review, is crucial for optimizing poultry health management and improving overall outcomes in poultry production. [ABSTRACT FROM AUTHOR]

Newcastle disease (ND) is among the most common and deadliest poultry diseases worldwide. Thermostable Newcastle disease virus (NDV) vaccines have been widely used to protect village chickens against ND due to their decreased dependence on cold chains for transport and storage. The NDV4 Heat-Resistant (NDV4HR) vaccine is an apathogenic, heat-resistant, live vaccine that can induce immunity in chickens. In this study, 60 one-day-old Arain local hybrid broilers were divided into three groups of 20. Group A had the usual vaccination program in broiler flocks (seven days old: B1 type by eye drop and ND killed vaccine intramuscularly; 18 and 28 days old: LaSota strain orally). Group B did not receive any vaccine, and group C received the NDV4HR vaccine orally, six times from the first day to the 35th day of rearing. All groups were nasally challenged with acute Newcastle virus (genotype VIId) on the 35th rearing day. Regarding the hemagglutination inhibition serum antibody titer of the birds after the challenge, group B had the highest (7.12±1.05), and group C (6.37±1.31) had a higher titer than group A (6±1.22). After the challenge with the Newcastle virus, the necropsy findings and clinical symptoms of the disease were almost similar in groups A and C. Group B showed the most signs, with higher casualties than other groups. Regarding weight gain, group C had the highest weight at the end of the study (2204±106). On the second day after the challenge, groups A and B had virus shedding through the trachea and cloaca, while group B shed the virus only through the trachea. Furthermore, on the seventh day after the challenge, group A shed the virus through the cloaca, whereas group B did it through the trachea and the cloaca. On the other hand, there was no virus shedding in group C. This study showed that the NDV4HR vaccine provokes an antibody response that protects the birds against a virulent virus challenge. [ABSTRACT FROM AUTHOR]

Each year, millions of poultry succumb to highly pathogenic avian influenza A virus (AIV) and infectious bursal disease virus (IBDV) infections. Conventional vaccines based on inactivated or live-attenuated viruses are useful tools for disease prevention and control, yet, they often fall short in terms of safety, efficacy, and development times. Therefore, versatile vaccine platforms are crucial to protect poultry from emerging viral pathogens. Self-amplifying (replicon) RNA vaccines offer a well-defined and scalable option for the protection of both animals and humans. The best-studied replicon platform, based on the Venezuelan equine encephalitis virus (VEEV; family Togaviridae) TC-83 vaccine strain, however, displays limited efficacy in poultry, warranting the exploration of alternative, avian-adapted, replicon platforms. In this study, we engineered two Tembusu virus (TMUV; family Flaviviridae) replicons encoding varying capsid gene lengths and compared these to the benchmark VEEV replicon in vitro. The TMUV replicon system exhibited a robust and prolonged transgene expression compared to the VEEV replicon system in both avian and mammalian cells. Moreover, the TMUV replicon induced a lesser cytopathic effect compared to the VEEV replicon RNA in vitro. DNA-launched versions of the TMUV and VEEV replicons (DREP) were also developed. The replicons successfully expressed the AIV haemagglutinin (HA) glycoproteins and the IBDV capsid protein (pVP2). To assess the immune responses elicited by the TMUV replicon system in chickens, a prime-boost vaccination trial was conducted using lipid nanoparticle (LNP)-formulated replicon RNA and DREP encoding the viral (glyco)proteins of AIV or IBDV. Both TMUV and VEEV replicon RNAs were unable to induce a humoral response against AIV. However, TMUV replicon RNA induced IBDV-specific seroconversion in vaccinated chickens, in contrast to VEEV replicon RNA, which showed no significant humoral response. In both AIV and IBDV immunization studies, VEEV DREP generated the highest (neutralizing) antibody responses, which underscores the potential for self-amplifying mRNA vaccine technology to combat emerging poultry diseases. [ABSTRACT FROM AUTHOR]

Background and Objectives: Antibiotic resistance within the poultry sector presents a considerable health concern due to treatment inefficacy and resistance transmission to humans and the environment. The investigation of plasmid-mediated quinolone resistance (PMQR) in Escherichia coli, acknowledged for its role in advancing resistance, remains inadequately studied in Iranian poultry. This study aimed to evaluate PMQR gene prevalence as well as to determine correlation between resistance phenotype and genotype in E. coli obtained from poultry colibacillosis. Materials and Methods: A collection of 100 E. coli isolates from the viscera of broilers suspected to colibacillosis was assessed. Using the Kirby-Bauer disk diffusion method, antimicrobial susceptibility tests were conducted for ofloxacin, nalidixic acid, levofloxacin, ciprofloxacin, and ampicillin. Additionally, PCR was employed to screen for qnrS, qnrB, and aac(6)Ib-cr genes. Results: Among the analyzed E. coli isolates, 51% demonstrated resistance to at least one of the tested antibiotics, with 17% exhibiting resistance to four different antibiotics. Nalidixic acid displayed the highest resistance rate at 48%, while ampicillin had the lowest at 16%. PMQR genes were detected in 28% of the E. coli isolates, with aac(6')-Ib-cr being the most prevalent at 14%, followed by qnrB in 13%, and qnrS in 7%. Conclusion: The study underscores the vital need for careful antibiotic usage in poultry to curb the emergence of antibiotic-resistant bacteria. The results illuminate the prevalence of PMQR genes and their association with resistance trends in Iranian poultry, forming a pivotal basis for forthcoming approaches to combat antibiotic resistance within the poultry sector. [ABSTRACT FROM AUTHOR]

