Avian Pathology最新文献

Research highlights: Flocks differ in levels for Lactobacillales, Lachnospiraceae and Ruminococcaceae.Gut Damage Ratio differs between broilers with or without gut health problems.Results of both assays in 21-day-old broilers relate significantly to slaughter weight.

Inclusion body hepatitis (IBH) outbreaks have been reported globally over the past two decades, predominantly affecting broiler flocks and resulting in significant economic losses due to increased mortality and diminished production performance. In Iran, fowl adenovirus (FAdV) infections have been circulating for several years, with recurrent reports of clinical cases suggesting IBH and hepatitis-hydropericardium syndrome (HHS) in commercial poultry operations. In response to these concerns, the present study was conducted to comprehensively characterize circulating FAdV strains in Iranian poultry farms over a 3-year period. A total of 200 pooled liver samples were collected from 200 broiler flocks that exhibited clinical signs consistent with IBH/HHS. Partial amplification and sequencing of the hexon gene were performed to detect and genotype the FAdV strains. The phylogenetic analysis assigned 66.32% of the detected strains to FAdV-D, 16.32% to FAdV-C, 11.22% to FAdV-E, and 6.12% to FAdV-B. Notably, this investigation provided the first genomic evidence of FAdV serotype 5 in Iran. Within the FAdV-C group, both serotypes 4 and 10 were identified. Additionally, serotype 6, closely related (98% nucleotide identity) to a Chinese reference strain, was reported for the first time in Iran. Given the high diversity of FAdV serotypes, continued vaccination of broiler breeders, using vaccines that cover the strains circulating in the country, is recommended. Monitoring broilers and broiler breeders remain essential for effective disease control and prevention.

Research highlights: Five causes of mortality accounted for 71.1% of total mortality of laying hens.Non-infectious causes of mortality (63.9%) more prevalent than infectious (37.6%).Risk periods were inconclusive due to flock variation.Egg binding can cause mortality, and may be linked to above normal body condition.

Research highlights: Deleting avrA, gtgA, pipA, and sseL genes did not affect serovar Pullorum (SP) persistence.The absence of avrA and gtgA increased tissue damage associated with inflammation.SP mutants lacking anti-inflammatory proteins had reduced survival in host tissues.SP ΔgtgA caused liver and spleen lesions resembling those observed in S. Gallinarum (SG) infection.

Gastrointestinal nematode infections, particularly Ascaridia galli (A. galli), pose challenges to the poultry industry especially in free-range chickens. These nematodes employ sophisticated immunomodulation strategies to evade host immune defences, allowing them to establish chronic infections. Excretory-secretory (ES) products, including extracellular vesicles (EVs), play a pivotal role in host-parasite communication. Thus, this study aimed to investigate the immunomodulatory properties of nematode-derived ES/EVs, and evaluate the impact of ivermectin (IVM) on these interactions in vitro. Adult A. galli worms were collected from the jejunum of infected chickens and cultured in vitro with or without IVM treatment. ES products were collected, and EVs were enriched using size-exclusion chromatography. T-cell proliferation and macrophage activation assays were performed to assess the immunomodulatory effects of ES/EVs. A. galli-derived ES products suppressed T-cell activation (CD25+CD57+ cells) and reduced blast transformation in both CD4+ and CD8+ T-cells (P < 0.05). Furthermore, ES promoted TLR4-induced macrophage NO production, changed macrophage-activated surface phenotype, and inhibited macrophage phagocytosis in high concentration but promoted it in low concentration (P < 0.05). Additionally, A. galli-derived EVs were detected in culture supernatants, and this EV secretion was decreased with the IVM treatment (P < 0.05). Fourier-transform infrared spectroscopy confirmed IVM treatment altered EV cargo composition. Finally, the EVs influenced cytokine profiles of activated macrophages, decreasing pro-inflammatory cytokine gene expression (IL-1β and IL-8, P < 0.05) which may mirror immune evasion in vivo. In summary, this study highlights immunomodulatory mechanisms of A. galli ES/EVs and provides fundamental information for developing diagnostic and therapeutic strategies targeting nematode ES products including EVs.RESEARCH HIGHLIGHTSExcretory-secretory (ES) products, including extracellular vesicles (EVs), demonstrated immunomodulatory properties.A. galli ES suppressed T-cell activation, proliferation, and macrophage phagocytosis.A. galli ES, including EVs, may help in evading the host immune system.

