Intestinal spirochaetes (Brachyspira spp.) colonizing flocks of layer and breeder chickens in Malaysia

Avian intestinal spirochaetosis causes problems including delayed onset of lay and wet litter in adult chickens, and results from colonization of the caecae/rectum with pathogenic intestinal spirochaetes (genus Brachyspira). Because avian intestinal spirochaetosis has not previously been studied in South East Asia, this investigation was undertaken in Malaysia. Faecal samples were collected from 25 farms and a questionnaire was administered. Brachyspira species were detected by polymerase chain reaction in 198 of 500 (39%) faecal samples from 20 (80%) farms, including 16 (94%) layer and four (50%) breeder farms. Pathogenic Brachyspira pilosicoli was identified in five (29%) layer and two (25%) breeder farms whilst pathogenic Brachyspira intermedia was detected in nine (53%) layer and one (12.5%) of the breeder farms. Twelve (80%) layer farms had egg production problems and 11 (92%) were positive for Brachyspira: three (25%) for B. pilosicoli and six (50%) for B. intermedia. Of three breeder farms with egg production problems, one was colonized with B. pilosicoli. Three of ten layer farms with wet litter were positive for B. pilosicoli and six for B. intermedia. Of four breeder farms with wet litter, one was colonized with B. pilosicoli and one with B. intermedia. No significant associations were found between colonization and reduced egg production or wet litter, perhaps because so many flocks were colonized. A significant association (P = 0.041) occurred between a high prevalence of colonization and faecal staining of eggs. There were significant positive associations between open-sided housing (P = 0.006), and flocks aged >40 weeks (P < 0.001) and colonization by pathogenic species.     

Prevalence and transmission of haemolytic Gallibacterium species in chicken production systems with different biosecurity levels

A stratified cross-sectional study consisting of four strata of biosecurity based on production system type, including organic/free-range layer, battery-cage layer, layer parent, broiler parent and broiler grandparentflocks, was performed to estimate the prevalence of haemolytic Gallibacterium spp. Thirty birds were sampled by tracheal and cloacal swabs in each flock. A flock was considered infected when just one bird tested positive. A total of 27 flocks was included in the study. All chickens from the broiler grandparent flocks sampled negative, whereas 28% of the broiler parents, 40% of the layer parents, 67% of the battery-cage layers and 96% of the organic/free-range chickens sampled positive. A total of 95.9% (standard deviation ± 7.6%) of birds from infected flocks was colonized by haemolytic Gallibacterium species. A significantly higher number of tracheal swabs was positive compared with cloacal swabs. The probability of vertical transfer was investigated by sampling offspring from an infected as well as a non-infected parent flock. None of the samples were found positive. In conclusion, we showed that haemolytic Gallibacterium spp. were widely distributed within the Danish commercial chicken production systems. However, prevalence proportions were highly influenced by the production system and found to be significantly associated with the biosecurity level observed in the flocks. In general, flock infections resembled an 'all or none' type of colonization as practically all of the chickens in infected flocks sampled positive. There was no evidence of vertical transmission of Gallibacterium.     

Experimental infection of laying hens with Serpulina intermedia causes reduced egg production and increased faecal water content

Serpulina intermedia strain HB60, isolated from an Australian hen with diarrhoea, was used to infect 10 individually caged 14-week-old laying hens. Another 10 birds were sham inoculated with sterile broth. Birds were kept for 16 weeks, and faecal water content, egg production and body weights recorded. Strain HB60 was isolated from the faeces of nine of the infected birds at irregular intervals throughout the experiment, and from their caeca at slaughter. Infected birds tended to be lighter and their faeces, on average, were significantly wetter (by 2.85%; P < 0.002) than those of the controls. Significant reductions in mean number of eggs laid (1.4/week; P < 0.002) and mean egg weights (1.16 g; P < 0.05) were recorded in infected birds. Colonization did not induce any characteristic pathological changes. S. intermedia is potentially an economically significant cause of reduced egg production, and wet faeces in layer and broiler breeder flocks.     

Observations on the influence of intestinal spirochaetosis in broiler breeders on the performance of their progeny and on egg production.

