Reovirus serology in broiler parents and their progeny and its correlation with performance.

An intensive vertically integrated monitoring program for broiler breeders and their offspring was set up in a Belgian poultry integration between 1993 and 1997. Serology for anti-reovirus antibodies was performed by enzyme-linked immunosorbent assay on blood samples taken from the broiler parents throughout rearing and production and also on blood samples taken at day-old and at slaughter from the broilers. Furthermore, production parameters of the birds were registered. All data were used two by two in a simple correlation study to calculate the degree to which these variables were linearly correlated. The reovirus antibody pattern indicated frequent field infections breaking through vaccinal immunity in the broiler parents. Under the epidemiologic conditions of this study, high antibody titers in the parents or in the broilers at day-old were significantly correlated with poor feed conversion, increased mortality, increased slaughterhouse condemnation, and low production score in the broilers. These correlations strongly support the view that reovirus infections can be economically important under European conditions of broiler production. Improvement of reovirus vaccines or the vaccination scheme in broiler parents or both may lead to better production results in the broiler offspring.     

Monitoring the Immune Status of Broilers Against Reoviruses Using Challenge and Serologic Data

Reoviruses are an important cause of suboptimum performance in commercial broilers worldwide. Integrators use the enzyme-linked immunosorbent assay against the S1133 antigen for monitoring serum of breeders for indicating pullet vaccine success. However, without correlating serology to reovirus challenge, it is difficult to determine whether titers reflect protective immunity. We developed a broiler challenge test against 2 common reovirus isolates (2408 and S1133) to evaluate the efficacy of reovirus pullet vaccine programs. Two reovirus serologic and challenge studies were undertaken using chicks from broiler integrators from the southeastern United States. Breeder flocks, from which the chicks were obtained, received at least 1 live and 2 inactivated reovirus vaccines during their pullet phase. One-day-old progeny were collected from 6 breeder flocks. At 1 d of age, 20 chicks from each broiler flock were bled, and serum was analyzed for antibodies. At 3 to 4 d of age, 20 progeny per flock were challenged with the 2408 reovirus by intratracheal route. At 10 to 14 d of age, another 20 birds per flock were challenged with the S1133 reovirus by footpad. Twenty birds per flock were used as nonchallenged controls. At 3 wk of age, all birds were killed and weighed. Percentage of protection was calculated for each flock based on the absence of gross lesions. Flocks with at least 50% protection were considered well protected. Most flocks were well protected against both viruses. The percentage of protection correlated with day-old enzyme-linked immunosorbent assay titers. Chicks from younger hens had higher titers and the best protection against challenge. Producers, whose hen flocks were monitored herein, were doing a good job of immunizing pullets against reovirus. They are now using reovirus progeny challenge studies along with breeder antibody titers to determine vaccination success of their pullets.     

Infectious tenosynovitis in broilers and broiler breeders in Egypt

Two infectious tenosynovitis-producing viruses were isolated from tendon sheaths and synovial fluids of 59 broilers and 15 broiler breeders obtained from different flocks in Egypt during June to October 1983. The viruses grew well on the chorioallantoic membrane of developing chicken embryos, produced small localized white pock lesions with oedematous swellings at the inoculation sites and death of most of the embryos 72 to 96 hours post-inoculation. They also induced cytopathic effect in chicken embryo rough, Vero and MS cell lines. The viruses were neutralized by reovirus S1133 antiserum, both in tissue culture and. on the chorioallantoic membrane. Inoculation of the viruses into 2-day-old broiler chicks via the foot pad, intramuscular and oral routes reproduced the disease with the development of characteristic clinical, pathological and serological responses. The infection was transmitted to in-contact control chicks. This is the first report of the disease and of the isolation and identification of the causative virus in Egypt.     

