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1.
Previously, we have shown differences in susceptibility to the cecal carrier state in chicks orally infected with Salmonella enteritidis (SE) at 1 wk of age for four outbred lines: L2, B13, PA12, and Y11. The egg-type line L2 was one of the most susceptible lines and presented a large variability in cecal SE colonization. The heritability (h2) of the resistance to SE colonization in ceca was estimated in L2 chickens to determine whether genetic factors might be involved in its control. In three independent trials, a total of 819 L2 chicks produced from 88 sires and 232 dams were challenged orally with SE at 1 wk of age. Each week after inoculation, the frequency of cecal colonization was estimated. When this value had fallen to 50%, all the remaining animals were killed. The extent of cecal colonization by SE was estimated directly by counting the viable organisms in organs and determining the numbers of positive ceca. Enrichment culture was used in Trials 2 and 3. The effects of trial, of room within trial, and of cage within room on the frequency of SE contaminated ceca were often significant. No significant effect of sex was observed. Estimation of h2 using the frequency of SE positive ceca was low, 0.06 +/- 0.07, when results of direct culture were considered. In contrast, when considering the frequency obtained after enrichment, the h2 was estimated at 0.20 +/- 0.12. This result suggests a genetic basis for the expression of the resistance to colonization. An experiment of selection for resistance to SE carrier state in the chicken ceca should definitively confirm the genetic origin of the resistance.  相似文献   

2.
Leghorn chicks were treated with cultures of cecal bacteria from adult chickens by crop gavage, upper body spray, or vent lip application on the day of hatch. The chicks were challenged orally with 10(4) Salmonella enteritidis (SE) at 3 d of age and evaluated for SE cecal colonization at 10 d of age. The concentration of volatile fatty acids (VFA) in the cecal contents was determined on the day after culture treatment and at 10 d of age. Compared with controls, SE colonization was significantly decreased in each of the treatment groups. Vent lip application of a single .05-mL drop of cecal bacteria culture resulted in resistance against SE challenge comparable to crop gavage or spray treatment with .5 mL of culture. Resistance to SE challenge was directly associated with the concentrations of total VFA and propionic acid in the cecal contents of the treated chicks on the day after culture treatment. The results indicated that cecal bacteria from adult chickens that increase SE colonization resistance may rapidly become established in the ceca of newly hatched chicks following contact with the vent lips.  相似文献   

3.
The prevalence of Campylobacter and Salmonella on retail poultry carcasses remains a significant public health concern. The stresses associated with transporting poultry prior to slaughter have been shown to increase pathogen populations both in the intestinal tract and on the carcass exterior. The yeast, Saccharomyces boulardii, was evaluated for its ability to reduce populations of Salmonella and Campylobacter in broiler chickens subjected to transport stress. Chicks, inoculated with individual strains of Salmonella and Campylobacter were held for 6 wk and then divided into two groups with half of the chickens receiving 10% dried yeast in the feed for 60 h. The birds were then caged and transported to simulate commercial conditions. After euthanatizing the birds, the ceca were aseptically removed and analyzed for Salmonella and Campylobacter. With no yeast treatment, transport stress caused the Salmonella colonization frequency to increase more than fivefold, from 3.3 to 16.7%. Yeast treatment significantly reduced the frequency of Salmonella colonization to lower than prestress levels, as no Salmonella were recovered from the ceca of these birds (P < 0.05). Similar results were obtained from birds challenged with a mixture of Salmonella and Campylobacter strains. Before transport, 53.3% of these chickens were positive for Salmonella. Transport stress increased the colonization rate to 67.5% in control birds, whereas the colonization of yeast-treated chickens decreased to 40% (P < 0.05). Frequency of Campylobacter isolation from the ceca was not affected by treatment, but Campylobacter populations present in the ceca were significantly reduced in the mixed strain trial (P < 0.05).  相似文献   

