The effect of biological isolation and a molt-inducing regimen on the recovery of Mycoplasma gallisepticum from commercial Leghorn hens

Two trials were conducted to determine the effect of induced molt on the reisolation of Mycoplasma gallisepticum (MG) from commercial leghorn hens that had been eyedrop-inoculated with MG at 10 weeks of age. Chickens were maintained in a conventional floored chicken house on dry litter through 100 weeks of age. At age 64 weeks, 4 days (Trial 1), and at 100 weeks (Trial 2), hens were swabbed and cultured for MG and then molted in biological isolation units. Swabs were again taken at the end of each molt. No difference was observed in the number of MG isolations between molted hens and controls that did not undergo molting. However, a significant decrease in MG isolations was observed in both trials from swabs obtained when hens were housed on dry litter floors as compared with swabs taken from the same hens after 18 days (Trial 1) or 21 days (Trial 2) of confinement in isolation units.     

Egg production, egg weight, eggshell strength, and mortality in three strains of commercial layers vaccinated with F strain Mycoplasma gallisepticum

Three strains of commercial leghorns vaccinated at 17 to 22 weeks of age with F strain Mycoplasma gallisepticum (MG) were maintained through 117 weeks of age. The three strains differed in both mortality and percent egg production per hen housed; however, the strains did not differ in egg weight (EW), eggshell strength (ESS), or percent daily egg production. Results of this study indicate EW and ESS for F strain MG-vaccinated hens follow patterns previously reported for uninfected layers. Further, mortality may account, in part, for differences in percent egg production per hen housed between strains of F strain MG-vaccinated hens.     

Campylobacter jejuni infection in broiler chickens

Day-old, straight-run broiler chickens were procured from a hatchery located in the Pacific Northwest. The chickens were subdivided individually into nine groups of 20 chickens. The chickens were tagged, housed in isolation chambers on wire, fed commercial broiler feed, and given water ad libitum. Three isolates of Campylobacter jejuni of poultry origin and one of human origin were tested in this study. Various C. jejuni cultures were inoculated into 9-day-old chickens by crop gavage. Four groups of 20 chickens were inoculated at a dose level of 0.5 ml of 1 x 10(2) colony-forming units (CFU)/ml. The other four groups were inoculated with 0.5 ml of 1 X 10(4) CFU/ml. One group of 20 chickens was kept as an uninoculated control group. Four randomly selected chickens from each of the inoculated and uninoculated groups were necropsied at 5, 12, and 19 days postinoculation (DPI). The C. jejuni was cultured and enumerated from a composite of the upper and midintestine and the cecum. Body weights of all chicken groups at 7 days of age and at 5, 12, and 19 DPI were measured and statistically analyzed. No significant differences were present in the mean body weights (MBWs) of 7-day-old, 5 DPI, and 12 DPI male and female broiler chickens inoculated with C. jejuni at both dose levels compared with uninoculated controls. Differences in MBWs of the male and female broilers at 19 DPI were observed in some of the groups. Results of the C. jejuni culture enumeration mean (CEM) of composite intestine samples at 5 DPI from all inoculated chicken groups, irrespective of the dose level, ranged from (2.5 +/- 5.0) x 10(2) to (2.8 +/- 4.8) x 10(5) CFU/g (mean +/- SD). Results of cecum C. jejuni CEM at 5 DPI inoculated at both dose levels ranged from (2.5 +/- 5.0) x 10(6) to (1 +/- 0.0) x 10(7) CFU/g in all treatment groups irrespective of the dose level. CEM results from the composite intestine samples at 12 and 19 DPI increased by 1 log unit, or sometimes more. Results of cecum C. jejuni CEM at 5 DPI inoculated at both dose levels ranged from (2.5 +/- 5.0) x 10(6) to (1 +/- 0.0) x 10(7) CFU/g in all treatment groups irrespective of the dose level. Increases of 2-5 log units in C. jejuni CEM was present in chicken groups inoculated with 1 X 10(2) CFU of C. jejuni, and a 2- to 3-log increase was present in groups inoculated with a higher dose level of C. jejuni at 12 DPI. The results of C. jejuni CEM from cecal samples at 19 DPI were similar to chicken groups at 12 DPI. Campylobacterjejuni was not isolated from the uninoculated control chickens at 5, 12, and 19 DPI. Clinical signs of illness or gross pathologic lesions were not present in any of the chicken groups during this study. No lesions were present on histopathologic evaluations in C. jejuni-inoculated chickens or uninoculated control chickens.     

