Deoxynivalenol and fumonisin predispose broilers to bacterial chondronecrosis with osteomyelitis lameness.

Bacterial chondronecrosis with osteomyelitis (BCO) lameness is the most critical animal health and welfare issue facing the broiler industry worldwide. It is estimated that 1 to 2% of bird condemnation at marketing age is caused by BCO lameness, resulting in tens of millions of dollars in annual losses. Fast-growing broilers are prone to mechanical stress that triggers bacterial translocation across epithelial barriers into the bloodstream, followed by bacterial colonization in the growth plate of long bones, and eventually, bone necrosis and lameness. Mycotoxins (MTX) are secondary metabolites produced naturally by microfungi, of which deoxynivalenol (DON), fumonisin (FUM), and zearalenone are the most prevalent in corn and soybean-meal-based diets. The presence of these mycotoxins in feed has been proven to reduce the barrier strength of the intestinal tracts and trigger immunosuppressive effects. In this study, we investigated the effects of the DON and FUM-contaminated feeds on the incidence of BCO lameness in broilers reared in both wire- and litter-floors. 720 one-day-old broiler chicks were assigned to the 2 × 2 factorial design: 2 MTX diets containing DON and FUM on wire flooring (MTX-W) and litter flooring (MTX-L), and 2 diets without MTX contamination on control wire flooring (CW) and control litter flooring (CL). Throughout the trial, the cumulative incidence of lameness per treatment was assessed by necropsying the lame birds. Birds in the MTX-W group had a higher incidence of lameness compared to those in CW (73.3% vs. 62.0%) (P < 0.05), and birds in the MTX-L group had a higher incidence of lameness compared to birds in CL (54.0% vs. 34.0%) (P < 0.05). MTX elicited net increases in BCO to a greater degree on litter (+20%) than on wire flooring (+12%). The increased incidence of BCO lameness in the MTX-W coincided with increased intestinal permeability supporting a correlation between intestinal barrier integrity and BCO lameness. To conclude, DON and FUM are predisposing factors for increasing BCO. However, no significant interaction exists between the diet and floor types in inducing lameness in broilers.

Identification of epidemiological risk factors for spotty liver disease in cage-free layer flocks in houses with fully slatted flooring in Australia.

Spotty liver disease (SLD) is recognized to be caused by infection with Campylobacter hepaticus in adult layer hens farmed in cage-free environments. SLD is an emerging disease as cage-free egg production increases in popularity in response to desires for improved welfare of poultry. Outbreaks of SLD are frequently experienced around peak egg production in flocks, commonly between 25 and 40 wk of age. The disease becomes manifest with increased exposure and access of the birds to the feces of the flock. This study follows from a previous epidemiological survey of free-range and barn flocks in Australia which identified the presence of a scratch area within the laying house as a major risk factor for the occurrence of SLD. However, that survey also observed SLD occurrence in 45% of houses with a fully slatted floor (no scratch area). The present study describes a further analytical survey aimed at identification of risk factors for SLD in houses with fully slatted flooring. A comprehensive questionnaire was completed for 49 cage-free flocks from point of lay until 40 wk of age across Australia, retrieving information on house design, bird breed, flock size, stocking densities, bird growth, and performance and the occurrence of SLD. Multiple logistic regression model building was used to separate factors and identify important management factors that may be amenable to modify the occurrence of SLD in egg layers. Key determinants of SLD identified from the analyses were that houses with mechanical ventilation (such as tunnel ventilation) have some protection from SLD and an increase of an extra 1 bird/m2 of nest space increased odds of occurrence of SLD by 1.172 times. A recommendation to not exceed 112 brown egg layer hens/m2 of nest space in naturally ventilated houses with a full slat floor was suggested. A delay in birds reaching 60% hen day production (HD) by 1 wk is suggested as a possible predictor for a subsequent outbreak of SLD.

Leg disorders in broiler chickens: a review of current knowledge.

Ensuring improved leg health is an important prerequisite for broilers to achieve optimal production performance and welfare status. Broiler leg disease is characterized by leg muscle weakness, leg bone deformation, joint cysts, arthritis, femoral head necrosis, and other symptoms that result in lameness or paralysis. These conditions significantly affect movement, feeding and broiler growth performance. Nowadays, the high incidence of leg abnormalities in broiler chickens has become an important issue that hampers the development of broiler farming. Therefore, it is imperative to prevent leg diseases and improve the health of broiler legs. This review mainly discusses the current prevalence of broiler leg diseases and describes the risk factors, diagnosis, and prevention of leg diseases to provide a scientific basis for addressing broiler leg health problems.

Dehydroepiandrosterone activates the GPER-mediated AMPK signaling pathway to alleviate the oxidative stress and inflammatory response in laying hens fed with high-energy and low-protein diets.