Introduction Today, the businesses of the poultry industry are facing many challenges, because this industry has to manage a number of unique processes, methods and risks at the same time. Therefore, identifying the business risks of poultry production units can play an effective role in reducing the level of vulnerability of these businesses. Considering the need to increase the productivity of the poultry industry, one of the basic solutions is to identify the risk and measure the existing risks of this industry. Risk identification and quantification can reduce costs for industry stakeholders, and risk reduction leads to better production planning. In this regard, this study identifies the business risks of poultry production units in Khorasan Razavi province. Materials and Methods This study is applied as purpose and descriptive survey in terms of nature and method. This research is based on mixed research, qualitatively and quantitatively. The statistical population is poultry industry experts, 18 of whom were investigated by snowball sampling method as the research sample. This study proposes a new Delphi technique that uses the features of traditional Delphi techniques and the Fuzzy Delphi method. The proposed new Delphi technique is based on the integration of pentagonal fuzzy sets and the Delphi technique. Results and Discussion The results of the modified pentagonal Fuzzy Delphi method showed that five main risks and 36 secondary risks out of 58 identified risks are part of the business risks of poultry production units. Identified business risks of poultry production units, in order of priority, include inputs price fluctuations, command pricing, exchange rate fluctuations, sanctions, chicken price fluctuations, delay in accessing inputs, fluctuations in the purchase price of day-old chickens, fluctuations in drug and vaccine prices, imported inputs, lack of government support in the matter of production, fluctuations in subsidies to inputs, lack of animal inputs, import of poultry products, Promulgation of various instructions, poultry diseases, lack of liquidity of poultry farmers, bankruptcy of poultry farmers, fluctuations in current costs, losses, lack of medicine and vaccines, lack of expansion of poultry business, lack of confidence of poultry farmers in the government, fluctuations in profitability, investment, seasonal fluctuations in egg demand, dependence of poultry farmers on Special suppliers, supply of day-old chicks, lack of energy, exclusivity of the livestock and poultry feed supply system, egg price fluctuations, seasonal fluctuations in chicken production, seasonal fluctuations in chicken demand, weakness in providing working capital facilities to poultry farmers, lack of skilled human resources in time Appropriate, lack of technical knowledge of advanced technologies and lack of variety of poultry food ingredients. Conclusion The business of poultry production units is facing various challenges and risks, and due to the many risks of this industry, production in this industry is facing problems and it is not possible to plan for it, and production will be disrupted in the future. Therefore, in this research, an effort was made to fully identify the business risks of poultry production units. In order to complete and finalize the business risks of poultry production units, the pentagonal Fuzzy Delphi method was used. In this regard, a questionnaire was prepared that included two parts. The first part is about the survey and information about the background of the respondents, and the second part includes the ranking of 54 identified risks. Fuzzy Delphi method in this study was done in two rounds and based on the opinion of experts, 4 more risks were added to the total of 54 risks, and finally 58 risks were analyzed using Fuzzy Delphi method. In Fuzzy Delphi, the selection of risk components among all the components that were identified in the research literature was based on the accepted threshold criterion. The results of the second round of modified pentagonal Fuzzy Delphi showed that there are 36 important sub-risks in the sector of production, market, financial, institutional and personal business risks of poultry production units. Considering the price fluctuations of livestock inputs and exchange rate fluctuations, it is suggested to allocate currency and control it by government policies in order to reduce mentioned fluctuations, or move towards diversifying poultry feed ingredients and formulating new poultry feed rations. Also, in order to avoid fluctuations in the price of chicken or eggs, it is suggested to make the distribution network smarter to prevent these fluctuations. In the poultry market, it is better to set a fair price for each kilogram of chicken according to the production costs of poultry farmers, or not to interfere with the government in the market and allow the government to set the price based on the supply and demand mechanism. [ABSTRACT FROM AUTHOR]

Four turkeys from a commercial flock with acutely elevated mortality levels were submitted for postmortem examination and diagnostic workup. No clinical signs had been observed before death. On gross examination, hemorrhage and necrosis were present throughout the intestinal tracts, and the spleens were markedly enlarged and speckled. Microscopically, numerous, large basophilic-to-amphophilic intranuclear inclusion bodies were observed in mononuclear cells of the spleen and the lamina propria of the small intestine. In addition, there were lesions of diffuse villus blunting and necrosis of the small intestine, with large numbers of rod-shaped bacteria adhered to the epithelium and in the intestinal lumen. Hemorrhagic enteritis virus (HEV) infection was confirmed via PCR on the spleen. Clostridium perfringens was demonstrated in the small intestine by anaerobic culture and immunohistochemistry. The C. perfringens isolate was type F by PCR and, to our knowledge, necrotic enteritis in turkeys has not been described in association with C. perfringens type F infection.

The intended audience for this publication is commercial poultry producers and poultry veterinarians. This publication aims to provide an update and summary of fowl adenovirus hepatitis. Written by Gary D. Butcher and Mohamed Hossiny, and published by the UF College of Veterinary Medicine, UF/IFAS Extension, July 2024.

