Chicken Lung Research Articles

Protection against genotype VII Newcastle disease virus challenge by a minicircle DNA vaccine coexpressing F protein and chicken IL-18 adjuvant

Genotype VII Newcastle disease virus (NDV) is still one of the most important virus threats severely affecting poultry production worldwide. Although inactivated vaccines are commercially available, there is still an urgent need to develop novel vaccine candidates for convenient and affordable vaccine application. Oral immunization using live attenuated bacteria such as Salmonella has recently attracted increasing interest, and in a previous study, we used a regulated delayed lysis Salmonella vector to deliver a DNA vaccine encoding the F protein and chicken IL-18 adjuvant together, named pYL23. To further improve its efficiency, we employed a novel in vivo minicircle DNA (mcDNA) platform to construct pYL58, which could maintain the complete plasmid during in vitro culture conditions and then transform into mcDNA in vivo whenever the plasmid was delivered by Salmonella into host cells. Compared with immunization with the parental strain harboring plasmid pYL23, immunization with Salmonella with pYL58 induced increased levels of serum IgY and mucosal sIgA in chickens, especially the intestinal and tracheal sIgA levels. Production of cytokines, including IL-4, IFN-γ, IL-18 and IFN-α, was also determined in serum and spleen cell culture supernatants after the 3rd immunization, and the results showed that the production of IFN-γ in the pYL58 group was significantly increased compared with that in the negative control group. Interestingly, compared with pYL23, significantly increased production of IFN-α in the cell supernatants from the pYL58 group was also observed. In addition, the CCK-8 assay results showed that the minicircle pYL58 significantly increased spleen cell proliferation. After virulent VII NDV challenge, pYL58 immunization could provide 70% protection compared with 50% protection in the pYL23 group, together with decreased virus titers in chicken lung samples at Day 5 and virus shedding at Days 3 and 5 post-challenge. This study demonstrated that the application of mcDNA technology dramatically increased the DNA vaccine efficiency, providing additional support for the use of our mcDNA platform in the veterinary field.

Andrographolide attenuates Mycoplasma gallisepticum-induced inflammation and apoptosis by the JAK/PI3K/AKT signal pathway in the chicken lungs and primary alveolar type II epithelial cells

Mycoplasma gallisepticum (MG) is the primary etiologic agent of chronic respiratory disease (CRD) in chickens. Respiratory tract inflammation and apoptosis are the main features of CRD. Andrographolide (Andro), a natural small molecule compound, is known for its excellent anti-pathogenic and anti-inflammatory properties. Hence, this study was to evaluate the anti-inflammation and anti-apoptosis effects of Andro as well as the underlying mechanism in the chicken lungs and primary alveolar type II epithelial cells (AEC II). Results showed Andro had no side effects on AEC II viability at concentrations below 200 μg/ml. Compared with the model group, terminal deoxynucleotidyl transferase-mediated dUTP nick endlabeling (TUNEL), western blot (WB), quantitative real-time polymerase chain reaction (qRT-PCR) and enzyme-linked immunosorbent assays (ELISA) results showed Andro treatment significantly reduced apoptosis in the chicken lungs and AEC II, and down-regulated the expression levels of the protein of MG adhesin 1.2 (pMGA1.2), IL-1β, TNF-α, IL-6, Bax, Caspase 9 and Caspase 3, and up-regulated the expression levels of Bcl-2 and Bcl-xL in the chicken lungs, serum and AEC II (P ≤ 0.05). Moreover, Andro inhibited the MG-induced JAK/PI3K/AKT signal pathway activation in the chicken lungs and AEC II. Inhibiting of the JAK/PI3K/AKT signal pathway significantly alleviated MG-induced inflammation and apoptosis in the AEC II. Andro may exert an anti-inflammatory and anti-apoptotic effect by inhibiting the JAK/PI3K/AKT signal pathway in the chicken lungs and AEC II. In conclusion, Andro could act as a potential agent against MG infection by inhibiting the JAK/PI3K/AKT signal pathway and pMGA1.2 expression in the chickens.

