Investigations into Increased Incidence of Severe Gizzard Erosions and Ulcerations in U.S. Commercial Broilers.

During a series of pathology surveys in four production complexes of a U.S. broiler integrator, the technical services veterinarians of an animal health company noted a high incidence of severe gizzard erosions and ulcerations (GEU), prompting further clinical investigation and a battery trial. No growth-promoting antibiotics or ionophore coccidiostats were used during the period of these surveys. All used tribasic copper chloride (TBCC) at ≤120 ppm added copper in broiler rations. Clostridium perfringens was isolated from 83% and 67% of gizzard lesions cultured in two complexes, and cecal C. perfringens most probable number determinations were higher in severely affected than in mildly affected or unaffected birds. Histopathology revealed both acellular koilin fusion defects characteristic of copper toxicity, as well as inflammatory cell infiltrates. Intralesional bacilli suggestive of C. perfringens were noted in 78% of affected flocks examined. Species E Aviadenovirus was isolated from one bird in one complex, and that bird had a single intranuclear inclusion body; no other flocks had Adenoviruses isolated or detected on PCR, nor any inclusion bodies. Other viruses detected were thought to be incidental. A pilot study using feed with supplemental copper from TBCC or copper sulfate and challenge with one of the isolated C. perfringens strains reproduced the lesions. A battery study was conducted with an unchallenged negative control group fed a diet with 16 ppm added copper, a group fed the control diet and orally challenged with 108 organisms of a field strain of C. perfringens at 21 and 22 days, and a group treated with the same diet containing 250 ppm added copper from TBCC and orally challenged with C. perfringens. Birds were necropsied at 23 and 28 days. All challenged groups developed lesions, with those receiving both TBCC and C. perfringens having significantly higher gross and histopathological lesion scores than the unchallenged negative controls. Lesions were qualitatively similar to those in the field and contained suspected C. perfringens bacilli. Because the levels of TBCC used in the commercial birds and in the battery trial generally have been considered safe, and because C. perfringens is usually regarded as a pathogen of the lower GI tract, the possible association of these two agents with GEU is a novel observation and warrants further investigation.

Investigaciones sobre el aumento de la incidencia de erosiones y ulceraciones severas en la molleja en pollos de engorde comerciales en los Estados Unidos. Durante una serie de estudios de patología en cuatro complejos de producción de un integrador de pollos de engorde de los Estados Unidos, veterinarios de servicio técnico de una empresa de salud animal observaron una alta incidencia de erosiones y ulceraciones severas de la molleja (GEU), lo que motivó una mayor investigación clínica y un estudio en batería. Durante el período de estas encuestas no se utilizaron antibióticos promotores del crecimiento ni coccidiostáticos ionóforos. Todos utilizaron cloruro de cobre tribásico (TBCC) con un nivel de ≤120 ppm de cobre agregado en raciones para pollos de engorde. Se aisló Clostridium perfringens del 83% y el 67% de las lesiones de molleja cultivadas en dos complejos, y las determinaciones del número más probable de C. perfringens en los sacos ciegos fueron mayores en aves severamente afectadas que en aves levemente afectadas o no afectadas. La histopatología reveló defectos de fusión de la capa córnea acelular característicos de la toxicidad por cobre, así como infiltrados de células inflamatorias. Se observaron bacilos intralesionales sugestivos de C. perfringens en el 78% de las parvadas afectadas examinadas. La especie Aviadenovirus E se aisló de un ave en un complejo, y esa ave tenía un único cuerpo de inclusión intranuclear; en ninguna otra parvada se aislaron o detectaron adenovirus mediante PCR, ni se observaron cuerpos de inclusión. Se pensó que otros virus detectados fueron incidentales. Un estudio piloto que utilizó alimento con cobre suplementario de cloruro de cobre tribásico o sulfato de cobre y con desafío con una de las cepas aisladas de C. perfringens reprodujo las lesiones. Se realizó un estudio de batería con un grupo de control negativo no desafiado alimentado con una dieta con 16 ppm de cobre agregado, un grupo alimentado con la dieta de control y desafiado por vía oral con 108 organismos de una cepa de campo de C. perfringens a los 21 y 22 días, y un grupo tratado con la misma dieta que contenía 250 ppm de cobre agregado de cloruro de cobre tribásico y desafiados por vía oral con C. perfringens. A las aves se les realizó la necropsia a los 23 y 28 días. Todos los grupos desafiados desarrollaron lesiones, y aquellos que recibieron cloruro de cobre tribásico y C. perfringens tuvieron puntuaciones de lesiones macroscópicas e histopatológicas significativamente más altas que los controles negativos no desafiados. Las lesiones eran cualitativamente similares a las del campo y contenían bacilos sospechosos de C. perfringens. Debido a que los niveles de cloruro de cobre tribásico utilizados en las aves comerciales y en el ensayo en batería generalmente se han considerado seguros, y debido a que C. perfringens generalmente se considera un patógeno del tracto gastrointestinal inferior, la posible asociación de estos dos agentes con erosiones y ulceraciones severas de la molleja es una observación reciente y justifica una mayor investigación.

