Endoplasmic reticulum stress and associated apoptosis are linked with the pathogenesis of white striping in broiler breast muscles.

White striping (WS) that appears as white stripes parallel to the muscle fibrils is an emerging growth-related abnormality of broiler breast meat. The pathomechanism of this defect has not been fully understood despite intensive studies over the past decade. In the present study, endoplasmic reticulum (ER) stress and its associated apoptotic pathways were investigated to elucidate the potential role of these pathways in the development of WS. To this end, a total of 60 Pectoralis major (Pm) muscle samples were collected from 55-d-old Ross 308 male broiler chickens according to the severity of gross WS lesions (normal, mild, and severe). Histopathological and molecular analyses were conducted to evaluate the lesions and genes involved in the ER stress and related apoptosis. All the Pm samples, both with and without macroscopic WS lesions, showed varying degrees of myodegenerative lesions. Molecular analysis revealed that the transcript abundances of many components related to protein kinase R-like ER kinase (PERK) and inositol-requiring enzyme type 1 (IRE-1) signals of the ER stress response were significantly greater in severely WS-affected breast tissues compared to their mildly affected and normal counterparts. Similarly, the transcript abundances of apoptotic markers related to both signaling pathways were significantly greater in severe WS lesions than those of mildly affected and normal Pm tissues. Besides these, a significant increase in caspase-3 transcript abundance was seen in severe WS lesions in comparison with mild WS and normal breast muscles. Findings of this study suggest that ER stress response and its related apoptotic pathways are possibly activated in the breast muscle of broiler chickens with severe WS lesions. Based on these findings, it is speculated that ER stress-mediated apoptosis occupies a central role in the progression of WS in broiler chickens.

Changes of bone and articular cartilage in broilers with femoral head necrosis.

Femoral head necrosis (FHN) in broilers is a common leg disorder in intensive poultry farming, giving rise to poor animal health and welfare. Abnormal mechanical stress in the hip joint is a risk factor for FHN, and articular cartilage is attracting increasing attention as a cushion and lubrication structure for the joint. In the present study, broilers aged 3 to 4 wk with FHN were divided into femoral head separation (FHS) and femoral head separation with growth plate lacerations (FHSL) groups, with normal broilers as control. The features of the hip joint, bone, and cartilage were assessed in FHN progression using devices including computed tomography (CT), atomic force microscope (AFM), and transmission electron microscopy (TEM). Broilers with FHN demonstrated decreased bone mechanical properties, narrow joint space, and thickened femoral head stellate structures. Notably, abnormal cartilage morphology was observed in FHN-affected broilers, characterized by increased cartilage thickness and rough cartilage surfaces. In addition, as FHN developed, cartilage surface friction and friction coefficient dramatically increased, while cartilage modulus and stiffness decreased. The ultramicro-damage occurred in chondrocytes and the extracellular matrix (ECM) of cartilage. Cell disintegration, abnormal mitochondrial accumulation, and oxidative stress damage were observed in chondrocytes. A notable decline in cartilage collagen content was observed in ECM during the initial stages of FHN, accompanied by a pronounced reduction in collagen fiber diameter and proteoglycan content as FHN progressed. Furthermore, the noticeable loosening of the collagen fiber structure and the appearance of type I collagen were noted in cartilage. In conclusion, there was a progressive decrease in bone quality and multifaceted damage of cartilage in the femoral head, which was closely linked to the severity of FHN in broilers.

Morphomolecular identification of heavy parasitic typhlitis in layer flocks: tissue response and cell-mediated reaction.