4.
Broiler chicks were treated by oral gavage on the day of hatch with a continuous-flow competitive exclusion culture (PREEMPT). At 4 h, 1 day, or 2 days posttreatment, chicks were challenged by oral gavage with 10(2) or 10(4) Salmonella CFU to determine the effects of challenge time on Salmonella cecal colonization. Cecal propionic acid concentrations in two trials increased (P < or = 0.001) within 1 day posttreatment in chicks given PREEMPT, and the increases were indicative of the establishment of the PREEMPT bacteria. Salmonella cecal populations decreased (P < or = 0.001) on average 6 log10 units in these two trials in chicks challenged 4 h posttreatment with 10(4) Salmonella CFU. In a third trial propionic acid did not increase significantly until 2 days after treatment, and there was no decrease in Salmonella colonization when chicks were challenged at 4 h after treatment. However, there were decreases in that same trial when chicks were challenged at 1 and 2 days after treatment. The early establishment of PREEMPT followed by challenges with 10(2) and 10(4) Salmonella CFU resulted in 3% and 3%, respectively, of the ceca testing Salmonella-culture-positive, compared to 28% and 95%, respectively, culture-positive ceca in untreated chicks. The results from this study indicated that in most instances young broiler chicks can be protected against cecal colonization when challenged with 10(2) and 10(4) Salmonella CFU as early as 4 h posttreatment on the day of hatch with the PREEMPT bacteria.  相似文献   

5.
Much previously published research has focused on the role of cecal and intestinal Salmonella contamination of poultry carcasses within commercial processing plants. Presently, we have evaluated the persistence of experimentally inoculated Salmonella enteritidis in the crops and ceca of commercial broiler chickens during the last week of growth (Weeks 6 to 7) and the presence of crop and cecal Salmonella in 7-wk-old broilers in a commercial processing plant. When broilers were inoculated with 1 x 10(6) cfu S. enteritidis at 6 wk of age by oral gavage, the incidence of crop and cecal contamination was equivalent 2d after challenge (30%), with only 1 of 29 crops contaminated and 0 of 29 ceca contaminated at 7 d following challenge. When broilers were inoculated with 1 x 10(8) cfu S. enteritidis at 6 wk of age by oral gavage, 2 d after challenge the crops and ceca were observed to be 57 and 67% positive for S. enteritidis, respectively. Seven days after inoculation with 1 x 10(8) S. enteritidis, the crops and ceca were 37 and 57% positive, respectively, for the challenge organism. At a commercial broiler processing plant, 286 of 550 crops from three flocks were Salmonella-positive, whereas only 73 of 500 ceca from these flocks were contaminated. Furthermore, data from this plant indicated that the crops were far more likely to rupture than ceca (86-fold) during processing, increasing the possibility of carcass contamination with Salmonella derived from crop contents. The results of these studies suggest that the crop may serve as a source of carcass contamination with Salmonella within some processing plants.  相似文献   

6.
Expression of progesterone receptor (PR) in various organs of sexually immature chickens and after estrogen treatment was studied by immunohistochemical and Western blotting analyses. Constitutive PR expression was observed in the mesothelium and stroma of the esophagus, proventriculus, liver, spleen, pancreas, heart and lung. In the urogenital tract, PR was expressed in the mesothelial and stromal cells and smooth muscle of blood vessels. Estrogen treatment induced PR expression in the stroma and smooth muscle of the gall bladder and in the epithelium and stroma of the trachea. In the ovary of immature chickens PR was localized in the epithelium, stroma and smooth muscle and was induced in the granulosal cells by estrogen. In most tissues there was more PR-B than PR-A expression and this PR-B dominance remained after estrogen treatment. These results suggest that progesterone and estrogen may have physiological effects on many organs outside the genital tract not previously known as steroid-target tissues.  相似文献   

