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1.
Twenty-eight one-day-old chickens with infectious bronchitis virus (IBV) maternal antibodies were immunized with strain H120 (Bronchovac-I, Phylaxia) in spray form. The chickens were kept in an isolator. On day 42 and 56 the chickens were immunized with IBV strain M41 (10(3.0)EID50/0.1 ml). Serum antibody titres were measured by both serial dilution and single dilution ELISA on day 42, 56 and 76. "Twice negative average" (TNA), "sample to positive" (SP) and "subtraction method" (SM) titres were calculated from the serially diluted sera, and SP and SM titres were calculated from the single dilution. Titres obtained by the different methods showed a good correlation for sera of low, medium and high antibody levels. The authors recommend the use of the single dilution method.  相似文献   

2.
SUMMARY: Australian lentogenic Newcastle disease viruses were evaluated as uninactivated vaccines in Australian chickens, the response being evaluated by the production of haemagglutination-inhibition (HI) antibodies. Two viruses, V4 and PM9, induced high levels of antibody and were readily transmissible between chickens by contact exposure. Three other viruses were poorly immunogenic and poorly transmissible. Chickens vaccinated intramuscularly with the V4 strain produced higher HI antibody titres than chickens vaccinated by the orotracheal, intranasal and intraocular routes. HI antibody titres in chickens vaccinated with the V4 strain reached peak levels 3 to 5 weeks after vaccination and waned considerably during the next 2 to 4 weeks. However, low levels of HI antibody persisted for at least 36 weeks after vaccination. Intramuscular vaccination with the V4 strain of one-day-old chicks lacking maternal antibody to Newcastle disease virus resulted in 42–70% mortality and the survivors developed very high titres of HI antibody. Similar chickens inoculated orotracheally showed signs of depression and developed high titres of HI antibody, but there were no mortalities. Chickens 1-, 2-, 3- and 4-weeks-old and lacking maternally derived HI antibody to Newcastle disease virus suffered no adverse reaction to intramuscular or orotracheal vaccination. The antibody response of the 1-week-old chickens was considerably poorer than that of the older chickens. Following orotracheal vaccination with the V4 strain, chickens with low levels of maternally derived antibody responded with low levels of HI antibody. On the other hand, in the progeny of hens hyperimmunised with the V4 strain the production of active antibody following orotracheal vaccination was delayed until the level of passive antibody had declined considerably. There was no response to intramuscular vaccination in congenitally hyperimmune chickens. The minimum HI antibody inducing dose of V4 vaccine, when measured 3 weeks after vaccination of 6-weeks-old chickens, was 105.6 50% egg infectious doses.  相似文献   

3.
孙晓艳  刁有祥  裴苹苹  王蛟  刘鑫 《兽医大学学报》2013,(11):1636-1641,1646
利用分离的1株B亚型禽偏肺病毒,采用静脉注射和点眼滴鼻两种途径接种SPF鸡,并在接种同时免疫新城疫弱毒疫苗。在攻毒后3、6、9、12、15d,每组随机抽取3只翅下采血,检测血液生化指标,利用血凝和血凝抑制试验检测新城疫HI抗体效价;利用流式细胞术分析外周血CD40／CD8比值,ELISA试剂盒测定血清中IL-2、IFN7的含量;同时观察静脉注射组和点眼滴鼻组鸡的临床症状、剖检病变和病理组织学变化。结果表明,攻毒后9～15d,静脉注射组和点眼滴鼻组外周血CD4＋/CD8＋比值和血清II-2、IFN-γ的含量均显著低于对照组（P〈0．05）,而静脉注射组与点眼滴鼻组间无显著差异（P〉0．05）;静脉注射组和点眼滴鼻组的免疫器官指数低于对照组,但各组间差异不显著（P〉0．05）;各组间新城疫HI抗体水平无显著差异（P〉0．05）;血液生化指标仪谷丙转氨酶（ALT）和谷草转氨酶（AST）在攻毒后显著升高（P〈0．05）,其他指标在各组间无显著差异（P〉0．05）;静脉注射组和点眼滴鼻组在感染后3～10d出现轻微临床症状;病理组织学检测结果显示,静脉注射组和点眼滴鼻组的呼吸道和肝脏病变最明显。综上所述,B亚型禽偏肺病毒感染SPF鸡后,在一段时间内抑制机体细胞免疫,导致免疫机能下降,并引起轻微的组织病变;B亚型禽偏肺病毒通过两种不同的攻毒途径对SPF鸡的致病性无显著差异。  相似文献   

