Detection of antibody to Salmonella enteritidis and S typhimurium in the yolk of hens' eggs

Enzyme-linked immunosorbent assays (ELISAs) have been developed to detect IgG antibodies to Salmonella enteritidis and S typhimurium in the yolk of hens' eggs. Better discrimination and more consistent results were obtained between eggs from experimentally infected and uninfected hens by using saline-dilution of yolk rather than chloroform extraction. Threshold absorbance values were determined in three salmonella-free flocks, and on the basis of these results ELISA optical density values greater than 0.25 were considered to be positive for antibodies to salmonella. Four flocks with a history of salmonella infection were examined; three contained birds which were seropositive for S enteritidis by ELISA and from which S enteritidis was isolated, and a large proportion of eggs from these birds contained antibody to S enteritidis. Eggs from the fourth flock had no detectable antibody, although serum antibody was detected in some birds. No salmonellae were isolated from the yolks of the eggs from any of the four flocks.     

Control, prevention and eradication of Salmonella enteritidis infection in broiler and broiler breeder flocks

Salmonella enteritidis was identified by serological and bacteriological techniques in two clinically normal breeder flocks in an integrated broiler organisation in Northern Ireland. The organism was transmitted vertically to clinically affected progeny flocks. The infected breeder flocks were slaughtered and the infection throughout the organisation controlled and subsequently eradicated. A working group, consisting of the senior management of the broiler organisation and veterinary staff from the Veterinary Research Laboratories at Stormont, was formed to establish procedures to minimise the risk of the reintroduction of salmonella infection, by preventing vertical transmission from grandparent flocks, or lateral transmission from personnel, other animal species and fomites, or transmission through the feed. All feed was heated to a minimum of 70 degrees C for 12 minutes immediately before it was pelleted and subsequently transported to the flocks through a dedicated system of conveyor belts, bins and lorries. A comprehensive system for monitoring the efficacy of the preventive procedures was established and is now used throughout the poultry industry of Northern Ireland.     

Alterations in levels of various host antioxidant factors in turkey knockdown syndrome

Five components (selenium, glutathione peroxidase, copper, superoxide dismutase, and vitamin E) of the antioxidant system of turkey poults were examined to determine if they play any role in the knockdown (KD) syndrome. All flocks were provided with feed formulated to contain monensin at 54-60 g/ton. Flock data were analyzed as a case-control study with three treatment groups (KD-affected and unaffected turkey poults from a KD flock and poults from an unaffected flock [control]). Affected turkey poults had lower (P < 0.001) serum vitamin E levels compared with unaffected poults from KD flocks or poults from unaffected flocks. No significant differences were observed for the other parameters evaluated but there was a trend towards lower copper and superoxide dismutase values in affected birds. It appears that serum vitamin E concentrations in turkey poults may play a significant role in susceptibility to or protection against KD syndrome. Other components of the antioxidant system may also be involved, and complex interactions among several body systems may be critical.     

The role of litter beetles as potential reservoir for Salmonella enterica and thermophilic Campylobacter spp. between broiler flocks

We evaluated the role of beetles infesting broiler chicken rearing facilities as potential reservoirs for Salmonella enterica infections between successive broiler flocks. In addition, their role as potential reservoirs for thermophilic Campylobacter spp. was also investigated. Fourteen broiler houses located at 11 different farms were included in the study. The houses were nonrandomly selected on the basis of their salmonella status; nine were persistently contaminated with salmonella whereas five were salmonella negative. For each broiler house, two consecutive broiler flocks (i.e., 28 broiler flocks in all) as well as beetles collected during both rotations of production and in the empty period (after cleaning and disinfection) between these flocks were monitored for the presence of salmonella. Examinations for the presence of campylobacter in the same sample materials were also performed. Beetles sampled during production were positive for salmonella or campylobacter or both. Furthermore, in one house, the occurrence of Salmonella indiana in two consecutive broiler flocks coincided with the presence of S. indiana-contaminated beetles in the empty period between the flocks. The genotype of the identified S. indiana was in all cases identical when analyzed by pulsed-field gel electrophoresis. However, our results also suggest that salmonella from beetles may not always be transmitted to the chickens and that beetles living in contaminated houses can remain free of infection. All cases of campylobacter-positive beetle samples were detected in connection with a positive chicken flock; in no case was campylobacter isolated from beetles taken from the empty period between rotations. Four beetle species were identified during this study. Alphitobius diaperinus was found in all houses and was relatively abundant in most. Typhaea stercorea and Ahasverus advena were found in eight and nine houses, respectively, and were abundant in most of these. Carcinops pumilio was found in small numbers in eight houses. No other insect species was identified. These investigations have shown that beetles in broiler houses infrequently are positive for salmonella. However, transmission of S. indiana between two consecutive broiler flocks can coincide with the presence of salmonella-contaminated beetles in the empty period, indicating that the beetles were the reservoir of S. indiana between the two flocks. Concerning campylobacter, the results suggest that beetles do not play a significant role as a reservoir of campylobacter from one rotation to the next.     

