Detection of avian reovirus (ARV) by ELISA based on recombinant σB, σC and σNS full-length proteins and protein fragments.

Introduction. Avian reovirus (ARV) is associated with arthritis/tenosynovitis and malabsorption syndrome in chickens. The σC and σB proteins, both exposed to the virus capsid, are highly immunogenic and could form the basis for diagnostic devices designed to assess the immunological status of the flock.Gap Statement. Commercial ARV ELISAs cannot distinguish between vaccinated and infected animals and might not detect circulating ARV strains.Aim. We aimed to develop a customized test to detect the circulating field ARV strains as well as distinguish between vaccinated and unvaccinated animals.Methodology. We developed ELISA assays based on recombinant (r) σB, σC and the nonstructural protein σNS and tested them using antisera of vaccinated and unvaccinated chickens as well as negative controls. Fragments of σB and σC proteins were also used to study regions that could be further exploited in diagnostic tests.Results. Vaccinated and unvaccinated birds were positive by commercial ELISA, with no difference in optical density values. In contrast, samples of unvaccinated animals showed lower absorbance in the rσB and rσC ELISA tests and higher absorbance in the rσNS ELISA test than the vaccinated animals. Negative control samples were negative in all tests. Fragmentation of σB and σC proteins showed that some regions can differentiate between vaccinated and unvaccinated animals. For example, σB amino acids 128-179 (σB-F4) and σC amino acids 121-165 (σC-F4) exhibited 85 and 95% positivity among samples of vaccinated animals but only 5% and zero positivity among samples of unvaccinated animals, respectively.Conclusion. These data suggest that unvaccinated birds might have been exposed to field strains of ARV. The reduction in absorbance in the recombinant tests possibly reflects an increased specificity of our test since unvaccinated samples showed less cross-reactivity with the vaccine proteins immobilized on ELISAs. The discrepant results obtained with the protein fragment tests between vaccinated and unvaccinated animals are discussed in light of the diversity between ARV strains.

The Effects of Aflatoxin B1 on Liver Cholestasis and Its Nutritional Regulation in Ducks.

The aim of this study was to investigate the effects of aflatoxin B1 (AFB1) on cholestasis in duck liver and its nutritional regulation. Three hundred sixty 1-day-old ducks were randomly divided into six groups and fed for 4 weeks. The control group was fed a basic diet, while the experimental group diet contained 90 µg/kg of AFB1. Cholestyramine, atorvastatin calcium, taurine, and emodin were added to the diets of four experimental groups. The results show that in the AFB1 group, the growth properties, total bile acid (TBA) serum levels and total superoxide dismutase (T-SOD), glutathione peroxidase (GSH-Px), and glutathione (GSH) liver levels decreased, while the malondialdehyde (MDA) and TBA liver levels increased (p < 0.05). Moreover, AFB1 caused cholestasis. Cholestyramine, atorvastatin calcium, taurine, and emodin could reduce the TBA serum and liver levels (p < 0.05), alleviating the symptoms of cholestasis. The qPCR results show that AFB1 upregulated cytochrome P450 family 7 subfamily A member 1 (CYP7A1) and cytochrome P450 family 8 subfamily B member 1 (CYP8B1) gene expression and downregulated ATP binding cassette subfamily B member 11 (BSEP) gene expression in the liver, and taurine and emodin downregulated CYP7A1 and CYP8B1 gene expression (p < 0.05). In summary, AFB1 negatively affects health and alters the expression of genes related to liver bile acid metabolism, leading to cholestasis. Cholestyramine, atorvastatin calcium, taurine, and emodin can alleviate AFB1-induced cholestasis.

Assessment of Survival Kinetics for Emergent Highly Pathogenic Clade 2.3.4.4 H5Nx Avian Influenza Viruses.

