RESUMEN
Brachyspira species are frequent colonizers of the gastrointestinal tract in a variety of domestic animals, including birds. In chickens, Brachyspira species are associated with a clinical condition known as avian intestinal spirochetosis (AIS), a disease characterized by chronic diarrhoea, weight loss, low egg production, and faecal-stained eggs. The purpose of this study was to identify risk factors associated with the presence of Brachyspira species in Ontario layer chicken flocks. Pooled faecal samples were collected from 89 flocks from 58 farms between August 2010 and February 2011; 52 flocks were classified as dirty flocks (history of downgrades for dirty eggs) and 37 were classified as clean flocks (no history of downgrades for dirty eggs). A questionnaire related to management, biosecurity practices, and antimicrobial use was administered prior to sample collection. Using real-time polymerase chain reaction; 63.5% of the dirty flocks and 24.3% of the clean flocks were positive for Brachyspira species. A logistic regression model with a random effect for farm showed that the odds of Brachyspira species for flocks ≥ 60 weeks of age were higher than for flocks ≤ 34 weeks (OR=9.3; P=0.014). The odds of Brachyspira species in flocks housed in A-frame cages with manure curtains (OR=20.0; P=0.002) and flocks from multi-age farms (OR=8.5; P=0.001) were higher than for flocks in cage-stacked houses and from single-age farms, respectively. The odds of Brachyspira species for flocks housed in barns ≥ 30 years old was lower than for flocks housed in barns ≤ 14 years old (OR=0.1; P=0.002). The calculated intra-class correlation coefficient was 5.6 × 10(-14); the notably low proportion of variation among farms after the fixed effects were included in the model suggests that the farm-level variable (multi-age farm) included in the final model accounted for most of the farm-to-farm variation in Brachyspira presence. Therefore, it is recommended that strict biosecurity, and between-flock decontamination efforts to reduce the infection pressure, be followed on farms with multiple flocks of different ages to avoid transmission of the bacteria between flocks.
Asunto(s)
Brachyspira/aislamiento & purificación , Pollos , Enfermedades Gastrointestinales/veterinaria , Infecciones por Bacterias Gramnegativas/veterinaria , Enfermedades de las Aves de Corral/microbiología , Crianza de Animales Domésticos , Animales , Brachyspira/genética , ADN Bacteriano/química , ADN Bacteriano/genética , Heces/microbiología , Femenino , Enfermedades Gastrointestinales/epidemiología , Enfermedades Gastrointestinales/microbiología , Infecciones por Bacterias Gramnegativas/epidemiología , Infecciones por Bacterias Gramnegativas/microbiología , Modelos Logísticos , Ontario/epidemiología , Enfermedades de las Aves de Corral/epidemiología , Reacción en Cadena en Tiempo Real de la Polimerasa/veterinaria , Factores de Riesgo , Encuestas y CuestionariosRESUMEN
Enterococcus cecorum is a normal inhabitant of the intestine of birds and other vertebrates. It has recently emerged in Canada and other countries as an important cause of arthritis and osteomyelitis in chickens. The objectives of this study were to assess if this emergence was caused by a particular clone of E. cecorum and to assess the antimicrobial susceptibility of this organism. One hundred and thirteen E. cecorum isolates from infections in Canadian chickens (cases) and from the ceca of control chickens from Canada and Belgium were examined. Isolates were identified using biochemical tests and, for a number of them, identification was confirmed by partial 16S rRNA gene sequencing. Case and control isolates were typed by pulsed-field gel electrophoresis and tested for antimicrobial susceptibility using the broth microdilution method. Cecal isolates from control birds were genetically very diverse but the vast majority of those from cases belonged to a single major clonal lineage. Reduced susceptibility was widespread for tetracycline, bacitracin, and erythromycin. Isolates from cases were generally less susceptible to antimicrobial agents than isolates from control birds.