7.
An avirulent live delta cya delta crp Salmonella typhimurium strain chi 3985 that precludes colonization and invasion of chickens by homologous and heterologous Salmonella serotypes was evaluated for its long-term protection efficacy. Chickens vaccinated orally at 2 and 4 wk of age were assessed for protection against oral challenge with wild-type S. typhimurium and Salmonella enteritidis strains at 3, 6, 9, and 12 mo of age. A comparison of Salmonella isolation from vaccinated and nonvaccinated layers after challenge with S. typhimurium or S. enteritidis showed that delta cya delta crp S. typhimurium chi 3985 induced excellent protection against intestinal, visceral, reproductive tract, and egg colonization, invasion, and/or contamination by Salmonella. The duration of protection lasted for 11 mo after vaccination, at which time the experiment was terminated. S. enteritidis and S. typhimurium were isolated from the yolk, albumen, and shells of eggs laid by nonvaccinated chickens challenged with Salmonella. S. typhimurium caused pathological lesions in nonvaccinated chickens, whereas vaccinated and nonvaccinated chickens challenged with S. enteritidis showed no pathological lesion in the visceral and reproductive organs. Vaccination with chi 3985 prevented transmission of S. typhimurium or S. enteritidis into eggs laid by vaccinated layers with no effect on egg production. To our knowledge, this is the first publication confirming that vaccination with live avirulent Salmonella can induce long-term protection against Salmonella infection in layers.  相似文献   

8.
Eight groups of 1-day-old chickens were inoculated with 0, 250, 5000, or 100,000 white blood cells of chickens infected with Marek's disease virus strain K (MDV-WBC). Four of these groups were additionally infected with 10(5) TCID50 chicken anaemia virus (CAV). At day 14 after inoculation, chickens infected with CAV had reduced haematocrit levels, reduced body weights, and depletion of the thymic cortex and bone marrow. Semi-quantitative immunohistochemical examination of nerves and visceral organs was performed at day 28 by immunoperoxidase staining in which a monoclonal antibody specific for leucocytes was used. CAV significantly enhanced the number of lymphoproliferative lesions induced by 5000 MDV-WBC. In contrast, CAV significantly reduced the number of lymphoproliferative lesions induced by 100,000 MDV-WBC. Comparable results were found at day 61 after macroscopic examination of nerves and visceral organs. These findings show that the pathogenesis of MD in experimental infections appears to be enhanced or inhibited by CAV, depending on the dose of MDV.  相似文献   

9.
Serial passage of Salmonella enteritidis (SE) in chicken heterophils resulted in heterophil-adapted SE (HASE). We now report that an additional five heterophil passages have further reduced the number and frequency of fecal shedding of HASE. Eleven-times HASE (11 x HASE) given to 12 laying hens for three consecutive days reduced fecal shedding of 11 x HASE to three isolations from fecal samples during the 70-day postexposure observation period. Hens were exposed to challenge SE 74 days after treatment with 11 x HASE. Three of 12 11 x HASE-treated hens were positive for challenge SE (11/396 fecal samples, or 2.8%) between days 5 and 40 postchallenge, whereas all 12 challenge control birds were positive (118/420 fecal samples, or 28.1%) for SE. None of 12 11 x HASE-treated hens was fecal positive from day 9 postchallenge, whereas 10 of 12 challenge control hens (82/372 fecal samples, or 22.0%) remained positive until day 40, the termination of the experiment. None of 525 eggs and eggshells cultured after 11 x HASE exposure was positive for Salmonella, and none of 422 eggs and eggshells cultured after challenge SE exposure was positive for Salmonella. Eggs or eggshells from challenge control hens were positive for Salmonella in 12/479 (2.5%) cases after challenge SE exposure.  相似文献   