4.
为进一步明确柔嫩艾美耳球虫对球虫易感性差异鸡种的致病性,本研究以1×105个柔嫩艾美耳球虫孢子化卵囊的剂量分别感染对球虫具有抗性的藏鸡和易感的隐性白羽鸡,接种后观察记录各组鸡的临床表征、血便记分、死亡率、增重、盲肠病变记分、卵囊产量,并于感染前和感染后3、6和8 d每个品种分别随机选择5只鸡采集抗凝血,应用流式细胞仪（FCAS）检测外周血CD4+T和CD8+T淋巴细胞亚群数量。结果显示,柔嫩艾美耳球虫感染后藏鸡相对增重率高于隐性白羽鸡,死亡率、血便记分和盲肠病变记分均低于隐性白羽鸡,但卵囊产量高于隐性白羽鸡。外周血T淋巴细胞亚群变化方面,感染前,藏鸡CD4+T淋巴细胞数及CD4+/CD8+比值均高于隐性白羽鸡。感染后第3天,藏鸡CD4+、CD8+ T淋巴细胞数及CD4+/CD8+比值下降,隐性白羽鸡CD8+ T淋巴细胞数略有下降,CD4+T淋巴细胞数及CD4+/CD8+比值上升,但CD4+/CD8+比值仍显著低于藏鸡（P<0.05）。感染后第6天,2个品种鸡CD4+ T淋巴细胞数及CD4+/CD8+比值均下降,其中藏鸡表现为显著下降（P<0.05）,而隐性白羽鸡仅CD4+/CD8+比值显著降低（P<0.05）,隐性白羽鸡CD8+ T淋巴细胞数显著升高（P<0.05）。感染后第8天,2个品种鸡CD4+/CD8+比值显著下降（P<0.05）,藏鸡CD8+ T淋巴细胞数显著高于隐性白羽鸡（P<0.05）,但CD4+/CD8+比值显著低于隐性白羽鸡（P<0.05）。结果表明,球虫对藏鸡和隐性白羽鸡的致病性存在差异,这种差异与T淋巴细胞介导的免疫应答反应密切相关。  相似文献   

5.
To evaluate immunocompetence in commercially raised chickens, we immunophenotyped Dekalb Delta and H&N White Leghorn (WLH) hybrids, 20 chickens in each of 3 age groups (9 wk [juvenile], 25 wk [young adult], and 79 or 80 wk [adult]), for circulating CD3+, CD4+, CD8+, TCR1+, TCR2+, and TCR3+ lymphocytes. The proportion of CD3+ T cells, including CD4+ and CD8+ subsets, was increased in the hybrids as compared with published values for laboratory-raised outbred WLH chickens. The proportion of the TCR2+ (Vbeta1) T cell subpopulation was also increased. An age-related decrease in the proportion of TCR1+ (gammasigma) T cells was noted in both hybrids. Further, a remarkably low CD4:CD8 ratio was evident in all age groups of both hybrids, indicating decreased immunocompetence. Overall, these experiments provide age-related proportions of various peripheral-blood T lymphocyte subpopulations in commercially raised Dekalb Delta and H&N chickens that diverge from the proportions in laboratory-raised outbred WLH chickens and suggest reduced immunocompetence. Such a decline in immunocompetence, including humoral immune capacity, could be attributed to genetic selection for production traits, environmental factors associated with commercial operations, and intense immunization.  相似文献   