Chicks are ideal to follow the development of the intestinal microbiota and to understand how a pathogen perturbs this developing population. Taxonomic/metagenomic analyses captured the development of the chick microbiota in unperturbed chicks and in chicks infected with Salmonella enterica serotype Typhimurium (STm) during development. Taxonomic analysis suggests that colonization by the chicken microbiota takes place in several waves. The cecal microbiota stabilizes at day 12 posthatch with prominent Gammaproteobacteria and Clostridiales. Introduction of S. Typhimurium at day 4 posthatch disrupted the expected waves of intestinal colonization. Taxonomic and metagenomic shotgun sequencing analyses allowed us to identify species present in uninfected chicks. Untargeted metabolomics suggested different metabolic activities in infected chick microbiota. This analysis and gas chromatography-mass spectrometry on ingesta confirmed that lactic acid in cecal content coincides with the stable presence of enterococci in STm-infected chicks. Unique metabolites, including 2-isopropylmalic acid, an intermediate in the biosynthesis of leucine, were present only in the cecal content of STm-infected chicks. The metagenomic data suggested that the microbiota in STm-infected chicks contained a higher abundance of genes, from STm itself, involved in branched-chain amino acid synthesis. We generated an ilvC deletion mutant (STM3909) encoding ketol-acid-reductoisomerase, a gene required for the production of l-isoleucine and l-valine. ΔilvC mutants are disadvantaged for growth during competitive infection with the wild type. Providing the ilvC gene in trans restored the growth of the ΔilvC mutant. Our integrative approach identified biochemical pathways used by STm to establish a colonization niche in the chick intestine during development. IMPORTANCE Chicks are an ideal model to follow the development of the intestinal microbiota and to understand how a pathogen perturbs this developing population. Using taxonomic and metagenomic analyses, we captured the development of chick microbiota to 19 days posthatch in unperturbed chicks and in chicks infected with Salmonella enterica serotype Typhimurium (STm). We show that normal development of the microbiota takes place in waves and is altered in the presence of a pathogen. Metagenomics and metabolomics suggested that branched-chain amino acid biosynthesis is especially important for Salmonella growth in the infected chick intestine. Salmonella mutants unable to make l-isoleucine and l-valine colonize the chick intestine poorly. Restoration of the pathway for biosynthesis of these amino acids restored the colonizing ability of Salmonella. Integration of multiple analyses allowed us to correctly identify biochemical pathways used by Salmonella to establish a niche for colonization in the chick intestine during development.

Newcastle disease (ND) is a highly contagious viral disease that constantly threatens poultry production. The velogenic (highly virulent) form of ND inflicts the most damage and can lead to 100% mortality in unvaccinated village chicken flocks. This study sought to characterize responses of local chickens in Ghana after challenging them with lentogenic and velogenic Newcastle disease virus (NDV) strains. At 4 wk of age, chicks were challenged with lentogenic NDV. Traits measured were pre- and post-lentogenic infection growth rates (GR), viral load at 2 and 6 d post-lentogenic infection (DPI), viral clearance rate and antibody levels at 10 DPI. Subsequently, the chickens were naturally exposed to velogenic NDV (vNDV) after anti-NDV antibody titers had waned to levels ≤1:1,700. Body weights and blood samples were again collected for analysis. Finally, chickens were euthanized and lesion scores (LS) across tissues were recorded. Post-velogenic exposure GR; antibody levels at 21 and 34 days post-velogenic exposure (DPE); LS for trachea, proventriculus, intestines, and cecal tonsils; and average LS across tissues were measured. Variance components and heritabilities were estimated for all traits using univariate animal models. Mean pre- and post-lentogenic NDV infection GRs were 6.26 g/day and 7.93 g/day, respectively, but mean post-velogenic NDV exposure GR was -1.96 g/day. Mean lesion scores ranged from 0.52 (trachea) to 1.33 (intestine), with males having significantly higher (P < 0.05) lesion scores compared to females. Heritability estimates for the lentogenic NDV trial traits ranged from moderate (0.23) to high (0.55) whereas those for the vNDV natural exposure trial were very low (≤ 0.08). Therefore, in contrast to the vNDV exposure trial, differences in the traits measured in the lentogenic challenge were more affected by genetics and thus selection for these traits may be more feasible compared to those following vNDV exposure. Our results can form the basis for identifying local chickens with improved resilience in the face of NDV infection for selective breeding to improve productivity.

Mycoplasma gallisepticum is one of the smallest self-replicating organisms. It causes chronic respiratory disease, leading to significant economic losses in poultry industry. Following M. gallisepticum invasion, the pathogen can persist in the host owing to its immune evasion, resulting in long-term chronic infection. The strategies of immune evasion by mycoplasmas are very complex and recent research has unraveled these sophisticated mechanisms. The antigens of M. gallisepticum exhibit high-frequency changes in size and expression cycle, allowing them to evade the activation of the host humoral immune response. M. gallisepticum can invade non-phagocytic chicken cells and also regulate microRNAs to modulate cell proliferation, inflammation, and apoptosis in tracheal epithelial cells during the disease process. M. gallisepticum has been shown to transiently activate the inflammatory response and then inhibit it by suppressing key inflammatory mediators, avoiding being cleared. The regulation and activation of immune cells are important for host response against mycoplasma infection. However, M. gallisepticum has been shown to interfere with the functions of macrophages and lymphocytes, compromising their defense capabilities. In addition, the pathogen can cause immunological damage to organs by inducing an inflammatory response, cell apoptosis, and oxidative stress, leading to immunosuppression in the host. This review comprehensively summarizes these evasion tactics employed by M. gallisepticum, providing valuable insights into better prevention and control of mycoplasma infection. [ABSTRACT FROM AUTHOR]