High pathogenicity avian influenza viruses (HPAIVs) cause high morbidity and mortality in poultry species. HPAIV prevalence means high numbers of infected wild birds could lead to spill over events for farmed poultry. How these pathogens survive in the environment is important for disease maintenance and potential dissemination. We evaluated the temperature-associated survival kinetics for five clade 2.3.4.4 H5Nx HPAIVs (UK field strains between 2014 and 2021) incubated at up to three temperatures for up to ten weeks. The selected temperatures represented northern European winter (4 °C) and summer (20 °C); and a southern European summer temperature (30 °C). For each clade 2.3.4.4 HPAIV, the time in days to reduce the viral infectivity by 90% at temperature T was established (DT), showing that a lower incubation temperature prolonged virus survival (stability), where DT ranged from days to weeks. The fastest loss of viral infectivity was observed at 30 °C. Extrapolation of the graphical DT plots to the x-axis intercept provided the corresponding time to extinction for viral decay. Statistical tests of the difference between the DT values and extinction times of each clade 2.3.4.4 strain at each temperature indicated that the majority displayed different survival kinetics from the other strains at 4 °C and 20 °C.

Prevalence, Genotype Diversity, and Distinct Pathogenicity of 205 Gammacoronavirus Infectious Bronchitis Virus Isolates in China during 2019-2023.

Gammacoronavirus infectious bronchitis virus (IBV) causes a highly contagious disease in chickens and seriously endangers the poultry industry. The emergence and co-circulation of diverse IBV serotypes and genotypes with distinct pathogenicity worldwide pose a serious challenge to the development of effective intervention measures. In this study, we report the epidemic trends of IBV in China from 2019 to 2023 and a comparative analysis on the antigenic characteristics and pathogenicity of isolates among major prevalent lineages. Phylogenetic and recombination analyses based on the nucleotide sequences of the spike (S) 1 gene clustered a total of 205 isolates into twelve distinct lineages, with GI-19 as a predominant lineage (61.77 ± 4.56%) exhibiting an overall increasing trend over the past five years, and demonstrated that a majority of the variants were derived from gene recombination events. Further characterization of the growth and pathogenic properties of six representative isolates from different lineages classified four out of the six isolates as nephropathogenic types with mortality rates in one-day-old SPF chickens varying from 20-60%, one as a respiratory type with weak virulence, and one as a naturally occurring avirulent strain. Taken together, our findings illuminate the epidemic trends, prevalence, recombination, and pathogenicity of current IBV strains in China, providing key information for further strengthening the surveillance and pathogenicity studies of IBV.

Hemagglutinin glycosylation pattern-specific effects: implications for the fitness of H9.4.2.5-branched H9N2 avian influenza viruses.

Since 2007, h9.4.2.5 has emerged as the most predominant branch of H9N2 avian influenza viruses (AIVs) that affects the majority of the global poultry population. The spread of this viral branch in vaccinated chicken flocks has not been considerably curbed despite numerous efforts. The evolutionary fitness of h9.4.2.5-branched AIVs must consequently be taken into consideration. The glycosylation modifications of hemagglutinin (HA) play a pivotal role in regulating the balance between receptor affinity and immune evasion for influenza viruses. Sequence alignment showed that five major HA glycosylation patterns have evolved over time in h9.4.2.5-branched AIVs. Here, we compared the adaptive phenotypes of five virus mutants with different HA glycosylation patterns. According to the results, the mutant with 6 N-linked glycans displayed the best acid and thermal stability and a better capacity for multiplication, although having a relatively lower receptor affinity than 7 glycans. The antigenic profile between the five mutants revealed a distinct antigenic distance, indicating that variations in glycosylation level have an impact on antigenic drift. These findings suggest that changes in the number of glycans on HA can not only modulate the receptor affinity and antigenicity of H9N2 AIVs, but also affect their stability and multiplication. These adaptive phenotypes may underlie the biological basis for the dominant strain switchover of h9.4.2.5-branched AIVs. Overall, our study provides a systematic insight into how changes in HA glycosylation patterns regulate the evolutionary fitness and epidemiological dominance drift of h9.4.2.5-branched H9N2 AIVs, which will be of great benefit for the glycosylation-dependent vaccine design.

Live performance, nutrient digestibility, immune response and fecal microbial load modulation in Japanese quails fed a Bacillus-based probiotic alone or combination with xylanase.