10.
Broiler chicks were spray treated on the day of hatch with titrated dosages (10(6), 10(7), or 10(8) anaerobic CFU) of a characterized competitive exclusion culture (CF3) and challenged orally on day 3 with 10(4) CFU of Salmonella typhimurium. On day 10, cecal contents from control and CF3-treated chicks were cultured for S. typhimurium to determine the minimal efficacious dosage of the CF3 culture. The experiment was repeated in three replicated trials. Resistance to Salmonella cecal colonization was dosage related and progressively enhanced at the 10(7)- and 10(8)-CFU dosages compared with the 10(6)-CFU dosage. The 10(7)-CFU dosage was selected as the minimal effective dosage and evaluated for efficacy during a 43-day broiler growout study. Six hundred broilers were spray treated on the day of hatch and compared with 600 controls. One-half of the control and CF3-treated birds were challenged orally on day 3 with 10(4) CFU of S. typhimurium and designated "seeders." The remaining unchallenged birds were designated "contacts." Compared with the controls, the recovery of Salmonella cells from the ceca of the CF3-treated broilers was significantly decreased (P < 0.01) in the challenged seeders on days 21 and 43 of growout. Salmonella contamination of floor pen litter was significantly reduced (P < 0.05) in pens of CF3-treated birds compared with controls. The transmission of Salmonella cells from seeder to contact birds in the same pens was decreased significantly (P < 0.01). The results indicated that treatment of broiler chicks on the day of hatch with the 10(7)-CFU dosage of CF3 culture effectively increased resistance to S. typhimurium challenge during growout to market age.  相似文献   

11.
Effects of chicken anemia virus on macrophage function in chickens   总被引:1,自引:0,他引:1  
One-day-old chicks were inoculated intramuscularly with chicken anemia virus (CAV). Four birds were killed at 7, 14, 21, 28, and 42 days postinoculation (PI), and macrophages were recovered from spleen and bone-marrow suspensions. These were tested for interleukin-1 (IL-1) production, Fc receptor expression, phagocytosis, and bactericidal activity. Macrophages recovered from uninoculated chickens at the same sample times, and exposed to CAV in vitro, were also tested. IL-1 production, Fc receptor expression, phagocytosis, and bactericidal activity were significantly lower in all macrophage cultures from CAV-inoculated chickens, and in cultures exposed to the virus in vitro, than in uninfected controls.  相似文献   

12.
BACKGROUND: There is a need to identify the follicular dendritic cells (FDC) of the chicken spleen at the ultrastructural level during a secondary immune response. METHODS: The cells were identified after intravenous priming BSA and boosting with biotinylated BSA conjugated to colloidal gold particles. Monoclonal antibodies raised specifically either to chicken IgG or IgM were used to characterize these immune complex-trapping cells. RESULTS: The FDC had an irregular morphology which varied through time, supporting the existence of two types of FDC in the chicken spleen, one showing filiform cell processes, the other provided with beaded dendrites. When the filiform dendrites were observed, the FDC bound the antigen on their surfaces. These dendrites showed an intrincate convoluted configuration, forming tightly wrapped networks near the cell body. The networks had the same features as those described in mammals as antigen retaining reticulum (ARR). In chickens, the ARR, which represents sites of antigen localization on FDC, reached maximum development on day 5 after the second injection of BSA and had disappeared by day 8. At this time FDC had beaded dendrites. CONCLUSIONS: Antigen is retained on FDC in the chicken spleen for long periods of time.  相似文献   

13.
A study was undertaken to determine the susceptibility or resistance of 9 outbred experimental or commercial poultry lines to Salmonella enteritidis PT4. Young chicks were inoculated either intramuscularly or orally just after hatching. After intramuscular challenge the lines could be divided into susceptible lines (LD 50% < or = 10(2) Salmonella per animal), intermediate lines (LD 50% about 10(4) Salmonella) and resistant lines (LD 50% > 10(5) Salmonella). The results obtained after oral challenge confirmed these 3 groups for both mortality rates and the probability of the presence of salmonellae in the spleen and liver. There was no difference between lines concerning caecal carriage.  相似文献   

14.
Specific-pathogen-free chickens were infected with chicken anemia virus (CAV) at 1 day of age and killed after 6 days. Using a double-antibody staining procedure, spleen, thymus, and bone-marrow cells containing CAV antigen were stained for presence of T-cell antigens and chicken major histocompatibility complex (MHC) Class 1 and 2 antigens. The results demonstrated CAV infection of precursor T-cells in the thymus and of mature T-lymphocytes in the spleen. A significant proportion of the cells infected in bone marrow expressed MHC Class 2 antigens but did not exhibit the characteristics of T-lymphocytes. Since CAV grows in MDCC-MSB1 cells, the staining characteristics of these cells were also studied. MSB1 cells possessed all of the characteristics of mature, helper T-lymphocytes.  相似文献   