6.
The effects of environmental enrichment and transport stress on the immune system were investigated in laying hens. A total of 48 1‐day‐old chickens were used, half of the chickens were reared in conventional cages (RCC) and the rest in enriched cages (REC). Transport stress was applied in the 17th week. Liver weight decreased, spleen and bursa of Fabricius weights, white blood cell count, CD4+ and CD8+ cell proportions increased due to the transport. Environmental enrichment significantly increased antibody production and tended to increase monocyte percentage and CD8+ cell proportion. The effect of transport on, heterophil (H) and lymphocyte (L) percentages was not significant in RCC chickens. While heterophil percentage and H:L ratio increased, lymphocyte percentage decreased in REC chickens subjected to transport. Transport stress increased heterophil functions both in REC and RCC chickens, but the increase was higher in REC hens than in RCC hens. In conclusion, although environmental enrichment did not neutralize the effect of transport on lymphoid organs, it activated the non‐specific immune system, cellular and the humoral branches of the specific immune system by increasing heterophil functions, CD8+ cells and antibody production, respectively. Therefore, environmental enrichment suggested for improving animal welfare may also be beneficial to improve the immune system of birds exposed to stress.  相似文献   

7.
试验选用1日龄健康爱拔益加(AA)肉鸡和北京油鸡公雏各72只。检测新城疫抗体效价,牛血清白蛋白抗体水平,外周血T、B淋巴细胞转化率以及T淋巴细胞亚群等指标。结果表明:北京油鸡二免后第7天的新城疫抗体效价和二免后第6天的牛血清白蛋白抗体水平都比AA肉鸡的高,但均无显著性差异(P>0.05)。北京油鸡的脂多糖(LPS)刺激指数始终比AA肉鸡的高(P>0.05);21日龄时,北京油鸡的刀豆素(A ConA)刺激指数、CD4+、CD8+T淋巴细胞数量以及CD4+/CD8+都比AA肉鸡的高,但均无显著性差异(P>0.05);而42日龄时,AA肉鸡的ConA刺激指数、CD4+、CD8+T淋巴细胞数量以及CD4+/CD8+却高于北京油鸡(P<0.05)。本试验结果提示,AA肉鸡和北京油鸡的体液免疫和细胞免疫功能之间存在一定的差异,但差异不显著。  相似文献   

8.
怀牛膝多糖对雏鸡疫苗免疫效果的影响   总被引：1，自引：1，他引：1  
150羽14日龄蛋公鸡随机均分成3组,用新支二联弱毒苗点眼滴鼻免疫的同时,2个试验组分别肌肉注射高、低剂量的怀牛膝多糖溶液,对照组注射生理盐水,每天注射1次,连续注射3次。分别于免疫后第7、14、21、28、35和42天各组随机抽取8只鸡翼下静脉采血,分离血清,用微量法测定新城疫血凝抑制（HI）抗体效价,于免疫后第10、20、30、40和50天每组随机抽取5只鸡心脏采血,分离淋巴细胞,用MTT法测定淋巴细胞增殖的动态变化,流式细胞仪双染色法检测CD^4＋、CD^8＋T淋巴细胞含量,并放血致死称取体重和胸腺、脾脏、法氏囊的质量,计算器官指数。结果表明,怀牛膝多糖高剂量组的HI抗体效价、CD^4＋/CD^8＋比值和免疫器官指数都明显高于对照组,并且高剂量怀牛膝多糖可以显著促进T淋巴细胞增殖。提示怀牛膝多糖对鸡新支二联疫苗的免疫效果有明显的增强作用。  相似文献   

