Search

Previous research into the viral community in the poultry gastrointestinal tract has revealed a number of novel and partially described enteric viruses. It is evident that the poultry gut viral community remains minimally characterized and incompletely understood. Investigations into the microbiome of the poultry gut have provided some insight into the geographical distribution and the rapidly evolving taxonomy of the avian enteric picornaviruses. The present investigation was undertaken to produce a comparative metagenomic analysis of the gut virome from a healthy turkey flock versus a flock placed in the field. This investigation revealed a number of enteric picornavirus sequences that were present in the commercial birds in the field that were completely absent in the healthy flock. A novel molecular diagnostic assay was used to track the shedding of field strains of turkey enteric picornavirus in commercial poults inoculated with picornavirus-positive intestinal homogenates prepared from turkeys that were experiencing moderate enteric disease. The propagation of this novel enteric picornavirus in commercial poults resulted in significant reduction in weight gain, and suggests that this common inhabitant of the turkey gut may result in performance problems or enteric disease in the field.

Made available in DSpace on 2013-08-12T19:13:06Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-03-01 Made available in DSpace on 2013-09-30T19:21:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-03-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T15:33:26Z No. of bitstreams: 0 Made available in DSpace on 2014-05-20T15:33:26Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-03-01 Because of recent interest in bacteriophage therapy in poultry, information regarding the interaction of bacteriophages and potential host bacteria in the environment should be collected. The present studies were initiated with a rather typical commercial broiler integrator within the south-central United States to examine environmental Salmonella levels in two broiler complexes, attempt to isolate Salmonella-lytic bacteriophages, and elucidate a possible reason for differing apparent Salmonella prevalence. Significantly ( P

SUMMARY. Cecal spirochetosis in chickens has been associated with enteric disease and reduced egg production in the United States and Europe. This report describes spirochete overgrowth of cecal mucosa in chickens from a flock of 100,000 commercial layers experiencing diarrhea and a 5% drop in egg production. Spirochetes were demonstrated in the ceca by darkfield and light microscopy. Apical surfaces of cecal enterocytes were covered by a dense layer of spirochetes aligned parallel to each other and perpendicular to the mucosal surface. Weakly fl-hemolytic, indole-negative spirochetes were isolated from the ceca on BJ media under anaerobic conditions at 42 C. Chicken cecal spirochetosis may represent an economically significant enteric disease of laying hens which has heretofore been infrequently recognized.

Skeletal deformities, a major contributing factor to economic losses in market-age turkeys, may be associated with the poult malabsorption syndrome. A study was performed to determine whether the naturally occurring malabsorption syndrome produces skeletal lesions in turkeys at market age. Poults were placed on litter on which poults had previously developed malabsorption. Exposed poults developed enteric disease with 21% mortality during the first 3 weeks. Controls had no enteric disease and no mortality. At the end of the study, 20-week-old exposed turkeys weighed 0.621 kg (5%) less than controls and had a higher incidence of angular limb deformities with significantly higher angulation scores. Exposed turkeys also had a greater incidence of rotated tibias and bowed tibias. The mechanical property of tibial shear strength was significantly lower in turkeys that had survived the earlier poult malabsorption syndrome.

Small round viruses, 18 to 24 nm in diameter, were detected by electron microscopy in droppings of young turkeys with enteritis. The virus was propagated in embryonated turkey eggs and tentatively identified as an enterovirus based on size, intracytoplasmic morphogenesis, buoyant density of 1.33 g/ml in CsCl, and a single-stranded RNA genome of approximately 7.5 kb. It was distinguished from avian encephalomyelitis virus by cross-immunofluorescence. These results identify an enterovirus-like virus as a possible etiologic agent of enteric disease of young turkeys. However, its role in this disease remains to be established.

In a natural outbreak of enteric disease in turkey poults, Salmonella, group D rotavirus, astrovirus, and a small (18-24 nm) round virus were detected in the gut contents. Except for the small virus, the pathogenic potential of the other agents is recognized. In experiments, the small round virus was shown to be transmissible and pathogenic in specific-pathogen-free turkey poults.

Intestinal samples from 91 turkey flocks between 1 day and 5 weeks of age were examined for enteric viruses using electron microscopy and electropherotyping. These flocks originated from eight operations in six states. Individual flocks were sampled only once. At the time of sampling, 31 flocks were considered normal/healthy and 60 were considered to have enteric disease. The most frequently identified viruses from diseased flocks were astroviruses (78%) and rotavirus-like viruses (RVLVs) (67%). Far less frequent were rotaviruses (22%), atypical rotaviruses (12%), enteroviruses (5%), and reoviruses (2%). Only 10% of the samples from diseased flocks were negative, but 48% of the samples from normal/healthy flocks were negative. Astroviruses and RVLVs were far less frequent in normal/healthy flocks than in diseased flocks, but rotaviruses were identified slightly more often. No viruses were detected from flocks sampled within the first few days of life. Astrovirus infections seemed to occur at an earlier age than other virus infections. Seldom was only one type of virus identified. Astrovirus + RVLV was the most frequently identified combination in diseased flocks.