BACKGROUND: Heterakis gallinarum (H. gallinarum) is a common poultry parasite that can be found in the ceca of many gallinaceous bird species, causing minor pathology and reduced weight gain. Most infections go unnoticed in commercial flocks due to the dependence on fecal egg counts, which are prone to false-negative diagnoses. Furthermore, there is a lack of research on gastrointestinal nematodes that use molecular identification methods, which could be essential for rapid diagnosis and developing efficient control approaches. As a result, the study aimed to look at the cause of mortality in layer chickens induced by H. gallinarum in Egyptian poultry farms using morphological, ultrastructural, and molecular characterization. Histopathological, immunohistochemical, and cell-mediated immune responses from damaged cecal tissues were also examined. RESULTS: Seventy bird samples from ten-layer flocks of different breeds (Native, white, and brown layers) suffering from diarrhea, decreased egg output, and emaciation were collected. Cecal samples were collected from affected and non-affected birds and were examined for parasitic diseases using light and a scanning electron microscope. The mitochondrial cytochrome oxidase 1 (COX1) gene was used to characterize H. gallinarum. Our results showed that the collected nematodal worms were identified as H. gallinarum (male and female), further confirmed by COX1 gene amplification and sequence alignment. Gene expression analysis of the inflammatory markers in infected tissues showed a significant up-regulation of IL-2, IFN-γ, TLR-4, and IL-1ß and a significant down-regulation of the anti-inflammatory IL-10. The mRNA level of the apoptotic cas-3 revealed apoptotic activity among the H. gallinarum samples compared to the control group. CONCLUSIONS: Our results implemented the use of molecular methods for the diagnosis of Heterakis, and this is the first report showing the tissue immune response following infection in layers: upregulation of IL-1ß, IFN-γ, Il-2, and TLR-4, while down-regulation of anti-inflammatory IL-10 in cecal tissue, Cas-3 apoptotic activity and Nuclear factor-κB (NF-κB)activity with immunophenotyping of T-cells in Heterakis infected tissue.

Histological species differences among chickens, rats, and mice in experimental cholestasis by bile duct ligation.

Cholestasis is a hepatic disease reported in humans, dogs, and chickens and is characterized by various signs. Bile duct ligation (BDL) is a standard model for research in cholestasis in male rats and mice. However, the timing and degree of structural changes in BDL-subjected liver differ in the two animal species. This study focused on chickens as a choice model for cholestasis. Specifically, we aimed to evaluate the features of BDL in hens and compare them with those in rats and mice. Eighteen hens, 19 female ICR mice, and 18 female SD rats were randomly divided into the sham-operated and BDL groups. At 2, 4, and 6 weeks after BDL, and 4 weeks after the sham operation, liver and blood samples were collected and analyzed histologically and biochemically. Histologically, bile duct proliferation in BDL-subjected livers was first observed in the chickens and then the rats and mice, whereas CD44-positive small hepatocytes were observed only in chickens in the BDL group. Biochemically, the mRNA expression of the hepatocyte growth factor was higher in BDL-subjected chickens, while Interleukin 6 expression was higher in the BDL-subjected rats and mice than in animals in the sham group. In addition, farnesoid X receptor mRNA expression was lower in the BDL-subjected chickens than in the sham chickens. The BDL group had significantly higher total bile acid blood concentration than the sham group. In conclusion, the signs of hepatopathy caused by BDL differ among animal species. Furthermore, we propose that compared to BDL-subjected mice and rats, BDL-subjected chickens are a novel cholestasis animal model that demonstrates severe hepatopathy and liver restructuring.

Bone lesions and intestinal barrier disruption caused by the isolated novel goose parvovirus infection in ducks.

Short beak and dwarfism syndrome (SBDS) is attributed to Novel Goose Parvovirus (NGPV), which has inflicted significant economic losses on farming in China. Despite its significant impact, limited research has been conducted on the pathogenesis of this disease. The SD strain, a parvovirus variant isolated from ducks in Shandong province, was identified and characterized in our study. Phylogenetic analysis and sequence comparisons confirmed the classification of the SD strain as a member of NGPV. Based on this information, we established an animal model of SBDS by inoculating Cherry Valley ducks with the SD strain. Our findings indicate that infection with the SD strain leads to a reduction in body weight, beak length, width, and tibia length. Notably, significant histopathological alterations were observed in the thymus, spleen, and intestine of the infected ducks. Furthermore, the SD strain induces bone disorders and inflammatory responses. To evaluate the impact of NGPV on intestinal homeostasis, we performed 16S rDNA sequencing and gas chromatography to analyze the composition of intestinal flora and levels of short-chain fatty acids (SCFAs) in the cecal contents. Our findings revealed that SD strain infection induces dysbiosis in cecal microbial and a decrease in SCFAs production. Subsequent analysis revealed a significant correlation between bacterial genera and the clinical symptoms in NGPV SD infected ducks. Our research providing novel insights into clinical pathology of NGPV in ducks and providing a foundation for the research of NGPV treatment targeting gut microbiota.