A general controllable release amplification strategy of liposomes for single-particle collision electrochemical biosensing

As an important component of the COVID-19 mRNA vaccines, liposomes play a key role in the efficient protection and delivery of mRNA to cells. Herein, due to the controllable release amplification strategy of liposomes, a reliable and robust single-particle collision electrochemical (SPCE) biosensor was constructed for H9N2 avian influenza virus (H9N2 AIV) detection by combining liposome encapsulation-release strategy with immunomagnetic separation. The liposomes modified with biotin and loaded with platinum nanoparticles (Pt NPs) were used as signal probes for the first time. Biotin facilitated the coupling of biomolecules (DNA or antibodies) through the specific reaction of biotin-streptavidin. Each liposome can encapsulate multiple Pt NPs, which were ruptured under the presence of 1 × PBST (phosphate buffer saline with 0.05% Tween-20) within 2 min, and the encapsulated Pt NPs were released for SPCE experiment. The combination of immunomagnetic separation not only improved the anti-interference capabilities but also avoided the agglomeration of Pt NPs, enabling the SPCE biosensor to realize ultrasensitive detection of 18.1 fg/mL H9N2 AIV. Furthermore, the reliable SPCE biosensor was successfully applied in specific detection of H9N2 AIV in complex samples (chicken serum, chicken liver and chicken lung), which promoted the universality of SPCE biosensor and its application prospect in early diagnosis of diseases.

Hcp2b of T6SS affects colonization of avian pathogenic Escherichia coli and host keratin filament expression

ABSTRACT T6SS (type VI secretion system) is a type of nano-syringe that exists in APEC (avian pathogenic Escherichia coli). Hcp (haemolysin-coregulated protein) of T6SS participates in the regulation of virulence during APEC infection. However, whether hcp plays a role in bacterial colonization by expression in host cells remains unclear. In this study, we analysed the biological characteristics of the mutant hcp2b strain. Our results showed that the hcp2b gene was involved in the regulation of bacterial motility, biofilm formation, anti-serum and anti-oxidative stress. Moreover, our data indicate that the colonization of the hcp2b mutation strain (Δhcp2b) in the lung, liver and kidney of chickens decreased significantly. Hence, overexpression of Hcp2b protein in DF-1 cells was used to analyse the effect of Hcp2b on colonization of APEC. Proteomics analysis showed that overexpression of Hcp2b induced differentially expressed proteins in DF-1 cells (230 were significantly upregulated and 96 were significantly downregulated) and differentially expressed proteins were enriched in keratin filament. In conclusion, our data indicated that hcp2b promoted the colonization of APEC by affecting the expression of keratin filament.

Structural analysis of N-glycans in chicken trachea and lung reveals potential receptors of chicken influenza viruses

Although avian influenza A viruses (avian IAVs) bind preferentially to terminal sialic acids (Sia) on glycans that possess Siaα2-3Gal, the actual glycan structures found in chicken respiratory tracts have not been reported. Herein, we analyzed N-glycan structures in chicken trachea and lung, the main target tissues of low pathogenic avian IAVs. 2-Aminopyridine (PA)-labeled N-glycans from chicken tissues were analyzed by combined methods using reversed-phase liquid chromatography (LC), electrospray ionization (ESI)-mass spectrometry (MS), MS/MS, and multistage MS (MSn), with or without modifications using exoglycosidases, sialic acid linkage-specific alkylamidation (SALSA), and/or permethylation. The results of SALSA indicated that PA-N-glycans in both chicken trachea and lung harbored slightly more α2,6-Sia than α2,3-Sia. Most α2,3-Sia on N-glycans in chicken trachea was a fucosylated form (sialyl Lewis X, sLex), whereas no sLex was detected in lung. By contrast, small amounts of N-glycans with 6-sulfo sialyl LacNAc were detected in lung but not in trachea. Considering previous reports that hemagglutinins (HAs) of avian IAVs originally isolated from chicken bind preferentially to α2,3-Sia with or without fucosylation and/or 6-sulfation but not to α2,6-Sia, our results imply that avian IAVs do not evolve to possess HAs that bind preferentially to α2,6-Sia, regardless of the abundance of α2,6-Sia.