Fatty liver hemorrhagic syndrome (FLHS) seriously threatens the layer industry due to it can cause a sudden decline in egg production and acute death, and dietary supplement with bioactive substance is considered an effective way to prevent the FLHS occurrence. Dehydroepiandrosterone (DHEA) is a popular dietary supplement and it possesses anti-oxidative and anti-inflammatory functions; however, the effect and underlying mechanism about DHEA in protecting against the occurrence and development of FLHS remain elucidated. The current results showed that DHEA relieved HELP-induced decrease of egg productivity and liver injury in laying hens. Meanwhile, DHEA markedly enhanced the antioxidant capacity and then alleviated oxidative stress via activation of nuclear factor (erythroid-derived 2)-like 2 (NRF-2) signal in laying hens fed with HELP diets. In addition, DHEA significantly alleviated HELP-stimulated systemic inflammatory response by suppressing the overproduction of hepatic pro-inflammatory factors in laying hens, and further found this beneficial effect was achieved by blocking the activation of NF-κB pathway. Furthermore, we found that DHEA promoted the AMP-activated protein kinase α (AMPKα) activation and increased the G-protein-coupled estrogen receptor (GPER) expression level in laying hens fed with HELP diets. In summary, our data demonstrated that DHEA attenuates oxidative stress and inflammation through the activation of GPER-AMPK signal axis in laying hens fed with HELP diets. These results might facilitate an understanding of the benefits and mechanism of DHEA on the development of FLHS, and provide sufficient data to support it as a dietary supplement to control the FLHS-related metabolic diseases in chickens.

Long-Term Prognosis and Treatment of Crop Impaction in Chickens via Ingluviotomy with Local Infiltration Anesthetic: Case Report.

Two hens from two backyard chicken flocks were presented to a private veterinary practice specializing in poultry, both with a chief complaint of crop distention. Crop impaction was diagnosed based on physical examinations and radiographic findings. The hens were admitted for ingluviotomy surgery to remove the impacted fibrous material under local anesthesia. Even though one of the hens was diagnosed with pendulous crop, both hens recovered uneventfully after ingluviotomy and postoperative care. Follow-up examinations and interviews with the owners confirmed excellent long-term recovery.

Reporte de caso- Pronóstico a largo plazo y tratamiento de la impactación del buche en pollos mediante ingluviotomía con anestesia local por infiltración: Reporte de un caso. Dos gallinas de dos parvadas de pollos de traspatio fueron presentadas a una clínica veterinaria privada especializada en aves, ambas aves mostraban como problema principal la distensión del buche. La impactación del buche se diagnosticó con base en exámenes físicos y hallazgos radiográficos. Las gallinas fueron ingresadas para cirugía de inluviotomía para remover el material fibroso impactado bajo anestesia local. A pesar de que a una de las gallinas se le diagnosticó buche pendular, ambas gallinas se recuperaron sin incidentes después de la ingluviotomía y el cuidado postoperatorio. Los exámenes de seguimiento y las entrevistas con los propietarios confirmaron una excelente recuperación a largo plazo.

In pursuit of a better broiler: walking ability and incidence of contact dermatitis in conventional and slower growing strains of broiler chickens.

In this study, the mobility, incidence, and severity of contact dermatitis and litter moisture content were assessed in 14 strains of broiler chickens differing in growth rate. The strains encompassed 2 conventional (CONV; ADG0-48 > 60 g/d) and 12 slower growing (SG) strains categorized as FAST (ADG0-62 = 53-55 g/d), MOD (ADG0-62 = 50-51 g/d), and SLOW (ADG0-62 < 50 g/d), with 4 strains in each category. A total of 7,216 mixed-sex birds were equally allocated into 164 pens (44 birds/pen; 30 kg/m2) in a randomized incomplete block design, with each strain represented in 8 to 12 pens over 2-3 trials. From each pen, 4 to 6 birds were tested in the latency-to-lie (LTL) and group obstacle tests 1 wk prior to the birds reaching 2 target weights (TWs) of approximately 2.1 kg (TW1: 34 d for CONV and 48 d for SG strains) and 3.2 kg (TW2: 48 d for CONV and 62 d for SG strains). The incidence of footpad dermatitis (FPD) and hock burns (HB) were evaluated a day prior to each TW. Litter moisture content was determined biweekly from d 14 to d 56. At TW1, CONV and SLOW had longer LTL than FAST birds. At TW2, CONV, MOD, and FAST birds had similar LTL. At both TWs, CONV birds were lighter than FAST birds in the group obstacle test, yet their number of obstacle crossings was similar. At TW1, CONV birds had greater incidence of FPD than FAST and MOD, while at TW2, CONV birds had greater incidence than the other categories. The incidence of HB in CONV and MOD was greater than SLOW birds at TW1, while at TW2, the incidence of HB was greater in CONV and FAST birds vs. MOD and SLOW birds. Litter moisture content was high in all categories from d 28 onward. Our results indicate that both BW and growth rate influence leg strength and walking ability, whereas the overall high litter moisture content and to a lesser extent growth rate influenced the incidence of contact dermatitis.