Differential Effects of Heat Stress in Three Strains of Laying Hens

Hy-Line Brown, W36, and W98 hens were housed for 2 wk at 22°C, exposed to 35°C heat stress (HS) for 2 wk, and had 2 wk of recovery at 22°C. Production parameters (egg production, feed intake, egg quality measures, and mortality), acid-base status (pH, pCO₂, HCO₃⁻, pO₂), intestinal calcium uptake, and expression of hepatic heat shock protein-70 were measured. All production parameters except mortality were reduced by HS in all 3 strains. There were strain × temperature interactions for egg production, feed intake, shell thickness, specific gravity, and yolk weight, with the least severe reduction in W98 hens. The W36 hens were intermediate for egg production and feed intake, and the Brown and W36 hens were equivalent for shell thickness, specific gravity, and yolk weight. There were no interactions for egg, albumen, and shell weights, Haugh units, and intestinal calcium uptake, and all were reduced by HS. Blood pH and pCO₂ were reduced by HS, and hepatic heat shock protein-70 was increased, with no differences among strains. Mortality rates during HS were 16, 8, and 4% for the Brown, W98, and W36 hens, respectively, but were not subjected to statistical analysis. The results suggest a mechanism in the W98 bird that appears to confer an advantage during HS with regard to egg production.     

Cold stress induces an adrenocortical response in bottlenose dolphins (Tursiops truncatus)

Two adult bottlenose dolphins (Tursiops truncatus) were individually housed in aboveground pools over a 10-day period and exposed to decreasing water temperatures to determine whether cold stress activated the hypothalamic-pituitary-adrenal axis. To serve as controls, two additional adult dolphins were similarly housed for the same duration but at ambient water temperatures (16.8-19.6 degrees C). Across all subjects, water temperatures ranged from 4.2 to 19.6 degrees C. Voluntary blood draws were made from each dolphin every 2-3 days, and serum was analyzed via radioimmunoassay for cortisol and aldosterone. Dolphins exposed to cold water showed an increase in serum cortisol and aldosterone as temperature declined; at the coldest water exposure, cortisol was more than three times and aldosterone more than two times the levels measured at ambient temperature. Elevations occurred before the water temperature declined below the individual animal's lower critical temperature, the point at which the metabolic rate increases to compensate for the loss of body heat. Variations in corticosteroids were unrelated to the 10-day isolation period, suggesting that the response was related to the cold stress and not impacted by the isolation. Elevations in cortisol and aldosterone were lower than those observed in force captured and stranded dolphins. Although potentially related to the general adaptive stress response, elevations in cortisol and aldosterone may have other adaptive functions related to mitigating impacts resulting from cold environmental temperatures.     

Effect of furnished small group housing systems and furnished cages on mortality and causes of death in two layer strains

1. Mortality and causes of death were recorded over two trials with 13045 Lohmann Selected Leghorn (LSL, white layer strain) and 4410 Lohmann Brown (LB) laying hens kept in furnished small group housing systems and furnished cages. In trial 1, hens were housed from weeks 19 to 71 (LSL) and 17 to 69 (LB). In trial 2, LSL hens were housed from weeks 18 to 57. 2. The hens were kept in groups of 40 and 60 in the furnished small group housing system Eurovent 625 + a-EU and in groups of 10 and 20 in the furnished cages Aviplus and Eurovent 625A-EU. 3. To investigate the possible effect on mortality of rearing the birds on litter floors or in cages, in trial 2 half of the LSL hens were reared on the floor and half in conventional cages. 4. Mortality was greater in the Eurovent furnished small group housing system (5.2%) than in the furnished cages Aviplus (4.0%) and Eurovent (4.2%). 5. Mortality was also affected by the interactions among housing system and trial, layer strain and rearing. In trial 1, more LB laying hens died in the Aviplus system than in the Eurovent group system. There was no significant difference in mortality of the LSL laying hens between housing systems in trial 1. In trial 2, mortality of the LSL hens was greater in the group housing system (hens reared on litter floors: 10.1%; hens reared in cages: 2.8%) than in the furnished cage Aviplus (hens reared on litter floors: 6.0%; hens reared in cages: 1.5%). 6. Mortality was greater in floor-reared LSL laying hens than in the LSL laying hens reared in conventional cages. 7. Group size within housing system had no significant effect on mortality. 8. The most common findings at autopsy were different types of cannibalism (65.51%), with vent cannibalism (38.57%) the most common.     