Serological investigations on reticuloendotheliosis in turkey flocks

Four meat turkey and one turkey breeding flocks were surveyed for antibodies against reticuloendotheliosis virus (REV) at different intervals using commercial enzyme-linked immunosorbent assays. In addition, serum samples collected from 18 flocks at different ages were also tested for antibodies against REV. No antibodies were detected in any of the four meat turkey flocks that were surveyed. In the breeder flock, 20%) of tested samples from 1-day-old poults were positive. Between the fourth and 12th weeks all samples that were tested yielded negative results. At 16 weeks of age 15% of samples yielded a positive reaction, but antibodies could not be detected 4 weeks later. Examination of serum samples from 18 different flocks at various ages revealed that antibodies could be detected in five flocks. The percentage of positive sera per flock ranged between 10 and 40%.     

A retrospective study on salmonella infection in Danish broiler flocks

A retrospective longitudinal study was conducted to identify risk factors associated with Salmonella enterica infection in Danish broiler production. The study was based on information in the antemortem database (AM database) where data were available for all broiler flocks slaughtered over the 2-year period from 1992 to 1993 in Denmark. The AM database contains information collected by the ante-mortem veterinarians, from the slaughterhouses, and from the salmonella examinations carried out at the National Veterinary Laboratory. The epidemiological unit was the individual broiler flock. The salmonella status of the flock was determined by examining the caecal tonsils from 16 3-week-old chickens from each flock. This procedure would detect a salmonella-infected flock, with a probability above 95%, if the prevalence is above 20%. Furthermore, the structure and quality of the collected data have been evaluated.

Fourteen variables were selected for analysis by multivariable logistic regression. An increased risk of salmonella infection in the broiler flocks was associated with the biggest hatcheries and feedmill, with an increasing number of houses on the farm, if the preceding flock was infected, and if the flock was reared in the autumn. Additionally, the main variables of the model were analysed by including a random effect at the house level. This resulted only in minor changes of the parameter estimates.     

The serologic response to Salmonella enteritidis and Salmonella typhimurium in experimentally infected chickens,followed by an indirect lipopolysaccharide enzyme-linked immunosorbent assay and bacteriologic examinations through a one-year period

Three groups of 100 individually marked salmonella-free chickens were followed for a period of 53 wk. The chickens were infected as day olds by crop instillation of 10(8) colony-forming units: one group with Salmonella enteritidis and a second group with Salmonella typhimurium. A third group was kept uninfected as controls. The groups were monitored bacteriologically by examination of cloacal swabs and organs and serologically by examination of serum and egg yolk by a lipopolysaccharide enzyme-linked immunosorbent assay throughout the period. Within the first week, 100% of birds in both infected groups were excreting salmonella bacteria in the feces. However, the number of fecal excretors declined rapidly with time, down to 6% in 16 wk for S. typhimurium and down to a similar level within the first 8 wk for S. enteritidis. For the latter, relapses with up to 40% positive birds were observed at the onset of egg production. For both S. typhimurium and S. enteritidis, positive bacteriologic cultures were obtained by sampling from internal organs at the end of the experiment, more than 1 yr from the time of infection. At the age of 6-7 wk, 50% of the chickens in the two infected groups showed a measurable serologic response in serum samples. The response persisted throughout the study in both serum and egg yolk samples. The inclusion of serologic methods is a valuable additional tool in the detection of salmonella in poultry, but serology should be used in conjunction with bacteriologic methods in surveillance programs, in particular to detect flocks in early stages of infection before a measurable serologic response has been raised.     

Breeder age affects small intestine development of broiler chicks with immediate or delayed access to feed

1. The relationship between breeder age and chick gastrointestinal tract development to 21 days of age, as influenced by immediate or delayed access to feed, was examined in three consecutive trials.

2. Ross 708 chicks, derived from breeder flocks at 31 (young), 40 (middle) and 63 (old) weeks of age were placed randomly into either a control group with immediate access to feed and water, or a 48?h feed delayed (FD) group with free access to water.