Isolation, identification, and pathogenicity of two novel goose astrovirus from goslings with severe gout in China.

Goose astroviruses (GAstVs) are important pathogens which can cause gout in goslings leading to huge economic losses for the goose farming industry in China. In 2023, an infectious disease characterized by visceral gout broke out in commercial goose farms in Guangxi and Guangdong provinces of China. In this study, two GAstV strains of GXNN and GDCS were successfully isolated from these two disease-ridden goose farms. The complete genomic lengths of these two strains were 7166 bp, and phylogenetic analysis showed that they were both GAstV-2 subtypes. The 3-dimensional structures of the capsid protein were predicted and six characteristic mutation sites at amino acid positions 60, 61, 228, 229, 456 and 523 were found within the strong antigenic regions. A recombination event occurred at 6833-7070 nt between the GAstV TZ03 and Turkey astrovirus CA/00 and this was detected in both the GXNN and GDCS strains. Another recombinant event occurred at 63-2747 nt between the GAstV XT1 and GAstV SDPY and this was detected in the GDCS strain. When 1-day-old goslings were infected with the novel GXNN and GDCS strains, they showed severe visceral gout. This was accompanied by enlarged spleens, liver hemorrhages and urate deposits in the kidneys and ureters and their blood urea nitrogen levels were significantly elevated. The mortality rates of the GXNN- and GDCS-infected groups were pathogenically high at 80 % and 60 %, respectively. These results will promote our understanding of the evolution and epidemic potential of GAstVs in China.

Pathogenicity studies and molecular characterization of DPV infection in ducklings.

In the spring of 2023, 10 to 21-day-old chicks in a broiler duck farm in Shandong Province, China, developed swelling of the head and neck, moist eyes with mucous discharge, difficulty in walking, shrinking of the neck, and loose and disorganized coat. Anatomical observation revealed hemorrhages in the esophageal mucosa, myocardium, and liver, and severe hemorrhages in the trachea with copious inflammatory secretions. Soon after, similar symptoms appeared in a large number of ducks in the flock, which eventually led to the elimination of all the 20,000-odd newly introduced ducklings on the farm, resulting in huge economic losses. We detected duck plague virus in the tissues of liver, spleen and lungs of diseased and dead ducks, and successfully isolated the pathogenic strain, named SD423, by inoculating duck embryos and inoculating duck embryo fibroblasts. We successfully conducted animal regression experiments with the isolated strain, and the experimental animals in the 1 d of age group showed symptoms of swollen eyes and tearing, shrinking of the neck, crouching, and hemorrhage in organs such as the liver and intestines successively from the 3rd d. We sequenced the whole genome of the isolated duck plague strain, and by comparing the homology with the published duck plague virus whole sequences in Genbank, the virus strain obtained in this study had the highest homology with the Chinese virulent strain SD (MN518864.1), with nucleotide (nt) homology of about 99.90% and amino acid (aa) homology of about 99.75%, which indicated that the isolate is a virulent strain. Previously, it was reported that the natural infection of duck plague virus mainly occurs above 30 d of age, but the duck plague virus found in this study can naturally infect ducklings up to 20 d of age, and the mortality rate is as high as 100%. In this study, the pathogenicity test and whole genome sequence analysis of this isolate provided data support and theoretical basis for further research on pathogenicity and virulence-related gene analysis of duck plague virus.

FAdV-4 can cause more noticeable clinical symptoms compared to FAdV-8b after infecting specific pathogen free chickens.