Evaluation of feeding spray-dried bovine plasma protein on production performance of laying hens exposed to high ambient temperatures

The purpose of this study was to evaluate feeding 2 levels of spray-dried bovine plasma protein (SDP) on production performance of laying hens subjected to high ambient temperatures. Two groups of 96 Hy-Line W-98 hens (38 wk of age) were housed in each of 2 environmentally controlled chambers. At 40 wk of age, all hens were fed 3 diet treatments consisting of (1) a control diet (0% SDP); (2) the control diet supplemented with 0.75% SDP; and (3) the control diet supplemented with 1.50% SDP. Hens in each chamber (8 cages of 4 hens per cage) were ad libitum fed 1 of each diet for 5 wk. The heat stress (HS) chamber was maintained at 21°C (wk 1), 29°C (wk 2), and 35°C (wk 3 to 5). The thermoneutral chamber was maintained at 21°C during wk 1 to 5. A significant main effect of week was observed for hens maintained in the HS chamber for egg production, egg weight, egg mass, and feed consumption, which resulted in acute heat stress causing a reduction in these parameters. Hens fed the 1.50% SDP diet in the HS chamber produced greater (P < 0.05) egg mass on average than hens fed the control or 0.75% SDP diet (wk 1 to 5). During the second week of acute HS (wk 4), hens fed the control and 1.50% SDP diets had greater (P < 0.05) egg production than those fed the 0.75% SDP diet. During wk 5, hens in the HS chamber that were fed the 1.50% SDP diet produced more (P < 0.05) eggs than those fed the control diet. Therefore, based on the results of this study, acute HS negatively affected short-term production performance. In addition, feeding hens an SDP-supplemented diet may have a slight positive effect on production performance when maintained in acute HS conditions.     

Effect of heat stress on oxidative stress, lipid peroxidation and some stress parameters in broilers

1. This study was conducted to determine the effects of heat stress on fearfulness, leucocyte components, oxidative stress and lipid peroxidation in two commercial broiler strains, Cobb (C) and Ross (R). 2. At 36 and 37 d of age birds were exposed to 38 +/- 1 degree C for 3 h. Rectal temperatures, duration of tonic immobility (TI), haematocrit values, proportions of leucocyte components (heterophil, lymphocyte, basophil, eosinophil, monocyte), malondialdehyde (MDA) concentrations and antioxidant enzyme activities (CAT, SOD, GPx) of all the birds were determined, before and after heat treatment. 3. Rectal temperatures increased and haematocrit values decreased in birds exposed to heat stress. Heat stress caused a significant increase in heterophil/lymphocyte and in basophil ratios. 4. Exposing birds to heat stress increased duration of TI, suggesting heat-stressed birds tended to be more fearful. 5. Heat stress resulted in a significant Genotype x Treatment interaction for MDA concentration. CAT, SOD and GPx activities; MDA concentrations in heat-stressed R strain birds were greater than in heat-stressed C strain birds.     

F strain Mycoplasma gallisepticum vaccination of post-production-peak commercial Leghorns and its effect on egg and eggshell quality

Forty-five-week-old commercial leghorns negative for antibodies to Mycoplasma gallisepticum (MG) and M. synoviae were vaccinated with high-passage F strain MG (FMG). Hens were confined in modified Horsfall-Bauer isolation units through 60 weeks of age. Egg production (% hen day) and parameters of egg and eggshell quality were monitored, including egg weight, eggshell strength, Haugh unit score, pimpling, and blood/meat spot incidence. Egg production was significantly lower (P less than 0.05) for FMG vaccinates than controls (down 5.76% and 5.80% in Trials 1 and 2, respectively). However, vaccinates and controls did not differ significantly in eggshell strength, shell thickness, pimpling, or blood/meat spot incidence. Haugh unit scores were significantly (P less than 0.05) greater for FMG vaccinates. At necropsy, all reproductive tracts appeared grossly normal. These studies suggest that high-passage FMG vaccination of post-production-peak hens does not adversely affect oviduct function.     

Effects of an S6 strain of Mycoplasma gallisepticum inoculation before beginning of lay on the leukocytic characteristics of commercial layers

A clinical study was conducted on commercial layers housed in biological isolation units, within which exogenous stress factors potentially affecting bird performance were minimized. This set-up was devised in order to assess how a pre-lay inoculation of S6 strain Mycoplasma gallisepticum affects the leukocytic properties of laying chickens. Previous studies have demonstrated relative decreases in lymphocyte and relative increases in heterophil percentages in birds infected with other strains of Mycoplasma gallisepticum. However, current results showed that the differential percentages of lymphocytes were decreased, whereas those of heterophils were increased, in both sham-inoculated control birds and birds inoculated with S6 Mycoplasma gallisepticum between 19 and 26 wk of age. This study clearly shows that a pre-lay inoculation of S6 Mycoplasma gallisepticum alone had no apparent effect on the leukocyte profile of commercial layers housed in biological isolation units.     