Histomorphometric lung density evaluation of Immulina treatment using a murine influenza pneumonia model.

Histomorphometric lung density measurements were used to evaluate the effects of Immulina on mouse pneumonia. Mice were intra-nasally exposed to H1N1 influenza virus at a dose of 5 × 104 PFU/50 µL/mouse. Lung density was measured using the NIH ImageJ software program. Density values were compared to semiquantitative pneumonia severity scores. Lung photomicrographs were evaluated at 25-×, 40-× and 400-× magnification. The study included viral inoculated controls (IC) and non-inoculated controls (NC) and mice either treated or not treated with Immulina. Three doses of Immulina were included (25, 50 or 100 mg/kg) and administered using 3 protocols: prophylactic treatment (P), prodromal treatment (PD) and therapeutic treatment (TH) (note that in most of the evaluations of the data for the three treatment protocols were combined). Groups of mice were evaluated on days 3, 5, 7, 10 and 15 following exposure. The occurrence of "digital pneumonia" (DP) was defined as a density measurement above the 95% confidence limit of the corresponding NC values. A significant reduction in the occurrence of DP with Immulina treatment at the higher doses compared to IC was seen as early as day 3 and persisted up to day 15. There were also statistically significant dose-variable reductions in lung density in response to Immulina. The study suggests early administration of Immulina (P or PD protocols) may enhance resistance against influenza-induced viral pneumonia. A moderate correlation between pneumonia severity scores and lung density was observed for the 25-× and 40-× images (R = 0.56 and 0.53 respectively), and a strong correlation (R = 0.68) for 400-× images.

Morphology, microbiota, and metabolome along the intestinal tract of female turkeys.

The global turkey industry is confronted with emerging challenges regarding health and welfare. Performance and disease resilience are directly linked to gut health. A clear definition of a healthy gut is a prerequisite to developing new strategies for improved gut health and, thus, general health, welfare and productivity. To date, detailed knowledge about gut health characteristics, especially during the critical fattening period, is still lacking for turkeys. Therefore, the goal of this study was to describe the morphology, microbiota, and metabolome along the intestinal tract of clinically healthy Salmonella- and Campylobacter-free commercial turkey hens throughout the fattening period from 7 to 10 wk posthatch, and obtain information on the stability of the investigated values over time. Feed changes were avoided directly preceding and during the investigation period. Investigation methods included histomorphometric measurement of intestinal villi and crypts, Illumina-sequencing for microbiota analysis, and proton nuclear magnetic resonance spectroscopy for metabolite identification and quantification. Overall, the study demonstrated a high repeatability across all 3 experiments and gut section differences observed coincided with their functions. It was demonstrated that gut maturation, defined by gut microbiota stability, is reached earlier in the ceca than any other intestinal section where morphological changes are ongoing throughout the fattening period. Therefore, the present study provides valuable information necessary to advise future studies on the development and implementation of measures to support gut maturation and establish a protective microbiota in commercial turkeys.

The effect of Campylobacter jejuni and Campylobacter coli colonization on the gut morphology, functional integrity, and microbiota composition of female turkeys.