Animal industry seeks cost-effective solutions to enhance performance and health of domestic animals. This study investigated the effects of supplementing Bacillus spp. probiotics and xylanase on 2000 one-day-old Japanese quails, randomly assigned to four treatment groups (10 replicates). The control group received no supplementation, while the others were supplemented with a Bacillus-based probiotic at 7.5 × 107 cfu/kg of feed, xylanase enzyme (2,000 U/kg) alone or in combination. Quails receiving both probiotic and enzyme exhibited significantly (p < 0.01) higher weekly and overall weight gain, and lower feed conversion ratios compared to the control group. Dressing percentage was higher (p < 0.01), and mortality lower in birds supplemented with a combination of enzyme and probiotic. Antibody titres against infectious bronchitis and infectious bursal disease were significantly (p < 0.01) higher in quails receiving combined probiotic and enzyme supplementation, while titres against Newcastle disease virus were higher (p < 0.01) in groups supplemented with probiotic and enzyme individually or in combination. Additionally, digestibility was significantly (p < 0.01) higher in groups receiving combined enzyme and probiotic supplementation, with higher apparent metabolizable energy compared to the control. The populations of beneficial Lactobacillus increased, while harmful E. coli and Salmonella decreased significantly in quails supplemented with both probiotic and enzyme. In conclusion, supplementing xylanase enzyme and probiotic together in Japanese quails positively influenced growth, nutrient digestibility, immune response, and cecal microbiota.

Biological features of fowl adenovirus serotype-4.

Fowl adenovirus serotype 4 (FAdV-4) is highly pathogenic to broilers aged 3 to 5 weeks and has caused considerable economic loss in the poultry industry worldwide. FAdV-4 is the causative agent of hydropericardium-hepatitis syndrome (HHS) or hydropericardium syndrome (HPS). The virus targets mainly the liver, and HPS symptoms are observed in infected chickens. This disease was first reported in Pakistan but has now spread worldwide, and over time, various deletions in the FAdV genome and mutations in its major structural proteins have been detected. This review provides detailed information about FAdV-4 genome organization, physiological features, epidemiology, coinfection with other viruses, and host immune suppression. Moreover, we investigated the role and functions of important structural proteins in FAdV-4 pathogenesis. Finally, the potential regulatory effects of FAdV-4 infection on ncRNAs are also discussed.

Genistein Promotes M2 Macrophage Polarization via Aryl Hydrocarbon Receptor and Alleviates Intestinal Inflammation in Broilers with Necrotic Enteritis.

The aryl hydrocarbon receptor (AhR) is a transcription factor that regulates the immune system through complicated transcriptional programs. Genistein, an AhR ligand, exhibits anti-inflammatory properties. However, its role in modulating immune responses via the AhR signaling pathway remains unclear. In this study, 360 male Arbor Acre broilers (1-day-old) were fed a basal diet supplemented with 40 or 80 mg/kg genistein and infected with or without Clostridium perfringens (Cp). Our results demonstrated that genistein ameliorated Cp-induced intestinal damage, as reflected by the reduced intestinal lesion scores and improved intestinal morphology and feed-to-gain ratio. Moreover, genistein increased intestinal sIgA, TGF-ß, and IL-10, along with elevated serum IgG, IgA, and lysozyme levels. Genistein improved intestinal AhR and cytochrome P450 family 1 subfamily A member 1 (CYP1A1) protein levels and AhR+ cell numbers in Cp-challenged broilers. The increased number of AhR+CD163+ cells in the jejunum suggested a potential association between genistein-induced AhR activation and anti-inflammatory effects mediated through M2 macrophage polarization. In IL-4-treated RAW264.7 cells, genistein increased the levels of AhR, CYP1A1, CD163, and arginase (Arg)-1 proteins, as well as IL-10 mRNA levels. This increase was attenuated by the AhR antagonist CH223191. In summary, genistein activated the AhR signaling pathway in M2 macrophages, which enhanced the secretion of anti-inflammatory cytokines and attenuated intestinal damage in Cp-infected broilers Cp.

Recombination and amino acid point mutations in VP3 exhibit a synergistic effect on increased virulence of rMDPV.