9.
选择17头28日龄的CSFV和PRRSV抗体均为阴性的仔猪,于试验的第1天和第14天分别对其进行猪瘟耐热保护剂活疫苗（兔源）和高致病性猪繁殖与呼吸综合征Nsp2A1882—2241弱毒疫苗免疫。在免疫后的第28、42天采集外周血液,分析特异性抗体表达量和外周血T淋巴细胞表型的变化,评估猪瘟免疫对猪繁殖与呼吸综合征免疫的影响。结果显示,在CSF免疫后第28、42天,CSFV高抗组中的CD4^＋、CD4^＋／CD8^＋、CD4^＋CD8^＋和CD4-CD8数目均比CSFV低抗组高,CD3^＋和CD8^＋细胞数量比CSFV低抗组低;PRRS高抗组中,CD4CD8-细胞含量高于PRRS低抗组;在CSF免疫后第28天,CSFV抗体产生较高（阳性比率为73．33％）,PRRSV抗体产生较低（阳性比率仅为6．67％）。在CSF免疫后的第42天,CSF高抗组中PRRSV抗体阳性比率较CSF低抗组高8．33％。结果表明,CSFV特异性抗体产生高时能增加PRRSV特异性细胞免疫应答,增加CD4^＋细胞、CD4^＋CD8^＋细胞数量,提高机体免疫水平。CD3＋和CD4CD8-细胞应答作用值得重视。  相似文献   

10.
Salmonellosis is one of the most common worldwide zoonosis, and the Enteritidis and Typhimurium serotypes are most prevalent. In this study, we evaluated the effects of a diet supplemented with mannanoligosaccharides (MOS) on CD3+, CD4+, CD8+, and goblet cell counts in the intestines of broilers vaccinated and challenged withSalmonella Enteritidis. The evaluation was based on randomized experiments including 45 chickens divided into 3 experimental groups. Group 1 received a nonsupplemented control diet. Group 2 received a diet supplemented with 1 kg MOS/t from d 1 to 21 and 0.5 kg MOS/t from d 22 to 56. Group 3 received a diet supplemented with 2 kg MOS/t from d 1 to 21 and 1 kg MOS/t from d 22 to 56. Chickens fed the lower level of MOS demonstrated reduced fecal shedding ofSalmonella 14 d after being challenged (P < 0.05). Both groups of MOS-supplemented chickens showed an increase in CD4+ and CD8+ cell counts in the ileal and cecal mucosa after being challenged withSalmonella Enteritidis (SE). Supplementation with MOS increased the specific T lymphocyte infiltration in the intestinal mucosa of chickens vaccinated and challenged withSalmonella Enteritidis.  相似文献   

11.
1. The effects of early-age thermal conditioning and food restriction on performance and thermotolerance were studied in male broiler chickens, in 2 trials. 2. Chickens were exposed to 36 degrees +/- 1 degree C and 70% to 80% relative humidity (RH) for 24 h at the age of 5 d (thermal conditioning, TC), or to food restriction (FR) at the age of 7 to 14 d, or to both treatments (TC+FR), while a control group was reared under standard conditions. At the age of 42 d, chickens were thermally challenged by a heat stress of 350 degrees +/- 1 degree C and 20% to 30% RH for 6 h. 3. In both experiments, weight gain of the TC chickens between the ages of 7 and 42 d was significantly higher than those of other treatments and was associated with higher food intake. 4. Early-age TC significantly increased body temperature (Tb). Thermal challenge at the age of 42 d markedly increased Tb in all groups but that of the TC groups was the lowest. 5. Mortality during thermal challenge was significantly lower in the treated chickens, except for the FR group in trial 2. 6. Plasma triiodothyronine (T3) concentration was greatly depressed in all treatment groups during the thermal challenge. However, the lowest concentration was observed in the TC group, suggesting that these chickens exhibit the lowest rate of heat production under such conditions. 7. Thermal conditioning reduced the increase of haematocrit with age, whereas food restriction resulted in an increase in haematocrit immediately after FR. Thermal challenge resulted in a haematocrit decline in all groups, with the lowest values in the TC and TC+FR chickens. 8. It can be concluded that, because the TC treatment improved thermotolerance (possibly by reducing heat production) and performance, it has advantages over the FR and TC+FR treatments.  相似文献   