Observations were made on the effect of avian intestinal spirochaetosis (AIS) in eight broiler breeder flocks on the performance of their commercial broiler progeny flocks, and also on the production of eggs and the selection of hatching eggs. The effect of treatment on egg production was analysed. The broiler breeder flocks were examined for the presence or absence of antibodies, spirochaetes and clinical signs of AIS, and correlated with the performance data from 136 commercial broiler flocks produced by them. Broiler flocks from affected breeders with clinical signs of AIS had a poorer feed conversion of approximately 90 g per kg growth, an increased number of weak chicks, slower growth and poorer feed digestion than the offspring of unaffected flocks including those previously infected with AIS but without clinical signs. Breeder flocks with clinical signs produced 7.5% less eggs than unaffected flocks. A larger number of eggs (+ 3%) was considered to have insufficient weight for successful hatching. Treatment of hens before the onset of lay prevented the negative effects on egg production but later treatment was less effective. These findings indicate that AIS in broiler breeder flocks is associated with significant production losses through decreased broiler flock performance and decreased egg production and quality.     

Prevalence of antibodies to avian paramyxoviruses 1, 2 and 3 in wild and domestic birds in southern Spain

Haemagglutination inhibition tests were used to study the prevalence of antibodies to avian paramyxovirus (PMV) serotypes 1, 2 and 3 in wild and domestic birds in Andalusia (southern Spain). Tests were performed on 341 sera from layer hens drawn from 44 flocks, 198 from nine breeder hen flocks, 123 from five broiler chicken flocks, 329 from 47 turkey flocks, 51 from four pigeon flocks, 123 from five partridge flocks, 112 from five mixed domestic flocks and 361 sera from 24 wild species. The incidence PMV-1 antibodies was very low in wild species (1%), though higher in domestic birds (18%), due to the systematic vaccination of these species, particularly layer and breeder hens. The highest rate of infection for PMV-2 was found in domestic species (27%) and particularly in turkeys (47%). Among wild species, the house sparrow recorded the greatest prevalence of PMV-2 (69%). The PMV-3 infection rate was very low both in wild (6%) and domestic species; the figure of 15% recorded for the latter appears to be due to cross reacting PMV-1 vaccinal antibodies. The highest incidence in wild birds was recorded in the summer, whereas prevalence reached its maximum in domestic species in the winter.     

Molecular typing of avian pathogenic Escherichia coli colonies originating from outbreaks of E. coli peritonitis syndrome in chicken flocks

Escherichia coli colonies isolated from the bone marrow of fresh dead hens of laying flocks with the E. coli peritonitis syndrome (EPS) were genotyped using pulsed-field gel electrophoresis (PFGE). Typing is important from an epidemiological point of view and also if the use of autogenous (auto)vaccines is considered. Birds with EPS originated from one house of each of three layer farms and one broiler breeder farm. Farms were considered as separate epidemiological units. In total, six flocks were examined including two successive flocks of one layer farm and the broiler breeder farm. E. coli colonies (one per bird) from nine to 16 hens of each flock were genotyped. The clonality of E. coli within birds was studied using five colonies of each of nine to 14 birds per flock. E. coli genotypes, which totalled 15, differed between farms and flocks except for two successive layer flocks that shared three genotypes. One to five genotypes were found per flock with one or two genotypes dominating each outbreak. Within hens, E. coli bacteria were always clonal. Colonies of the same PFGE type always had the same multilocus sequence type. However, four PFGE types shared sequence type 95. Neither PFGE types nor multilocus sequence types were unambiguously related to avian pathogenic E. coli from EPS. In cases where persistence of E. coli strains associated with EPS is found to occur frequently, routine genotyping to select strains for autovaccines should be considered.     

Epidemiological and pathological investigation of fowl aviadenovirus serotypes 8b and 11 isolated from chickens with inclusion body hepatitis in Spain (2011–2013)

Inclusion body hepatitis caused by different fowl aviadenovirus (FAdV) serotypes has been described in several countries in recent years. In Spain, from the spring of 2011 to 2013, an increased number of outbreaks in broiler and broiler breeder flocks from different regions occurred. The objectives of the present work were to carry out the molecular characterization of FAdV strains from Spanish inclusion body hepatitis cases and to study the pathogenicity and viral dynamics of these strains in specific pathogen-free (SPF) chickens. A total of 52 inclusion body hepatitis clinical cases, including 45 from broiler farms and seven from broiler breeder farms, were analysed by conventional polymerase chain reaction and sequencing targeting the FAdV hexon gene. From these, 37 strains were classified as FAdV type 8b, while the remaining 15 were classified as FAdV types 11 (n?=?10), 2 (n?=?4) and 8a (n?=?1). In addition, two different FAdVs belonging to the genotypes 8b and 11 were used for experimental infection. Specific pathogen-free five-day-old birds were inoculated intramuscularly with a high (10^6.5 tissue culture infective dose (TCID)₅₀/ml) or low (10⁴ TCID₅₀/ml) dose of the above-mentioned FAdVs. No mortality was observed in any of the experimental groups, and only one bird showed evident clinical signs. However, macroscopic and microscopic hepatic lesions, as well as viral DNA, were detected in birds from all infection groups. Inclusion bodies and viral DNA were also detected in the pancreas and in the small and the large intestine in some birds. Long-lasting shedding and transmission to contact birds were confirmed in all infected groups.     