Claudin-3 regulates luminal fluid accumulation in the developing chick lung

Claudins are a family of tight junction proteins expressed in epithelial tissues during development and in postnatal life. We hypothesized that claudins are required for branching morphogenesis in the developing chick lung. To test this hypothesis, we exposed cultured chick lung explants at embryonic day 5 to a truncated non-toxic form of the Clostridium perfringens enterotoxin known as C-CPE that removes C-CPE-sensitive claudins from tight junctions. Using in situ hybridization and immunofluorescence studies, we established that only one C-CPE-sensitive claudin, Claudin-3, was expressed in the chick lung at this stage. C-CPE treated lung explants did not exhibit any defect in lung branching compared to controls. However, they did exhibit a significantly smaller lumen area, suggesting that paracellular permeability was perturbed. The decrease in lumen area was associated with a loss of Claudin-3 expression within tight junctions of the respiratory epithelium and an increase in permeability of the respiratory epithelium. When C-CPE-treated lung explants were treated with forskolin, lumen area was restored. In summary, removal of a sealing claudin, Claudin-3, from tight junctions in embryonic lung epithelium results in a decrease in lumen area and in hydrostatic pressure needed for lung development.

Decellularization and Recellularization Methods for Avian Lungs: An Alternative Approach for Use in Pulmonary Therapeutics.

The shortage of compatible allogeneic organs and an increase in the number of patients requiring long-term lung assist devices while waiting for lung transplantation have motivated scientists to explore alternatives to bioengineer new lungs, including through decellularization and recellularization processes. A novel approach for bioengineering an extracorporeal membrane oxygenator is based on the parenchymal structure of avian lungs which utilizes a cross-current unidirectional flow of air and blood rather than bidirectional airflow, and thus eliminates dead-space ventilation. This provides more efficient gas exchange than mammalian lungs. The novel approach utilized is to decellularize avian lungs and then to recellularize with patient-derived human lung epithelial and vascular endothelial cells with the goal of creating a fully functional structure that can be used as a gas-exchange device. Here, we present avian lung decellularization and recellularization methods for chicken and emu lungs, in order to study both small- and large-scale avian lung models. For decellularization, a detergent-based protocol is utilized, and different techniques are used to validate the de- and recellularization of those lungs, including microscopy, mass spectrometry, and immunohistochemical analyses. For recellularization, techniques for seeding different human lung cell types into the decellularized scaffolds are presented.

An Endogenous Retroviral LTR-Derived Long Noncoding RNA lnc-LTR5B Interacts With BiP to Modulate ALV-J Replication in Chicken Cells.

Infection with the avian leukosis virus subgroup J (ALV-J) impairs host genes and facilitates the establishment of chronic infection and the viral life cycle. However, the involvement of long noncoding RNAs (lncRNAs) in ALV-J infection remains largely unknown. In this study, we identified a novel chicken lncRNA derived from LTR5B of the ERV-L family (namely lnc-LTR5B), which is significantly downregulated in ALV-J infected cells. lnc-LTR5B was localized in the cytoplasm and was relatively high expressed in the chicken lung and liver. Notably, the replication of ALV-J was inhibited by the overexpression of lnc-LTR5B but enhanced when lnc-LTR5B expression was knocked down. We further confirmed that lnc-LTR5B could bind to the binding immunoglobulin protein (BiP), a master regulator of endoplasmic reticulum (ER) function. Mechanistically, lnc-LTR5B serves as a competing endogenous RNA for BiP, restricting its physical availability. Upon ALV-J infection, the reduction of lnc-LTR5B released BiP, which facilitated its translocation to the cell surface. This is crucial for ALV-J entry as well as pro-survival signaling. In conclusion, we identified an endogenous retroviral LTR-activated lnc-LTR5B that is involved in regulating the cell surface translocation of BiP, and such regulatory machinery can be exploited by ALV-J to complete its life cycle and propagate.

Proteomic analysis of differential expression of lung proteins in response to highly pathogenic avian influenza virus infection in chickens