BACKGROUND: Campylobacter (C.) species are the most common bacterial cause of foodborne diarrhea in humans. Despite colonization, most animals do not show clinical signs, making recognition of affected flocks and disruption of the infection chain before slaughter challenging. Turkeys are often cocolonized with C. jejuni and C. coli. To understand the pathogen-host-interaction in the context of two different Campylobacter species, we compared the colonization patterns and quantities in mono- and co-colonized female commercial turkeys. In three repeated experiments we investigated the impact on gut morphology, functional integrity, and microbiota composition as parameters of gut health at seven, 14, and 28 days post-inoculation. RESULTS: Despite successful Campylobacter colonization, clinical signs or pathological lesions were not observed. C. coli persistently colonized the distal intestinal tract and at a higher load compared to C. jejuni. Both strains were isolated from livers and spleens, occurring more frequently in C. jejuni- and co-inoculated turkeys. Especially in C. jejuni-positive animals, translocation was accompanied by local heterophil infiltration, villus blunting, and shallower crypts. Increased permeability and lower electrogenic ion transport of the cecal mucosa were also observed. A lower relative abundance of Clostridia UCG-014, Lachnospiraceae, and Lactobacillaceae was noted in all inoculated groups compared to controls. CONCLUSIONS: In sum, C. jejuni affects gut health and may interfere with productivity in turkeys. Despite a higher cecal load, the impact of C. coli on investigated parameters was less pronounced. Interestingly, gut morphology and functional integrity were also less affected in co-inoculated animals while the C. jejuni load decreased over time, suggesting C. coli may outcompete C. jejuni. Since a microbiota shift was observed in all inoculated groups, future Campylobacter intervention strategies may involve stabilization of the gut microbiota, making it more resilient to Campylobacter colonization in the first place.

Testicular Atrophy and Epididymitis-Orchitis Associated with Infectious Bronchitis Virus in Broiler Breeder Roosters.

Infectious bronchitis is a respiratory disease of chickens caused by a gammacoronavirus named infectious bronchitis virus (IBV). In addition to affecting the respiratory tract, IBV may also induce urogenital infections, leading to nephropathogenic disease, false layer syndrome in laying hens, and epididymal lithiasis and epididymitis in males. Here, we report a case of decreased reproductive efficiency due to male infertility in 33- to 38-wk-old broiler breeders. At necropsy, the males presented with urates deposited on the skin around the vent and testicular asymmetry due to marked unilateral atrophy. Histopathology revealed lymphocytic epididymitis, epididymal lithiasis, and orchitis. IBV antigen was detected within collecting and efferent ducts of epididymides by immunohistochemistry. IBV strain DMV/1639 was detected by reverse transcription-quantitative PCR in pools of testes, oviducts, tracheas, cecal tonsils, and kidneys from a 37-wk-old affected flock. This report shows evidence of the role of IBV in male chicken infertility and highlights the importance of performing molecular surveillance of IBV to monitor vaccine strains and to detect emerging variants that can potentially hinder production.

Reporte de caso- Atrofia testicular y epididimitis-orquitis asociadas con el virus de la bronquitis infecciosa en gallos reproductores pesados. La bronquitis infecciosa es una enfermedad respiratoria del pollo causada por un gammacoronavirus llamado virus de la bronquitis infecciosa (con las siglas en inglés IBV). Además de afectar el tracto respiratorio, el IBV también puede inducir infecciones urogenitales, lo que conduce a enfermedad nefropatogénica, síndrome de la falsa ponedora en gallinas de postura y litiasis epididimaria y epididimitis en machos. En este reporte se describe un caso de disminución de la eficiencia reproductiva debido a la infertilidad de machos en reproductores pesados de 33 a 38 semanas de edad. En la necropsia, los machos presentaron depósitos de uratos sobre la piel alrededor de la cloaca y asimetría testicular por atrofia unilateral marcada. La histopatología reveló epididimitis linfocítica, litiasis epididimaria y orquitis. Antígenos del virus de la bronquitis infecciosa se detectaron dentro de los conductos colectores y eferentes de los epidídimos mediante inmunohistoquímica. La cepa del virus de la bronquitis DMV/1639 se detectó mediante transcripción reversa y PCR cuantitativa en muestras agrupadas de testículos, oviductos, tráqueas, tonsilas cecales y riñones de una parvada afectada de 37 semanas de edad. Este reporte muestra evidencia del papel del virus de la bronquitis infecciosa en la infertilidad de los pollos machos y destaca la importancia de realizar una vigilancia molecular de este virus para monitorear las cepas vacunales y detectar variantes emergentes que potencialmente pueden dificultar la producción.

Histopathologic Lesion Scoring and Histomorphometric Methods for Measuring Vaccine Reactions in the Trachea of Broiler Chickens.