Recombinant Muscovy duck parvovirus (rMDPV) is a product of genetic recombination between classical Muscovy duck parvovirus (MDPV) and goose parvovirus (GPV). The recombination event took place within a 1.1-kb DNA segment located in the middle of the VP3 gene, and a 187-bp sequence extending from the P9 promoter to the 5' initiation region of the Rep1 ORF. This resulted in the alteration of five amino acids within VP3. Despite these genetic changes, the precise influence of recombination and amino acid mutations on the pathogenicity of rMDPV remains ambiguous. In this study, based on the rMDPV strain ZW and the classical MDPV strain YY, three chimeric viruses (rZW-mP9, rZW-mPR187, and rYY-rVP3) and the five amino acid mutations-introduced mutants (rZW-g5aa and rYY-5aa(ZW)) were generated using reverse genetic technology. When compared to the parental virus rZW, rZW-g5aa exhibited a prolonged mean death time (MDT) and a decreased median lethal dose (ELD50) in embryonated duck eggs. In contrast, rYY-5aa(ZW) did not display significant differences in MDT and ELD50 compared to rYY. In 2-day-old Muscovy ducklings, infection with rZW-g5aa and rYY-5aa(ZW) resulted in mortality rates of only 20% and 10%, respectively, while infections with the three chimeric viruses (rZW-mP9, rZW-mPR187, rYY-rVP3) and rZW still led to 100% mortality. Notably, rYY-rVP3, containing the VP3 region from strain ZW, exhibited 50% mortality in 6-day-old Muscovy ducklings and demonstrated significant horizontal transmission. Collectively, our findings indicate that recombination and consequent amino acid changes in VP3 have a synergistic impact on the heightened virulence of rMDPV in Muscovy ducklings.

Molecular characterisation of fowl adenovirus associated with hydropericardium hepatitis syndrome in broiler and layer breeders in Azerbaijan.

BACKGROUND: Fowl adenovirus-4 is a causative agent of hydropericardium hepatitis syndrome (HHS) in chickens and has been frequently reported from many countries. Fowl adenoviruses cause severe disease and mortality in broiler and layer breeders in Azerbaijan. Therefore, in this study, pathological lesions and the dissemination of fowl adenovirus-4 into the visceral organs of infected birds were investigated as well as molecular characterisation of detected strains. For this, liver, heart and spleen from 20 necropsied chickens originated from a broiler breeder flock and a layer breeder flock were embeded on the FTA cards and the samples were analysed for adenovirus-DNA by PCR and sequencing. RESULTS: The findings of necropsy in both broiler and layer breeder chickens were similar, and the liver was severely effected showing hepatitis, and the heart with hydropericardium lesions. The kidneys were swollen with haemorrhages and small white foci on the surface of the spleens were noted. Intestinal congestion and ecchymotic hemorrhages were also observed in some birds. Fowl adenovirus-4-DNA was detected by PCR in all collected organs of 20 birds. The sequence analysis revealed that fowl adenovirus-4 present in Azerbaijan and close similarity of the hexon genes of the adenoviruses existing in the Middle East, North America, far east and Indian subcontinent were determined by phylogenetic analysis. However, sequence diversity was detected from the adenovirus strains circulating in Europe, North and South America. CONCLUSIONS: This study indicates the impact of fowl adenovirus-4 on the poultry health and production, and improved disease control and prevention strategies are necessary to reduce the HHS disease in chickens in Azerbaijan.

Isolation and phylogenetic analysis of avian infectious bronchitis virus from an imported chicken meat product in Malaysia.

Avian infectious bronchitis (IB), a Gammacoronavirus, is a highly contagious upper respiratory disease, affecting chickens of all ages with a significant economic threat to the poultry industry. In February 2020, a specimen of imported chicken meat product was received and requested for coronavirus testing. The result was positive for the avian coronavirus, the IB virus (IBV) by molecular detection in the pre-screening test. Thus, this study aimed to isolate and characterize the IBV from the specimen. Virus isolation via egg inoculation was attempted and IBV was successfully isolated. The S1 subunit of the spike (S) gene of the IBV was amplified, sequenced, and the Basic Local Alignment Search Tool (BLAST) analysis showed that the IBV has 99% and 98% nucleotide similarity with the Malaysian and China IBVs, respectively. The phylogenetic analysis indicated that the virus belongs to the GI-19 lineage (also known as the QX strain) and is grouped with other IBVs from Malaysia and China. The GI-19 lineage is one of the primary IB strains that circulate in Malaysia. The recovery of the virus may be due to the persistence characteristic of the virus on meat; and the cold chain practices in the imported food product prolong the survival of this coronavirus. Though IBV is not identified as a hazard in chicken meat or meat products, raw food should be cooked thoroughly before being consumed. With the increase in international trade in poultry and poultry products, disease screening at the entry point and import risk analysis is crucial to ensure food safety and prevent the introduction of new viruses into Malaysia.