Elucidation of the molecular pathogenesis underlying virus-host interactions is important for the development of new diagnostic and therapeutic strategies against highly pathogenic avian influenza (HPAI) virus infection in chickens. However, the pathogenesis of HPAI virus in chickens is not completely understood. To identify the intracellular signaling pathways and critical host proteins associated with influenza pathogenesis, we analyzed the lung proteome of a chicken infected with HPAI H5N1 virus (A/duck/India/02CA10/2011/Agartala). Mass spectrometry data sets were searched against the chicken UniProt reference database. At the local false discovery rate level of 5%, a total of 3313 proteins with the presence of at least one unique peptide were identified in the chicken lung proteome datasets. Differential expression analysis of these proteins showed that 247 and 1754 proteins were downregulated at 12 h and 48 h postinfection, respectively. We observed expression of proteins of the predominant signaling pathways, including Toll-like receptors (TLRs), retinoic acid-inducible gene I-like receptors (RLRs), NOD-like receptors (NLRs), and JAK-STAT signaling. Activation of these pathways is associated with the cytokine storm effect and thus may be the cause of the severity of HPAI H5N1 infection in chickens. We also observed the expression of myeloid differentiation primary response protein (MyD88), inhibitor of nuclear factor kappa B kinase subunit beta (IKBKB), interleukin 1 receptor associated kinase 4 (IRAK4), RELA proto-oncogene NF-κB subunit (RELA), and mitochondrial antiviral signaling protein (MAVS), which are involved in critical signaling pathways, as well as other, less-commonly identified proteins such as hepatocyte nuclear factor 4 alpha (HNF4A), ELAV-like RNA binding protein 1 (ELAVL1), fibronectin 1 (FN1), COP9 signalosome subunit 5 (COPS5), cullin 1 (CUL1), breast cancer type 1 susceptibility protein (BRCA1), and the FYN proto-oncogene Src family tyrosine kinase (FYN) as main hub proteins that might play important roles in influenza pathogenesis in chickens. In summary, we identified the signaling pathways and the proteomic determinants associated with disease pathogenesis in chickens infected with HPAI H5N1 virus.

DF-1 cells prevent MG-HS infection through gga-miR-24-3p/RAP1B mediated decreased proliferation and increased apoptosis

Mycoplasma gallisepticum (MG) is a major poultry pathogen that can induce Chronic Respiratory Disease (CRD) in chickens, causing serious economic losses in the poultry industry worldwide. Increasing evidence suggests that microRNAs (miRNAs) act as a vital role in resisting microbial pathogenesis and maintaining cellular mechanism. Our previous miRNAs sequencing data showed gga-miR-24-3p expression level was significantly increased in MG-infected chicken lungs. The aim of this study is to reveal the cellular mechanism behind the MG-HS infection. We found that gga-miR-24-3p was significantly upregulated and Ras-related protein-B (RAP1B) was downregulated in chicken fibroblast cells (DF-1) with MG infection. Dual luciferase reporting assay and rescue assay confirmed that RAP1B was the target gene of gga-miR-24-3p. Meanwhile, overexpressed gga-miR-24-3p increased the levels of tumor necrosis factor alpha (TNF-α) and interleukin-1β (IL-1β), and significantly inhibited cell proliferation as well as promoted MG-infected DF-1 cell apoptosis, whereas inhibition of gga-miR-24-3p had the opposite effect. More importantly, the results of overexpression and knockdown of target gene RAP1B demonstrated that the presence of RAP1B promoted cell proliferation and it saved the reduced or increased cell proliferation caused by overexpression or inhibition of gga-miR-24-3p. Furthermore, the overexpression of gga-miR-24-3p could significantly inhibit the expression of MG-HS adhesion protein. Taken together, these findings demonstrate that DF-1 cells can resist MG-HS infection through gga-miR-24-3p/RAP1B mediated decreased proliferation and increased apoptosis, which provides a new mechanism of resistance to MG infection in vitro.

Molecular characterization of Streptococcus and Enterococcus species isolated from broiler chickens

Streptococcus and Enterococcus infections in chickens may result in significant negative effect on economy. In the current study, the prevalence of Streptococcus and Enterococcus species was planned in different broiler chickens farms in Beni-Suef Governorate. A total of 272 samples were collected from lesions (septicemic organs, enlarged organs, necrotic focci) of the affected organs including heart, lung, liver and kidney of diseased broiler chickens and freshly dead ones. Out of 272 samples a total of 49 isolates were recovered with incidence of 18% including 26Streptococcus spp. (53.1%) and 21 Enterococcus spp. (42.8%) meanwhile 2 isolates (4.1%) were unidentified. Streptococcus isolates were identified as S.gallinaceous (24.5%), S. dysgalactiae (16.3%) and S. durans (12.2%). Meanwhile all Enterococcus isolates were identified as E. faecalis. The in-vitro antibiotic sensitivity testing showed that all isolates were highly sensitive to amoxicillin (77.6%), sulfamethoxazole-trimethoprim (73.5%) and amoxicillin-clavulanic acid (65.3%). Meanwhile, all isolates were resistant to cephalexin, cefotaxime sodium, cefipime, cefotriaxone, tetracycline, kanamycin and apramycin while 87.8 and 63.2% of isolates showed resistance aganist gentamicin and enrofloxacin, respectively. Moreover, multidrug resistant were detected in all isolates. Polymerase chain reaction (PCR) was applied to identify 4 resistance-associated genes including (tetO, aac(6')aph(2''), blaZ and Pbp 1A) as well as 6 virulence-associated genes including (cylE, brp A, hyl, cylA, asa1 and gelE). The results indicated that tetO, aac(6')aph(2''), blaZ, Pbp 1A, cylE, brp A, cylA and asa1 genes were recovered from all the tested isolates (100%). Meanwhile, none of streptococcus isolates had hly gene also, gelE gene not detected in enterococcus isolates.