Infectious tenosynovitis in broilers and broiler breeders in Egypt

Two infectious tenosynovitis-producing viruses were isolated from tendon sheaths and synovial fluids of 59 broilers and 15 broiler breeders obtained from different flocks in Egypt during June to October 1983. The viruses grew well on the chorioallantoic membrane of developing chicken embryos, produced small localized white pock lesions with oedematous swellings at the inoculation sites and death of most of the embryos 72 to 96 hours post-inoculation. They also induced cytopathic effect in chicken embryo rough, Vero and MS cell lines. The viruses were neutralized by reovirus S1133 antiserum, both in tissue culture and on the chorioallantoic membrane. Inoculation of the viruses into 2-day-old broiler chicks via the foot pad, intramuscular and oral routes reproduced the disease with the development of characteristic clinical, pathological and serological responses. The infection was transmitted to in-contact control chicks. This is the first report of the disease and of the isolation and identification of the causative virus in Eqypt.     

Prevalence of antibody to chicken anaemia virus (CAV) in Swedish chicken breeding flocks correlated to outbreaks of blue wing disease (BWD) in their progeny

A serological survey for antibody to Chicken Anaemia Virus (CAV) was performed on broiler breeders as well as layer breeding birds in Sweden at the end of their rearing period. Grandparents (GP) of both types leaving quarantine were in 21 out of 26 cases free from antibody to CAV, but often became infected soon thereafter. A total of 10 outbreaks of blue wing disease (BWD) in 3 series were recorded in the broiler and layer parent generation, all of which were progeny of 3 late seroconverting GP-flocks. All but one of 22 layer parent flocks had been infected and had seroconverted during the rearing period. Subsequently BWD was not recorded from commercial layers. Broiler parent flocks were more protected from CAV infection during rearing. Eighteen out of 94 broiler parent flocks had not developed antibody to CAV before coming into lay. Outbreaks of BWD were reported in progeny flocks from all these broiler breeders, with the exception of those that had been vaccinated. Good hygienic routines along with isolation of the birds delayed the seroconversion to CAV in broiler breeders and vaccination of these breeders protected their progeny from outbreaks of BWD. Broiler flocks in houses where BWD had occurred recently had always antibodies to CAV at slaughter. It was possible to eradicate the infection from the house and prevent the infection between flocks by proper cleaning and disinfection of the broiler houses.     

Isolation of avian reovirus as a possible etiologic agent of osteoporosis ("brittle bone disease"; "femoral head necrosis") in broiler chickens

Avian reovirus was isolated from intestines of 3-to-7-day-old broiler chickens with enteritis from broiler houses where osteoporosis was a problem. The virus was purified in a cesium chloride gradient (buoyant density 1.37 gm/ml) and identified as a reovirus by electron microscopy. Specific-pathogen-free (SPF) chickens and commercial broiler chickens with anti-reovirus maternal antibodies inoculated at 1 day of age with the reovirus isolate developed lesions of femoral head fractures and/or osteoporosis; reovirus could be reisolated from the bone marrow and intestinal tracts of experimentally infected SPF birds. The reovirus isolate, although isolated from intestines, induced development fo tenosynovitis lesions in SPF and commercial broiler chickens.     

Infectious bronchitis serology in broilers and broiler breeders: correlations between antibody titers and performance in vaccinated flocks

In this study, a follow-up was made between 1993 and 1997 from broiler breeders at birth down to offspring broilers at processing, through vertically integrated registration of infectious bronchitis virus (IBV) antibody titers and performance data. All measurements were used two by two in a simple correlation study to calculate the degree to which they were linearly correlated. The antibody patterns in the broiler breeders indicated frequent field infections breaking through vaccinal immunity. Significant correlations measured between antibody titers and production parameters within and between the generations strongly suggested negative effects of IBV infections on laying percentage in the breeders and on mortality and daily weight gain in the broilers. Economic losses associated with IBV infections in the broilers occurred predominantly in flocks hatched with low and erratic maternal antibody titers. We concluded that IBV vaccination strategies should aim at high and uniform antibody titers in the broiler breeders.     