Reversal of gentamicin sulfate resistance in avian pathogenic Escherichia coli by matrine combined with berberine hydrochloride.

In recent years, the evolution of antibiotic resistance has led to the inefficacy of several antibiotics, and the reverse of resistance was a novel method to solve this problem. We previously demonstrated that matrine (Mat) and berberine hydrochloride (Ber) had a synergistic effect against multidrug-resistant Escherichia coli (MDREC). This study aimed to demonstrate the effect of Mat combined with Ber in reversing the resistance of MDREC. The MDREC was sequenced passaged in the presence of Mat, Ber, and a combination of Mat and Ber, which did not affect its growth. The reverse rate was up to 39.67% after MDREC exposed to Mat + Ber for 15 days. The strain that reversed resistance was named drug resistance reversed E. coli (DRREC) and its resistance to ampicillin, streptomycin, gentamicin, and tetracycline was reversed. The MIC of Gentamicin Sulfate (GS) against DRREC decreased 128-fold to 0.63 µg/mL, and it was stable within 20 generations. Furthermore, the susceptible phenotype of DRREC remained stable within 20 generations, as well. The LD50 of DRREC for chickens was 8.69 × 109 CFU/mL. qRT-PCR assays revealed that the transcript levels of antibiotic-resistant genes and virulence genes in the DRREC strain were significantly lower than that in the MDREC strain (P < 0.05). In addition, GS decreased the death, decreased the bacterial loading in organs, alleviated the injury of the spleen and liver, and decreased the cytokine levels in the chickens infected by the DRREC strain. In contrast, the therapeutic effect of GS in chickens infected with MDREC was not as evident. These findings suggest that the combination of Mat and Ber has potential for reversing resistance to MDREC.

Widespread prevalence of plasmid-mediated blaCTX-M type extended-spectrum beta-lactamase Escherichia coli in backyard broiler production systems in the United States.

Extended-spectrum beta-lactamase (ESBL) Escherichia coli (E. coli) is an emerging pathogen of high concern given its resistance to extended-spectrum cephalosporins. Broiler chicken, which is the number one consumed meat in the United States and worldwide, can be a reservoir of ESBL E. coli. Backyard poultry ownership is on the rise in the United States, yet there is little research investigating prevalence of ESBL E. coli in this setting. This study aims to identify the prevalence and antimicrobial resistance profiles (phenotypically and genotypically) of ESBL E. coli in some backyard and commercial broiler farms in the U.S. For this study ten backyard and ten commercial farms were visited at three time-points across flock production. Fecal (n = 10), litter/compost (n = 5), soil (n = 5), and swabs of feeders and waterers (n = 6) were collected at each visit and processed for E. coli. Assessment of ESBL phenotype was determined through using disk diffusion with 3rd generation cephalosporins, cefotaxime and ceftazidime, and that with clavulanic acid. Broth microdilution and whole genome sequencing were used to investigate both phenotypic and genotypic resistance profiles, respectively. ESBL E. coli was more prevalent in backyard farms with 12.95% of samples testing positive whereas 0.77% of commercial farm samples were positive. All isolates contained a blaCTX-M gene, the dominant variant being blaCTX-M-1, and its presence was entirely due to plasmids. Our study confirms concerns of growing resistance to fourth generation cephalosporin, cefepime, as roughly half (51.4%) of all isolates were found to be susceptible dose-dependent and few were resistant. Resistance to non-beta lactams, gentamicin and ciprofloxacin, was also detected in our samples. Our study identifies prevalence of blaCTX-M type ESBL E. coli in U.S. backyard broiler farms, emphasizing the need for interventions for food and production safety.

FdeC expression regulates motility and adhesion of the avian pathogenic Escherichia coli strain IMT5155.