Severity of the tracheal histologic inflammatory response induced in broilers by ocular inoculation of two infectious bronchitis (IBV) and three Newcastle disease virus (NDV) commercial vaccines were evaluated. The vaccine was delivered by eye drop with a coarse spray to day-old chicks. The vaccines were given individually or in various combinations and were evaluated relative to nonvaccinated controls. Evaluations were performed on postvaccination (PV) days 7 and 14. Histologic endpoints included semiquantitative severity scoring of inflammatory components and quantitative morphometric determinations of inflammatory cell concentration, mucosal thickness, and percentage of ciliated mucosal surface. Strong positive correlations were observed between routine severity scoring and morphometric inflammatory parameters, whereas a negative correlation was present between inflammation severity and the percentage of mucosal ciliation. Variable, sometimes extensive, and often statistically significant differences in inflammatory responses were observed between the various vaccines. One IBV Massachusetts strain vaccine (IBV-A) produced the greatest overall inflammatory response when given alone or in combination with the NDV vaccines. Enhancement of tracheitis was seen on PV day 14 by covaccination of IBV-A with the NDV vaccines, but not by covaccination of another IBV Massachusetts strain vaccine (IBV-B) with NDV. Reduction in cilia percentage was observed for all vaccine groups relative to controls on PV day 7. However, although reactive cilia regeneration occurred on PV day 14 for most vaccine groups, a cilia regenerative response was not apparent for individual or NDV combination vaccination for IBV-A. The study also demonstrates that substantial microscopic trachea pathology may be present in vaccinated birds not exhibiting apparent clinical respiratory signs.

Artículo regular­Métodos de calificación de lesiones histológicas e histomorfométricos para medir las reacciones a las vacunas en la tráquea de pollos de engorde. Se evaluó la gravedad de la respuesta inflamatoria histológica traqueal en pollos de engorde inducida mediante la inoculación ocular de dos vacunas comerciales contra la bronquitis infecciosa (IBV) y tres vacunas del virus de la enfermedad de Newcastle (NDV). Las vacunas se administraron mediante aplicación ocular a pollitos de un día de edad. Las vacunas se administraron individualmente o en varias combinaciones y se evaluaron en relación con los controles no vacunados. Las evaluaciones se realizaron en los días 7 y 14 después de la vacunación (PV). Los criterios de valoración histológicos incluyeron puntuación semicuantitativa de la severidad de los componentes inflamatorios y determinaciones morfométricas cuantitativas de la concentración de células inflamatorias, el grosor de la mucosa y el porcentaje de superficie de la mucosa con cilios. Se observaron fuertes correlaciones positivas entre la puntuación rutinaria de severidad y los parámetros morfométricos inflamatorios, mientras que se observó una correlación negativa entre la severidad de la inflamación y el porcentaje de la superficie con cilios en la mucosa. Se observaron diferencias variables, a veces extensas y a menudo estadísticamente significativas en las respuestas inflamatorias entre las diversas vacunas. Una vacuna de la cepa de Massachusetts del virus de la bronquitis infecciosa (IBV-A) produjo la mayor respuesta inflamatoria general cuando se administró sola o en combinación con las vacunas de Newcastle. Se observó un aumento de la traqueítis en el día 14 después de la vacunación mediante la vacunación simultánea de la vacuna de bronquitis infecciosa A con las vacunas de Newcastle, pero no mediante la vacunación simultánea de la otra vacuna de la cepa Massachusetts (IBV-B) con Newcastle. Se observó una reducción en el porcentaje de los cilios para todos los grupos vacunados en comparación con los controles en el día siete después de la vacunación. Sin embargo, aunque la regeneración de cilios reactivos ocurrió en el día 14 después de la vacunación para la mayoría de los grupos vacunados, no fue evidente una respuesta de regeneración de cilios para la vacunación individual o combinada de Newcastle con la vacuna de bronquitis infecciosa Massachusetts A. El estudio también demuestra que puede estar presente una patología microscópica sustancial de la tráquea en aves vacunadas que no presentan signos respiratorios clínicos aparentes.

The Pathology of Infectious Bronchitis.

Infectious bronchitis (IB) is an acute disease of chickens caused by a gammacoronavirus, infectious bronchitis virus (IBV). Infection of the nasal and tracheal mucosa causes a rapid loss of ciliated epithelium and impaired mucociliary clearance that predispose chickens to secondary bacterial infections. In poultry production, disease progression and severity are influenced by other live virus vaccines, immunosuppression, and coexisting pathogens. The digestive tract supports viral replication in the proventriculus, intestines, cloaca, and the bursa of Fabricius. Acute enteritis and stunted growth in young chickens are caused by an enterotropic IBV. IBV spreads systemically by infection of tracheal macrophages and blood monocytes, deep respiratory infections, and potentially ascending viral infection from the cloaca. Nephrotropic IBV causes severe disease in the kidney with necrosis of tubular epithelial cells, inflammation, and renal failure. Viral infection of the female reproductive tract in the first 2 weeks of life causes necrosis and scarring of the oviduct mucosa, resulting in a chronic cystic oviduct that precludes egg formation when the hen matures. Virus infection of mature hens causes necrosis and inflammation of the oviduct mucosa, leading to the deterioration of egg quality and transient interruption of egg production. In males, IBV infection of seminiferous tubules in the testicle and efferent ductules in the epididymis results in epididymitis and epididymal lithiasis, decreases in sperm production and fertility, and viral shed to semen, leading to venereal transmission. The role IBV in gastrointestinal and urogenital disease merits further study.