Battery gage shape: The laying performance of medium‐ and light‐body weight strains of hens

1. One thousand two hundred and ninety‐six medium‐ and 1296 lightweight hens were housed, four to a cage, in deep (conventional) cages, 405 mm wide by 460 mm deep, or shallow cages, 610 mm wide by 305 mm deep, between 18 and 70 weeks of age. The performance of the hens during different periods of the laying stage and over the full laying year was measured.

2. Egg number per medium‐weight hen housed in shallow cages was significantly higher than of hens housed in deep cages between 18 and 30 weeks and 31 and 42 weeks. Thereafter significant differences were not found. With the light‐weight hens the increase was significant only in the 18‐ to 30‐week period. Apart from the 19‐ to 30‐week period hens of both strains housed in shallow cages consumed significantly less food than those in deep cages, the reduction over the full year being about 4%. In all periods the hens housed in the shallow cages converted food more efficiently. Gage shape had no significant effect on mortality.

3. The incidence of hair‐cracked, cracked and broken eggs between 60 and 70 weeks of age from hens housed in shallow cages was lower than that from hens housed in the deep cages but only with the light‐weight hens did this difference reach significance. Shell thickness, shell weight and albumen quality of eggs laid by hens housed in the different shaped cages were not significantly different.     

Pathogenicity of embryo-adapted serotype 2 OH strain of infectious bursal disease virus in chickens and turkeys

The pathogenicity of serotype 2 OH strain of infectious bursal disease virus (IBDV) to specific-pathogen-free (SPF) chicken embryos and 2-wk-old SPF chickens and turkey poults was investigated. The virus was pathogenic for chicken embryos after five passages as evidenced by pathologic changes in inoculated embryos. The embryo-adapted virus was not pathogenic for 2-wk-old SPF chickens and turkey poults as indicated by lack of clinical signs, gross or microscopic lesions in the bursa of Fabricius of inoculated birds. Bursa-to-body-weight ratios of the inoculated chickens and turkey poults were not significantly different from those of uninoculated controls. Virus-neutralizing antibodies to serotype 2 IBDV were detected in inoculated chickens and turkeys. Results of this study indicated that the embryo-adapted serotype 2 OH IBDV isolate that is pathogenic for chicken embryos is infectious but not pathogenic in chickens and turkeys.     

Horizontal transmission of Salmonella and Campylobacter among caged and cage-free laying hens

In each of five sequential trials, laying hens (56-72 wk of age) were challenged with Salmonella and Campylobacter, and 1 wk postinoculation, the challenged hens (n = 3) were commingled with nonchallenged hens (n = 12) in conventional wire cages, on all-wire slats, or on all-shavings floor housing systems. After 12 days, challenged and nonchallenged hens were euthanatized for sample collection. Ceca were aseptically collected from all hens, and the spleen, liver/gallbladder (LGB), lower (LRT) and upper (URT) reproductive tracts, and ovarian follicles (mature and immature) were collected from only the challenged hens after commingling. Samples were divided equally and cultured separately for Salmonella and Campylobacter. Differences in the horizontal transmission of the challenge Salmonella to nonchallenged hens housed in cages (12%), on slats (15%), and on shavings (14%) were not significantly different (P > 0.05) from the challenged pen-mate hens over the five trials. However, with the inclusion of residual environmental Salmonella, the recovery of Salmonella from nonchallenged hens housed in cages was lowest at 15%, intermediate for hens on slats at 20%, and highest for hens on shavings at 38%. Among challenged hens housed in cages, Salmonella was recovered from only 27% of the cecum and LRT samples. From challenged hens housed on slats, Salmonella was recovered from 38% of the cecum, 12% of the spleen, 19% of the LGB, 44% of the LRT, and 19% of the URT samples. From challenged hens housed on shavings, Salmonella was recovered from 31% of the cecum; 15% of the spleen, LGB, and URT; and 31% of the LRT samples. Horizontal transmission of Campylobacter among nonchallenged pen-mate hens was significantly lower for hens housed in cages at 28% than for hens on shavings at 47%, with hens on slats being intermediate at 36%. For challenged hens housed in cages, Campylobacter was recovered from 27% of the cecum, 13% of the LRT, 7% of the URT, and 17% of the follicle samples. Among the challenged hens housed on slats, Campylobacter was recovered from 44% of the cecum, 6% of the spleen, 19% of the LGB, 12% of the LRT, 6% of the URT, and 14% of the follicle samples. Among challenged hens housed on shavings, Campylobacter was recovered from 46% of the cecum, 8% of the LRT and URT, and 40% of the follicle samples. The overall results of this study indicate that the caged housing system provided the lowest horizontal transmission level of Salmonella and Campylobacter among egg-laying hens.     