Adaptation of avian pathogenic E. coli (APEC) to changing host environments including virulence factors expression is vital for disease progression. FdeC is an autotransporter adhesin that plays a role in uropathogenic Escherichia coli (UPEC) adhesion to epithelial cells. Expression of fdeC is known to be regulated by environmental conditions in UPEC and Shiga toxin-producing E. coli (STEC). The observation in a previous study that an APEC strain IMT5155 in which the fdeC gene was disrupted by a transposon insertion resulted in elevated adhesion to chicken intestinal cells prompted us to further explore the role of fdeC in infection. We found that the fdeC gene prevalence and FdeC variant prevalence differed between APEC and nonpathogenic E. coli genomes. Expression of the fdeC gene was induced at host body temperature, an infection relevant condition. Disruption of fdeC resulted in greater adhesion to CHIC-8E11 cells and increased motility at 42 °C compared to wild type (WT) and higher expression of multiple transporter proteins that increased inorganic ion export. Increased motility may be related to increased inorganic ion export since this resulted in downregulation of YbjN, a protein known to supress motility. Inactivation of fdeC in APEC strain IMT5155 resulted in a weaker immune response in chickens compared to WT in experimental infections. Our findings suggest that FdeC is upregulated in the host and contributes to interactions with the host by down-modulating motility during colonization. A thorough understanding of the regulation and function of FdeC could provide novel insights into E. coli pathogenesis.

Molecular detection and genetic characterization of Mycoplasma gallisepticum and Mycoplasma synoviae in selected chicken breeds in South Africa.

BACKGROUND: The impact of chickens on maintaining the economy and livelihood of rural communities cannot be overemphasized. In recent years, mycoplasmosis has become one of the diseases that affect the success of South African chicken production. Mycoplasma gallisepticum (MG) and Mycoplasma synoviae (MS) are the most prevalent strains of Mycoplasma in South Africa. MG and MS are significant respiratory pathogens affecting the productivity of chickens. The present study aimed to molecularly detect using qPCR and characterize the presence of MG and MS using phylogenetic analysis. The phylogenetic analysis was utilized to clarify general evolutionary relationships between related taxa of different MG and MS observed in tracheal swabs from South African chicken breeds. METHODS: Forty-five tracheal swabs of the Lohmann Brown (n = 9), Rhode Island Red (n = 9), Ovambo (n = 9), Venda (n = 9), and Potchefstroom Koekoek (n = 9) breeds were collected from symptomatic chickens present in the commercial farm. To detect MG and MS, DNA was extracted from tracheal swabs and faecal samples, and qPCR was performed with a 16 s rRNA (310 bp) and vlhA (400 bp) gene fragment. Following the sequencing of all the amplicons, MG, and MS dendrograms showing the evolutionary relationships among the five South African chicken breeds and the GeneBank reference population were constructed. RESULTS: The qPCR revealed the presence of MG and MS in 22% (2/9) of the tracheal swab samples tested for MS only in Rhode Island Red breeds; 66.6% (6/9) and 33% (3/9) of the tested samples in Ovambo breeds; and 11.1% (1/9) and 44.4% (4/9) of the tested samples in Venda breeds. No MG or MS were detected in the Lohmann Brown or Potchefstroom Koekoek breed. Furthermore, qPCR revealed the presence of MG in pooled faecal samples from Lohmann Brown and Ovambo breeds. Eight different bacterial isolates were recognized from both samples. Four isolates were of the 16 s ribosomal ribonucleic acid (rRNA) gene (named PT/MG51/ck/00, PT/MG48/ck/00, PT/MG41/ck/00 and PT/MG71/ck/00) gene of Mycoplasma gallisepticum, and the other was Mycoplasma Synoviae variable lipoprotein hemagglutinin A (vlhA) gene (named PT/MSA22/ck/01, PT/MS41/ck/01, PT/MS74/ck/01 and PT/MS46/ck/01) which were available in GenBank. These isolates were successfully sequenced with 95-100% similarity to the isolates from the gene bank. CONCLUSION: The study revealed the presence of both MG and MS in the chicken breeds sampled. Furthermore, the different breeds of chicken were found to be susceptible to infection under the intensive or commercial management system. Therefore, continuous surveillance is encouraged to prevent the spread and outbreak of MG and MS in the poultry industry in South Africa.

Chlamydia psittaci detected at a live poultry wholesale market in central China.