Necrotic enteritis causes significant losses in the global poultry industry, necessitating accurate diagnosis for effective intervention. This study aimed to develop a diagnostic tool for detecting necrotic enteritis in poultry based on the presence of Clostridium perfringens (C. perfringens) Alpha-toxin in poultry feces. The reagent of the detection kit was developed by conjugation of IgG against C. perfringens toxin and Staphylococcus cells containing protein A. The IgG antibody was derived from an 8-month-old thin-tailed male sheep immunized with purified 2 ml of C. perfringens Alpha-toxin. Sensitivity assays were carried out to determine the detection limit, while Escherichia coli (E. coli) and Salmonella enteritidis (S. enteritidis) were used to identify specificity. A purified Alpha-toxin with a protein concentration of 2.8 mg/ml and a specific molecular weight of 43 kDa was successfully obtained. A strong reaction of the hyperimmune antibody (IgG) was also detected in the thin-tailed male sheep serum. The developed rapid detection kit in this study indicated C. perfringens Alpha-toxin with a lower concentration (12 ng/ml). Agglutination reactions could differentiate positive control from negative without significant cross-reactivity towards other bacteria (S. enteritidis and E. coli). [ABSTRACT FROM AUTHOR]

Marek's Disease (MD) is an economically important disease of poultry caused by the MD virus, a member of the genus Mardivirus. MD results in immunosuppression and the disease affects poultry of all ages and is characterized by neoplastic lesions in the visceral organs. In this report, the prevalence and epidemiological features of MD in Plateau State were determined. Records of poultry disease cases presented to selected veterinary clinics in 4 Local Government Areas of Plateau State from 2007 to 2016 were analyzed. In addition, data were collected using questionnaires administered to 160 poultry farmers from February to May 2017. The prevalence of MD in Plateau State was 10.92% (5,620/5,1484). Cases of MD were reported in layers (92.49%), broilers (6.98%), turkeys (0.32%), and geese (0.21%). Also, co-morbidity of MD with coccidiosis (2.24%), colibacillosis (3.26%), Newcastle disease (2.58%), fatty liver syndrome (0.36%), fowl typhoid (2.86), and chronic respiratory disease (0.34%) were documented in the records. Analyzed data from the questionnaire survey revealed that 90.63% (145/160) of poultry farmers in Plateau State were familiar with MD, and 16.88% (27/160) of farmers indicated they have experienced MD outbreaks in their farms. Additionally, 90.00% (144/160) of poultry farmers claimed their birds were vaccinated against MD of which 53.13% (85/160) have vaccinated their birds once, while 36. 25% (58/160) and 0.63% (1/160) vaccinated their birds against MD twice and thrice respectively. On the economic impact of MD, twenty-seven poultry farms had experienced MD with an overall mortality of 17.02% (12,114/71,176) and most of the affected farms claimed to frequently medicate their birds during the outbreaks. To mitigate the impact of MD on poultry in Plateau State, adequate biosecurity measures and vaccination need to be instituted in poultry farms. [ABSTRACT FROM AUTHOR]

Poultry products in Zambia form an integral part of the human diet in many households, as they are cheap and easy to produce. The burden of poultry diseases has, however, remained a major challenge. Growing consumer demand for poultry products in Zambia has resulted in non-prudent antimicrobial use on farms, intending to prevent and treat poultry diseases for growth optimisation and maximising profits. This cross-sectional study aimed to identify the different types of bacteria causing diseases in chickens in Lusaka and to detect the extended-spectrum lactamase (ESBL)-encoding genes. We collected 215 samples from 91 diseased chickens at three post-mortem facilities and screened them for Gram-negative bacteria. Of these samples, 103 tested positive for various clinically relevant Enterobacteriaceae, including Enterobacter (43/103, 41.7%), Escherichia coli (20/103, 19.4%), Salmonella (10/103, 9.7%), and Shigella (8/103, 7.8%). Other isolated bacteria included Yersinia, Morganella, Proteus, and Klebsiella, which accounted for 21.4%. E. coli, Enterobacter, Salmonella, and Shigella were subjected to antimicrobial susceptibility testing. The results revealed that E. coli, Enterobacter, and Shigella were highly resistant to tetracycline, ampicillin, amoxicillin, and trimethoprim-sulfamethoxazole, while Salmonella showed complete susceptibility to all tested antibiotics. The observed resistance patterns correlated with antimicrobial usage estimated from sales data from a large-scale wholesale and retail company. Six (6/14, 42.9%) E. coli isolates tested positive for blaCTX-M, whilst eight (8/14, 57.1%) Enterobacter samples tested positive for blaTEM. Interestingly, four (4/6, 66.7%) of the E. coli isolates carrying blaCTX-M-positive strains were also positive for blaTEM. Sanger sequencing of the PCR products revealed that five (5/6, 83.3%) of the abovementioned isolates possessed the blaCTX-M-15 allele. The results suggest the presence of potentially pathogenic ESBL-producing Enterobacteriaceae in poultry, threatening public health. [ABSTRACT FROM AUTHOR]