3. FD negatively affected body weight (BW) of chicks derived from young and old flocks through the first and second weeks of age, respectively. Chicks from the older flock absorbed more yolk in the first 48?h with no FD effect. When feed was made available, chicks from the FD group showed a large increase in small intestine weight relative to BW, surpassing (P? 4. Morphological measurements in all intestinal sections had higher values in chicks derived from the middle age breeder flock. FD to newly hatched chicks from the young breeder flock shortened villi (P?P? 5. Crypt depths were maximised between 7 and 14?d post-hatch in chicks from young and old breeder flocks, but crypt depths in chicks from the middle aged flocks continued to deepen.

6. The increased crypt depth may augment the number of enterocytes available for villus growth, and facilitate longer villi and greater villus surface area, in chicks from the middle age flocks. Intestinal morphological variation was associated with breeder flock age, which accounted for differential growth in chicks derived from young, middle, and old aged breeder flocks.     

Characteristics of fowl cholera outbreaks in turkeys in Georgia in 1986

Information was gathered from 64 cases of fowl cholera (FC) in turkey flocks through diagnostic case records, flock records, and telephone and mail surveys. Forty-five cases came from flocks of commercial turkeys, of which 15 were presented twice, and four came from mature breeder flocks. The prevalence of FC was 18.0% of commercial flocks and 14.7% of breeder flocks at risk. The average age at first diagnosis of FC was 90 days in commercial turkey flocks and 32 weeks 5 days in breeder flocks. Acute mortality was the most common presenting complaint, with a 0.37% average mortality in commercial flocks on the day of first presentation, 0.80% in commercial flocks presented a second time, and 0.43% in breeder flocks. Pasteurella multocida was cultured from 69.8% of the 361 tissue samples submitted from these cases. Novobiocin, penicillin, and chlortetracycline (CTC) had the greatest in vitro activity against isolates. Serotype 3-cross-4 was found in all 18 commercial flocks from which isolates were typed. All breeder flocks and 88.6% of commercial flocks were vaccinated before disease onset. Flocks were treated for an average of 14.3 days, most commonly with high levels of sulfadimethoxine and/or CTC. Body weights of affected birds were comparable to those of birds in unaffected flocks, but mortality and feed efficiency were worse.     

Clinical, cultural, and serologic observations of avian mycoplasmosis in two chicken breeder flocks.

Two chicken breeding flocks from different breeding lines were studied serologically and culturally for Mycoplasma gallisepticum (MG) throughout their growing and laying period. Infection was proven by successful isolation of MG from both breeders and progeny originating from these two flocks. Observations of these flocks which were serologically and culturally negative for Mycoplasma synoviae (MS) further disclosed that: 1) negative plate tests of large numbers of day-old progeny may sometimes be found in flocks known to be infected with MG; 2) it may be very difficult to isolate MG consistently from some infected flocks; 3) overgrowth of M. gallinarum may interfere with successful cultivation of MG; 4) a persistent breeder flock reactor rate of greater than 10-20% but less than 80-100% for a 4-to-12-week period is a strong indication of MG infection despite weak or negative MG hemagglutination-inhibition (HI) test results; and 5) antibodies for all strains of MG may not react equally to the standard USDA MG-HI antigen.     

Salmonella contamination of poultry flocks in The Netherlands

The contamination of poultry in the Netherlands with Salmonella enteritidis was tested. For this, different methods (detection of S. enteritidis in faecal samples of 25 g; detection of S. enteritidis in cloacal swabs; detection of S. enteritidis by serological testing of antibodies in serum) were compared for their efficiency to detect S. enteritidis in flocks of poultry. Testing of faecal samples clearly yielded the best results. This method was used in a transmission study, in which 14 flocks descending from a contaminated primary mother flock were screened for the presence of S. enteritidis. The method was also used for screening 49 flocks of laying hens and 52 flocks of broiler chickens throughout the Netherlands. From the transmission study it became clear that S. enteritidis, phage type 2 (Dutch phage set) was isolated both from the mother flock and from five of the descendent flocks. Screening of poultry flocks for the presence of salmonella revealed that salmonella was present in 47% of the layer flocks and in 94% of the broiler flocks. S. enteritidis was isolated from 15% of the flocks screened.     