BACKGROUND: We investigated the presence of Chlamydia psittaci in poultry and the environment in live poultry wholesale markets in Changsha during 2021-2022 and conducted a phylogenetic analysis to understand its distribution in this market. METHODS: In total, 483 samples were analyzed using real-time polymerase chain reaction and 17 C. psittaci-positive samples using high-throughput sequencing, BLAST similarity, and phylogenetic analysis. RESULTS: Twenty-two out of 483 poultry and environmental samples were positive for C. psittaci (overall positivity rate: 4.55%) with no difference in positivity rates over 12 months. Chlamydia psittaci was detected at 11 sampling points (overall positivity rate: 27.5%), including chicken, duck, and pigeon/chicken/duck/goose shops, with pigeon shops having the highest positivity rate (46.67%). The highest positivity rates were found in sewage (12.5%), poultry fecal (7.43%), cage swab (6.59%), avian pharyngeal/cloacal swab (3.33%), and air (2.29%) samples. The ompA sequences were identified in two strains of C. psittaci, which were determined to bear genotype B using phylogenetic analysis. Thus, during monitoring, C. psittaci genotype B was detected in the poultry and environmental samples from the poultry wholesale market in Changsha. CONCLUSIONS: To address the potential zoonotic threat, C. psittaci monitoring programs in live poultry markets should be enhanced.

Heterologous maternal antibodies derived from infectious bronchitis vaccines prevent the development of lesions associated with false layer syndrome.

Infectious bronchitis virus (IBV) strains of the Delmarva (DMV)/1639 genotype have been causing false layer syndrome (FLS) in the Eastern Canadian layer operations since the end of 2015. FLS is characterized by the development of cystic oviducts in layer pullets infected at an early age. Currently, there are no homologous vaccines for the control of this IBV genotype. Our previous research showed that a heterologous vaccination regimen incorporating Massachusetts (Mass) and Connecticut (Conn) IBV types protects layers against DMV/1639 genotype IBV. The aim of this study was to investigate the role of maternal antibodies conferred by breeders received the same vaccination regimen in the protection against the development of DMV/1639-induced FLS in pullets. Maternal antibody-positive (MA+) and maternal antibody-negative (MA-) female progeny chicks were challenged at 1 day of age and kept under observation for 16 weeks. Oviductal cystic formations were observed in 3 of 14 birds (21.4 %) in the MA- pullets, while the lesions were notably absent in the MA+ pullets. Milder histopathological lesions were observed in the examined tissues of the MA+ pullets. However, the maternal derived immunity failed to demonstrate protection against the damage to the tracheal ciliary activity, viral shedding, and viral tissue distribution. Overall, this study underscores the limitations of maternal derived immunity in preventing certain aspects of viral pathogenesis, emphasizing the need for comprehensive strategies to address different aspects of IBV infection.

Effect of dietary treatments on performance, oocysts shedding and lesion scores in broiler chickens experimentally challenged with Eimeria infection.

Although anticoccidials effectively control coccidiosis, a needed reduction in the reliance on antimicrobials in animal production leads to the exploration of alternative compounds. The present study aimed to test five different dietary treatments to counteract the negative impact of coccidiosis on broiler chickens' health and performance. 1-day-old male Ross 308 broilers (n = 960) were randomly assigned to one of eight treatments, with six cages per treatment (20 birds/cage). To the diet of the broiler chickens of treatments (Trt) 1-5, a synbiotic was added from d0-10. From d10-28, birds of Trt1 and Trt2 were fed synbiotics, whereas birds of Trt3 were fed diets with glutamine, and birds of Trt4 and Trt5 were fed diets with a combination of ß-glucans and betaine. From d28-35 onwards, birds of Trt1 were fed a diet with a synbiotic, whereas birds of Trt2-4 received diets with glutamine, and birds of Trt5 were fed a non-supplemented diet. Birds of the positive control group (PC; Trt6) were fed a standard diet supplemented with an anticoccidial (Decoquinate). The challenged negative control (NCchall; Trt7) and non-challenged negative control (NC) Trt8 were fed a standard diet without anticoccidial or other dietary treatment. At 7 days (d) of age, all birds were inoculated with 1 023, 115, and 512 sporulated oocysts of E. acervulina, E. maxima, and E. tenella, respectively, except for Trt8. Body weight gain (BWG), feed intake, and feed conversion ratio were assessed for each feeding phase (d0-10, d10-28 and d28-35) and overall experimental period (d0-35). Oocyst shedding, Eimeria lesion scores, cecal length, and relative weight were assessed at d13, d22, d28 and d35. Additionally, oocyst shedding was determined at d9 and d17. Litter quality was evaluated at d27 and d34, and footpad lesions at d34. During the starter (d0-10) and finisher (d28-35) periods, performance did not differ between the treatments. During the grower period (d10-28), Trt6 (PC) and Trt8 (NC) chickens had the highest BWG of all treatments (P < 0.001). Dietary treatment had no effect on litter quality and severity of footpad lesions. In the PC group (Trt6), low oocyst excretion and lesion scores were found. When comparing Trt1-5 with NCchall (Trt7), none of the treatments significantly reduced oocyst output or lesion scores. In conclusion, in this experiment, none of the dietary treatments performed similar or better compared to the PC group (Trt6) regarding performance or reducing Eimeria oocyst shedding or lesion scores.