12.
We explored the hypothesis that the outcome of bacterial invasion (infection or no infection) may depend on immunologic factors when bacterial and environmental factors are kept constant. Leukocyte surface molecules (CD3, CD2, CD4, CD8, CD11b, and CD45r) were assessed before and 3 times after intramammary infusion of Staphylococcus aureus in 5 dairy cows. The somatic cell count (SCC/mL), bacterial count (colony-forming units [CFUs]/mL), ratio of milk phagocytes (mononuclear [Mphi] plus polymorphonuclear [PMN] cells) to lymphocytes (P/L index), and ratio of PMN to Mphi cells (PMN/Mphi index) were determined. Although all cows showed evidence of inflammation resulting from the infusion (the median P/L ratio was 11 times greater 1 d after infusion than before infusion), bacteria were not obtained from the milk of 2 cows. Threshold-like responses, resulting in bacterial counts that approached zero (indicating no infection) and SCCs of less than 500000/mL, were observed when the milk CD2+ lymphocyte proportion exceeded 73% (P < or = 0.007). At 1 d after infusion, 7 immune factors distinguished infected cows from those without infection with more than 95% confidence: compared with infected cows, uninfected cows had higher proportions of CD3+, CD2+, CD4+, and CD8+ T cells, higher densities of CD3 and CD2 molecules per cell, and a higher density of CD11b molecules on milk Mphi cells. At 7 d after infusion, the PMN/Mphi index was lower (94% confidence) in uninfected than in infected cows. At 14 d, the CD2, CD8, and CD45r marker densities were lower than those at 1 d (P < 0.02), findings compatible with memory function. Synergism was suggested by the combined effects of the proportions of CD3+, CD2+, and CD11b+ cells, which explained 75.5% of the bacterial-count variability (P < 0.001); alone, none of these markers predicted CFU variability. These results support further studies aimed at identifying cows capable (or incapable) of early bacterial clearance.  相似文献   

13.
不同鸡新城疫疫苗免疫鸡血清HI抗体的测定   总被引：3，自引：0，他引：3  
将试验鸡分成3个试验组和1个对照组。A组鸡接种鸡新城疫系疫苗,B组鸡接种油乳剂灭活苗,C组鸡接种鸡新城疫系疫苗,并在接种疫苗后第3、4、5、6、7、9、11、13、15、20、25d采取各组鸡血并分离血清,检测HI抗体。结果表明,接种系疫苗的组,HI抗体效价均值从4.67log2上升到10log2,接种后第5d开始上升,接种后第11d达到峰值,持续6d保持高滴度抗体水平。接种系疫苗的组,HI抗体效价均值从4.67log2上升到7log2,接种后第4d开始上升,接种后第9d达到峰值。接种油乳剂灭活苗的组,HI抗体效价均值从4.67log2上升到9.33log2,接种后第5d开始上升,接种后第11d达到峰值,持续16d保持高滴度抗体水平。系疫苗HI抗体效价上升快,效价高,较适合于紧急接种,油乳剂灭活苗HI抗体效价可在高水平维持较长时间,较适合于预防接种。  相似文献   

14.
本实验目的是为了研究中药组方紫石散对肉鸡免疫效果的影响。试验用6日龄同一品种,体重接近,健康肉雏鸡作为实验动物150羽,随机分为5个处理组,饲喂低(1.0%)、中(1.5%)、高(3.0%)三种剂量浓度紫石散,连续灌服药物一星期。在13日龄、20日龄、27日龄、34日龄翅静脉采血,检测IBDV抗体含量,以及应用流式细胞仪(Flow Cytometry,FCM)检测外周血中CD4+,CD8+的含量。结果表明,在用药一周后IBDV抗体含量增加,CD4+,CD8+和CD4CD8均有明显提高,中高剂量组提高显著P<0.05,并且体现出明显的剂量依赖性。说明中药方剂紫石散具有明显促进免疫的作用。  相似文献   