15.
The presence of Campylobacter and Salmonella on poultry meat products remains a significant public health concern. Previous research has indicated that feed withdrawal may significantly increase Salmonella contamination of broiler crops and that crop contents may serve as an important source of Salmonella carcass contamination at commercial processing. The present study evaluated the effect of preslaughter feed withdrawal on the incidence of Campylobacter isolation in crops of market-age commercial broiler chickens prior to capture and transport to the processing plant. The incidence of Campylobacter isolation from the crop was determined immediately before and after feed withdrawal in 40 7-wk-old broiler chickens obtained from each of nine separate broiler houses. Ceca were collected from broilers in six of the same flocks for comparison with the crop samples. Feed withdrawal caused a significant (P < 0.025) increase in Campylobacter-positive crop samples in seven of the nine houses sampled. Furthermore, the total number of Campylobacter-positive crops increased significantly (P < 0.001) from 90/360 (25%) before feed removal to 224/359 (62.4%) after the feed withdrawal period. Alternatively, feed withdrawal did not significantly alter the Campylobacter isolation frequency from ceca. Similar to our previous studies with Salmonella, the present results suggest that preharvest feed withdrawal increases the frequency of Campylobacter crop contamination and, thus, provides a source of Campylobacter contamination of carcasses at commercial processing.  相似文献   

16.
The avirulent Salmonella typhimurium chi3985 was used to vaccinate white leghorn chickens at 16 and 18 weeks of age, and the effect of maternal antibody on Salmonella colonization of progeny of vaccinated hens was assessed with S. typhimurium F98 or chi3985. Progeny of hens that had been vaccinated at 1 and 3 or 2 and 4 weeks of age with chi3985 were used to determine the effect of maternal immunity on vaccine efficacy. Vaccination of hens induced long-lasting Salmonella-specific antibodies which were transferred into eggs and were detected as immunoglobulin G (IgG) in the egg yolk. Maternal antibody was detected in the progeny of vaccinated birds as IgG and IgA in serum and intestinal fluid, respectively. The titer of maternally transmitted IgG or IgA was highest in the first week of life of the progeny and declined with age. Maternal antibodies prevented colonization of the chicks by S. typhimurium chi3985 and reduced colonization by S. typhimurium F98. Overall, chicks from vaccinated hens had significantly higher antibody responses than did the progeny of nonvaccinated hens after oral infection with Salmonella strains. Maternal antibody reduced the efficacy of vaccination of progeny with chi3985 at 1 and 3 weeks of age. But vaccination at 2 and 4 weeks of age induced excellent protection against challenge with S. typhimurium F98 or S. enteritidis 27A PT 8 in birds from vaccinated hens and in specific-pathogen-free chickens. Vaccination of chickens at 2 and 4 weeks of age has been shown to protect the birds against challenge with homologous and heterologous Salmonella serotypes. A combination of vaccination of adult animals and use of the progeny of vaccinated birds will enhance effective control of Salmonella infections in the poultry industry. This will complement the present control of Salmonella-associated food poisoning caused by Salmonella enteritidis in eggs because the avirulent S. typhimurium vaccine strain chi3985 induced excellent protection against S. enteritidis in chickens.  相似文献   

17.
The phagocytic and bactericidal activities to Salmonella pullorum (strain 9-25) or Salmonella senftenberg (strain 99D) were examined in chicken splenic phagocytes from 0-day-old to 2-month-old chickens. The phagocytic activity against S pullorum increased in splenic phagocytes from chickens older than 7 days, but significant changes in activity against S senftenberg were not observed during the experimental period. The bactericidal activity of splenic phagocytes against S senftenberg was higher than that of phagocytes against S pullorum during the same period. Increase of the bactericidal activity against S pullorum was observed with increasing age, but the activity of the splenic phagocytes from 0-day-old chickens against S senftenberg was similar to that of the phagocytes from 2-month-old chickens. Although delayed hypersensitivity was confirmed by delayed wattle reaction in 2-month-old chickens sensitized with living S pullorum, the sensitization did not markedly affect phagocytic and bactericidal activities.  相似文献   