Pathological and phylogenetic characterization of a rare fowl adenovirus (FAdV-8b) associated with inclusion body hepatitis in naturally infected Meleagris gallopavo.

Adenoviruses are a diverse group of viruses that can cause a variety of diseases in poultry, including respiratory and gastrointestinal infections. In turkeys (Meleagris gallopavo), adenoviruses commonly cause hemorrhagic enteritis and, rarely, inclusion body hepatitis. In this study, we investigated fowl adenoviruses (FAdVs) circulating in turkeys in Egypt. Following clinical examination of 500 birds, a portion of the hexon gene was amplified from four out of 50 samples from diseased birds (8%), and one amplicon that produced a strong band was selected for sequencing. Molecular and phylogenetic analysis revealed that the virus in that sample belonged to serotype FAdV-8b. Histopathological and immunohistochemical examinations of prepared tissue sections were performed to confirm the pathological findings. Diseased birds exhibited ruffled feathers, low body weight, a crouching posture, and diarrhea. Gross examination revealed petechial hemorrhage on the spleen, swollen pale liver, and congested intestine. Microscopic examination revealed the presence of eosinophilic and basophilic intranuclear inclusion bodies, nuclear pyknosis, and apoptotic bodies in the liver, congestion, hemorrhage, and fibrosis in the lungs, and desquamation of enterocytes. The presence of viral antigens in the liver, lungs, and intestine was confirmed by immunohistochemistry. To our knowledge, this is the first report of the characterization of an outbreak of inclusion body hepatitis in turkeys (hybrid converter breeds) due to FAdV-8b in Egypt. This finding raises an epidemiological alarm, necessitating further studies, including full-genome sequencing, to trace the virus's origin and genetic diversity.

Paeoniflorin protects chicken against APEC-induced acute lung injury by affecting the endocannabinoid system and inhibiting the PI3K/AKT and NF-κB signaling pathways.

Avian pathogenic Escherichia coli (APEC) is the causative agent of chicken colibacillosis. Paeoniflorin, a natural ingredient extracted from Paeonia lactiflora, has a variety of pharmacological effects including anti-inflammatory and immunomodulatory. However, its effects and mechanism in APEC-induced acute lung injury (ALI) in chicken is not clear. The aim of this study was to investigate the protective effect of paeoniflorin on APEC-induced ALI and its possible mechanism. Paeoniflorin (25, 50, and 100 mg/kg) was administered by gavage for 5 d starting at 9 d of age and the chicken were infected with APEC by intraperitoneal injection at 12 d of age. The tissues were collected after APEC infection for 36 h for analysis. The results showed that paeoniflorin significantly alleviated the symptoms, increased the survival rate and body weight gain of APEC-infected chicken, and improved the histopathological damages, and reduced APEC loads in lung tissues. In addition, paeoniflorin restored the gene expression of ZO-1, Occludin and Claudin-3 during APEC infection. Moreover, paeoniflorin pretreatment significantly affected the endocannabinoid system (ECs) by increasing DAGL, decreasing MAGL, increasing secretion of 2-AG. Then, paeoniflorin significantly decreased the secretion of IL-1ß, IL-6 and TNF-α in lung tissues, and decreased the mRNA expression of CXCL8, CXCL12, CCL1, CCL5, and CCL17. In addition, paeoniflorin significantly reduced the phosphorylation levels of PI3K, AKT, P65, and IκB. In summary, we found that paeoniflorin inhibited APEC-induced ALI, and its mechanism may be through affecting ECs and inhibiting the activation of PI3K/AKT and NF-κB signaling pathways, which provides a new idea for the prevention and treatment of chicken colibacillosis.