Serologic prevalence of Ornithobacterium rhinotracheale infections in broilers and broiler breeder chickens in Kermanshah Province,west of Iran

The presence of Ornithobacterium rhinotracheale (ORT) in poultry farms in several parts of Iran has been confirmed over the last few years. The purpose of this study was to determine the presence of ORT antibodies by enzyme-linked immunosorbent assay (ELISA) in broiler and broiler breeder chickens in western parts of Iran. In a one-year period, from April 2009 to February 2010, a total of 435 blood samples were collected from 30 commercial chicken flocks (24 broiler flocks and six broiler breeder flocks) located in Kermanshah Province, west of Iran. None of the broilers and broiler breeders have been vaccinated against ORT prior to sampling. The province was divided into four geographical areas: southwest, southeast, northwest, and northeast. Flocks in each area, specifically the birds in each flock, were randomly sampled. The presence of antibodies against ORT in each serum sample was tested twice by ELISA using a commercial kit. The results revealed that 50.1 % broiler and 70.5 % broiler breeder chickens were serologically positive for ORT. Out of 347 serum samples obtained from broiler chickens, 174 (50.1 %) were positive for ORT antibodies, which represented 18 (75.0 %) of 24 examined broiler flocks. A higher rate of seropositivity (71.4 % of samples and 83.3 % of broiler flocks) was observed in the northwest. Out of 88 samples obtained from broiler breeder chickens, 62 (70.5 %) were positive for ORT antibodies, which belonged to six (100 %) of the examined broiler breeder flocks. Detection of anti-ORT antibodies among broiler breeders was significantly higher than that of broilers.     

Comparison of serological and virological findings from subgroup J avian leukosis virus-infected neoplastic and non-neoplastic flocks in Israel

Blood samples from nine broiler breeder flocks comprising five flocks clinically affected with myeloid leukosis tumours (ML+) and four tumour-free flocks from the same commercial background (ML?) were compared for avian leukosis virus subgroup J (ALV-J) serum antibodies by enzyme-linked immunosorbent assay (ELISA), for antigenemia (group-specific antigen) by antigen-trapping ELISA and for viremia. Group-specific antigen was detected in the sera of 58.1% of ML+ birds and 46.4% of the ML? birds (P=not significant), while 45.5% of ML+ birds and 24.1% of the ML? birds had ALV-J antibodies (P=0.065). In inoculated cell culture, 64.1% of the ML+ sera were viremic compared with 16.7% of the ML? sera (P=0.001). Similar significant differences were found between the two groups of flocks when ALV-J viremia was detected by immunofluorescence using a monoclonal env antibody (P=0.004), and for proviral DNA by polymerase chain reaction using two different sets of env-gene primers, H5?H7 (P=0.001) and R5–F5 (P=0.001). Using the primer pair R5–F5 the product size was approximately 1 kbp, while some heterogeneity in size among isolates was discernable. Our results indicate that a combination of diagnostic tests should be adopted in routine examination of tumour material in order to rule out false-negative findings.     

Vertical transmission and clinical signs in broiler breeders and broilers experiencing adenoviral gizzard erosion

The present report documents an outbreak of adenoviral gizzard erosion in 22 broiler flocks in Germany. The clinical picture was characterized by uneven growth of affected broilers that resulted in considerably lower than average weight at slaughtering. Fowl adenovirus serotype 1 (FAdV-1) was isolated from gizzard lesions and histological examinations demonstrated FAdV-1-positive intranuclear inclusion bodies in gizzard epithelial cells of affected broilers by in-situ hybridization. Birds from all affected flocks originated from one broiler breeder farm. During production of affected birds, broiler breeders were between 27 and 32 weeks old. Enzyme-linked immunosorbent assay and specific virus neutralization assay of sera from parent birds demonstrated an acute FAdV-1 infection within the first 5 weeks of the production cycle. Clinically, broiler breeders exhibited a moderate fall in the hatchability of their chicks, while egg production remained normal. No further clinical signs could be observed. Genetically identical FAdV-1 strains were isolated from gizzards of embryos at the lowest point of hatchability and from affected broiler flocks raised on independent farms. For the first time, direct detection of viable FAdV-1 from gizzards of embryos and progenies of one FAdV-1-seropositive broiler breeder farm in the course of an outbreak of adenoviral gizzard erosion could be demonstrated, highlighting the importance of vertical transmission of this disease. Additionally, growth retardation and subsequent reduced average weight at the time of slaughter of broiler chickens underline the economic impact of adenoviral gizzard erosion for poultry production.     