Chickens infected with FAdV-4 and FAdV-8b both exhibit hepatic lesions characterized by hemorrhagic necrosis and intranuclear inclusion body formation. However, only FAdV-4 induces pericardial effusion and acute mortality in chickens. To investigate the similarities and differences in the pathogenicity of HPS and IBH, this study intends to compare the infectivity and pathogenicity of FAdV-4 and FAdV-8b, 2 serotypes of fowl adenovirus isolated in our laboratory. The 2 viruses were respectively inoculated subcutaneously into SPF chicks at the neck. The clinical manifestations and pathological changes in these infected groups of chickens differed to some extent. Chickens infected with FAdV-4 exhibit evident depression and acute mortality, with a mortality rate of 60%; while those infected with FAdV-8b only display mild depression. Postmortem examination reveals serosanguinous effusion in the pericardial sac, spot-like hemorrhage, and focal necrosis in the liver of chickens infected with FAdV-4. Additionally, various degrees of edema are observed in organs such as the lungs, spleen, kidneys, and pancreas. In contrast, chickens infected with FAdV-8b exhibit spot-like hemorrhage and focal necrosis in the liver but do not display pericardial effusion or widespread organ edema. Histopathological examination demonstrates that both FAdV-4 and FAdV-8b can induce inflammatory reactions of varying degrees in the kidneys, pancreas, and duodenum of chickens, while reducing the necrosis of bursa of Fabricius, thymus, and spleen lymphocytes. Our data preliminarily reveal that both FAdV-4 and FAdV-8b can induce strong pathogenicity in chickens.

Myotendinopathy of Unknown Etiology in Broiler Breeder Males.

This case series describes an emerging and ongoing lameness condition observed in broiler breeder males in flocks owned by a broiler integrator in the United States between February 2021 and April 2023. The lameness is characterized by an upright, penguin-like posture and gait. Affected flocks are typically 12-22 wk of age at presentation, but birds with similar stance and gross lesions can be observed as early as 1 day of age. Male mortality associated with this condition ranges from 0.01% to 6% per flock. The condition is infrequently observed in pullets from the female line but has not been observed in males (sex slips) from the female line. On postmortem examination, affected birds have bilateral hemorrhage due to a tearing of the iliotibialis muscles and fascia. In one case, a higher proportion of affected birds had unilateral lesions concurrently with broken legs or severe inguinal vaccine reaction. In this case, the affected leg was the weight-bearing leg. Histopathology confirmed the presence of hemorrhage in fascial sheaths surrounding major muscles, in addition to muscle fiber necrosis, edema, fibroplasia, and dissociation of tendon collagen. Bacteriology, histopathology, and clinical presentation identified no factors that were suggestive of an infectious etiology for this condition. No etiology has been established, but a suggested pathogenesis involves excessive biomechanical force resulting in tendon structural stress, leading to separation of tendon collagen fibers and associated muscle fiber stretching, separation, necrosis, and hemorrhage. The condition has been reported in multiple genetic lines, but the role of inheritance in the condition has not been fully evaluated.

Miotendinopatía de etiología desconocida en machos reproductores pesados. Esta serie de casos describe una condición de cojera emergente y recurrente observada en parvadas de machos reproductores pesados propiedad de un integrador de pollo de engorde en los Estados Unidos entre febrero del 2021 y abril del 2023. La cojera se caracteriza por una postura y desplazamientos corporales en forma erguida, parecidos a los de los pingüinos. Las parvadas afectadas suelen tener entre 12 y 22 semanas de edad en el momento de la presentación, pero se han podido observar aves con similar postura corporal y lesiones macroscópicas tan temprano como al primer día de edad. La mortalidad de los machos asociada con esta condición oscila entre el 0.01% y el 6% por parvada. La condición se observa con poca frecuencia en pollitas de la línea hembra, pero no se ha observado en machos provenientes de la misma línea hembra (errores de sexado). En el examen post mortem, las aves afectadas presentan hemorragia bilateral debido a un desgarramiento de los músculos iliotibiales y la fascia. En un caso, una mayor proporción de aves afectadas tuvieron lesiones unilaterales simultáneamente con patas rotas o una reacción postvacunal severa en la región inguinal. En este caso, la pierna afectada era la misma que soportaba peso. La histopatología confirmó la presencia de hemorragia en las vainas fasciales que rodean los músculos principales, además de necrosis de fibras musculares, edema, fibroplasia y disociación del colágeno del tendón. Mediante la bacteriología, la histopatología y la presentación clínica no se identificaron factores que sugirieran una etiología infecciosa para esta afección. No se ha establecido una etiología, pero una patogénesis sugerida implica una fuerza biomecánica excesiva que produce estrés estructural del tendón, lo que lleva a la separación de las fibras de colágeno del tendón y al estiramiento, separación, necrosis y hemorragia de las fibras musculares asociadas. La afección se ha informado en múltiples líneas genéticas, pero no se ha evaluado completamente el papel de la genética en esta condición.