Experimental infection of pigs with a thymidine kinase negative strain of pseudorabies virus

Sixteen 20 day old pigs, devoid of neutralizing antibody to pseudorabies virus (PRV), were divided into two groups of eight, and the animals of each group were housed in a separate unit. In each group 6 pigs were inoculated intranasally with the thymidine kinase (TK⁻) mutant (Group 1) or the field strain of PRV (Group 2), each pig receiving an inoculum of 4 ml. The remaining 2 pigs in each group served as uninoculated controls. The only clinical sign observed in the pigs of Group 1 was a transient febrile reaction, in the case of six pigs inoculated with the TK⁻ mutant of PRV, whereas no signs of disease were seen in the uninoculated controls. The virus was isolated from the 6 infected pigs of the group only on post infection day (PID) 2, whereas it was never isolated from the controls. By contrast, the pigs of Group 2, had a severe clinical response and one, among those that were inoculated with the field strain of the PRV, died on PID 9. Virus was consistently isolated from all pigs of Group 2, inoculated and control. On PID 30 all pigs, i.e. the 8 of Group 1 and 7 of the Group 2 which survived to the infection, were subjected to dexamethasone (DMS) treatment. After DMS treatment virus was never isolated from the nasal swabbings obtained from the pigs of Group 1, whereas it was consistently isolated from pigs of Group 2. After 30 d from the start of DMS treatment the pigs were killed and several tissues were collected from each pig for virus detection, by isolation in tissue culture and by PCR analysis. At necropsy no lesions were found in pigs of Group 1, whereas acute pneumonia and gliosis in the trigeminal ganglia were observed in pigs of Group 2. Virus was never isolated from any of the tissues taken from pigs of both, Group 1 and Group 2, nevertheless sequences of PRV were detected by PCR analysis in the trigeminal ganglia of the pigs of both Groups.     

鸡传染性贫血病疫苗免疫母鸡后子代雏鸡外周血液T细胞数量及免疫球蛋白含量变化

应用免疫SPA菌体不法和间接ELISE法对鸡传染性贫血病（CIA）疫苗免疫母鸡后，其子代雏鸡外周血液T细胞数量和血清IgG,IgM,IgA含量进行了动态研究。结果发现：CIA疫苗免疫母鸡后，其子代雏鸡外周血液T细胞数量和IgG,IgM,IgA含量均不同和蔼地高于未免疫的相对照雏鸡，表明CIA疫苗免疫母后，其子代雏鸡全身的体液上述各项指标均明显低于疫苗免疫的子代雏鸡，这与CIAV强毒攻击子代雏鸡后，未免疫的子代雏鸡外周血液上述各项指标均明显低于疫苗免疫的子代雏鸡，这与CIAV强毒感染雏鸡后，其免疫器官组织，尤其是胸腺严重损害，淋巴细胞变性坏死子等密切相关，是导致感染鸡免疫功能低下的基础。     

Effects of age at inoculation and induced molt on the recovery of Mycoplasma gallisepticum from layer chickens.

An experiment was conducted to determine the effects of age at inoculation and induced molt on the reisolation of Mycoplasma gallisepticum (MG) from commercial leghorn hens that had been eyedrop-inoculated with F strain MG at either 10 or 66 wk of age. Chickens were maintained in biological isolation units from 10 wk of age through 78 wk of age. At 70 wk of age (premolt), hens were swabbed, cultured for MG, and molted. Swabs were taken both at the end of molt (postmolt [74 wk]) and again 4 wk later (postmolt+4 [78 wk]). A significant (P < or = 0.05) decrease in MG isolations was observed in the postmolt swabs as compared with the premolt swabs of hens inoculated at either 10 or 66 wk of age. A significant (P < or = 0.05) increase in isolations was observed in the postmolt+4 swabs as compared with the postmolt swabs of hens inoculated at either 10 or 66 wk of age. For the hens inoculated at 10 wk, no significant difference was found in premolt as compared with postmolt+4 MG isolations; however, for hens inoculated at 66 wk, a significant (P < or = 0.05) decrease was observed between premolt and postmolt+4 isolations. Significantly (P < or = 0.05) fewer MG isolations were obtained from the premolt swabs of hens inoculated at 10 wk as compared with hens inoculated at 66 wk. No significant difference in MG isolations was observed in either the postmolt or postmolt+4 swabs between hens inoculated at either 10 or 66 wk.     