Cadmium and molybdenum co-induce pyroptosis and apoptosis via the PTEN/PI3K/AKT axis in the livers of Shaoxing ducks (Anas platyrhynchos).

Cadmium (Cd) and excessive molybdenum (Mo) have adverse impacts on animals. However, the hepatotoxicity co-induced by Cd and Mo in ducks has not been fully elucidated. In order to explore the impacts of Cd and Mo co-exposure on pyroptosis and apoptosis by the PTEN/PI3K/AKT pathway in the livers of ducks, 40 healthy 7-day-old Shaoxing ducks (Anas platyrhynchos) were randomly assigned into 4 groups, and Cd or/and Mo were added to the basic diet per kilogram (kg): control group (0 mg Mo and 0 mg Cd), Mo group (100 mg Mo), Cd group (4 mg Cd), and Mo + Cd group (100 mg Mo and 4 mg Cd), with 16 weeks feed management. Results signified that Cd or/and Mo caused trace element imbalance, liver function and histomorphological abnormalities in the duck liver, and activated the PTEN/PI3K/AKT pathway through increasing PTEN mRNA and protein levels, reducing PI3K, AKT mRNA and p-AKT/AKT protein levels, which triggered pyroptosis and apoptosis via increasing Caspase-1, NLRP3, NEK7, ASC, GSDME, GSDMA, IL-1ß and IL-18 mRNA levels, Caspase-1 p20, NLRP3, ASC and GSDMD protein levels, and IL-1ß and IL-18 contents, and increasing Bak-1, Bax, Cyt C and Caspase-3 mRNA levels and cleaved Caspase-3/Caspase-3 protein level, and downregulating Bcl-2 mRNA level and the ratio of Bcl-2 to Bax, respectively. Overall, the results illustrate that pyroptosis and apoptosis induced by Cd or/and Mo may be associated with activating the PTEN/PI3K/AKT pathway in the livers of ducks. There may be a synergy between these two elements.

Mitigating the detrimental effects of heat stress in poultry through thermal conditioning and nutritional manipulation.

The poultry industry faces several obstacles and challenges, including the changes in global temperature, increase in the per capita demand for meat and eggs, and the emergence and spread of various diseases. Among these, environmental challenges are one of the most severe hurdles impacting the growth and productivity of poultry. In particular, the increasing frequency and severity of heat waves over the past few years represent a major challenge, and this is expected to worsen in the coming decades. Chickens are highly susceptible to high ambient temperatures (thermal stress), which negatively affect their growth and productivity, leading to enormous economic losses. In the light of global warming, these losses are expected to increase in the near future. Specifically, the worsening of climate change and the rise in global temperatures have augmented the adverse effects of heat on poultry production worldwide. At present, the world population is approximately 7.9 billion, and it has been predicted to reach 9.3 billion by 2050 and approximately 11 billion by 2100, implying a great demand for protein supply; therefore, strategies to mitigate future poultry challenges must be urgently devised. To date, several mitigation measures have been adopted to minimize the negative effects of heat stress in poultry. Of these, thermal acclimation at the postnatal stage or throughout the embryonic stages has been explored as a promising approach; however, for large-scale application, this approach warrants further investigation to determine the suitable temperature and poultry age. Moreover, molecular mechanisms governing thermal conditioning are poorly understood. To this end, we sought to expand our knowledge of thermal conditioning in poultry, which may serve as a valuable reference to improve the thermotolerance of chickens via nutritional management and vitagene regulation. Vitagenes regulate the responses of poultry to diverse stresses. In recent years, nutritionists have paid close attention to bioactive compounds such as resveratrol, curcumin, and quercetin administered alone or in combination. These compounds activate vitagenes and other regulators of the antioxidant defense system, such as nuclear factor-erythroid 2-related factor 2. Overall, thermal conditioning may be an effective strategy to mitigate the negative effects of heat stress. In this context, the present review synthesizes information on the adverse impacts of thermal stress, elucidating the molecular mechanisms underlying thermal conditioning and its effects on the acquisition of tolerance to acute heat stress in later life. Finally, the role of some polyphenolic compounds, such as resveratrol, curcumin, and quercetin, in attenuating heat stress through the activation of the antioxidant defense system in poultry are discussed.

Seroprevalence and Associated Risk Factors of Infectious Bronchitis Virus in Chicken in Northwest Ethiopia.