Asunto(s)
Ciego/microbiología , Pollos/microbiología , Enterococcus/clasificación , Variación Genética , Animales , Secuencia de Bases , Bélgica , Enfermedades de las Aves/microbiología , Canadá , Estudios de Casos y Controles , ADN Bacteriano/genética , Electroforesis en Gel de Campo Pulsado , Enterococcus/genética , Enterococcus/aislamiento & purificación , Pruebas de Sensibilidad Microbiana , Datos de Secuencia Molecular , Osteomielitis/microbiología , Osteomielitis/veterinaria , ARN Ribosómico 16S/genética , Alineación de SecuenciaRESUMEN
Provincial broiler-chicken marketing boards in Canada have recently implemented an on-farm food safety program called Safe, Safer, Safest. The purpose of this study was to measure broiler chicken producers' attitudes toward the program and food safety topics and use of highly recommended good production practices (GPP). Mailed and Web-based questionnaires were administered to all producers registered in British Columbia, Ontario, and Quebec in 2008. The response percentage was 33.2% (642 of 1,932). Nearly 70% of respondents rated the program as effective in producing safe chicken, and 49.1% rated the program requirements as easy to implement. Most respondents (92.9%) reported that they do not raise other poultry or keep birds as pets, and 79.8% reported that they clean and disinfect their barns between each flock cycle. Less than 50% of respondents reported that visitors wash their hands or change their clothes before entering barns, 38.4% reported that catching crews wear clean clothes and boots, and 35.8% reported that a crew other than from the hatchery places chicks. Respondents who rated the program requirements as effective or easy to implement were more likely to report the use of five of six highly recommended GPP. Only 21.1% of respondents indicated that Campylobacter can be transmitted from contaminated chicken meat to humans, and 26.6% believed that antimicrobial use in their industry is linked to antimicrobial resistance in humans. Continuing education of producers should focus on improving their awareness of these issues, while mandatory GPP should include those that are known to be effective in controlling Campylobacter and Salmonella in broiler chicken flocks.
Asunto(s)
Pollos/microbiología , Control de Enfermedades Transmisibles/normas , Contaminación de Alimentos/prevención & control , Manipulación de Alimentos/métodos , Conocimientos, Actitudes y Práctica en Salud , Crianza de Animales Domésticos/métodos , Crianza de Animales Domésticos/normas , Animales , Campylobacter/aislamiento & purificación , Infecciones por Campylobacter/epidemiología , Infecciones por Campylobacter/microbiología , Infecciones por Campylobacter/prevención & control , Infecciones por Campylobacter/veterinaria , Canadá , Seguridad de Productos para el Consumidor , Humanos , Higiene , Enfermedades de las Aves de Corral/epidemiología , Enfermedades de las Aves de Corral/microbiología , Enfermedades de las Aves de Corral/prevención & control , Salmonella/aislamiento & purificación , Salmonelosis Animal/epidemiología , Salmonelosis Animal/microbiología , Salmonelosis Animal/prevención & control , Encuestas y CuestionariosRESUMEN
Commensal bacteria in the intestine play an important role in the development of immune response. These bacteria interact with cells of the gut-associated lymphoid tissues (GALT). Among cells of the GALT, B-1 cells are of note. These cells are involved in the production of natural antibodies. In the present study, we determined whether manipulation of the intestinal microbiota by administration of probiotics, which we had previously shown to enhance specific systemic antibody response, could affect the development of natural antibodies in the intestines and sera of chickens. Our findings demonstrate that when 1-day-old chicks were treated with probiotics, serum and intestinal antibodies reactive to tetanus toxoid (TT) and Clostridium perfringens alpha-toxin in addition to intestinal immunoglobulin A (IgA) reactive to bovine serum albumin (BSA) were increased in unimmunized chickens. Moreover, IgG antibodies reactive to TT were increased in the intestines of probiotic-treated chickens compared to those of untreated controls. In serum, IgG and IgM reactive to TT and alpha-toxin were increased in probiotic-treated, unimmunized chickens compared to levels in untreated controls. However, no significant difference in serum levels of IgM or IgG response to BSA was observed. These results are suggestive of the induction of natural antibodies in probiotic-treated, unimmunized chickens. Elucidating the role of these antibodies in maintenance of the chicken immune system homeostasis and immune response to pathogens requires further investigation.