拜城油鸡与良凤花鸡杂交后代(F3A型)屠宰性能及肉品质分析

利用拜城油鸡公鸡与良凤花母鸡杂交一代(F_1),再利用拜城油鸡的公鸡与F_1中的青脚母鸡级进杂交,得到F_2代,选取F_2代的青脚母鸡与F_2代的高脚公鸡进行横交,得到油麻鸡F_3A型,测定其公、母鸡的屠宰性能与肉品质指标。结果表明:F_3A型公、母鸡的屠宰率、半净膛率、全净膛率分别比拜城油鸡公、母鸡提高6.73%(P<0.01)、5.8%(P<0.05)、2.82%(P>0.05)和4.42%(P<0.05)、4.22%(P<0.05)、1.65%(P>0.05);公、母鸡胸肌肉色分别比良凤花鸡提高7.31和11.08,公、母鸡腿肌肉色比良凤花鸡提高21.23和16.88;公、母鸡胸肌滴水损失分别比良凤花鸡提高1.26%(P<0.01)和4.73%(P<0.01)。拜城油鸡与良凤花鸡杂交后,杂交后代的屠宰性能有明显改善,肉品质指标亦有相应变化。     

Responses to heat stress in commercial and local broiler stocks. 1. Performance traits.

1. This study investigated effects of conditioning at 5 d of age and food restriction during a hot period on responses to prolonged heat stress of two fast (G1 and G2) and one slower-growing (G3) broiler stocks. 2. Chicks from each stock were divided into 3 groups: control, conditioned (chicks exposed to 36 degrees C for 24 h at 5 d of age) and food restricted (during the heat stress food was withdrawn 2 h before the hot period and chicks were fed between 17.00 and 08.00 h). Prolonged heat stress was induced daily from 28 to 49 d by heating until the ambient temperature reached 32 degrees to 35 degrees C between 10.00 and 17.00 h. 3. Body weights, mortality and rectal temperatures were lower and food conversion higher for stock G3 than G1 or G2. 4. Management procedures used in this study improved food conversion and lowered mortality without affecting body weight. Rectal temperatures of the treated groups were similar to those of the controls.     

Effects of Eimeria mitis on egg production of single-comb White Leghorn hens.

Single-comb white leghorn hens infected with either B4 or C2 strain of Eimeria mitis produced watery droppings as early as day 5 PI. E. mitis infection did not affect egg weight. However, specific gravities of the eggs produced by the hens infected with E. mitis were lower than those produced by the controls. Egg production was significantly reduced temporarily, but most birds returned to production within 14 days. Many of the birds that ceased to lay went through a complete-body molt (56% of the C2-infected hens and 20% of the B4-infected hens). Hens that ceased to lay regained considerable amounts of pigment in their skin, beaks, and shanks.     

CIA-IBD联合免疫种鸡后子代雏鸡外周血液免疫学变化

应用免疫SPA菌体花环法、MTT法和间接ELISA法对鸡传染性贫血病(CIA)-传染性法氏囊病(IBD)联合免疫种鸡后,其子代雏鸡外周血液T细胞数量和增殖功能以及免疫球蛋白IgG、IgM、IgA含量变化进行了动态研究。结果发现,CIA-IBD联合免疫种鸡后,其子代雏鸡外周血液T细胞数量和IgG、IgM、IgA含量均不同程度地高于未免疫的相应对照雏鸡,表明CIA-IBD联合免疫种鸡后,其子代雏鸡外周血液体液免疫和细胞免疫功能明显增强。而CIAV、IBDV强毒攻击后,未免疫的子代雏鸡,其外周血液的上述指标均明显低于疫苗免疫的子代雏鸡,表明未免疫的子代雏鸡外周血液的免疫机能降低,这与未免疫雏鸡缺乏特异性抗体,强毒攻击后,雏鸡免疫器官组织广泛损害,淋巴细胞变性坏死等有关。