Estudio recapitulativo- La patología de la bronquitis infecciosa: una revisión La bronquitis infecciosa es una enfermedad aguda de los pollos causada por un gammacoronavirus, el virus de la bronquitis infecciosa (IBV). La infección de la mucosa nasal y traqueal provoca una pérdida rápida del epitelio ciliado y la alteración de la función mucociliar que predispone a los pollos a infecciones bacterianas secundarias. En la producción avícola, el desarrollo y la severidad de la enfermedad están influenciadas por otras vacunas con virus vivos, inmunosupresión y patógenos coexistentes. En el tracto digestivo se lleva a cabo la replicación viral en el proventrículo, los intestinos, la cloaca y en la bolsa de Fabricio. La enteritis aguda y el retraso del crecimiento en pollos jóvenes son causados por virus de bronquitis infecciosa enterotrópicos. El virus de la bronquitis infecciosa se propaga sistémicamente por infección de macrófagos traqueales y monocitos sanguíneos, infecciones respiratorias profundas e infección viral potencialmente ascendente desde la cloaca. Los virus de la bronquitis infecciosa nefrotrópicos causan una enfermedad severa en el riñón con necrosis de las células epiteliales tubulares, inflamación e insuficiencia renal. La infección viral del aparato reproductor femenino en las primeras dos semanas de vida causa necrosis y cicatrización de la mucosa del oviducto, lo que resulta en un oviducto quístico crónico que impide la formación de huevos cuando la gallina llega a la madurez. La infección por el virus en gallinas maduras causa necrosis e inflamación de la mucosa del oviducto, lo que conduce al deterioro de la calidad del huevo y la interrupción transitoria de la producción de huevos. En los machos, la infección por bronquitis infecciosa de los túbulos seminíferos en el testículo y los conductos eferentes en el epidídimo da como resultado epididimitis y litiasis epididimaria, disminución de la producción y fertilidad de espermatozoides, y la diseminación viral al semen, lo que lleva a la transmisión venérea. El papel del virus de la bronquitis en las enfermedades gastrointestinales y urogenitales merece un estudio más a fondo.

A Field Study of Histologic and Bacteriologic Characterization of Femoral Head Separation and Femoral Head Necrosis.

Histologic and bacteriologic features for groups of average 31-day-old broilers displaying three gross categories of femoral head alterations were documented. Categories included simple femoral head separation (FHS), femoral head transitional changes (FHT), and femoral head necrosis (FHN). Groups with grossly normal (NORM) femoral heads and cull birds with FHN and having gross signs of sepsis (Cull-FHN) were also included in the study. There was a 10% occurrence of positive bacterial cultures for all birds tested. Most positive cultures (33%) were found in the Cull-FHN group, while only a 12% occurrence was seen in the FHS group, and no positives were present in the FHT or FHN groups. A 14% total occurrence of femoral bacterial chondronecrosis with osteomyelitis or simple osteomyelitis (BCO-O) was observed. A progressive increase in the prevalence of BCO-O was apparent between groups going from NORM (0%), FHS (4%), FHT (14%), FHN (13%), and reaching a maximum of 67% in the Cull-FHN group. Minimal to mild femoral head cartilage necrosis was present in 40% of NORM broilers and 100% of the FHS, FHT, and FHN groups, but at moderate severity in 20% of the Cull-FHN group. Thus, the majority of FHN cases were associated with aseptic cartilage necrosis rather than BCO-O. These findings suggest that aseptic cartilage necrosis may be as important as septic necrosis as a cause of gross femoral head disease. A 26% overall occurrence was seen for hip synovitis-arthritis, but group differences were not statistically significant. Synovitis was not seen in the NORM group and was present in some (12%) of the FHS group but was observed at a high rate in both the FHN (43%) and the Cull-FHN (50%) groups. Morphometric measurements demonstrated that the area size of femoral fibrous cortical defects or "cutback zones" were generally larger for all gross categories relative to NORM, with a significant difference between NORM and FHS groups. This study underscores the multifactorial etiology of FHN and the importance of conducting both histologic and bacteriologic evaluations in which gross evidence of FHN or BCO-O occurs.