Substitution Arg140Gly in Hemagglutinin Reduced the Virulence of Highly Pathogenic Avian Influenza Virus H7N1.

The H7 subtype of avian influenza viruses (AIV) stands out among other AIV. The H7 viruses circulate in ducks, poultry and equines and have repeatedly caused outbreaks of disease in humans. The laboratory strain A/chicken/Rostock/R0p/1934 (H7N1) (R0p), which was previously derived from the highly pathogenic strain A/FPV/Rostock/1934 (H7N1), was studied in this work to ascertain its biological property, genome stability and virulent changing mechanism. Several virus variants were obtained by serial passages in the chicken lungs. After 10 passages of this virus through the chicken lungs we obtained a much more pathogenic variant than the starting R0p. The study of intermediate passages showed a sharp increase in pathogenicity between the fifth and sixth passage. By cloning these variants, a pair of strains (R5p and R6p) was obtained, and the complete genomes of these strains were sequenced. Single amino acid substitution was revealed, namely reversion Gly140Arg in HA1. This amino acid is located at the head part of the hemagglutinin, adjacent to the receptor-binding site. In addition to the increased pathogenicity in chicken and mice, R6p differs from R5p in the shape of foci in cell culture and an increased affinity for a negatively charged receptor analogue, while maintaining a pattern of receptor-binding specificity and the pH of conformational change of HA.

Real Time Detection of different Variant Strains of Infectious Bronchitis Virus in Trachea, Lung and Kidney of Infected Broiler Chickens

BACKGROUND: Avian infectious bronchitis virus (IBV) has a great potential for genetic variability which leads to generating new virus strains. The changes in IBV genome often cause alterations in the virulence, tissue tropism and viral replication in the host tissues. OBJECTIVES: This study was conducted to identify the virus variant strains in trachea, lung and kidney of infected birds. The possible relationship of IBV variants with the relative quantity of virus in each organ was also investigated.METHODS: IBV variant strains were detected by polymerase chain reaction (PCR) and direct sequencing. Amongst samples collected during one season (spring), from infected commercial broiler flocks located at Golastan and Mazandaran province of Iran, 9 flocks (3 flocks per each variant) were selected based on the identified variants. Trachea, lung and kidney samples of 5 birds per flock were examined for the presence of virus and variants. Virus also quantified in target organs using relative quantitative real time PCR.RESULTS: Based on the PCR and sequencing, three IBV variants were selected (A, B and C). Virus type A and B were detected in all target organs but virus type C detected in trachea and kidney. Virus type C had the highest quantity (17.02 ± 5.22) and virus type A showed the lowest quantity (5.68 ± 2.4) in infected tissues. Relative quantity of virus detected in tissues significantly correlated with IBV variant. CONCLUSIONS: Genetic polymorphism at IBV field strains has revealed significant correlations with viral quantity in lung, trachea and kidney. Our finding is an update of current knowledge on the associations between viral genotype, virulence and pathogenicity.

Selenomethionine alleviates LPS-induced JNK/NLRP3 inflammasome-dependent necroptosis by modulating miR-15a and oxidative stress in chicken lungs.