Prevalence,disease associations and risk factors for colonization with intestinal spirochaetes (Brachyspira spp.) in flocks of laying hens in north-eastern Italy

The present study investigated the occurrence of anaerobic intestinal spirochaetes of the genus Brachyspira in laying hen flocks in Treviso province, north-eastern Italy, with respect to prevalence, spirochaete species present, disease associations and risk factors for colonization. A total of 450 faecal samples from 45 sheds on 29 laying hen farms were cultured for intestinal spirochaetes. Nineteen sheds on 12 farms contained chickens with symptoms consistent with avian intestinal spirochaetosis, including reduced egg production, wet litter and/or pasty vents. Spirochaetes were isolated from 157 (34.8%) samples from 21 (72.4%) farms, and from 32 (71.1%) sheds. From these positive samples, 189 spirochaetal isolates were speciated using three polymerase chain reaction assays and a restriction fragment polymorphism analysis of 16S rDNA polymerase chain reaction products. Overall, 52 (27.5%) isolates were identified as pathogenic Brachyspira intermedia, 26 (13.8%) as pathogenic Brachyspira pilosicoli, 93 (49.7%) as non-pathogenic (Brachyspira innocens/Brachyspira murdochii), and 18 (9.6%) were unidentified. Faeces from 14 sheds (31%) on 10 farms (34.5%) contained B. intermedia and/or B. pilosicoli, and disease consistent with avian intestinal spirochaetosis was observed in nine of these sheds on seven farms. There was a significant association (P=0.042) between the presence of spirochaetes and using deep pits rather than conveyor belts for manure disposal. Sheds housing chickens >40 weeks of age were significantly more likely to contain spirochaetes (P=0.048) and pathogenic species (P=007) than sheds housing younger chickens. A significant association (P=0.02) was found between infection with pathogenic spirochaetes and reduced egg production.     

Zinc bacitracin enhances colonization by the intestinal spirochaete Brachyspira pilosicoli in experimentally infected layer hens

Brachyspira pilosicoli strain CPSp1 isolated from a chicken in a broiler breeder flock in Queensland was used to experimentally infect 40 individually caged 22-week-old laying hens. Another 10 birds were sham-inoculated with sterile broth. All chickens received a commercial layer diet, but 10 infected birds had 50 parts/10 6 zinc bacitracin (ZnB) incorporated in their food. Birds were kept for 7 weeks, and faecal moisture, egg numbers, egg weights and body weights were recorded weekly. B. pilosicoli was isolated from the faeces of only three of the 30 inoculated birds receiving the diet without ZnB, whereas seven of the 10 inoculated birds receiving ZnB in their diet were colonized. This difference in colonization rate was highly significant ( P = < 0.001). Dietary ZnB at 50 parts/10 6 therefore predisposed to colonization by B. pilosicoli. Despite colonization, no significant production differences were found between the birds in the three groups.     

Thermophilic Campylobacter spp. in Danish broiler production: A cross-sectional survey and a retrospective analysis of risk factors for occurrence in broiler flocks

In order to elucidate the rate of thermophilic Campylobacter spp. carriage in Danish broiler production and to identify risk factors for occurrence of campylobacter in broiler flocks, a total of 88 randomly selected broiler flocks were tested for campylobacter infection, and a subsequent study of risk factors based on a questionnaire was conducted. The sample material comprised cloacal swabs from live birds before slaughter, and neck skin samples from carcasses at the end of the processing line. A total of 52% of the flocks were found Campylobacter spp.-positive before slaughter. At the end of processing, 24% of the flocks were positive. The species distribution was 87% Campylobacter jejuni, 8% Campylobacter coli and 5% Campylobacter lari. The following parameters were identified as significant risk factors: lack of a hygiene barrier (odds ratio (OR) = 3.1, 1.1 < OR < 9.3), presence of animals in the vicinity of the broiler house on farms with a missing hygiene barrier (OR = 7.0, 1.6 < OR < 33.9), livestock other than chickens on farms with a missing hygiene barrier (OR = 7.6, 1.4 < OR < 44.9), dividing the flock into batches for staggered slaughter (OR = 6.8, 1.2 < OR < 49.3), a down period of less than 14 days (OR = 5.0, 1.2 < OR < 22.6), and feeding purchased wheat rather than home-grown wheat (OR = 3.1, 1.0 <OR < 9.9). The presence of a hygiene barrier was found to be the single most important biosecurity measure for production of campylobacter-free broilers.     