Lymphoid leukosis is a poultry neoplastic disease caused by avian leukosis virus (ALV) and is characterized by high morbidity and variable mortality rates in chicks. Currently, no effective treatment and vaccination is the only means to control it. This study exploited the immunoinformatics approaches to construct multi-epitope vaccine against ALV. ABCpred and IEDB servers were used to predict B and T lymphocytes epitopes from the viral proteins, respectively. Antigenicity, allergenicity and toxicity of the epitopes were assessed and used to construct the vaccine with suitable adjuvant and linkers. Secondary and tertiary structures of the vaccine were predicted, refined and validated. Structural errors, solubility, stability, immune simulation, dynamic simulation, docking and in silico cloning were also evaluated.The constructed vaccine was hydrophilic, antigenic and non-allergenic. Ramchandran plot showed most of the residues in the favored and additional allowed regions. ProsA server showed no errors in the vaccine structure. Immune simulation showed significant immunoglobulins and cytokines levels. Stability was enhanced by disulfide engineering and molecular dynamic simulation. Docking of the vaccine with chicken's TLR7 revealed competent binding energies.The vaccine was cloned in pET-30a(+) vector and efficiently expressed in Escherichia coli. This study provided a potent peptide vaccine that could assist in tailoring a rapid and cost-effective vaccine that helps to combat ALV. However, experimental validation is required to assess the vaccine efficiency. [ABSTRACT FROM AUTHOR]

Simple Summary: Using antibiotics as growth promoters or antimicrobials is a potential health hazard. Garlic (Allium sativum L.) has been extensively used in several aspects of poultry production systems. Therefore, this review article discusses the impact of using garlic as a feed additive on the performance, immunity, gut health, anti-oxidant status, blood parameters, and intestinal microbiota of poultry. Garlic feeding has been regarded as a potential antibiotic-alternative feed additive due to its great benefits to the health of poultry. The use of antibiotics as growth promoters or for the prevention of some poultry diseases has faced global concern and serious criticism. Their addition to poultry feed has shown hazardous effects, including the development of antimicrobial resistance and a potentially harmful effect on human health. To eliminate these threats, there is increasing interest in natural alternatives. Plant derivatives such as garlic (Allium sativum L.) and its derivatives are presently extensively used in the poultry production system. The dietary supplementation of broilers and layers with garlic induced improvement in the production parameters, carcass quality, and intestinal integrity. The modulation of the immune response against some important viral diseases has resulted from the supplementation of poultry with garlic. Moreover, garlic has been shown to modulate gut health through antibacterial and antiparasitic activities. Treatment with garlic can also mitigate oxidative stress and reduce free-radical production. The reduction of cholesterol levels and improvement of some liver and blood parameters were also reported following the dietary inoculation of garlic. This review was designed to investigate the influence of garlic as a dietary additive on the performance, immunity, gut health, anti-oxidant status, blood parameters, and intestinal microbiota of poultry. [ABSTRACT FROM AUTHOR]

Poultry diseases pose major constraints on smallholder production in Africa, causing high flock mortality and economic hardship. Infectious diseases, especially viral diseases like Newcastle disease and highly pathogenic avian influenza (HPAI) and bacterial diseases, especially colibacillosis and salmonellosis, are responsible for most chicken losses, with downstream effects on human nutrition and health. Beyond production impacts, poultry diseases directly harm public health if zoonotic, can give rise to epidemics and pandemics, and facilitate antimicrobial resistance through treatment attempts. HPAI, campylobacteriosis, and salmonellosis are the priority zoonoses. Sustainable solutions for poultry health remain elusive despite recognition of the problem. This review summarises current knowledge on major poultry diseases in smallholder systems, their impacts, and options for prevention and control. We find biosecurity, vaccination, good husbandry, and disease-resistant breeds can reduce disease burden, but practical limitations exist in implementing these measures across smallholder systems. Treatment is often inefficient for viral diseases, and treatment for bacterial diseases risks antimicrobial resistance. Ethnoveterinary practices offer accessible alternatives but require more rigorous evaluation. Multisectoral collaboration and policies that reach smallholder poultry keepers are essential to alleviate disease constraints. Successful control will improve livelihoods, nutrition, and gender equity for millions of rural families. This review concludes that sustainable, scalable solutions for smallholder poultry disease control remain a critical unmet need in Africa. [ABSTRACT FROM AUTHOR]

Background: Enteric viruses are among the most prominent etiological agents of Runting-Stunting Syndrome (RSS). The Avian Nephritis Virus (ANV) is an astrovirus associated with enteric diseases in poultry, whose early diagnosis is essential for maintaining a good poultry breeding environment. ANV is an RNA virus that rapidly mutates, except for some conserved regions such as ORF1b. Therefore, the approach of a diagnostic method based on fast-RT-qPCR using SYBR® Green that focuses on the amplification of a fragment of ORF1b is presented as a feasible alternative for the diagnosis of this viral agent. In this study, the proposed assay showed a standard curve with an efficiency of 103.8% and a LoD and LoQ of 1 gene viral copies. The assay was specific to amplify the ORF 1b gene, and no amplification was shown from other viral genomes or in the negative controls. 200 enteric (feces) samples from chickens (broilers) and laying hens with signs of RSS from Ecuadorian poultry flocks were examined to validate the proposed method. Results: Using our method, 164 positive results were obtained out of the total number of samples run, while the presence of viral RNA was detected in samples collected from one day to 44 weeks old in both avian lines. Conclusions: Our study presents a novel, rapid, robust, and sensitive molecular assay capable of detecting and quantifying even low copy numbers of the ANV in commercial birds, therefore introducing a handy tool in the early diagnosis of ANV in enteric disease outbreaks in poultry. [ABSTRACT FROM AUTHOR]