Asunto(s)
Anticuerpos/sangre , Pollos/inmunología , Probióticos/farmacología , Animales , Formación de Anticuerpos , Bovinos , Ensayo de Inmunoadsorción Enzimática , Femenino , Inmunoglobulina A/sangre , Inmunoglobulina G/sangre , Inmunoglobulina M/sangre , Mucosa Intestinal/inmunología , Distribución Aleatoria , Albúmina Sérica Bovina/inmunología , Toxoide Tetánico/inmunología , Fosfolipasas de Tipo C/inmunologíaRESUMEN
Five cases of infectious laryngotracheitis (ILT) occurred in the fall of 2004 in the Niagara Peninsula, in Southern Ontario. At about the same time two more cases occurred in Eastern Ontario and one case in South-Western Ontario. We examined, at a molecular level, 10 Ontario ILT virus field isolates from 2004 and early 2005 as well as four ILT vaccine viruses by polymerase chain reaction-restriction fragment length polymorphism analyses of ICP4 and glycoprotein E genes, and partial sequencing of UL47 and glycoprotein G genes. We determined that the five Niagara Peninsula ILT viruses were identical among themselves. They represented an independent cluster of ILT cases and were not related to other cases that occurred during 2004 and early 2005. Viruses isolated during the outbreaks in Eastern and South-Western Ontario could not be differentiated from chicken embryo origin ILT vaccine viruses. Niagara Peninsula isolates were different, at a molecular level, from all four vaccine viruses that were examined and from ILT viruses that had been previously analysed and reported in the literature. Taken together our data indicate that both "wild-type" and vaccine-derived viruses are involved in ILT cases in Ontario.
Asunto(s)
Pollos/virología , Infecciones por Herpesviridae/veterinaria , Herpesvirus Gallináceo 1/genética , Herpesvirus Gallináceo 1/aislamiento & purificación , Enfermedades de las Aves de Corral/virología , Animales , Infecciones por Herpesviridae/virología , Ontario , Proteínas del Envoltorio Viral/genética , Proteínas Reguladoras y Accesorias Virales/genéticaRESUMEN
Feather follicles of birds infected with Marek's disease virus (MDV) serve as the sole source of infectious virus particles. The present study was aimed at developing a SYBR Green real-time PCR assay to detect and quantify MDV loads in feather tips targeting meq gene of the virus. The assay had a dynamic range of 8 logs, mean inter- and intra-assay coefficient variation (CV) of <5% and minimum detection limit of 15 MDV genome copies when plasmid DNA was used as the template. The sensitivity of the assay was compared with that of the conventional PCR technique and found to be 2.5-10 times more sensitive than the conventional PCR technique. The assay was validated using feather tip DNA preparations derived from chickens infected with 250 plaque forming units (PFU) of RB1B strain of MDV and sampled on days 7, 14, 21 and 28 post-infection (p.i.) along with uninfected chickens. MDV genome was quantifiable in feather tips of infected birds by day 7 p.i. and the number of MDV copies peaked by day 14 p.i., but then gradually decreased by day 28. This reliable real-time PCR assay may be used for monitoring MDV genome loads in tissues of experimentally or naturally infected birds.
Asunto(s)
Pollos/virología , Plumas/virología , Genoma Viral , Enfermedad de Marek/virología , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/veterinaria , Animales , Benzotiazoles , Diaminas , Colorantes Fluorescentes , Técnicas de Amplificación de Ácido Nucleico , Proteínas Oncogénicas Virales/genética , Compuestos Orgánicos , Reacción en Cadena de la Polimerasa/métodos , Quinolinas , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Carga ViralRESUMEN
Probiotic bacteria, including Lactobacillus acidophilus and Bifidobacterium bifidum, have been shown to enhance antibody responses in mammals. The objective of this study was to examine the effects of a probiotic product containing the above bacteria in addition to Streptococcus faecalis on the induction of the chicken antibody response to various antigens, both systemically and in the gut. The birds received probiotics via oral gavage and subsequently were immunized with sheep red blood cells (SRBC) and bovine serum albumin (BSA) to evaluate antibody responses in serum or with tetanus toxoid (TT) to measure the mucosal antibody response in gut contents. Control groups received phosphate-buffered saline. Overall, BSA and SRBC induced a detectable antibody response as early as week 1 postimmunization (p.i.), which lasted until week 3 p.i. Probiotic-treated birds had significantly (P Asunto(s)
Anticuerpos/sangre
, Bifidobacterium/inmunología
, Pollos/inmunología
, Enterococcus faecalis/inmunología
, Inmunoglobulina M/sangre
, Lactobacillus acidophilus/inmunología
, Probióticos/farmacología
, Animales
, Bovinos
, Ensayo de Inmunoadsorción Enzimática
, Eritrocitos/inmunología
, Pruebas de Hemaglutinación
, Inmunoglobulina A/sangre
, Inmunoglobulina G/sangre
, Análisis de los Mínimos Cuadrados
, Albúmina Sérica Bovina/inmunología
, Ovinos