Enterococcus cecorum infections in broiler breeders and their offspring: molecular epidemiology

Increased mortality and problems with lameness were reported in Dutch broiler flocks from the year 2008 onwards. Therefore, a field inventory, including 10 affected broiler flocks, nine corresponding broiler breeder flocks and five hatcheries, was carried out. The onset of clinical signs (lameness and increased mortality) started at about 2 weeks of age. The flock mortality varied from 3.1 to 8.1% at slaughter. Post-mortem lesions of broiler flocks were characterized by the occurrence of pericarditis/hydropericardium, arthritis and femoral head necrosis. Enterococcus cecorum was isolated from approximately 30% of the lesions. In the broiler breeders, E. cecorum was not isolated from any of the lesions. However, it was isolated from 31 out of 65 (47%) cloacal swabs, from two out of 65 (3%) oviduct samples, from one out 65 (1.5%) bone marrow samples and from two out of 25 (8%) blood samples. E. cecorum was not isolated from the air samples or dead-in-shell originating from the hatcheries involved. In total, 78 isolates were subjected to further typing by means of tRNA intergenic spacer PCR and confirmed as E. cecorum. The genetic relatedness of these cocci was subsequently studied using pulsed-field gel electrophoresis. The banding patterns of approximately 68% of E. cecorum isolates originating from parent stock flocks were clonal to one or more isolates of the same or other parent flocks. In contrast, isolates originating from their diseased offspring showed much greater genetic variation. Therefore, the vertical transmission of E. cecorum could not be demonstrated.     

High prevalence of Brachyspira spp. in layers kept in alternative husbandry systems associated with frequent species variations from end of rearing to slaughter

A longitudinal survey was conducted to investigate the presence of Brachyspira species in layer flocks. A total of 66 layer flocks kept in alternative husbandry systems were sampled at three time points: end of rearing, at peak of lay and at end of lay. Content from caecal samples of freshly killed birds was cultured at each sampling time point and processed for further investigations. Gross pathological lesions in caeca were recorded during post mortem investigation. Spirochaetes were isolated from 50 flocks: three flocks were positive at all three sampling points, 25 flocks at two and 22 flocks at one sampling point, respectively. The presence of Brachyspira spp. could not be related to specific gross pathological caecal lesions or antibiotic treatments. The number of positive flocks increased with the age of birds. Furthermore, organic flocks were more often positive than flocks from barn systems. In total 80 spirochaetal cultures were obtained. B. intermedia (43.8%) was the most common species, followed by B. pulli (13.8%) and B. pilosicoli (12.5%). Brachyspira murdochii and B. innocens were found in 5.0% and 2.5%, respectively, whereas 11.3% of Brachyspira isolates could not be identified to species level. In 11.3% of the samples mixed infections were detected. Finally, the longitudinal survey revealed for the first time a possible shift in the Brachyspira species in a substantial number (32%) of layer flocks during their lifetime.     

Pathological and microbiological investigations into cases of bacterial chondronecrosis and osteomyelitis in broiler poultry

Bacterial chondronecrosis and osteomyelitis (BCO) is increasingly recognized as a major cause of lameness in commercial broilers chickens worldwide, but the pathogenesis of the condition is incompletely understood. This was a longitudinal study of 20 commercial broiler farms in Victoria, Australia, to investigate the aetiology and pathology of BCO. Thorough postmortem examination was performed on culled and dead birds (n?=?325) from 20 different flocks at either 1 week, 4 weeks or 5 weeks of age and samples were analysed by conventional bacteriology, molecular identification of infectious organisms detected, serology and histopathology. BCO occurs throughout the life of broiler flocks at a very high rate, with lesions detected in 28% (95% CI 23–34%) of the mortalities and culls. The condition occurs with similar prevalence in both the femur and tibiotarsus. BCO is an infectious process that appears to result from bacteraemia and haematological spread of bacterial pathogens, especially Escherichia coli, to the bones, with 65.3% bacterial isolates from histologically confirmed BCO identified as E. coli, 11.5% as Staphylococcus and the remainder composed of mixed infections or a range of other minor isolates. We observed that almost all E. coli isolated from cases of BCO are avian pathogenic E. coli, suggesting that preventative measures should be directed at this organism.     