Background: Nowadays veterinarians and poultry producers use antibiotics to increase growth rates, bird health, and feed efficiency, egg production, for preventative and therapeutic purposes, and to lessen the prevalence of poultry diseases. Most poultry producers have used a variety of antibiotics, either with or without veterinarian instruction. Although antibiotics are beneficial for the majority of their uses, their unauthorized use has resulted in residues accumulated in poultry products intended for human consumption which represents a serious risk to the general public that could be toxicological, microbiological, or immunological. Aim: This study aimed to the estimation of the residues of three major antimicrobials used in the intensive chickenrearing systems in Egypt, namely Oxytetracycline (OTC), Gentamicin, and Ciprofloxacin. Moreover, the effect of cooking on such residues was investigated. Methods: A total of 100 chicken meat samples (breast, thigh, gizzard, liver, 25 each) were examined for detection of the aforementioned antimicrobials using the microbial inhibition assay and high-performance liquid chromatography (HPLC). Besides, samples containing the highest antimicrobial residues were examined for the effect of boiling for 30 minutes on such residues. Results: The obtained results revealed that 23%, 21%, and 17% of the examined samples were positive for OTC, gentamicin, and ciprofloxacin residues, respectively. Cooking (boiling) for 30 minutes showed a reduction of the antibiotic residue by 88.2%, 95.2%, and 31.3%, respectively. Conclusion: Antimicrobial residues were detected in the chicken meat parts retailed in Egypt. Cooking can reduce the antimicrobial residues at least in part. [ABSTRACT FROM AUTHOR]

Velogenic Newcastle disease virus (VNDV) causes a highly contagious and devastating disease in poultry and causes up to 100 percent mortality in susceptible populations during devastating outbreaks. Newcastle disease causes heavy economic losses to the global poultry industry by decreasing the growth rate, decreasing egg production, and increasing morbidity and mortality. The households face substantial economic losses throughout the year due to Newcastle disease. It is ranked first among other poultry diseases in village chickens. The economic losses caused by this disease in the poultry industry have given awareness about the importance of Newcastle disease and made it easier to justify the operations against this disease. So, estimating the economic losses caused by Newcastle disease is very important. Regarding the Newcastle disease's huge impact on production and causing a lack of eggs, we will have to compensate for this reduction by importing eggs from other countries. Hence, a tremendous amount of money will be needed to compensate for the shortage of eggs, which will result in a huge economic loss. Finally, these will directly affect the poultry industry and its financial resources, which clarifies the importance of correct and on-time vaccination and caring for Newcastle disease in poultry flocks to prevent enormous economic losses. In this study, the economic impact of Newcastle Disease on egg-laying farms was quantitatively assessed. Data were collected on the total number of egg-laying poultry monthly and annually. Subsequently, the economic loss for each period was calculated based on the total production period. The minimal damage caused by this disease is about 116,591 Tons. Summing all these periods' production decreases, the total loss will be 10538 Tons. To estimate the losses of the disease, it is necessary to estimate the losses in breeding herds and broiler herds so that the loss resulting from the endemic Newcastle disease of the country can be measured. [ABSTRACT FROM AUTHOR]

Feeding broiler chickens a probiotic biopreparation containing bacteria of the genus Bacillus subtilis and Bacillus licheniformis leads to improved feed digestion, increased productivity, and immune status, as well as reduced insemination by opportunistic and pathogenic microorganisms of slaughter products. It enhances the level of prevention and treatment of various poultry diseases. The purpose of the work is to carry out a microbiological analysis of the slaughter products of broiler chickens after drinking the probiotic biological preparation "Subtiform" in doses of 0.5 g, 2.0, and 4.0 g per 10 dm³ of water. The material (major pectoral muscle and internal organs) was examined by bacteriological methods. It was established that the content of MAFAM in the control and experimental groups 1, 2, and 3 of the chilled slaughter products of broiler chickens for 1, 3, and 5 days of storage at a temperature of 0-4 ℃ was within the limits of standards (no more than 1.0×104 CFU/d). It was established that when broiler chickens were given 4.0 g/10 dm3 of water, the MAFAM content for one day of poultry meat storage decreased by 10.4 % (P < 0.05); on the third day of storage, it decreased by 9.6 % (P < 0.05); at the beginning of the fifth day of storage, the decrease was, respectively, by 11.3 % (P < 0.01) compared to the indicators of the control group. The content of MAFAM in offal, in particular in the heart of broiler chickens, was reduced in experimental group 3 by 36.9 % (P < 0.001); in the liver - by 33.6% (P < 0.001); in the muscular part of the stomach - by 27.2 % (P < 0.001); in the spleen and lungs, there was also a decrease in the content of MAFAM in experimental group 3, respectively, by 20.2 % (P < 0.01) and 23.6 % (P < 0.01) compared to the indicators of the control group of broiler chickens. It was established that opportunistic pathogenic microorganisms, in particular BGCP, bacteria of the genus Proteus, and pathogenic microorganisms, in specific bacteria of the genus Salmonella, bacteria of the species Staphylococcus aureus, Listeria monocytogenes in 25 grams of the large pectoral muscle of broiler chickens and internal organs (heart, spleen, liver, the muscular part of the stomach and lungs) were not detected. According to the results of the conducted research, an adverse effect of the probiotic biopreparation at a dose of 4.0 g/10 dm³ of water on the development of microorganisms in the large pectoral muscle and internal organs of broiler chickens was established. Therefore, the probiotic "Subtiform" at a dose of 4.0 g/10 dm3 of water during the drinking of broiler chickens can be recommended to increase productivity and obtain safe slaughter products. The practical value of the work consisted of establishing the microbiological indicators of poultry slaughter products after drinking probiotics, as well as establishing safety criteria and the technological process. [ABSTRACT FROM AUTHOR]