Serological Incidence of Avian Reovirus Infection in Broiler-breeders and Progeny in Nova Scotia

The plaque neutralization test and the agar gel precipitation test were used to detect neutralizing and precipitating antibody to avian reovirus strain WVU2937 in sera from 14 commercial broiler breeder flocks and eight progeny flocks. Ten breeder flocks (71%) possessed positive agar gel precipitation reactors (598 sera tested) and 12 (86%) possessed plaque neutralization reactors (114 serum pools tested). All broiler flocks possessed agar gel precipitation reactors, but these were not examined for neutralizing antibody. As no avian reovirus vaccine had been used in Canada prior to this survey these reactions were presumably due to natural infection. Clinical evidence suggested that such infection was asymptomatic in most cases.The development and persistence of antibody to reovirus strain WVU2937 was followed in chicks exposed to the virus by oral inoculation or by contact. Neutralizing antibody was demonstrated in all birds by postinoculation day 17 and this persisted for at least six months. Precipitating antibody was also demonstrated in most chicks by postinoculation day 17, but by six months only 12% of the chicks were still agar gel precipitation positive.     

Rupture of gastrocnemius tendon in broiler breeder hens

Lameness and mortality of 0.55% to 1.00% per week occurred in 32-to-33-wk-old broiler breeder hens in a complex involving eight houses. Males were not affected. Laboratory evaluation of 19 birds, over 2 wk, revealed complete rupture or partial tear, primarily of the gastrocnemius tendon; the fibularis longus, fibularis brevis, and flexor muscles and their tendons were injured in a few birds. Rupture of the gastrocnemius tendon has been observed in broiler breeder chickens older than 12 wk of age and it is characterized by lameness secondary to unilateral or bilateral rupture of the tendon. The cause of this condition has been primarily attributed to reovirus infection but rupture by other causes can also occur. In this case, there was no evidence of synovitis or reovirus infection in the birds. The cause of the ruptures was attributed to aggressive males when the ratio of males to females was increased from seven or eight males per 100 females at 22-23 wk to nine or 10 per 100 at 31 wk of age.     

饲粮色氨酸水平对黄羽肉种鸡生产性能、抗氧化功能及血清生化指标的影响

本试验旨在研究饲粮色氨酸水平对黄羽肉种鸡生产性能、抗氧化功能及血清生化指标的影响,以期探明肉种鸡饲粮的适宜色氨酸水平.试验采用单因素4水平试验设计,将360只28周龄黄羽肉种鸡随机分成4组,每组3个重复,每个重复30只.对照组饲喂基础饲粮,基础饲粮色氨酸水平为0.16％,3个试验组分别在基础饲粮中添加0.02％、0.0...     

Rapid serological profiling by enzyme-linked immunosorbent assay. IV. Association of infectious bursal disease serology with broiler flock performance

Breeder and broiler flocks were serologically evaluated using a multiple enzyme-linked immunosorbent assay (M-ELISA). The serologic status of two commercial broiler-breeder flocks and their progeny was monitored, and 840 sera were promptly assessed for antibodies against six infectious agents using the M-ELISA. Breeder flocks were sampled at lay, and broiler chicks were hatched from fertile eggs collected on the scheduled lay date of the breeders. The broiler chicks were placed for growout as eight separate flocks (four from each breeder), and the serologic survey of broilers included sequentially sampling each flock five times between 1 day of age and market. Association of broiler vaccination schedules, mortality, and condemnation data with the temporal serologic data obtained indicated that the earlier appearance of active antibody against infectious bursal disease (IBD) in some unvaccinated flocks was associated with subsequent higher growout mortality and with the poorer overall performance that these flocks experienced. The results of this serologic survey also demonstrated that if a constant, well-timed monitoring program had not been used, major serologic differences between flocks would not have been detected. Serologic profiles of selected broiler flocks by virus-neutralization (VN) tests for infectious bronchitis virus (IBV) and reovirus or by hemagglutination-inhibition (HI) tests for Newcastle disease virus (NDV) compared favorably with the serologic profiles obtained by M-ELISA. Comparison of vaccination histories with serologic results derived from M-ELISA, VN or HI tests indicated that response to vaccination for IBV and NDV at 1 day was either blocked or significantly delayed by moderate levels of maternal antibody and/or were suppressed by an apparent field outbreak of IBD that occurred in all eight broiler flocks.     