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.

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.

Pathological and phylogenetic characteristics of fowl AOAV-1 and H5 isolated from naturally infected Meleagris Gallopavo.

BACKGROUND: In this study, we investigated the prevalence of respiratory viruses in four Hybrid Converter Turkey (Meleagris gallopavo) farms in Egypt. The infected birds displayed severe respiratory signs, accompanied by high mortality rates, suggesting viral infections. Five representative samples from each farm were pooled and tested for H5 & H9 subtypes of avian influenza viruses (AIVs), Avian Orthoavulavirus-1 (AOAV-1), and turkey rhinotracheitis (TRT) using real-time RT-PCR and conventional RT-PCR. Representative tissue samples from positive cases were subjected to histopathology and immunohistochemistry (IHC). RESULTS: The PCR techniques confirmed the presence of AOAV-1 and H5 AIV genes, while none of the tested samples were positive for H9 or TRT. Microscopic examination of tissue samples revealed congestion and hemorrhage in the lungs, liver, and intestines with leukocytic infiltration. IHC revealed viral antigens in the lungs, liver, and intestines. Phylogenetic analysis revealed that H5 HA belonged to 2.3.4.4b H5 sublineage and AOAV-1 belonged to VII 1.1 genotype. CONCLUSIONS: The study highlights the need for proper monitoring of hybrid converter breeds for viral diseases, and the importance of vaccination programs to prevent unnecessary losses. To our knowledge, this is the first study that reports the isolation of AOAV-1 and H5Nx viruses from Hybrid Converter Turkeys in Egypt.

Short beak and dwarfism syndrome among Pekin ducks: First detection, full genome sequencing, and immunohistochemical signals of novel goose parvovirus in tongue tissue.

Novel goose parvovirus (NGPV) is continuously threatening the global duck industry, as it causes short beak and dwarfism syndrome among different duck breeds. In this study, we investigated the viral pathogenesis in the tongue of affected ducks, as a new approach for deeper understanding of the syndrome. Seventy-three, 14- to 60-day-old commercial Pekin ducks were clinically examined. Thirty tissue pools of intestine and tongue (15 per tissue) were submitted for molecular identification. Clinical signs in the examined ducks were suggestive of parvovirus infection. All examined ducks had short beaks. Necrotic, swollen, and congested protruding tongues were recorded in adult ducks (37/73, 51%). Tongue protrusion without any marked congestion or swelling was observed in 20-day-old ducklings (13/73, 18%), and no tongue protrusion was observed in 15-day-old ducklings (23/73, 32%). Microscopically, the protruding tongues of adult ducks showed necrosis of the superficial epithelial layer with vacuolar degeneration. Glossitis was present in the nonprotruding tongues of young ducks, which was characterized by multifocal lymphoplasmacytic aggregates and edema in the propria submucosa. Immunohistochemical examination displayed parvovirus immunolabeling, mainly in the tongue propria submucosa. Based on polymerase chain reaction, goose parvovirus was detected in 9 out of 15 tongue sample pools (60%). Next-generation sequencing confirmed the presence of a variant goose parvovirus that is globally named NGPV and closely related to Chinese NGPV isolates. Novel insights are being gained from the study of NGPV pathogenesis in the tongue based on molecular and immunohistochemical identification.

Anatomopathological changes in laying quails.