Poultry farming is one of the pillar industries of global animal husbandry. In order to guarantee production, poultry are frequently vaccinated from the moment they are hatched. Even so, the initial immunity of chicks is still very poor as they are in the "window period" of immune protection. In ovo vaccination pushes the initial immunization time forward to the incubation period, thereby providing earlier immune protection for chicks. In ovo vaccination is currently a research hotspot of poultry disease prevention and control, which is in line with the intensification of poultry production. However, the vaccines currently available for in ovo vaccination are limited and cannot meet the needs of industrial development, so how to efficiently activate the adaptive immune response of chicken embryos becomes the key to restrict product development and technological progress of in ovo vaccination. Its breakthrough, to a large extent, depends on systematic illustration of the mechanism underlying the adaptive immune response post immunization. Clarification of this issue will provide us with theoretical support and potential solutions for the development of novel vaccines for in ovo vaccination, the augmentation of efficacy of current vaccines and the optimization of immune programs. [ABSTRACT FROM AUTHOR]

Mites are considered a threat to the commercial poultry industry due to their direct and indirect pathogenic effects. Dermanyssus gallinae is among the mite species that endanger production, as it is hematophagous and poses a serious sanitary risk. Recently, Tyrophagus putrescentiae has also drawn attention as a potential pest in the poultry industry, and its attacks have been related to clinical symptoms such as cutaneous eruptions and bird restlessness. Considering the potential economic, sanitary, and productive losses both species represent to the laying-hen industry, the aim of the present study was to evaluate the influence of D. gallinae and T. putrescentiae on the health and productivity of commercial laying hens by carrying out infestation experiments and by monitoring laying hens for a period of 60 days. Tyrophagus putrescentiae and D. gallinae affected egg quality and zootechnical parameters in laying hens. Hens infested by T. putrescentiae had behavioral changes, weight loss, stress symptoms, and decreased egg laying and quality, as well as diarrhea, gradual feather loss, and itching. Hens infested by D. gallinae also had weight loss, behavioral changes, and stress symptoms, leading to decreased laying and egg quality. The present study proposes an experimental model to understand the impacts caused by T. putrescentiae and D. gallinae on commercial laying production and egg quality parameters. [ABSTRACT FROM AUTHOR]

Mycoplasma synoviae (MS) and Mycoplasma gallisepticum (MG) are two of the most serious infections in poultry, causing financial losses across the globe. Antibiotics treatment can lessen the clinical signs of MG and MS infection in birds and help restrict the spread of these infections. However, the rise of antibiotics multidrug resistance (MDR) among poultry diseases is still a problem for the world's health. Minimum inhibitory concentration (MIC) is crucial to resolving this issue since it helps ensure correct antibiotic use and fights the development of antibiotic resistance. This investigation aims to assess the In vitro and In vivo efficacy of several antibiotics (tilmicosin, tylosin, erythromycin, spiramycin, lincomycin, and doxycycline) against MG and MS field isolates, in addition to guava leaves extract (GLE) against MG. For In vivo study, 510, one day old chicks were randomly split into 17 groups the birds were experimentally infected at 3 days old and supplied with different treatments in drinking waters for 5 successive days at 18 days old. The results of In vitro study showed that tilmicosin was the most effective against MG isolates with MIC values ranging from 0.0078 to 0.0156 μg/ml and spiramycin considered effective against MS with MIC values ranging from 0.015625 to16μg/ml and MIC value of GLE was 0.25 μg/ml that was considered as moderate sensitive to MG infection. The In vivo study revealed that tilmicosin and spiramycin were able to significantly lower the clinical score, lesion score, and re-isolation rate of MG and MS, respectively in the treated birds at p-value < 0.05 in contrast with control positive infected untreated groups. Additionally, the treated groups with tilmicosin in MG infection and spiramycin in MS infection showed significantly higher mean body weights (MBW) compared to the infected untreated ones at p-value < 0.05. The current study demonstrates that MG and MS's sensitivity to many of the most popular drugs changed as in tylosin become low sensitive and erythromycin become resistant. GLE has moderate sensitivity antibacterial effect against MG isolates both In vivo and In vitro and can be used as a natural antibiotic alternative. Therefore, we recommend periodical monitoring of the sensitivity of the circulation MG and MS strains using MIC test to overcome MDR of avian mycoplasmas with further suggestion to evaluate GLE as nano-preparation against MG infection. [ABSTRACT FROM AUTHOR]