Vitamin and trace mineral content in feed of breeders and their progeny: effects of growth, feed conversion and severity of malabsorption syndrome of broilers

1. A study was conducted to investigate the effects of several vitamins and trace elements chickens and in chickens experimentally infected with malabsorption syndrome (MAS). 2. Vitamins and trace minerals in feed were varied. Breeders received either a basal amount of vitamins and trace minerals (low mix) or an increased amount (high mix). Their progeny also received either a low mix or a high mix. Effects of different breeder and broiler mix combinations on broiler performance, heamatology, spleen weight and humoral response were examined in control chickens. The effects of the different feeds and breeder, broiler combinations at the severity and recovery of MAS infection were also studied. 3. In general, the immune system can be stimulated by addition of vitamins and trace minerals, without affecting the growth potential of the controls. The number of leukocytes increased on d 1 in the broilers descended from breeders receiving high mix. The response to Newcastle disease virus boost was affected by the different amount of vitamins. 4. When breeders received a high mix the number of infiltrating polymorphonuclear leukocytes in the intestine was higher compared with breeders receiving basal amounts of minerals and vitamins. Also the recovery rate of intestinal lesions, cystic crypts of Lieberkühn and villus atrophy, as observed by histopathology, was faster in the groups where the breeders received high mix.     

A study of breeder vaccination programs and problems in the broiler progeny in Saskatchewan utilizing enzyme-linked immunosorbent assay

A survey of antibodies against infectious bursal disease virus (IBDV), infectious bronchitis virus (IBV), Newcastle disease virus (NDV), and reovirus (RV) was conducted in broiler-breeder flocks and selected progeny broiler flocks utilizing the enzyme-linked immunosorbent assay. Marked differences in antibody titers between different breeder flocks were related to differences in vaccination programs. Poor performance in some progeny broiler flocks was related to low antibody titers against IBDV in the source breeder flocks. Progeny broiler flocks in which there was a high incidence of condemnations for airsacculitis had elevated antibody titers against IBV. A few progeny broiler flocks that experienced high mortality due to gangrenous dermatitis had no antibody titers against IBDV at processing. Antibody titers against RV were very variable and could not be related to any production problems.     

Swollen head syndrome: clinical observations and serological examinations in West Germany

Swollen Head Syndrome (SHS) affects both broiler and broiler breeders and has become a problem in many countries. Clinical signs similar to those described in SHS conditions have been observed in northern Germany with the disease observed mostly in chicken broilers between 4 and 5 weeks of age and in broiler breeders between 24 and 36 weeks of age. The mortality rate in broilers has been variable from negligible to 5%. In broiler breeders, the symptoms were accompanied with a drop in egg production reaching 2-3% after 1 to 2 weeks. 422 Serum samples from 21 broiler flocks were examined for the presence of antibodies to TRT-virus using indirect ELISA tests. Antibodies were detected in 2 flocks which suffered from SHS, but not in 2 flocks showing respiratory manifestations nor in 17 apparently healthy flocks. The results obtained from testing 178 serum samples from 10 breeder flocks revealed that antibodies to TRT-virus were present in one flock with SHS signs as well as in 6 apparently healthy flocks. In addition, no antibodies were found in sera collected from 3 flocks--one with SHS and respiratory disease history; one recovered from respiratory infection and one without disease history. Examination of paired serum samples from 3 breeder flocks that suffered from typical SHS-signs collected at the onset of the disease and during the convalescent stage, as well as sera from one broiler and one breeder flocks that showed respiratory manifestations, showed that there are significant increases in the number of positive sera in the flocks with SHS symptoms. The other flocks remained free from TRT antibodies.     