15.
Virulent Newcastle disease virus (NDV) was isolated from susceptible and immune chickens following intra-ocular challenge with the Essex '70 strain. Challenge virus was isolated from the trachea and cloaca of susceptible birds until they died 7 to 9 days after challenge. This virus was isolated from immunised chickens for up to 14 days after challenge. The duration of excretion was influenced by the prechallenge serum antibody titre to NDV. It persisted longest in chickens with titres of 2(3) to 2(7) and decreased in length and frequency from chickens with titres in the range 2(8) to 2(12). Chickens with pre-challenge titres of 2(3) to 2(5) developed 2- to 3- fold increases in post-challenge titres, whereas those with higher pre-challenge titres had smaller proportional increases in titre. Excretion of virulent virus from immunised birds should be considered in the development of Newcastle disease control programs.  相似文献   

16.
The influence of an attenuated classical swine fever virus C strain vaccine and a subunit E2 vaccine against classical swine fever on the peripheral blood leucocyte proportion and phenotypic expression in 12-week-old pigs was studied. The C strain was amplified in minipig kidney cell culture and final product contained 10(4 +/- 0.15) TCID50/ml, while the subunit vaccine contained 32 microg per dose of gp E2. Haematological findings showed that the vaccines did not cause leucopenia or lymphocytopenia and the number of neutrophils and eosinophils during the observation period was within physiological range. The results of the proportion of CD4a+, CD5a+, CD8a+, wCD21+, CD45RA+, CD45RC+ , non-T non-B, SWC3a+ and CD11b+ cells were gained by single-colour flow cytometry. At the end of the trial a significantly increase of percentage of CD4+, CD5a+, CD8+, wCD21+ cells has been found in pigs that received the subunit vaccine and the percentage of CD4+, CD5a+, CD8+, CD45RA+ and CD45RC+ cells was higher in pigs that received the attenuated vaccine. Twenty-eight days after vaccination the percentage of CD4+, CD45RA+ and CD45RC+ was significantly higher in pigs vaccinated with the C strain than in pigs vaccinated with the subunit vaccine. In contrary, the percentage of the wCD21- cells was higher in pigs that received the subunit vaccine. Statistically higher values of SWC3a+ and lower values of CD11b+ cells was observed in pigs that received the attenuated vaccine than in pigs vaccinated with the subunit vaccine. Taken altogether, our results showed that the subunit vaccine produced a better stimulation of B cells and CD11b+ monocytes/macrophages /granulocytes/NK cells, whereas the attenuated vaccine induced a higher response of Th cells, naive/memory cells and macrophages/neutrophils. Thus, both vaccines were able to influence the porcine immune system, by activating different subsets of the immune effector/accessory cells.  相似文献   

17.
为了解肉鸡生长期内免疫前后的细胞免疫反应,本实验采用CD3/CD4/CD8三色流式细胞术、MTT法和Griess法依次检测了AA肉鸡免疫禽流感灭活疫苗和非免疫状态下外周血、胸腺和脾脏中T淋巴细胞及其亚群的相对含量、外周血中T淋巴细胞对PHA-P的增殖反应能力和诱导巨噬细胞NO分泌量的变化。结果表明,非免疫状态下,AA肉鸡外周血CD4+、CD8+、CD3+T淋巴细胞相对百分含量在7日龄时均为最低,脾脏中CD4+T淋巴细胞相对百分含量在整个试验期一直呈下降趋势,免疫后外周血、脾脏和胸腺中CD4+、CD8+、CD3+T淋巴细胞相对百分含量均明显高于非免疫组,且脾脏CD4+T淋巴细胞呈阶段性上升状态;各时期淋巴细胞刺激指数(SI)值和巨噬细胞NO分泌量检测结果表明,免疫组均高于同期对照组(p<0.05)。研究结果还表明:肉鸡在7日龄时细胞免疫水平最低,灭活疫苗可以激发肉鸡产生较强的细胞免疫应答。  相似文献   