Disarticulation-Associated Femoral Head Separation in Clinically Normal Broilers: Histologic Documentation of Underlying and Predisposing Cartilage Abnormalities.

Routine and quantitative histologic studies on femoral head separation (FHS) associated with coxofemoral joint disarticulation at necropsy were conducted on 125 femoral heads collected from 21- to 50-day-old clinically normal broilers. The study compared groups demonstrating grossly detached femoral heads (DFHs) with those having attached femoral heads (AFHs). Marked microscopic lesions compatible with osteochondrosis (OCD) consistently occurred along the separation surface in the DFH population. The histologic changes consisted of cartilage degeneration and necrosis sometimes forming small clefts or microfractures. Hemorrhage and less frequent inflammatory cells were often present along the separation surfaces. Small foci of OCD in the femur occurred in the AFH group with lesser frequency and severity. The histologic changes were mainly found within the proximal proliferative zone of the physis near the epiphyseal junction. Histomorphometry disclosed significant quantitative reductions in chondrocyte density with increased pyknosis occurring adjacent to the separation site and to a lesser extent in deeper regions of the growth plate for the DFH compared with AFH. Measurements made along the separation surface of the percentage length occupied by osteochondrotic defects and actual separated cartilage disclosed significant differences between evaluation groups. However, determinations of vascular canal areas present within two or more regions of the growth plate revealed a slight and significant increased area for DFH compared with AFH. Severity scores for the occurrence of microthrombi within the growth plate showed no difference between the groups. The pathogenesis of FHS in broilers is related to defective cartilage production or degeneration resulting in increased fragility. This contrasts with the proposed pathogenesis of OCD in mammals, which involves ischemic necrosis due to underlying vascular defects. The results for the FHS-disarticulation model also differ from those reported for glucorticoid-induced femoral head necrosis in broilers. The FHS-associated lesions occurred without histologic evidence of bacterial chondritis or osteomyelitis.

Separación de la cabeza femoral asociada a la desarticulación en pollos de engorde clínicamente normales: documentación histológica de anomalías del cartílago subyacentes y predisponentes. Estudios histológicos de rutina y cuantitativos sobre la separación de la cabeza femoral (FHS) asociados con la desarticulación de la articulación coxofemoral durante la necropsia se realizaron en 125 cabezas femorales recolectadas de pollos de engorde clínicamente normales de 21 a 50 días de edad. El estudio comparó los grupos que demostraron cabezas femorales separadas (DFH) con los que tenían cabezas femorales unidas (AFH). Lesiones microscópicas marcadas compatibles con osteocondrosis (OCD) ocurrieron consistentemente a lo largo de la superficie de separación en la población de aves con cabezas femorales separadas. Los cambios histológicos consistieron en degeneración del cartílago y necrosis, formando a veces pequeñas hendiduras o microfracturas. La hemorragia y la presencia menos frecuente de células inflamatorias estaban presentes a lo largo de las superficies de separación. Se produjeron con menor frecuencia y gravedad, focos pequeños de osteocondrosis en el fémur en el grupo de aves con cabezas femorales unidas. Los cambios histológicos se encontraron principalmente en la zona proliferativa proximal de la fisis cerca de la unión epifisaria. La histomorfometría reveló reducciones cuantitativas significativas en la densidad de condrocitos con un aumento de la picnosis que ocurrió adyacente al sitio de separación y en menor medida en regiones más profundas de la placa de crecimiento en las aves con cabezas femorales separadas en comparación con las aves con cabezas femorales unidas. Las mediciones realizadas a lo largo de la superficie de separación del porcentaje de longitud ocupada por defectos osteocondróticos y con cartílago separado revelaron diferencias significativas entre los grupos de evaluación. Sin embargo, las determinaciones de las áreas del canal vascular presentes dentro de dos o más regiones de la placa de crecimiento revelaron un aumento leve y significativo del área para las aves con cabezas femorales separadas en comparación con las aves con cabezas femorales unidas. Las puntuaciones de severidad para la aparición de microtrombos dentro de la placa de crecimiento no mostraron diferencias entre los grupos. La patogenia de la separación de la cabeza femoral en pollos de engorde se relaciona con la producción o degeneración de cartílago defectuoso que resulta en un aumento de la fragilidad. Esto contrasta con la patogénesis propuesta para la osteocondrosis en mamíferos, que involucra necrosis isquémica debido a defectos vasculares subyacentes. Los resultados para el modelo de desarticulación-separación de la cabeza femoral también difieren de los reportados para la necrosis de la cabeza femoral inducida por glucorticoides en pollos de engorde. Las lesiones asociadas con la separación de la cabeza femoral ocurrieron sin evidencia histológica de condritis bacteriana u osteomielitis.