Effects of restricted feeding on physiological stress parameters in growing broiler breeders

1. In previous studies, a lack of agreement in measurements of plasma corticosterone concentrations and heterophil:lymphocyte (H/L) ratio as physiological indices of stress, caused by hunger and frustration in restricted-fed broiler breeders, was observed. It could be suggested that the differences between previous studies were caused by differences in duration of restriction and time of the day of the measurements. Therefore, in the present study the plasma corticosterone concentration and the H/L ratio were again determined in restricted- and ad libitum-fed growing broiler breeders, taking possible causes of disagreement between previous studies into account. In addition, we measured the daily rhythm in body temperature and heart rate, and the corticosterone responses to an acute stressor as physiological indices of stress. 2. Female broiler breeders (64 per treatment, housed in groups of 4 birds) were used in the experiment. Behaviour, baseline plasma corticosterone concentrations and H/L ratio were determined at 21 d of age (immediately after the start of food restriction), and at 42 and 63 d of age. Body temperature, heart rate and activity were measured by radiotelemetry for 36 h at 49 and 70 d of age. In addition, the plasma corticosterone response to acute stress (5 min manual restraint) was measured at 77 or 78 d of age. 3. Restricted broiler breeders had higher plasma corticosterone concentrations at 42 and 63 d of age, but no differences in H/L. ratio were found between restricted birds and unrestricted control birds. Restricted broiler breeders had a higher corticosterone response to 5 min manual restraint than unrestricted birds. Restricted birds displayed a clear day-night rhythm in body temperature, heart rate and activity whereas such a rhythm was blunted in ad libitum-fed birds. 4. It is discussed that some physiological differences (plasma corticosterone concentrations, body temperature and heart rate) between ad libitum-fed and restricted broiler breeders may have been caused by differences in metabolic rate as well as by differences in the level of stress. It is concluded that a combination of behavioural measurements and a wide range of physiological parameters should be used for the assessment of stress in growing broiler breeders.     

Influence of a 12.5 per cent rapeseed diet and an avian reovirus on the production of leg abnormalities in male broiler chickens

The incidence of different forms of leg abnormality were recorded in reovirus (S1133) infected and control male broiler chickens fed on a normal commercial diet or one of similar nutritive value containing 12.5 per cent rapeseed meal. Regular serological examination showed that birds remained free from Mycoplasma gallisepticum and M synoviae infection throughout the 10 week period of investigation. Precipitating antibodies to the reovirus were detected in 90 per cent of the infected birds between the third and 10th week after infection. Carotene levels in rapeseed fed groups showed no significant differences between reovirus infected and control birds or between birds with or without clinical signs of leg abnormality. The most frequent and severe leg abnormalities were present in the infected birds fed on the rapeseed diet, followed by those fed on the normal commercial diet. There was a highly significant difference (P less than 0.01) between the number of birds with leg abnormalities in each of these groups and their corresponding control groups. The lesions which were mainly responsible for these differences were tenosynovitis and enlarged hocks. Oral infection with reovirus did not appear to make the birds more susceptible to other types of leg abnormality, although the severest lesions of dyschondroplasia were seen in birds which had been exposed to the dual effects of reovirus and rapeseed diet.     

Prevalence of antibodies against Ornithobacterium rhinotracheale in broilers and breeders in Southern Brazil

In this investigation, we determined the prevalence of the Ornithobacerium rhinotracheale (ORT) infection in broilers and broiler breeders in southern Brazil. We also correlated the presence of antibodies in broilers with performance. Sera from 1550 broilers from 50 flocks were collected during the slaughter time in nine companies with federal veterinary inspection of the state of Rio Grande do Sul. Sera from 480 meat-type breeders of 40 flocks from 14 companies in southern Brazil were also analyzed by enzyme-linked immunosorbent assay, and the prevalence of antibodies was determined. The prevalence of ORT antibodies in broiler flocks was 63.83%, but in each individual flock only 6.52% of the birds were positive. The prevalence in broiler breeder flocks was 100.00%, and in each individual flock 94.62% of the birds were positive. There was a positive correlation between the presence of antibodies to ORT and decreased body weight in broilers. There was no significant correlation between presence of antibodies to ORT and age, lineage, efficiency index, feed conversion, and mortality. There was a positive correlation between the presence of respiratory signs and antibodies to ORT, although the reverse correlation was not significant. These results confirm that ORT is present and widespread in broilers and broiler breeders in southern Brazil.     