Avian infectious bronchitis virus is a highly contagious disease occurring in respiratory, urogenital, and reproductive tissues of chicken causing considerable losses due to death, egg drop, and reduced production. This preliminary study was conducted to investigate the prevalence of antibodies against infectious bronchitis virus (IBV) and to assess the potential risk factors in chickens of northwest Ethiopia. A cross-sectional study was conducted from November 2020 to June 2021. A total of 768 serum samples from three zones were collected. To investigate the presence of antibodies against IBV, the indirect ELISA serological test was applied. Positivity for anti-IBV antibodies was observed in 23.96% (95% CI: 20.98-27.14) of the samples. The mixed-effect logistic regression analysis of potential risk factors showed that IBV prevalence was significantly higher in young chickens than adults (p < 0.001) and higher in intensive farm type than in extensive type (p < 0.001). Based on the production purposes of the chickens, the odds of seropositivity for IB was significantly higher in layers than in broilers (p < 0.001) and dual purposes (p < 0.001). This study revealed higher seroprevalence in farms which had the "all-in-all-out" rearing method than in farms with different batches in one house with a significant difference (p < 0.001), higher seroprevalence in the poor ventilated type than in good ones (p < 0.001), and higher seroprevalence in the houses that did not remove used litter at all than houses of completely disposed and partially disposed litter (p=0.002). Moreover, disinfection of houses had significant effect on the occurrence of IB. Having personal protective equipment was significantly affecting the occurrence of IB, being higher in the farms that have no wearing clothes and shoe than in those having wearing clothes and shoe (p=0.002). In conclusion, the seroprevalence finding in the present study indicated that the organism is circulating among the population of chickens and high enough to cause significant economic losses Therefore, poultry houses should be cleaned, disinfected, and well ventilated and farm attendants should have separate farm shoe and clothes. Further studies on the virus isolation and molecular characterization of the target gene are needed in the study area.

Circulation of three genotypes and identification of unique mutations in neutralizing epitopes of infectious bronchitis virus in chickens in Bangladesh.

Infectious bronchitis (IB) is a highly contagious respiratory disease caused by a gammacoronavirus that has been circulating for many years in chickens in Bangladesh, resulting in significant economic losses. The aim of this study was to detect and characterize infectious bronchitis virus (IBV) from clinical outbreaks and surveillance samples. Real-time RT-PCR was used to detect IBV in pooled lung and tracheal tissue samples (n = 78), oropharyngeal swabs (n = 19), and pooled fecal samples (n = 13) from live-bird markets. Both respiratory and nephropathogenic forms of IB were suspected at necropsy (n = 7) from clinical outbreaks. Sequencing of hypervariable regions (HVR1-2 and HVR3) of the region of the spike gene (S) encoding the S1 subunit of five isolates revealed circulation of the Mass-like, QX-like, and 4/91-like genotypes of IBV in Bangladesh. Each genotype was extremely variable, as shown by separate clustering of the viruses in a phylogenetic tree and high nucleotide (nt) sequence divergence (38.8-41.2% and 25.7-37.4% in the HVR1-2 and HVR3 sequence, respectively). The unique mutation G65E was observed in each Mass-like isolate, and Y328S was observed in each 4/91-like Bangladeshi isolate. Three neutralizing epitope sites were predicted within the HVRs that differed significantly among the three genotypes. In addition, one Bangladeshi isolate carried fixed mutations at 294F and 306Y, like other pathogenic QX-like IBVs, which could affect epitopes involved in neutralization, facilitating virus circulation among vaccinated flocks. Therefore, continuous screening and genotype characterization will be necessary to track the epidemiology of IBV and control IB infection in Bangladesh.

Hemorrhagic Hepatopathy in Broiler Breeder Pullets: Gross and Microscopic Pathology and Factors Associated with Incidence.

Hemorrhagic hepatopathy is a syndrome reported in layer pullets resulting in mortality and lesions including hepatic, splenic, and intestinal necrosis; hepatic and splenic enlargement; hemorrhages; amyloidosis of the muscle, spleen, and liver; accumulation of noncoagulated hemorrhagic fluid in the coelom; and frequently, granulomatous myositis at bacterin injection sites. The syndrome is characterized in the literature in table egg layer pullets and is thought to be associated with the administration of bacterin vaccines, namely, frequently Salmonella enterica subsp. enterica bacterins. Hemorrhagic hepatopathy is recognized by industry veterinarians as also occurring infrequently in broiler breeder pullets in the United States. As the condition is likely due to an inflammatory process in response to bacterial lipopolysaccharide inoculation, it is important to characterize both the pathologic changes and predisposing factors for the condition in broiler breeds, which are immunologically different from table egg layer breeds. In this study, we characterize the gross and microscopic lesions observed in a series of diagnostic laboratory cases of hemorrhagic hepatopathy in broiler breeder pullets and suggest a possible pathophysiology for the condition. Additionally, we report results from a case survey of the United States broiler industry that suggest that the condition is due to a reaction to bacterin vaccination and that certain bacterin products may predispose pullet flocks to develop the condition. Although further research is indicated, these findings establish hemorrhagic hepatopathy as a pathologic condition of broiler breeder pullets and may aid in the diagnosis and prevention of the syndrome.