Testicular histomorphometrics including Sertoli cell quantitation for evaluating hatchability and fertility issues in commercial breeder-broiler roosters.

Testicular histomorphometric methods were developed for the investigation of fertility and hatchability problems in commercial broiler-breeder roosters. Sertoli cell (SC) evaluations were emphasized in view of their role in influencing embryonic testicular organogenesis and spermatogenesis in adults. H&E stained sections prepared from formalized tissues were examined. SC evaluations were mostly made from computer generated images using image analysis software, but were also compared to direct counting with ocular grid reticle. Other measurements were germinal epithelial and total seminiferous tubule widths, quantification of individual spermatozoa and sperm clusters, and determinations of stromal area. Age-associated changes in SC occurred between 15 to 54 wk of age. A significant reduction in SC concentration occurred at 29 wk of age (P < 0.001) that corresponded with the histologic initiation of spermatogenesis. Expanded morphometric evaluations were performed on 59-week-old roosters comparing a flock having good body condition and footpad scores with normal testicular and body weights (optimal profile or OP group) to a second flock demonstrating relatively poor expression of these parameters and decreased fertility (sub-optimal profile or SOP group). Significant reductions (P < 0.05) in SC concentration, spermatozoa, and tubular widths, but an increased percentage of stroma area occurred in SOP compared to OP flocks. SC results also correlated well with testes weight. A unique finding was a significant relationship between decreasing SC concentration and increasing severity scores for footpad lesions. Differences in all histomorphometric parameters occurred between flocks demonstrating good hatchability compared to flocks exhibiting either low or decreasing hatchability. Significant reductions in SC and other morphometric parameters were observed for the poor relative to good hatchability group. A strong positive association was observed for SC results using computer generated images and direct reticle ocular counting (R = 0.80). Replicate counts on control sections demonstrated generally good reproducibility of methods between experiments. The findings are supportive of the value of testicular histomorphometrics for evaluations of hatchability issues in commercial roosters.

Infectious bursal disease virus infection leads to changes in the gut associated-lymphoid tissue and the microbiota composition.

Infectious bursal disease (IBD) is an acute, highly contagious and immunosuppressive poultry disease. IBD virus (IBDV) is the causative agent, which may lead to high morbidity and mortality rates in susceptible birds. IBDV-pathogenesis studies have focused mainly on primary lymphoid organs. It is not known if IBDV infection may modify the development of the gut associated lymphoid tissues (GALT) as well as the microbiota composition. The aim of the present study was to investigate the effects of IBDV-infection on the bursa of Fabricius (BF), caecal tonsils (CT) and caecum, and to determine the effects on the gut microbiota composition in the caecum. Commercial broiler chickens were inoculated with a very virulent (vv) strain of IBDV at 14 (Experiment 2) or 15 (Experiment 1) days post hatch (dph). Virus replication, lesion development, immune parameters including numbers of T and B lymphocytes, macrophages, as well as the gut microbiota composition were compared between groups. Rapid IBDV-replication was detected in the BF, CT and caecum. It was accompanied by histological lesions including an infiltration of heterophils. In addition a significant reduction in the total mucosal thickness of the caecum was observed in vvIBDV-infected birds compared to virus-free controls (P < 0.05). vvIBDV infection also led to an increase in T lymphocyte numbers and macrophages, as well as a decrease in the number of B lymphocytes in the lamina propria of the caecum, and in the caecal tonsils. Illumina sequencing analysis indicated that vvIBDV infection also induced changes in the abundance of Clostridium XIVa and Faecalibacterium over time. Overall, our results suggested that vvIBDV infection had a significant impact on the GALT and led to a modulation of gut microbiota composition, which may lead to a higher susceptibility of affected birds for pathogens invading through the gut.

Infectious bronchitis virus in testicles and venereal transmission.