Selenium (Se) was involved in many physiological processes in humans and animals. microRNAs (miRNAs) also played important roles in lung diseases. However, the regulatory mechanism of miRNA in chicken lungs and the mechanism of lipopolysaccharide (LPS)-induced pneumonia remained unclear. To further study these mechanisms, we established a supplement of selenomethionine (SeMet) and/or LPS-treated chicken model and a cell model of LPS and/or high and low expression of miR-15a in chicken hepatocellular carcinoma (LMH) cells. We detected the expression of some selenoproteins, p-c-Jun N-terminal kinase (JNK), nod-like receptor protein 3 (NLRP3), caspase1, receptor-interacting serine-threonine kinase 1 (RIPK1), receptor-interacting serine-threonine kinase 3 (RIPK3), mixed lineage kinase domain-like pseudokinase (MLKL), miR-15a, and oxidative stress kits. Additionally, we observed the morphology of lungs by H.E. staining in vitro. The results indicated that necroptosis occurred in LPS-treated chicken and LMH cells. Moreover, LPS stimulation inhibited miR-15a, and increased the expression of JNK, NLRP3, caspase1, RIPK1, RIPK3, and MLKL. We also found that LPS treatment not only increased the content of H2O2 and MDA in the lungs but also increased the activities of iNOS and CAT and the content of GSH decreased. Conclusion: SeMet could reduce the oxidative damage and activate NLRP3 inflammasome reaction by stimulating miR-15a/JNK, thus reduced the pulmonary necroptosis induced by LPS.

Lung branching morphogenesis is accompanied by temporal metabolic changes towards a glycolytic preference

BackgroundLung branching morphogenesis is characterized by epithelial-mesenchymal interactions that ultimately define the airway conducting system. Throughout this process, energy and structural macromolecules are necessary to sustain the high proliferative rates. The extensive knowledge of the molecular mechanisms underlying pulmonary development contrasts with the lack of data regarding the embryonic lung metabolic requirements. Here, we studied the metabolic profile associated with the early stages of chicken pulmonary branching.MethodsIn this study, we used an ex vivo lung explant culture system and analyzed the consumption/production of extracellular metabolic intermediates associated with glucose catabolism (alanine, lactate, and acetate) by 1H-NMR spectroscopy in the culture medium. Then, we characterized the transcript levels of metabolite membrane transporters (glut1, glut3, glut8, mct1, mct3, mct4, and mct8) and glycolytic enzymes (hk1, hk2, pfk1, ldha, ldhb, pdha, and pdhb) by qPCR. ldha and ldhb mRNA spatial localization was determined by in situ hybridization. Proliferation was analyzed by directly assessing DNA synthesis using an EdU-based assay. Additionally, we performed western blot to analyze LDHA and LDHT protein levels. Finally, we used a Clark-Type Electrode to assess the lung explant's respiratory capacity.ResultsGlucose consumption decreases, whereas alanine, lactate, and acetate production progressively increase as branching morphogenesis proceeds. mRNA analysis revealed variations in the expression levels of key enzymes and transporters from the glycolytic pathway. ldha and ldhb displayed a compartment-specific expression pattern that resembles proximal–distal markers. In addition, high proliferation levels were detected at active branching sites. LDH protein expression levels suggest that LDHB may account for the progressive rise in lactate. Concurrently, there is a stable oxygen consumption rate throughout branching morphogenesis.ConclusionsThis report describes the temporal metabolic changes that accompany the early stages of chicken lung branching morphogenesis. Overall, the embryonic chicken lung seems to shift to a glycolytic lactate-based metabolism as pulmonary branching occurs. Moreover, this metabolic rewiring might play a crucial role during lung development.

TILMICOSIN INTAKE AND DISTRIBUTION IN THE BODY OF BROILER CHICKENS WITH ORNITHOBACTERIOSIS

One of the m T ain indicators that determine the effectiveness of the antibiotic in the body is its ability to penetrate and accumulate in high concentrations at the sites of the pathological process. The article presents the results of studies of the intake , distribution and excretion of tilmicosin phosphate – the active substance of the tilmox 25% antibiotic from the body of broiler chickens cross KOBB-500 , suffering ornithobacteriosis. It was found that 24 hours after the start of feeding the solution of the drug "Tilmox 25%" broiler chickens with ornithobacteriosis, most tilmicosin phosphate was contained in the lungs, while in the liver less than 1.6 times, kidneys - 3.0 times, heart muscle – 3.4 times, pectoral muscles – 3.5 times than in the lungs. After 48 and 72 hours, the tilmicosin content increased in all studied organs, but the pattern of its distribution was the same as after 24 hours. Tillmicosin phosphate levels in the lungs exceeded the values in the liver, kidneys, heart and chest muscles by 1.8, 2.7, 2.9 and 3.9 times, respectively, for 72 hours of the experiment. At 96 hours, tilmicosin levels were highest in the pectoral muscles, kidneys, liver, and lungs, and only slightly less in the heart than in previous study periods. The obtained results testify to the organ affiliation of tilmicosin phosphate to lung tissues in patients with ornithobacteriosis of broiler chickens. One day (120 h of the experiment) after discontinuation of tilmox 25%, the content of tilmicosin phosphate in the lungs, liver, kidneys, heart and pectoral muscles of broiler chickens was 53, 50, 57, 68 and 34%, respectively, according to 96 hours. The Ornithobacterium rhinotracheale sensitivity to tilmicosin and its distribution in maximum amounts in the lungs of broiler chickens with ornithobacteriosis provided a therapeutic effect, which was confirmed by microscopic studies. Studies on the pharmacokinetic properties of tilmicosin have been performed mainly in healthy birds. Therefore, the optimization of treatment regimens of already known antibiotics, which will be based on the study of pharmacokinetic and pharmacodynamic properties not only on clinically healthy but also on diseased organisms is a relevant and important issue in the field of veterinary pharmacology. Keywords: tilmox 25%, tilmicosin phosphate, broiler chickens, ornithobacteriosis, Ornithobacterium rhinotracheale, pharmacokinetics, distribution, accumulation, excretion