Artículo regular­La hepatopatía hemorrágica en pollitas reproductoras pesadas: Patología macroscópica y microscópica y factores asociados con la incidencia La hepatopatía hemorrágica es un síndrome reportado en pollitas ponedoras que resulta en mortalidad y lesiones, incluyendo necrosis hepática, esplénica e intestinal; agrandamiento hepático y esplénico; hemorragias; amiloidosis del músculo, bazo e hígado; acumulación de líquido hemorrágico no coagulado en la cavidad celómica; y con frecuencia, miositis granulomatosa en los lugares de inyección de bacterina. El síndrome se ha caracterizado en la bibliografía en pollitas ponedoras de huevo comercial y se cree que está asociado con la administración de vacunas de bacterianas, con frecuencia bacterinas de Salmonella. Los veterinarios de la industria reconocen que la hepatopatía hemorrágica también ocurre con poca frecuencia en pollitas de reproductoras pesadas en los Estados Unidos. Como es probable que esta condición se deba a un proceso inflamatorio en respuesta a la inoculación de lipopolisacáridos bacterianos, es importante caracterizar tanto los cambios patológicos como los factores predisponentes para la afección en las líneas de pollos de engorde, que son inmunológicamente diferentes de las líneas ponedoras de huevo comercial. En este estudio, se caracterizaron las lesiones macroscópicas y microscópicas observadas en una serie de casos de laboratorio de diagnóstico de hepatopatía hemorrágica en pollitas reproductoras de pollos de engorde y sugerimos una posible fisiopatología de esta condición. Además, se reportan los resultados de una encuesta de casos de la industria de pollos de engorde en los Estados Unidos que sugiere que la condición se debe a una reacción a la vacunación con bacterinas y que ciertos productos de las bacterinas pueden predisponer a las parvadas de pollitas a desarrollar la afección. Aunque se requieren más investigaciones, estos hallazgos establecen la hepatopatía hemorrágica como una condición patológica de las pollitas reproductoras pesadas y pueden ayudar en el diagnóstico y a la prevención del síndrome.

Comparison of Naturally Occurring vs. Experimental Infection of Staphylococcus aureus Septicemia in Laying Hens in Two Different Age Groups.

In April and November of 2018, multiple commercial laying hen flocks within the same company presented with a sharp increase in mortality and drop in egg production that persisted for several days. These flocks showed striking necropsy lesions consistent with systemic infection and responded to antimicrobial treatment in the feed. Staphylococcus aureus (SA) was the most frequently isolated organism from multiple tissues including comb and wattle lesions, lungs, liver, ovary, spleen, and bone marrow. Given such an uncommon presentation of SA, which is known as a secondary opportunistic pathogen, a challenge study was conducted to evaluate its role in these disease outbreaks. In the present study, laying hens of two ages (22 and 96 wk) were inoculated with SA via three routes: oral gavage, subcutaneous (SC) injection, and intravenous (IV) injection. Both young and old hens in the IV group showed a significant increase in body temperature and drop in body weight; however, the clinical signs observed in the naturally occurring outbreaks were not present. SA was reisolated at multiple time points postchallenge from all challenge groups except the negative control group. While the SC group showed localized necrosis at the injection site, microscopic changes were different from changes observed in birds from the natural outbreaks. Despite observed initial differences in route and age, the SA challenge strain was not capable of reproducing the disease on its own. The results of this study indicate that SA may have played a role in the increased mortality, clinical signs, and necropsy lesions reported with the naturally occurring outbreaks. However, SA should still be considered as a secondary opportunistic pathogen. Other factors that could have caused the initial insult are stress, immunosuppression, or other primary infectious agents. The results of this study may aid veterinary diagnosticians, clinicians, and all poultry professionals to include SA in their differentials list as a secondary opportunistic pathogen in similar cases. This is an uncommon presentation and further field observations and clinical studies are needed to better elucidate the pathogenesis of this disease, which will in turn help to prevent future outbreaks.