18.
本研究旨在探究唾液乳杆菌（Lactobacillus salivarius）对鸡毒支原体（Mycoplasma gallisepticum，MG）感染肉鸡生长性能及肺损伤的影响。选用1日龄AA肉鸡240只，按试验要求随机分为6组，包括对照组（Con）、低剂量唾液乳杆菌组（L）、高剂量唾液乳杆菌组（H）、MG感染组（MG）、MG感染+低剂量唾液乳杆菌组（MG+L）和MG感染+高剂量唾液乳杆菌组（MG+H）。Con组、MG组饲喂基础饲料，L组、MG+L组饲喂添加108 CFU·kg-1唾液乳杆菌的基础饲料，H组、MG+H组饲喂添加109 CFU·kg-1唾液乳杆菌的基础饲料，7日龄时给与MG组、MG+L组和MG+H组进行MG感染攻毒，饲养42 d后，通过分析各组鸡的体重、饲料转化率、肺部MG定植量、肺部病理损伤、肺部炎性损伤相关蛋白表达量及促炎性细胞因子含量来评价唾液乳杆菌缓解MG感染所致肉鸡生长性能下降及肺损伤效果。结果表明，MG感染极显著降低肉鸡体重（P<0.01），并极显著提高饲料转化率（P<0.01），而饲料中添加低剂量唾液乳杆菌和高剂量唾液乳杆菌均能极显著缓解MG感染所致肉鸡体重降低（P<0.01），并极显著改善饲料转化率（P<0.01）。饲料中添加低剂量唾液乳杆菌和高剂量唾液乳杆菌均能极显著降低MG肺部定植量（P<0.01）；明显改善MG感染所致肺部病理损伤；极显著降低MG感染所致炎性损伤相关蛋白（TLR2、HMGB1、p-p65/p65、NLRP3、Pro-Caspase-1/Caspase-1）表达（P<0.01）；极显著降低MG感染所致促炎性细胞因子（TNF-α、IL-1β、IL-6、IL-8）含量（P<0.01）。综上所述，饲料中添加唾液乳杆菌可以显著缓解MG感染所致肉鸡生长性能下降及肺损伤，该株唾液乳杆菌具有较大的应用潜力预防肉鸡感染MG。  相似文献   