18.
Insulin-like growth factor-I (IGF-I) effects on chicken growth and development are poorly understood. This study examined the effect of IGF-I on protein synthesis rates in various tissues in the male broiler chicken. At three weeks of age, osmotic minipumps were subcutaneously implanted in the scapular area. Chickens were infused with either chicken IGF-I (450 micrograms/kg BW/day) or saline. After treatment for 5 days, the chickens received a flooding dose of [3H]-phenylalanine, and were sacrificed 20 min later. Wing vein blood samples were taken at 0, 5, 10 and 20 min post-injection. The following tissues were removed and frozen for analysis: pectoralis muscle, gastrocnemius muscle, heart, liver, and small intestine. In vivo total protein synthesis measurements were made using the double-label technique. Contractile protein degradation was evaluated using intracellular free 3-methylhistidine concentrations in skeletal muscle. There were no significant differences in absolute or relative body growth rates over the treatment period. Skeletal muscle (pectoralis and gastrocnemius) weights were significantly decreased with IGF-I treatment, while heart weight was significantly increased. Plasma insulin levels were significantly lower in IGF-treated chickens compared to that in control birds. There was no effect of IGF-I on protein synthesis rates in any of the tissues examined. Intracellular free 3-methylhistidine concentrations were higher in both the gastrocnemius (17%) and pectoralis muscles (25%) of chickens treated with IGF-I. This data demonstrates that IGF-I may have an indirect effect to regulate muscle protein turnover rates.  相似文献   

19.
Horizontal transmission of Salmonella enteritidis and the effect of airflow on spreading were examined in 80 5-wk-old chickens divided into five groups. Sixteen chickens in each group were placed in four cages in a row separated by wire. One among four chickens placed in a cage at the downwind end of the row was inoculated orally with 10(9) colony-forming units of S. enteritidis. Cecal droppings, drinking water, and feed were cultured every day. Horizontal transmission was rapid in the row with low air velocity but slow in the row with high air velocity. However, in another experiment, where the inoculated chicken was situated in a cage upstream in the airflow, horizontal transmission was equally rapid whether the airflow was rapid or slow. Contamination of feed and water never preceded the appearance of positive cecal droppings. These findings suggest that the rapidity of horizontal transmission of S. enteritidis may be affected by airflow patterns.  相似文献   

20.
The role of immune complexes (Icx) in B-cell memory formation and affinity maturation allow for their potential use as vaccines. Recently, a new immune complex vaccine has been developed that is currently under field trials conducted in commercial poultry. This immune complex vaccine is developed by mixing live intermediate plus infectious bursal disease virus (IBDV) with hyperimmune IBDV chicken serum (IBDV-Icx vaccine). Here we have investigated the infectivity of this vaccine as well as the native IBDV (uncomplexed) vaccine in terms of differences in target organs, in target cells and speed of virus replication. At various days after inoculation on day 18 of incubation (in ovo) with either one dose of virus alone or the IBDV-Icx vaccine, the replication of IBDV and the frequency of B cells and other leucocyte populations were examined in the bursa of Fabricius, spleen, and thymus using immunocytochemistry. With both vaccines, IBDV was detected associated with B cells, macrophages and follicular dendritic cells (FDC) in bursa and spleen, although complexing IBDV with specific antibodies caused a delay in virus detection of about 5 days. Most remarkable was the low level of depletion of bursal and splenic B cells in IBDV-Icx vaccinated chickens. Furthermore, in ovo inoculation with the IBDV-Icx vaccine induced more germinal centres in the spleen and larger amounts of IBDV were localized on both splenic and bursal FDC. From these results we hypothesize that the working mechanism of the IBDV-Icx vaccine is related to its specific cellular interaction with FDC in spleen and bursa.  相似文献   

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