Investigation of a chronic feed-passage problem on a broiler farm in northwest Arkansas.

A commercial broiler farm with a history of poor feed conversion and chronic feed-passage problems was chosen for investigation. Chickens were taken from the broiler flock at specified intervals during growout and tested by virus isolation and enzyme-linked immunosorbent assay (ELISA) for avian reovirus. Abnormal tissue pathology was first seen in the broilers at 9 days of age and continued sporadically throughout the growout period. Antireovirus antibody levels began to increase at 24 days of age. Avian reovirus and avian adenovirus was recovered at different intervals starting at 17 and 31 days of age, respectively. One-day-old specific-pathogen-free chicks housed in filtered-air positive-pressure isolation units were inoculated with two inocula recovered from the field study. Avian reovirus was recovered from the tissues of both treatment groups using chick kidney cells. Significant weight differences were seen in one of the two treatment groups. This avian reovirus was given the name SS-412.     

Ovarian follicular structure of White Leghorns fed ad libitum and dwarf and normal broiler breeders fed ad libitum or restricted until point of lay

1. Yellow follicle numbers when the first egg was laid were 6.3, 9.0 and 12.4 for ad libitum reared Leghorns, sex-linked Dwarf (AL Dwarf) and Normal broiler breeders respectively. Multiple ovulation resulted in low egg production and a high proportion of defective egg shells in AL Dwarf and Normal broiler breeders during early lay. 2. Restricting the growth of broiler breeders during rearing by restricting food intake (R Dwarfs) reduced the number of yellow follicles to 6.8 and increased the rate of lay. 3. Atretic yellow follicles were common among broiler breeders but not in Leghorns or R Dwarfs when the first egg was laid. 4. Poor egg production in older broiler breeders was caused by birds with few or no developing yellow follicles, atresia in yellow follicles and the continued occurrence of multiple ovulations. 5. There was no relationship between the number of yellow follicles and the number of white follicles less than 5 mm diameter but atresia in white follicles 2 to less than 5 mm was negatively related to the number of yellow follicles. 7. No relationship was observed between abdominal fat weight and yellow follicle number, though birds which ate more had more yellow follicles. 8.The sex-linked dwarfing gene dw was associated with increased atresia among the white follicles and low numbers of yellow follicles compared with the Normal DW broiler breeder genotype.     

Seroprevalence and identification of Ornithobacterium rhinotracheale from broiler and broiler breeder flocks in Thailand

Ornithobacteriosis is an infectious disease of avian species that has been reported in almost all countries around the world, except Thailand. The objectives of this study were to determine the seroprevalence of Ornithobacterium rhinotracheale (ORT) and to isolate and identify ORT in broilers and broiler breeders in Thailand. Chicken antibodies had been randomly checked from 17 farms (19 flocks) of broilers and 23 farms (28 flocks) of broiler breeders. The seropositive flocks were 63% and 100% in broilers and broiler breeders, respectively. The sera analysis showed that the individual 280 broiler sera antibody responses were 67.5% negative, 12.9% suspect, and 19.6% positive. The individual antibody responses of 510 broiler breeder sera revealed 12.2% negative, 38.0% suspect, and 49.8% positive samples. The bacteria were isolated and identified by polymerase chain reaction (PCR). Bacterial isolation and identification revealed that nine isolates of the 12 PCR analysis samples showed positive results to PCR analysis. All the positive PCR samples were collected from the broiler breeder farms.