The objective of the current study was to carry out a survey of the main anatomopathological alterations in raising quails and evaluate possible interference of these in the bone tissue. To obtain the data, 23 quails were collected from farm in the central Serrana region of Espírito Santo. Necropsies with macroscopic descriptions, microbiological, coproparasitological, radiographic and histomorphometric tests were carried out. It was done data descriptive analysis and average comparision using Student T test. It was found that they presented lesions predominantly in the digestive system, followed by urinary and reproductive, and muscular system, were the altered color of the liver (47%) was the most frequent lesion. In the parasitological exams, it was found oocysts of Eimeira sp. (39.13%). In the microbiological exams, it was detected predominantly Escherichia coli (83%). Moderate osteopenia in quails, but the percentage of trabecular bone on bones was similar between healthy and diseased quails, without bone changes in histology. Microscopically, it was observed lung congestion as predominant lesion. It is concluded that there was predominance of alterations in the digestive system and mild parasitic infection; and although there was moderate level of osteopenia, there wasn't bone change as a result of the observed infections.

Research Note: Prospects for early detection of breast muscle myopathies by automated image analysis.

White Striping (WS), Wooden Breast (WB), and Spaghetti Meat (SM) are documented breast muscle myopathies (BMM) affecting broiler chickens' product quality, profitability and welfare. This study evaluated the efficacy of our newly developed deep learning-based automated image analysis tool for early detection of morphometric parameters related to BMM in broiler chickens. Male chicks were utilized, and muscle samples were collected on d 14 of rearing. Histological procedures, including microscopic scoring, blood vessel count, and collagen quantification, were conducted. A previous study demonstrated our automated image analysis as a reliable tool for evaluating myofiber size, conforming with manual histological measurements. A threshold for BMM detection was established by normalizing and consolidating myofiber diameter and area into a unified metric based on automated measurements, also termed as "relative myofiber size value." Results show that severe myopathy broilers consistently exhibited lower relative myofiber size values, effectively detecting myopathy severity. Our study, aimed as proof of concept, underscores the potential of our automated image analysis tool as an early detection method for BMM.

Natural Infection with H5N1 Highly Pathogenic Influenza (HPAI) Virus in 5- and 10-Day-Old Commercial Pekin Ducklings (Anas platyrhynchos domesticus).

Highly pathogenic avian influenza (HPAI) has resulted in catastrophic economic losses globally in poultry. This case report describes the diagnostic detection and pathology of HPAI H5N1 in 5-day-old commercial ducklings, which is an atypical age for detection of natural infection of HPAI in poultry. The pathology observed at 5 days of age was also compared to lesions observed in ducklings from the same flock evaluated at 10 days of age before depopulation. The California Animal Health and Food Safety (CAHFS) Laboratory, Tulare, received ten 5-day-old Pekin duckling (Anas platyrhynchos domesticus) carcasses for diagnostic evaluation due to mortality that started increasing at 3 days of age. The most common gross findings included bilateral pulmonary edema with congestion and enlarged, mottled livers and spleens. Microscopically, cerebral neuronophagia, pancreatic necrosis, and interstitial pneumonia with pulmonary edema were observed in the 5-day-old ducklings. Oropharyngeal and cloacal swabs were positive for avian influenza virus (AIV) by real-time reverse transcriptase PCR. The AIV was typed as HPAI, EA/AM 2.3.4.4b H5N1 goose/Guangdong clade lineage by the National Veterinary Services Laboratory. Ducks at the affected premises were depopulated 4 days after the 5-day-old ducklings were submitted to the CAHFS lab, at which time additional tissue samples were collected for comparison to 10-day-old ducklings on the same premises. Differences in microscopic lesions and AIV tissue distribution were observed between the 5-day and 10-day tissues collected. Notably, microscopic lesions were more severe in the brain and pancreas at 10 days of age. Findings in 10-day-old ducklings included cerebral lymphoplasmacytic perivascular cuffing, gliosis, neuronal degeneration, and pancreatic necrosis. AIV antigen distribution and intensity was greatest in the cerebral tissue of the brains at 10 days and in the lungs at 5 days of age. To the authors' knowledge, published studies are limited on AIV natural infection in domestic ducks less than 9 days of age.