Even though males represent only 8%-12% of the birds of a breeder flock, their role in infectious bronchitis virus (IBV) dissemination is largely unknown. We first assessed the effect of IBV replication in the chicken testes. Ten-week-old males were inoculated with Arkansas (Ark) or Massachusetts (Mass) IBV virulent strains. Seven days postinoculation (DPI) IBV RNA was detected in testicles of 100% of M41- and in 96% of Ark-infected males. Marginal nonsynonymous variation was detected in spike (S) gene of the predominant population of IBV replicating in the testes compared to the S gene of the predominant population of viruses prior to inoculation. IBV M41 and Ark were detected in spermatogonia and Sertoli cells of testicles of infected roosters by immunofluorescence, without evident histopathological changes. We next assessed venereal transmission of IBV by artificially inseminating 54-wk-old hens either with semen from IBV-infected roosters or with IBV suspended in naïve semen. IBV RNA was detected in the trachea of all hens inseminated with IBV-spiked semen and in 50% of hens inseminated with semen from IBV-infected males. The egg internal and external quality was negatively affected in hens inseminated with semen containing IBV. These results provide experimental evidence for IBV venereal transmission.

Clinical aspects of immunosuppression in poultry.

Chickens, turkeys, and other poultry in a production environment can be exposed to stressors and infectious diseases that impair innate and acquired immunity, erode general health and welfare, and diminish genetic and nutritional potential for efficient production. Innate immunity can be affected by stressful physiologic events related to hatching and to environmental factors during the first week of life. Exposure to environmental ammonia, foodborne mycotoxins, and suboptimal nutrition can diminish innate immunity. Infectious bursal disease (IBD), chicken infectious anemia (CIA), and Marek's disease (MD) are major infectious diseases that increase susceptibility to viral, bacterial, and parasitic diseases and interfere with acquired vaccinal immunity. A shared feature is lymphocytolytic infection capable of suppressing both humoral and cell-mediated immune functions. Enteric viral infections can be accompanied by atrophic and depleted lymphoid organs, but the immunosuppressive features are modestly characterized. Some reoviruses cause atrophy of lymphoid organs and replicate in blood monocytes. Enteric parvoviruses of chickens and turkeys merit further study for immunosuppression. Hemorrhagic enteritis of turkeys has immunosuppressive features similar to IBD. Other virulent fowl adenoviruses have immunosuppressive capabilities. Newcastle disease can damage lymphoid tissues and macrophages. Avian pneumovirus infections impair the mucociliary functions of the upper respiratory tract and augment deeper bacterial infections. Recognition of immunosuppression involves detection of specific diseases using diagnostic tests such as serology, etiologic agent detection, and pathology. Broader measurements of immunosuppression by combined noninfectious and infectious causes have not found general application. Microarray technology to detect genetic expression of immunologic mediators and receptors offers potential advances but is currently at the developmental state. Control methods for immunosuppressive diseases rely largely on minimizing stress, reducing exposure to infectious agents through biosecurity, and increasing host resistance to infectious immunosuppressive diseases by vaccination. A longer-term approach involves genetic selection for resistance to immunosuppressive diseases, which has shown promising results for MD but equivocal results for IBD and CIA.

Biological characteristics of chicken anemia virus regenerated from clinical specimen by PCR.

Our previous genetic characterization of chicken anemia virus (CAV) in commercial broiler chickens in Alabama revealed a previously undetected polymorphism: a glutamine codon at VP1 position 22, in 7 of the 14 sequences. The novel glutamine codon was always found in association with a VP1 "hypervariable region" identical to CAV field isolates that replicate poorly in culture. The complete genome of CAV73, representative of the sequences with the novel polymorphism, was generated from cloned polymerase chain reaction (PCR) fragments amplified directly from naturally infected tissues. CAV73 had been detected in 31-day-old broilers submitted for examination for reasons unrelated to anemia. After electroporation of the cloned genomes into MDCC-CU147 lymphoblastoid cells, the regenerated CAV caused the culture to fail within 9 days, and the medium contained 5 X 10(6) TCID50 CAV/ml. Use of MDCC-CU147 cells was essential, as identical electroporation of MDCC-MSB1 cells failed to generate CAV able to destroy the culture within 8 wk. Regenerated CAV73 produced anemia and severe lymphocytic depletion of the thymus when inoculated into susceptible 3-day-old chickens and was reisolated from these chickens. Furthermore, it replicated in low- and high-passage MDCC-MSB1 cells similarly to a low-passage CAV field isolate that contains a different VP 1 "hypervariable region." The regeneration of CAV from PCR products directly from naturally infected carcasses, as performed in this study, provides a tool for the evaluation of distinct genetic polymorphisms that may be detected in specimens where infective virions are no longer available. Our results also provide some insight into the differential susceptibility of cell lines for low-passage CAV field isolates.