Reporte de caso­Comparación de la septicemia por presentación natura o por infección natural por Staphylococcus aureus en gallinas de postura de dos grupos diferentes de edades. En abril y noviembre del 2018, múltiples parvadas comerciales de gallinas de postura dentro de la misma empresa presentaron un marcado aumento en la mortalidad y una caída en la producción de huevo que persistió durante varios días. Estas parvadas mostraron marcadas lesiones a la necropsia compatibles con una infección sistémica y respondieron al tratamiento antimicrobiano en el alimento. El organismo que se aisló con mayor frecuencia de múltiples tejidos fue Staphylococcus aureus (SA), incluyendo lesiones de cresta y barbillas, pulmones, hígado, ovario, bazo y médula ósea. Dada una presentación tan poco común de S. aureus, que se conoce como un patógeno oportunista secundario, se realizó un estudio de desafío para evaluar su papel en estos brotes de enfermedades. En el presente estudio, se inocularon con Staphylococcus aureus gallinas de postura de dos edades (22 y 96 semanas) a través de tres vías: sonda oral, inyección subcutánea (SC) e inyección intravenosa (IV). Tanto las gallinas jóvenes como las de mayor edad del grupo IV mostraron un aumento significativo de la temperatura corporal y una disminución del peso corporal; sin embargo, los signos clínicos observados en los brotes naturales no estaban presentes. Se aisló S. aureus en varios momentos posteriores al desafío de todos los grupos desafiados, excepto el grupo de control negativo. Si bien el grupo inoculado por inyección subcutánea mostraron necrosis localizada en el sitio de la inyección, los cambios microscópicos fueron diferentes de los cambios observados en las aves de los brotes naturales. A pesar de las diferencias iniciales observadas en la ruta y en la edad, la cepa de desafío de S. aureus no fue capaz de reproducir la enfermedad por sí sola. Los resultados de este estudio indican que S. aureus pudo haber jugado un papel en el aumento de la mortalidad, los signos clínicos y las lesiones a la necropsia reportadas con los brotes de origen natural. Sin embargo, se debe considerar S. aureus como un patógeno oportunista secundario. Otros factores que podrían haber causado el daño inicial son el estrés, la inmunosupresión u otros agentes infecciosos primarios. Los resultados de este estudio pueden ayudar a los patólogos veterinarios, clínicos y todos los profesionales avícolas para incluir S. aureus en su lista de diferenciales como patógeno oportunista secundario en casos similares. Esta es una presentación poco común y se necesitan más observaciones de campo y estudios clínicos para dilucidar mejor la patogénesis de esta enfermedad, lo que a su vez ayudará a prevenir futuros brotes.

Goose Nephritic Astrovirus Infection of Goslings Induces Lymphocyte Apoptosis, Reticular Fiber Destruction, and CD8 T-Cell Depletion in Spleen Tissue.

The emergence of a novel goose nephritic astrovirus (GNAstV) has caused economic losses to the Chinese goose industry. High viral load is found in the spleen of goslings infected with GNAstV, but pathological injuries to the spleen due to GNAstV are largely unknown. In this study, 50 two-day-old goslings were infected orally with GNAstV, and 50 goslings were treated with PBS as control. Spleens were collected at different times following infection to assess damage. GNAstV infection caused visceral gout and urate deposition in joints, and resulted in 16% mortality. GNAstV was found in the lymphocytes and macrophages within the spleen. Lymphocyte loss, especially around the white pulp, and destruction and decline in the number of reticular fibers was observed in GNAstV-infected goslings. Moreover, in GNAstV-infected goslings, ultrahistopathological examination found that splenic lymphocytes exhibited condensed chromatin and apoptotic bodies, and reticular cells displayed damage to plasma membrane integrity and swollen mitochondria. Furthermore, TUNEL staining confirmed apoptosis of lymphocytes, and the mRNA levels of Fas and FasL were significantly increased in the GNAstV-infected goslings. In addition, GNAstV infection reduced the number and protein expression of CD8. In conclusion, GNAstV infection causes lymphocyte depletion, reticular cell necrosis, reticular fiber destruction, lymphocyte apoptosis, and reduction in CD8 levels, which contribute to spleen injury.

Transcriptomic Analysis of Inbred Chicken Lines Reveals Infectious Bursal Disease Severity Is Associated with Greater Bursal Inflammation In Vivo and More Rapid Induction of Pro-Inflammatory Responses in Primary Bursal Cells Stimulated Ex Vivo.