Infección natural con el virus de la influenza altamente patógena (HPAI) H5N1 en patitos Pekín comerciales (Anas platyrhynchos domesticus) de 5 y 10 días de edad. La influenza aviar altamente patógena (HPAI) ha provocado pérdidas económicas catastróficas en todo el mundo entre las aves de corral. Este reporte de caso describe la detección diagnóstica y la patología de la infección por un virus de influenza aviar de alta patogenicidad H5N1 en patitos comerciales de 5 días de edad, que es una edad atípica para la detección de la infección natural del virus de la influenza aviar de alta patogenicidad en avicultura. La patología observada a los 5 días de edad también se comparó con las lesiones observadas en patitos de la misma parvada evaluados a los 10 días de edad, antes de la despoblación. El Laboratorio de Salud Animal y Seguridad Alimentaria de California (CAHFS), con sede Tulare, recibió 10 cadáveres de patito Pekín (Anas platyrhynchos domesticus) de 5 días de edad para su evaluación diagnóstica debido a que la mortalidad comenzó a aumentar a los 3 días de edad. Los hallazgos macroscópicos más comunes incluyeron edema pulmonar bilateral con congestión en hígado y bazos agrandados y moteados. Microscópicamente se observó neuronofagia cerebral, necrosis pancreática y neumonía intersticial con edema pulmonar en los patitos de 5 días de edad. Los hisopos orofaríngeos y cloacales fueron positivos para el virus de la influenza aviar (AIV) mediante transcripción reversa y PCR en tiempo real. El Laboratorio Nacional de Servicios Veterinarios clasificó al virus como de alta patogenicidad EA/AM 2.3.4.4b H5N1 clado de linaje de ganso/clado Guangdong. Los patos en las instalaciones afectadas fueron despoblados 4 días después de que los patitos de 5 días fueran enviados al laboratorio de CAHFS, momento en el cual se recolectaron muestras de tejido adicionales para compararlas con patitos de 10 días de las mismas instalaciones. Se observaron diferencias en las lesiones microscópicas y la distribución del tejido del AIV entre los tejidos recolectados de 5 y 10 días. En particular, las lesiones microscópicas fueron más severas en el cerebro y en el páncreas a los 10 días de edad. Los hallazgos en patitos de 10 días incluyeron infiltraciones linfoplasmocitarias perivasculares en el cerebro, gliosis, degeneración neuronal y necrosis pancreática. La distribución e intensidad del antígeno de influenza aviar fue mayor en el tejido cerebral de los cerebros a los 10 días y en los pulmones a los 5 días de edad. De acuerdo al conocimiento de los autores, los estudios publicados sobre la infección natural por el virus de la influenza aviar en patos domésticos de menos de 9 días de edad son limitados.

Factors associated with keel bone damage - a longitudinal study of commercial layer flocks during the laying period.

1. Keel bone damage, such as deformations and fractures, is a severe problem regarding animal welfare in layers. To identify risk factors under commercial conditions, 33 layer flocks (22 barn, 11 free range) with white (n = 18), brown (n = 11) and mixed (n = 4) genotypes were examined.2. Keel bone status was frequently scored by palpation throughout the laying period. Data on housing and management conditions were collected. Multiple regression and Generalized Estimating Equations procedure were used for analysis.3. At 65-74 weeks of age, the prevalence of keel bone damage ranged between 26% and 74%. White genotypes and those kept in multi-tier systems developed significantly (p < 0.05) more keel bone damage than brown genotypes or those kept in single-tier systems. Wing feather condition was associated with keel bone damage (p < 0.05), while other investigated variables regarding health, housing and management were not associated.4. In conclusion, housing and management should be adapted to meet the birds' specific needs in multi-tier systems, which may vary for brown and white genotypes. Whether those differences result from genotype associated predispositions or other individual traits remains to be determined.

Relationships of quality indices with wooden breast myopathy severity in chicken breast meat under refrigerated storage.