Research highlights: YbdO increases biofilm formation and acid resistance.YbdO upregulates the transcription levels of the biofilm-associated genes bcsE, csgD, pgaA, wcaD, fimH, and flhD.YbdO activates the expression of acid stress-associated genes hdeA and yqgB.YbdO contributes to improving the adaptability of APEC to environmental stresses.

Although poultry meat production supports the livelihood and provides food security for billions of people worldwide, it is facing substantial challenges. The emergence of broiler breast myopathies (white striping, woody breast, spaghetti meat) at large scale is one of the most significant economic and welfare challenges that menace poultry production sustainability and for which there is currently no effective prevention, due to its unknown aetiologies. Here, by inviting and gathering several experts with diverse, but complementary disciplines, the objective of the present review is to highlight the current progress and knowledge on these myopathies. Five sections are presented, describing in detail the history and geographic occurrence of these breast myopathies, their macroscopic morphologies and microscopic characteristics, their putative aetiologies and causes as well as their underlying molecular mechanisms, and potential strategies and solutions. The is review summarizes both descriptive and functional mechanistic studies, highlights the complexity of these myopathies and the kinship between broiler genome, nutrition, and management, and outlines some of the promising molecular signatures. It aims to offer new fundamental frameworks for future investigations.

Research highlights: Broiler birds as compared to layers are more susceptible to avian colibacillosis.An aerosol challenge using an ilux2-APEC effectively evaluates disease pathogenesis.The ilux2-APEC persistently colonized the bursa of Fabricius after aerosol exposure.

Eye drop (ED) and vent brush (VB) application of live infectious laryngotracheitis virus (ILTV) vaccine provides protective immunity against disease, but little is known regarding the immune responses following application. This study compared the gene expression of immune markers associated with VB and ED ILTV vaccination in the conjunctiva, trachea and cloaca at 3, 5, 7 and 10 days post-vaccination (dpv) and 3, 5 and 7 days post-revaccination (dprv). The relative gene expression of markers associated with inflammatory responses and their regulation (CCL4, CCR5, IL2, IL4, IL6, IL17C, IFNG), pathogen recognition receptors (TLR2-2, TLR4, TLR7) and cell surface markers (CD4, CD8A, CD14, CD80) was evaluated by RT-PCR after ED or VB vaccination and revaccination using the alternate route (ED/VB (primary/booster), VB/ED). There was increased expression of inflammatory markers at vaccination sites following primary vaccination. In the VB group, there was increased expression of IL6 and IFNG in cloaca (3 dpv) and IL2 in the conjunctiva (7 dpv) compared to the ED group (P < 0.05), while there was increased CCL4 expression in conjunctiva (5 dpv) in the ED group compared to the VB group. ED vaccination was associated with increased expression of IL2 and IL17C in trachea while VB vaccination was associated with increased expression of IL6 and IL17C in trachea. Similarly, ED/VB- and VB/ED-associated increases in IL2, IL6 and IL17C expression were observed at the revaccination sites. In conclusion, immune responses after the first and second ILTV vaccination were site-specific and associated with inflammatory responses in the mucosa of the vaccinated tissues and trachea.RESEARCH HIGHLIGHTS ILTV vaccination elicited inflammatory responses at the vaccination sites (conjunctiva and cloaca).Conjunctival or cloacal vaccination elicited similar inflammatory responses in the trachea after 3 and 5 days, respectively.Revaccination by a different route stimulated similar immune responses in conjunctiva, cloaca and trachea.

Research highlights: Management factors associated with the isolation of Salmonella spp.Increased Salmonella - ducks, sheep, barn size, bird numbers, age, shared equipment.Decreased Salmonella - competitive exclusion product, dedicated coat, parking signs.