Ascarid-associated hepatic foci in turkeys

Hepatic foci are a serious economic problem for most turkey-producing areas in the United States. Current estimates indicate that as much as 43% of the flocks sent to slaughter may experience condemnations because of hepatic foci. The present experiments were designed to duplicate naturally occurring lesions with Ascaridia dissimilis. Newly hatched poults were placed on fresh litter and given feed containing either 500 embryonated A. dissimilis ova/bird/day (from day of hatch) or no ova, in three experiments. Hepatic foci were reproduced in exposed poults in all three experiments, indicating that A. dissimilis is directly involved in the etiology of hepatic foci.     

Identification of a new source of Campylobacter contamination in poultry: transmission from breeder hens to broiler chickens

Campylobacter jejuni, a foodborne pathogen closely associated with market poultry, is considered to be the most frequent agent of human gastroenteritis in the United States. The pathways involved in the contamination of poultry flocks, vertical transmission and/or horizontal transmission, are unclear. In this study, Campylobacter isolates from two independent commercial broiler breeder flocks, as well as from their respective progeny, were characterized and compared by PstI ribotype analysis and by DNA sequence analysis of the short variable region (SVR) of the flaA gene (flaA SVR). Campylobacter isolates originating from one set of breeder hens and the feces from their respective progeny demonstrated identical ribotype patterns as well as identical flaA SVR DNA sequences, thereby suggesting that these isolates were clonal in origin. Ribotype analysis of Campylobacter isolates from the second set of breeder hens and processed carcasses from their offspring resulted in two patterns. Sequence analysis placed these isolates into two closely related groups and one distant group, similar to the ribotype analysis. These results demonstrate that Campylobacter isolates from commercial broiler breeder flocks and from the respective broiler progeny may be of clonal origin and that breeder hens can serve as a source for Campylobacter contamination in poultry flocks.     

四川地区蛋鸡孵化场沙门氏菌调查

通过对四川不同地区的4个蛋种鸡孵化场进行沙门氏菌感染调查,发现4个蛋种鸡孵化场中弱雏身上的沙门氏菌分离率最高(分别为25.2%、0、13.7%、5.3%),对应孵化场提供的早期死亡雏鸡身上的沙门氏菌分离率也较高(分别为25.3%、7.8%、16.5%、8.6%)。选择19株沙门氏菌用21种抗生素进行耐药性检测,发现该菌只对头孢类部分药物及个别其他类别药物敏感,而对喹诺酮类、磺胺类、大环内酯类、氨基糖苷类的大部分药物耐药。表明对蛋种鸡孵化场沙门氏菌耐药性的控制迫在眉睫。     

Assessment of the effects of electromagnetic field modification on egg-laying hens in commercial flocks as indicated by production measures

OBJECTIVE: To assess the effects of electromagnetic (EM) field modification by use of Nufield EM field modification (NEFM) units on egg-laying hens in commercial flocks as indicated by production measures, including hen-day mortality rate (HDMR) and eggs per hen housed (EHH). ANIMALS: 16 commercial flocks of egg-laying hens. PROCEDURE: 5 caged commercial table egg layer flocks (Single Comb White Leghorns) successively housed at the same location during a 6-year period were exposed to NEFM.There were 7 hens/cage (317 cm2 of floor space/bird). At the same site, 11 concurrent non-NEFM-exposed flocks (4 genetically different strains) were sequentially housed. All 16 flocks underwent the same feed and management practices. For each NEFM- and non-NEFM-exposed flock, HDMR and EHH were compared with their respective national breeder goals (BG), defined as the reasonable genetic potential expressed under optimal management and environmental conditions. Furthermore, the HDMRs and EHHs of the NEFM- and non-NEFM-exposed flocks were compared. RESULTS: Mean HDMR and EHH of the NEFM-exposed flocks was 36.9% less and 4.96% greater than the relevant BG, respectively. Mean HDMR and EHH of the non-NEFM-exposed flocks was 12.6% and 0.49% greater than the relevant BG, respectively. Compared with the 11 non-NEFM-exposed flocks, the NEFM-exposed flocks collectively had a 47.6% decrease in HDMR and 1.33% increase in EHH. CONCLUSIONS AND CLINICAL RELEVANCE: Results strongly suggest that application of NEFM in commercial egg-layer flocks improves production measures, which has important welfare implications as well as gross economic advantage.     