In order to better understand differences in the outcome of infectious bursal disease virus (IBDV) infection, we inoculated a very virulent (vv) strain into White Leghorn chickens of inbred line W that was previously reported to experience over 24% flock mortality, and three inbred lines (15I, C.B4 and 0) that were previously reported to display no mortality. Within each experimental group, some individuals experienced more severe disease than others but line 15I birds experienced milder disease based on average clinical scores, percentage of birds with gross pathology, average bursal lesion scores and average peak bursal virus titre. RNA-Seq analysis revealed that more severe disease in line W was associated with significant up-regulation of pathways involved in inflammation, cytoskeletal regulation by Rho GTPases, nicotinic acetylcholine receptor signaling, and Wnt signaling in the bursa compared to line 15I. Primary bursal cell populations isolated from uninfected line W birds contained a significantly greater percentage of KUL01+ macrophages than cells isolated from line 15I birds (p < 0.01) and, when stimulated ex vivo with LPS, showed more rapid up-regulation of pro-inflammatory gene expression than those from line 15I birds. We hypothesize that a more rapid induction of pro-inflammatory cytokine responses in bursal cells following IBDV infection leads to more severe disease in line W birds than in line 15I.

A critical review of the mechanisms involved in the occurrence of growth-related abnormalities affecting broiler chicken breast muscles.

In the past decade, the poultry industry has faced the occurrence of growth-related muscular abnormalities that mainly affect, with a high incidence rate, the Pectoralis major of the fast-growing genotypes selected for their production performances (high growth rate and breast yield). These myopathies are termed as White Striping, Wooden Breast, and Spaghetti Meat and exhibit distinctive phenotypes. A spatiotemporal distribution has been demonstrated for these disorders as in the early stage they primarily affect the superficial area in the cranial portion of the muscle and, as the birds grow older, involve the entire tissue. Aside from their distinctive phenotypes, these myopathies share common histological features. Thus, it might be speculated that common causative mechanisms might be responsible for the physiological and structural perturbations in the muscle associated with these conditions and might underpin their occurrence. The present review paper aims to represent a critical survey of the outcomes of all the histologic and ultrastructural observations carried out on White Striping, Wooden Breast, and Spaghetti Meat affected muscles. Our analysis has been performed by combining these outcomes with the findings of the genetic studies, trying to identify possible initial causative mechanisms triggering the onset and the time-series of the events ultimately resulting in the development and progression of the growth-related myopathies currently affecting broilers Pectoralis major muscles. Several evidences support the hypothesis that sarcoplasmic reticulum stress, primarily induced an accumulation of misfolded proteins (but also driven by other factors including altered calcium homeostasis and accumulation of fatty acids), may be responsible for the onset of these growth-related myopathies in broilers. At the same time, the development of hypoxic conditions, as a direct consequence of an inadequate vascularization, triggers a time-series sequence of events (i.e., phlebitis, oxidative stress, etc.) resulting in the activation of response mechanisms (i.e., modifications in the energetic metabolism, inflammation, degeneration, and regeneration) which are all strictly related to the progression of these myopathic disorders.

Research Note: Evaluation of the incidence of white striping and underlying myopathic abnormalities affected by fast weight gain in commercially fed broiler chickens.

Significant improvements in genetics, nutrition, and food efficiency have had a great impact on the rapid growth of broilers, notably with increases in muscle mass. However, with rapid growth, the broiler industry has been negatively impacted by the increased incidence of myopathies, including white striping. White striping affects the pectoralis major muscle of broilers, particularly the larger breasts of rapidly growing modern commercial broiler lines. In this study, we documented the growth process of commercial broiler chickens from hatching to market weight at 6 wk. Gross pathology and histopathology analyses were performed on pectoralis major muscle collected weekly from birds culled from 1 to 6 wk. The severity of both gross and histologic pathologies in the breast muscle increased over time. White striping was initially observed at week 2, with a rise in the incidence and severity through the sixth week. Mild histopathology was noted in week 2, characterized by macrophage infiltration and limited phagocytosis of the muscle. Muscle condition deteriorated with age and weight gain, with more prevalent macrophages, phagocytosis, and interstitial fibroblasts. By week 5 and 6, there was severe myopathy including regions of obliterated muscle tissue. Linear regression models show a positive correlation between white striping, gross pathology, and histopathology relative to weight and age.

Protective effect of the new prepared Atractylodes macrocephala Koidz polysaccharide on fatty liver hemorrhagic syndrome in laying hens.

Fatty liver hemorrhage syndrome (FLHS) is the most common noninfectious cause of death in backyard chickens worldwide, which can cause a sudden drop in egg production in the affected flocks and cause huge losses to the laying hens breeding industry. In this study, we prepared polysaccharide from Atractylodes macrocephala Koidz (PAMK) by one-step alcohol precipitation. The structural analysis found that PAMK with a molecular weight of 2.816 × 103 Da was composed of glucose and mannose, in a molar ratio of 0.582 to 0.418. Furthermore, we investigated the hepatoprotective effects of PAMK on high-energy and low-protein (HELP) diet-induced FLHS in laying hens. The results showed that the hens' livers of the HELP diet showed yellowish-brown, greasy, and soft, whereas the supplement of PAMK (200 mg/kg or 400 mg/kg) could alleviate such pathological changes. The liver index, the abdominal fat percentage, and liver injury induced by the HELP diet were reduced in PAMK (200 mg/kg or 400 mg/kg). Supplementing 200 mg/kg or 400 mg/kg PAMK showed improvements of the antioxidant capacity in laying hens. Furthermore, we found that the HELP diet increased the expression of hepatic lipogenesis genes and decreased the expression of fatty acid ß-oxidation genes, which could be reversed by 200 mg/kg or 400 mg/kg PAMK supplementation. Nevertheless, there is no difference between the addition of 40 mg/kg PAMK and the HELP group. Collectively, these results showed that PAMK supplements could ameliorate HELP diet-induced liver injury through regulating activities of antioxidant enzymes and hepatic lipid metabolism. Therefore, PAMK could be a potential feedstuff additive to alleviate FLHS in laying hens.