The incidence and economic impact of the Escherichia coli peritonitis syndrome in Dutch poultry farming

The incidence and economic impact of the Escherichia coli peritonitis syndrome (EPS), characterized by acute mortality, were estimated in chicken egg-producing farms in the Netherlands in 2013. The incidence was significantly higher (P?相似文献   

Avian hepatitis E virus infection and possible associated clinical disease in broiler breeder flocks in Hungary

In broiler breeder flocks in one broiler integration in Hungary, a new syndrome appeared in January 2005 with initially four successive post-peak flocks experiencing significant decreases in egg production. Clinically birds became depressed and there was a small increase in the mortality rate. Postmortem examinations revealed enlarged livers in up to 19% of birds dying, and enlarged spleens in some. Also observed were birds with either clotted blood or serosanguineous fluid in the abdomen and subcapsular haemorrhages of the liver. Histopathology and polymerase chain reaction excluded tumours and the presence of common tumour-associated viruses. Chronic bacterial infections (especially causing hepatitis, peritonitis and airsacculitis) were common but many enlarged livers had no obvious bacterial involvement. After a 9-month period during which a majority of flocks became affected, no newly affected flocks occurred. Investigations showed that all tested affected flocks were seropositive in the big liver and spleen (BLS) Agar Gel Immunodiffusion test. Subsequent flocks without post-peak egg-production drops were shown to be seronegative in the BLS AGID test, as were all the parent flocks contributing to the affected flocks. Liver samples and cloacal swabs were positive by polymerase chain reaction (aHEV helicase target), and calicivirus-like particles were demonstrated in bile samples from affected birds. These observations are similar to hepatitis-splenomegaly syndrome as described in North America and BLS syndrome as described in Australia. Histopathological features were a non-specific chronic hepatitis similar to those described in BLS and hepatitis-splenomegaly syndrome. Immunohistochemistry using a BLS-specific monoclonal antibody confirmed the presence of avian hepatitis E virus antigen in livers and spleen.     

Field studies on the association between amyloid arthropathy and Mycoplasma synoviae infection,and experimental reproduction of the condition in brown layers

Approximately 20% of outbreaks of amyloid arthropathy in The Netherlands were earlier attributed to Enterococcus faecalis but there was no explanation for the remaining cases. In a further study, material from the joints of 10 birds from each of 10 affected brown layer flocks and two broiler flocks was cultured in several bacteriological media. E. faecalis was isolated from one layer flock but Mycoplasma synoviae was recovered from purulent joints in six of the layer flocks and both broiler flocks. Brown layers were then infected experimentally with one of the M. synoviae isolates to assess its arthropathic and amyloidogenic potential. Using Congo red staining, articular amyloid deposits were seen 12 weeks after intra-articular or intravenous inoculation in almost all birds. After intra-articular inoculation of the left knee joint the contralateral hock tendon sheath tended to be affected, while hock and foot joints were mainly affected after intravenous inoculation. Amyloid deposits were seen in livers and spleens of many birds. This is the first demonstration of arthropathic strains of M. synoviae with an association with amyloid arthropathy, while for one isolate its amyloidogenic potential was shown experimentally.     

Experimental infection of broiler breeder hens with the intestinal spirochaete Brachyspira ( Serpulina ) pilosicoli causes reduced egg production

The pathogenic potential of the anaerobic intestinal spirochaetes Brachyspira ( Serpulina ) pilosicoli and Brachyspira innocens was evaluated in adult chickens. Thirty 17-week-old Cobb broiler breeder hens were individually caged in three groups of 10 birds. Control birds (group A) were sham inoculated with sterile broth medium. Birds in the other two groups (groups B and C) were inoculated, respectively, with an isolate of B. innocens or of B. pilosicoli . Birds were monitored daily, and killed at 41 weeks of age. Infection had no consistent effect on body weight gain, but inoculation with B. pilosicoli resulted in a transient increase in faecal water content. B. innocens infection had no effect on egg production, but B. pilosicoli infection caused a delayed onset of laying, and a highly significant reduction in egg production over the first 11 weeks of lay. This study confirms that B. pilosicoli can cause serious egg production losses in adult chickens, while B. innocens is not obviously pathogenic.