19.
A total of 128 1-week-old chicks were classified into four groups; T-2 toxin fed (T-2), IBV infected (IBV), T-2 toxin fed and co-infected with IBV (T-2+IBV), and untreated (control) for a period of 6 weeks. Within their respective groups, the birds belonged to T-2 and T-2+IBV were exposed to 2 ppm of T-2 toxin contaminated feed for 6 weeks, and 0.2 ml of 10 EID(50) (10(5.69)/0.2 ml) inoculums of IBV isolate (India/LKW/56/IVRI/08) was used to challenge the chicks belonged to IBV alone and T-2+IBV groups after 3 weeks of the experiment. To study immunopathological effects, parameters such as lymphocyte stimulation indices (SI), haemagglutination inhibition, enzyme linked immunosorbant assay (ELISA), peripheral lymphocytes CD(4)(+) and CD(8)(+) analysis, and histopathological examination of lymphoid organs were done. Accordingly, SI values were significantly (P<0.05) lower in all the treatment groups as compared to control, however, the SI values of IBV infected group were significantly higher than the values in toxin fed groups. The mean HI titres to ND vaccine was significantly (P<0.05) lower in the toxin groups at all the intervals, and the antibody titres in IBV infected group were significantly (P<0.05) higher than that of T-2 toxin fed and co-infected with IBV group but were significantly (P<0.05) lower than the control at 21 (3) and 28 (10) days of toxin feeding (DTF) (days post infection (DPI)). Similarly, the mean IBV ELISA antibody titres in the toxin fed groups were significantly (P<0.01) reduced as compared with the IBV ELISA antibody titres of IBV infected but not toxin fed group, at all intervals. Peripheral CD(4)(+):CD(8)(+) ratios in T-2+IBV group and number of CD(4)(+) and CD(8)(+) peripheral lymphocytes in all treatment groups were significantly reduced as compared to the values in control birds. However, CD(4)(+):CD(8)(+) ratios of IBV infected group at 42 (21) DTF (DPI) were found significantly (P<0.05) higher than the values in control birds. Histopathologically, lymphoid organs (bursa of Fabricius, spleen, thymus, caecal tonsils and Harderian glands) showed moderate to severe necrosis (lymphocytolysis) and extensive lymphocyte depletion in all the toxin groups (T-2 and T-2+IBV groups) where the severity and extent of the lesions were more in T-2+IBV group. The findings of the present experiment revealed immunosuppressive effects of T-2 toxin and aggravated the pathology and pathogenesis of IBV infection.  相似文献   

20.
孟祯  孙梦珂  许永得  秦韬  任喆 《畜牧兽医学报》2021,52(12):3627-3640
本试验旨在制备余甘子多糖（Phyllanthus emblica polysaccharide，PEP），通过对其结构表征进行分析，探索PEP对鸡新城疫（Newcastle disease，ND）疫苗免疫效果的影响。利用紫外光谱（ultraviolet spectroscopy，UV）、红外光谱（Fourier transform infrared spectroscopy，FT-IR）、高效液相色谱分析法（high performance liquid chromatography，HPLC）和扫描电镜（scanning electron microscope，SEM）分析PEP结构；选取175只1日龄河田鸡，随机分成5组，每组35只，分别为空白对照组，疫苗对照组，PEP低、中、高剂量组。除空白对照组外均用ND疫苗进行免疫，7日龄首免，并于28日龄二免。在免疫的同时，PEP低、中、高剂量组分别按照10、20、30 g·L-1的剂量给药PEP溶液0.5 mL，疫苗对照组和空白对照组给予等量生理盐水，每天1次，连续3 d。分别于7、14、21、28、35、42和49日龄时，测定血清中新城疫病毒（Newcastle disease virus，NDV）特异性抗体水平以及γ-干扰素（INF-γ）和白介素4（IL-4）的水平；于28和49日龄时测定外周血淋巴细胞增殖活性和T淋巴细胞CD4+/CD8+的比值；于49日龄剖杀后采集脾、法氏囊、胸腺和肝进行组织学观察以及检测免疫器官指数。结果表明，PEP为白色棉絮状，糖含量为（86.70±1.05）%，结构分析结果表明，PEP是含α型糖苷键的多糖，其组分均一，不含核酸和蛋白质，呈片状分布，总体结构规整且致密，单糖组成为葡萄糖醛酸（glucuronic acid，GlcA）、葡萄糖（glucose，Glu）、木糖（xylose，Xyl）和岩藻糖（fucose，Fuc），其摩尔比为0.5：8.3：1.8：0.3。动物试验结果表明，PEP能显著提高鸡血清中NDV特异性抗体、INF-γ和IL-4的水平（P<0.05），还能显著促进鸡外周血淋巴细胞增殖和T淋巴细胞CD4+/CD8+的比值（P<0.05），提高免疫器官指数（P<0.05），激活脾、法氏囊、胸腺和肝等器官的免疫功能。PEP糖含量高，结构稳定，可提高机体免疫活性，具有较良好的佐剂活性，对ND具有良好的防治效果。  相似文献   

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