Egg storage and breeder age impact on egg quality and embryo development

Prolonged hatching egg storage (>7 days) influences internal egg quality and embryo survival during both storage and subsequent incubation. Moreover, effects of storage of hatching eggs interact with the breeder age. The aim of this review was to investigate how this interaction between storage duration and breeder age affects egg, embryo, hatchling and chicken characteristics. Prolonged storage resulted in a reduction in egg quality in both young and old breeders. This reduction was more pronounced in young flocks than in older flocks. For example, albumen pH increased more after 8 days of storage in younger flocks than in older flocks. Additionally, the embryonic morphological stage appears to increase as well with storage duration, but this increase is again more pronounced in younger flocks than in older flocks. Short storage (<7 days) seems to increase hatchability of eggs from young breeders, probably as a result of albumen liquefaction with consequently better oxygen availability for the embryo. However, long storage (>7 days) resulted in a decline in hatchability, which was stronger in older breeders than in younger breeders. Prolonged storage duration resulted in lower chicken quality in both young and old breeders, but interaction between storage duration and breeder age on multiple chicken quality parameters is not clear. Based on this review, it can be concluded that (a) Short storage can improve hatchability of eggs from young breeders, but not from older breeders. (b) Negative impact of long storage appears to be lower with young breeders than with old breeders. (c) Adapted storage conditions related to the age of breeders might be an option to reduce negative effects of prolonged storage on hatching egg quality and chicken quality.     

Prevalence and epizootiology of equine salmonellosis.

Feces from 1,451 horses entering a veterinary hospital over a 13-month period were cultured for salmonella. A total of 46 horses (3.2%) yielded 1 or more salmonella-positive fecal cultures. Twenty horses were found to be excreting salmonella in the feces on admission, and 5 of these later had severe diarrhea associated with enteric salmonellosis. Abdominal surgery and other severe stresses were associated with all cases of severe enteric salmonellosis. Serotypes of salmonella isolated included Salmonella agona (15), S anatum (14), S typhimurium (7), S typhimurium var copenhagen (4), S infantis (2), S montevideo (1), S meleagridis (1), S drypool (1), and an unnamed Salmonella serotype (1). Seven deaths were attributed to 4 serotypes (S typhimurium, 3; S anatum, 2; S typhimurium var copenhagen, 1; and S montevideo, 1). A marked seasonal incidence is isolations was found with isolations highest in later summer to early fall and lowest in the spring. It was also found that horses can shed salmonella intermittently, and a minimal of 5 consecutive negative fecal cultures is recommended before considering a horse not to be infected with salmonella.     

A primary epidemic of inclusion body hepatitis in broilers

Inclusion body hepatitis (IBH) was diagnosed in 15 broiler flocks supplied by one breeder in the South Island of New Zealand. The affected flocks suffered mortality up to 30%. Malaise and slightly increased mortality were noticed by growers from about day 12 post-hatch; mortality peaked in the fourth week, and, in most flocks, declined to normally accepted levels from day 33 on. Gross signs seen at necropsy usually included bone-marrow aplasia, atrophy of the bursa of Fabricius and the thymus, and swollen hemorrhagic livers with focal necrosis. Jaundice was seen in many surviving birds. In some flocks, there was also proventricular hemorrhage, mild tracheitis, and airsacculitis. Downgrading and condemnation rates were increased in all flocks. Eosinophilic intranuclear inclusion bodies were seen in hepatocytes of some affected birds. An adenovirus was isolated from a number of cases investigated. The disease in broilers was preceded by production drops associated with feed refusal and increased mortality in the breeder stock.     

An enzyme-linked immunosorbent assay for detection of Bordetella avium infection in turkey flocks: sensitivity, specificity, and reproducibility.

An enzyme-linked immunosorbent assay (ELISA) for detection of Bordetella avium infection in turkey poults was developed. One-week-old poults challenged intratracheally with 10(12) colony-forming units of B. avium had detectable titers (greater than or equal to 11), with an average of 13.6% positive samples when the birds were 6 to 11 weeks old. The method was sensitive enough to detect maternal antibodies to B. avium in poults up to 3 weeks of age. The same poults challenged at 1 week of age had 100% tracheal infection up to 3 weeks of age, which dropped to 0% by 6 weeks. The method resulted in no false-positive samples (titer = 0) from birds not infected with B. avium and tested weekly between 4 and 11 weeks of age. Antibodies in turkey flocks infected with Newcastle disease virus, hemorrhagic enteritis virus, and Mycoplasma meleagridis, and birds infected with Escherichia coli had no apparent cross-reactivity to the B. avium antigens used in the ELISA. The percentages of B. avium-positive serum samples collected from different turkey flocks did not significantly differ (P greater than 0.05) when samples were tested by the developed ELISA at different times, an indication of the reproducibility of the method.