Conducting a comprehensive mycological study to prevent the occurrence of aspergillosis in chickens

Diseases of poultry aspergillosis are recorded in many poultry farms, the causes of the disease are the violation of the sanitary and hygienic conditions of hatcheries and poultry houses (unfavorable microclimate, affected feed and litter by microscopic fungi). To prevent the development of infection, it is necessary to control air pollution and equipment in hatcheries; determine the safety indicators of feed and water (the level of their mycological contamination) in poultry houses; monitor the status of feed storage facilities and water supply systems. According to the results of our research, in 15.1% of dead chickens at the age of 3 to 5 days and 6.6% at the age of 7-10 days, according to the results of mycological examination of pathological material, the diagnosis of aspergillosis was established. Aspergillus flavus (47%) Aspergillus fumigatus (34.5%), Aspergillus niger (10%) were isolated from the lungs of dead chickens. Macroscopically revealed edema and hyperemia of the lungs in chickens of 3-5 days of age. The formation of granulomas in the lungs and serous membranes was not detected, which may indicate an acute form of the pathological process. Chickens 7-10 days old showed a strong thickening of the air sacs, lungs with multiple spherical granulomas up to 2 mm in diameter. Spores of fungi entering the lungs cause a local inflammatory reaction - acute pneumonia. Histologically, in chickens of 3-5 days of age, a thickening of the parabronchial wall due to hyperplasia of local lymphoid formations (providing local immunity), signs of the development of interstitial pneumonia were revealed. Pathognomonic signs were found in the parenchyma - the formation of giant multinucleated cells, which is a characteristic sign of mycotic infections in poultry. The fusion of local pulmonary macrophages, histiocytes, into multinucleated cells is a prerequisite for the formation of granulomas, being a specific immune response in birds to the penetration of a pathogen. According to the development of the infectious process, caseous granulomas and fungal hyphae can be detected microscopically in the lungs. According to the results of histological examination, the formation of mycotic granulomas was found in the lung parenchyma in 7-10 days old chickens, which was accompanied by the formation of a zone of coagulation necrosis, in which the fungal hyphae were found. On the periphery, giant multinucleated epithelioid cells are located, the detection of which by histological examination is the basis for suspecting bird infection with microscopic fungi. Microscopic fungi Aspergillus flavus and Aspergillus fumigatus have been found in washes from hatchery ventilation cabinets, and Aspergillus flavus was found in the air from the chick sorting room and in washes from the feed mixer. Key words: aspergillosis, Aspergillus flavus, Aspergillus fumigatus, Aspergillus niger, micromycete, mold fungi, histiocytes, granulomas, phylaids, conidia, hyphae.