Changes of lipid and bone metabolism in broilers with spontaneous femoral head necrosis.

Blood biochemistry and bone metabolism were evaluated to investigate the etiology and mechanism of spontaneous femoral head necrosis (FHN) in broilers. According to the femoral head score of the fourth, fifth, and sixth week old FHN-affected broilers, they were divided into 3 groups, namely Normal group, femoral head separation group, and femoral head separation with growth plate lacerations group, and then carried out a comparative study. The results showed that the liver function (alanine aminotransferase and aspartate aminotransferase) and lipid metabolism (high-density lipoprotein and triglyceride) levels of broilers with spontaneous FHN were significant changed compared with the normal group. At the same time, accumulation of lipid droplets appeared in the liver, which illustrated that the occurrence of FHN may be related to lipid metabolism disorders. Tibia and femur parameters showed significant changes in bone mineral density and bone strength. The distribution of chondrocytes in the articular cartilage of broilers with FHN was irregular and vacuoles appeared, which indicated that cartilage homeostasis was destroyed. TUNEL staining showed that the apoptosis rate of articular chondrocytes in broilers with FHN in 6-week-old was significantly higher than that of normal broilers. Meanwhile, the bone markers (bone glaprotein and bone-specific alkaline phosphatase) changed significantly, indicating that the articular chondrocyte apoptosis and bone metabolism disorder may occur in FHN-affected birds. Therefore, FHN in broilers may be caused by dyslipidemia and abnormal bone metabolism.

Accumulation of lipofuscin in broiler chicken with wooden breast.

Lipofuscin is one of the indicators of oxidative stress. To elucidate the role of oxidative stress in the development of wooden breast, this study investigates lipofuscin accumulation in various parts of wooden breast muscles. Sampling was performed using 46-day-old broiler chickens housed at a commercial Japanese poultry slaughterhouse. Fourteen wooden breast fillets and 13 normal breast fillets were collected in the deboning line. The samples used to measure shear force, 2-thiobarbituric acid reactive substance (TBARS), and for histological analysis were taken from the six portions of breast muscle fillets. In muscles affected by wooden breast, vacuolated muscle fibers were observed, and connective tissues appearing like perimysium were expanded with fibrosis. TBARS value and accumulation of lipofuscin were significantly higher in the wooden breast than in the normal breasts. A lot of lipofuscin granules were localized in the cytoplasm of collapsed muscle fibers of the wooden breast. The cranial portion of the wooden breast showed the highest shear force. The cranial position had a large amount of connective tissue and lipofuscin granules. The results of the present study strongly suggest that high oxidative stress, especially with a significant accumulation of lipofuscin, is associated with the development of wooden breasts.

The cytotoxicity and molecular mechanisms of the Clostridium perfringens NetB toxin.

The necrotic enteritis toxin B-like (NetB) toxin secreted by Clostridium perfringens is a key virulence agent in the pathogenesis of avian necrotic enteritis, a disease that causes significant economic loss to the poultry industry worldwide. NetB was purified from Clostridium perfringens type G (CNEOP004) that was isolated from chickens with necrotic enteritis in Japan. EC50 of this purified NetB toward chicken liver-derived LMH cells was 0.63 µg/ml. In vivo pathogenicity of NetB to chicks produced characteristic lesions of necrotic enteritis. Analysis of the localization of the NetB monomer and oligomer molecules on LMH cells showed that both molecules of the toxin were localized in non-lipid raft regions. Moreover, removal of cholesterol with the cholesterol depletion assay carried out in LMH cells detected both oligomers and monomers of the NetB molecule. These data suggest that the NetB toxin may recognize membrane molecules different from cholesterol in non-raft region. Furthermore, NetB-binding molecules on LMH cell membranes using the toxin overlay assay with immunoblotting showed that protein molecules of different molecular sizes were bound to NetB on non-lipid raft fractions. Further studies are necessary to characterize these protein molecules to examine their specific association with NetB binding and oligomerization.