Background and Objectives: Antibiotic resistance within the poultry sector presents a considerable health concern due to treatment inefficacy and resistance transmission to humans and the environment. The investigation of plasmid-mediated quinolone resistance (PMQR) in Escherichia coli, acknowledged for its role in advancing resistance, remains inadequately studied in Iranian poultry. This study aimed to evaluate PMQR gene prevalence as well as to determine correlation between resistance phenotype and genotype in E. coli obtained from poultry colibacillosis. Materials and Methods: A collection of 100 E. coli isolates from the viscera of broilers suspected to colibacillosis was assessed. Using the Kirby-Bauer disk diffusion method, antimicrobial susceptibility tests were conducted for ofloxacin, nalidixic acid, levofloxacin, ciprofloxacin, and ampicillin. Additionally, PCR was employed to screen for qnrS, qnrB, and aac(6)Ib-cr genes. Results: Among the analyzed E. coli isolates, 51% demonstrated resistance to at least one of the tested antibiotics, with 17% exhibiting resistance to four different antibiotics. Nalidixic acid displayed the highest resistance rate at 48%, while ampicillin had the lowest at 16%. PMQR genes were detected in 28% of the E. coli isolates, with aac(6′)-Ib-cr being the most prevalent at 14%, followed by qnrB in 13%, and qnrS in 7%. Conclusion: The study underscores the vital need for careful antibiotic usage in poultry to curb the emergence of antibiotic-resistant bacteria. The results illuminate the prevalence of PMQR genes and their association with resistance trends in Iranian poultry, forming a pivotal basis for forthcoming approaches to combat antibiotic resistance within the poultry sector.

Augmentation of wild populations with captive-bred individuals presents an inherent risk of co-introducing novel pathogens to naïve species, but it can be an important tool for supplementing small or declining populations. Game species used for human enterprise and recreation such as the ring-necked pheasant (Phasianus colchicus) are commonly raised in captivity and released onto public and private wildlands as a method of augmenting naturalized pheasant populations. This study presents findings on pathogen exposure from three sources of serological data collected in California during 2014-2017 including (a) 71 pen-reared pheasants sampled across seven game bird breeding farms, (b) six previously released pen-reared pheasants captured at two study sites where wild pheasants occurred and (c) 79 wild pheasants captured across six study sites. In both pen-reared and wild pheasants, antibodies were detected against haemorrhagic enteritis virus (HEV), infectious laryngotracheitis (ILT), infectious bursal disease virus (IBDV), paramyxovirus type 1 (PMV-1) and Pasteurella multocida (PM). Previously released pen-reared pheasants were seropositive for HEV, ILT, and PM. Generalized linear mixed models accounting for intraclass correlation within groups indicated that pen-reared pheasants were more than twice as likely to test positive for HEV antibodies. Necropsy and ancillary diagnostics were performed in addition to serological testing on 40 pen-reared pheasants sampled from five of the seven farms. Pheasants from three of these farms tested positive by PCR for Siadenovirus, the causative agent of both haemorrhagic enteritis in turkeys and marble spleen disease of pheasants, which are serologically indistinguishable. Following necropsy, owners from the five farms were surveyed regarding husbandry and biosecurity practices. Farms ranged in size from 10,000 to more than 100,000 birds, two farms raised other game bird species on premises, and two farms used some form of vaccination. Biosecurity practices varied by farm, but the largest farm implemented the strictest practices.

Newcastle disease virus (NDV) is accountable for causing one of the most contagious avian diseases in poultry, resulting in substantial financial losses worldwide. Both genotype I and II vaccines are commonly used for live NDV vaccination, particularly in broiler flocks. Recent years have witnessed a significant surge in the number of Newcastle disease outbreaks in Egyptian poultry broiler flocks, demonstrating the evolving nature of NDV infections and raising concerns regarding the effectiveness of existing NDV vaccination programs. In our study, a total of 200 one-day-old commercial chicks were divided into six groups, including unvaccinated group and five vaccinated groups. To assess the immunogenicity and protective efficacy of commonly used NDV vaccines against the prevalent Velogenic Viscerotropic Newcastle Disease Virus (vvNDV), The birds were administered live vaccines LaSota (Genotype II) and I2 (Genotype I) either as a single booster or a double booster after the initial priming with the HB1 vaccine. The comparative protective efficiency of all vaccine regimens assessment was based on clinical evaluation, observation of survival rates, and examination of viral shedding following vvNDV challenge. We also, evaluated the immune response to live vaccination by weekly monitoring of IgG specific antibodies' levels in test sera. Our findings validated that the use of multiple live NDV vaccines can offer protection against the clinical symptoms of velogenic NDV, enhance protective immunity, and reduce the virus shedding after a challenge. The inclusion of heat stable I2 vaccine could be precious in the view of earth heating and weather change. [ABSTRACT FROM AUTHOR]

Thirty-five samples collected from chickens in 13 commercial farms in Eritrea between 2017 and 2021 following reports of disease were screened for Newcastle disease virus. Seventeen samples (50%) were shown to be positive by RT–PCR. An initial analysis of partial fusion (F) gene sequences of 10 representative samples indicated that the viruses belonged to subgenotype VII.1.1. Subsequently, full F gene sequence analysis of four of these representative samples confirmed the genotype of the viruses but also revealed that they were not identical to each other suggesting different origins of the VII.1.1 subgenotype viruses circulating in Eritrea. These data have implications for the control of Newcastle disease within the poultry population in Eritrea. [ABSTRACT FROM AUTHOR]