Down-regulated gga-miR-223 inhibits proliferation and induces apoptosis of MG-infected DF-1 cells by targeting FOXO3

Mycoplasma gallisepticum (MG) is a major poultry pathogen that can induce Chronic Respiratory Disease (CRD) in chickens, causing serious economic losses in the poultry industry worldwide. Increasing evidence suggests that microRNAs (miRNAs) act as a vital role in resisting microbial pathogenesis and maintaining cellular mechanism. Our previous miRNAs sequencing data showed that gga-miR-223 expression level significantly decreased in MG-infected chicken lungs. The aim of this study was to reveal the role of gga-miR-223 in MG-induced CRD progression. We found that gga-miR-223 was remarkably down regulated and forkhead box O3 (FOXO3) was up-regulated in both MG-infected chicken embryos lungs and the chicken embryonic fibroblast cell line (DF-1) by qPCR. FOXO3 was verified as the target gene of gga-miR-223 through bioinformatics analysis and dual-luciferase reporter assay. Further studies showed that overexpressed gga-miR-223 could promote cell proliferation, cell cycle, and inhibit cell apoptosis by notably promoting the expression of cell cycle marker genes cyclin-dependent kinase 1 (CDK1), cyclin-dependent kinase 6 (CDK6) and Cyclin D1 (CCND1) and inhibiting the expression of apoptosis markers Bcl-2-like 11(BIM), FAS ligand (FASLG) and TNF-related apoptosis-inducing ligand (TRAIL). As expected, FOXO3 knockdown group got similar results. Overexpression of gga-miR-223 observably promoted cell multiplication, cell cycle progression, and inhibited apoptosis of MG-infected DF-1 cells, while inhibited gga-miR-223 had the opposite effect. Taken together, upon MG-infection, downregulated gga-miR-223 could decrease proliferation, cycle progression, and increase apoptosis through directly targeting FOXO3 to exert an aggravating MG-infectious effect.

Differences in Highly Pathogenic H5N6 Avian Influenza Viral Pathogenicity and Inflammatory Response in Chickens and Ducks.

Infection with H5N6 highly pathogenic avian influenza virus caused high mortality in chickens, while ducks often appear to be asymptomatic. But, some recent H5Nx subtype viruses could cause high mortality in ducks. The variation between different species and the mechanisms by which some H5Nx viruses cause death in ducks requires investigation to identify the key processes in influenza susceptibility and pathogenesis. Here, we characterized two representative H5N6 viruses, A/Pavo cristatus/Jiangxi/JA1/2016 (JA1) and A/Anas crecca/shanghai/SH1/2016 (SH1), and compared their pathogenicity and expression profiles of immune-related genes in chickens and ducks to identify the elements of the host immune-related response that were involved in disease lethality. Results suggested that H5N6 HPAIVs had higher pathogenic and inflammatory effect in chickens than in ducks. Importantly, the TNF-α, IL-6, IFN-γ and iNOS levels were significantly higher in the lung of SH1 infected chickens compared to those of ducks. And we found higher systemic levels of IL-6 induced by JA1 in chickens than in ducks. In addition, our experiments demonstrated that JA1 was associated with greater pathogenicity in ducks were accompanied by the excessive expression of iNOS in the brain. These results are helpful to understand the relationship between the pathogenicity of H5N6 AIVs and inflammatory responses to them in chickens and ducks.

Baicalin ameliorates Mycoplasma gallisepticum-induced inflammatory injury in the chicken lung through regulating the intestinal microbiota and phenylalanine metabolism.

Baicalin shows excellent protective effects against Mycoplasma gallisepticum (MG) induced inflammatory injury as discussed in our previous studies. However, the physiological effects of baicalin are notable in contrast to its low bioavailability, and the critical mechanism for the protective effects of baicalin against MG infection is still unclear. The main objective of this study was to investigate whether baicalin alleviates MG-induced lung inflammatory injury through regulating gut microbiota. Using an MG infection model, results showed that baicalin treatment significantly reduced MG colonization and ameliorated the abnormal pathological changes in the lung. Baicalin treatment also reduced the level of proinflammatory cytokines and suppressed proinflammatory protein expression. Notably, MG infection changed the gut microbiota composition, however, the abnormal gut microbiota composition was partially alleviated by baicalin treatment. Baicalin significantly enriched the commensal bacterium Bacteroides fragilis, and gavaged with Bacteroides fragilis alleviating MG infection-induced inflammatory injury in the lung. In addition, baicalin reversed peripheral accumulation of phenylalanine induced by MG infection. Importantly, increased phenylalanine induced excessive necroptosis through the modulation of gga-miR-190a-3p-Fas-associated protein with death domain (FADD) axis in HD11 macrophages. Together, our findings highlighted the role of gut microbiota and phenylalanine metabolism in MG infection and confirmed that baicalin could effectively inhibit MG-induced inflammatory injury in the lung by remodeling the gut microbiota and phenylalanine metabolism.