1. This study investigated the relationships of quality indices with the severity of wooden breast (WB) myopathy in chicken breast meat under refrigerated storage. The physicochemical properties, water-holding capacity (WHC), microbial quality and fatty acid profiles of normal chicken breast meat samples (NOR samples, n = 63), moderate WB (MWB, n = 63) myopathy and severe WB (SWB, n = 63) myopathy (MWB and SWB samples, respectively) were evaluated immediately after sampling and after 4 and 8 d of refrigerated storage at 4°C.2. Total collagen, fat, saturated and monounsaturated fatty acid contents, redness and pH of the SWB and MWB samples were higher than the NOR samples. The SWB samples that were stored for 8 d had poor WHC, total viable counts (TVC) of higher than 7.0log colony-forming units, total volatile basic nitrogen (TVB-N) content of greater than 15 mg/100 g and a thiobarbituric acid - reactive substance level of higher than 1 mg/kg malondialdehyde.3. No significant difference was observed in the TVB-N content and TVC of the MWB and NOR samples during storage. Polyunsaturated fatty acid content was lower in the SWB and MWB samples than in the NOR samples. The SWB samples were tougher than the MWB and NOR samples after 8 d of refrigeration.4. In conclusion, the quality of chicken breast meat with SWB myopathy degraded considerably over time; thus, such meat should not be subjected to extended refrigeration for storage.

Impact of duck astrovirus on susceptibility to infection across duck ages.

An outbreak of duck astrovirus (DAstV) has occurred in duck farming regions of China, causing substantial economic setbacks in the duck industry. This investigation aimed to examine the variations in DAstV pathogenicity among ducks at different age intervals. Infections were induced in ducks at distinct age groups (1, 7, 14, 21, and 28 d) utilizing the DAstv-1-GDB-2022 strain. The results indicate increased pathogenicity of the DAstv-1-GDB-2022 strain in ducklings aged 21 to 28 d, manifesting as liver and kidney enlargement, severe bleeding, and potential fatalities. Conversely, ducklings aged 1 and 14 d displayed milder symptoms postinfection. Notably, viral shedding continued in ducks of diverse age groups even 21 d postinfection (Dpi). Moreover, DAstV replicates in various tissues, predominantly affecting the liver. Immunohistochemical tests using rabbit anti-DAstV antibodies revealed robust positive signals in both the liver and kidneys, which correlated with the clinical symptom severity observed through macroscopic and microscopic examinations. Serum biochemical assays and indirect ELISA demonstrated a consistent response to DAstV infection across different age groups, with older ducklings exhibiting increased sensitivity. In conclusion, this study successfully replicated clinical symptoms similar to those of natural DAstV infection using the DAstv-1-GDB-2022 strain. Importantly, we systematically delineated the differences in susceptibility to DAstV among ducks at various ages, laying the foundation for further research into the pathogenic mechanisms of DAstV and potential vaccine development.

Experimental infection of domestic turkeys with lymphoproliferative disease virus of North American origin.

Lymphoproliferative disease virus (LPDV) was first documented in wild turkeys in North America in 2009. LPDV infection is often subclinical but can manifest as lymphoid proliferation or round cell neoplasia. Despite high prevalence across many sampled areas corresponding to declining populations of wild turkeys, knowledge regarding LPDV pathogenesis, risk factors for disease development, and associated impacts on population dynamics are unknown. To understand transmission, viral shedding, and tissue tropism, we inoculated 21 domestic turkeys via the oral cavity, crop, nasal cavity, subcutis, or coelomic cavity. For 12 weeks, oropharyngeal swabs, cloacal swabs, and whole blood were collected weekly. At 1 week postinoculation, 3 turkeys (3/21; 14%) had detectable LPDV proviral DNA in blood by polymerase chain reaction, and 10 developed DNAemia (50%; 10/20) by 12 weeks. LPDV proviral DNA was intermittently detected in oropharyngeal and cloacal swabs. Splenomegaly was the most consistent gross finding in DNAemic birds (8/11; 73%). Lymphoid hyperplasia in the spleen was the most significant microscopic finding (9/11; 82%). Three turkeys (3/11; 27%) developed round cell neoplasia characterized by sheets of pleomorphic, round to polygonal cells in the adrenal gland, bone marrow, skin, small intestine, and/or spleen. LPDV was detected in the spleen and bone marrow from all turkeys with DNAemia and all neoplasms. Our study establishes that infection and disease with North American LPDV from wild turkeys can be experimentally reproduced in domestic turkeys, laying the groundwork for future investigations into LPDV pathogenesis, development of diagnostic techniques, and understanding the impacts of LPDV on wild turkey populations.