抗马立克氏病新品系选育第四代雏鸡MDV攻毒试验结果

F4雏鸡MDV攻毒试验结果显示,亲本父母代鸡均携带No614血型基因的选育试验组,60日龄死亡率显著低于不经血型基因选育的对照组(P＜0.05);其内脏器官组织肿瘤病变率也低于该对照组,但差异不显著(P＞0.05);选育试验组鸡的肝脏的肿瘤病变率仍显著低于血型基因选育对照组和非选育对照组鸡(P＜0.05).提示No614血型基因具有一定程度的马立克氏病(MD)抗性.     

抗马立克氏病新品系选育Ⅲ.第四代雏鸡MDV攻毒试验

F4 雏鸡MDV攻毒试验结果显示 ,亲代父母鸡均携带№ 6 14血型基因的选育试验组 ,6 0日龄死亡率显著低于不经血型基因选育的对照组 (P <0 .0 5 ) ;其内脏器官组织肿瘤病变率差异不显著 (P >0 .0 5 ) ;而肝脏的肿瘤病变率 ,选育试验组仍显著低于血型基因选育对照组和非选育对照组 (P <0 .0 5 )。提示№ 6 14血型基因具有一定程度马立克氏病(MD)抗性。     

中草药添加剂对雏鸡新城疫免疫效果及抗病力的影响

为了研究中草药添加剂对雏鸡新城疫免疫效果及抗病力的影响,试验选择健康雏鸡400只,随机分为2组,每组200只,试验组从1日龄开始将1%中草药添加到雏鸡饲料中混匀饲喂,连喂50 d;对照组不添加任何物质正常饲喂雏鸡饲料。7日龄时所有鸡只免疫新城疫Ⅳ系弱毒疫苗,分别在14日龄和25日龄时测定血清中免疫球蛋白含量并进行血凝抑制试验,30日龄时进行攻毒试验,测定发病率、死亡率、保护率和血清抗体效价。结果表明:14日龄和25日龄时,试验组血清IgG、IgM含量均显著高于对照组(P0.05);血清IgA含量组间差异不显著(P0.05);14日龄时试验组新城疫抗体效价略高于对照组(P0.05),25日龄时试验组显著高于对照组(P0.05);试验组的发病率、死亡率极显著低于对照组(P0.01);试验组免疫保护率达99%,极显著高于对照组(P0.01)。说明中草药添加剂有明显提高雏鸡免疫球蛋白含量和促进新城疫抗体形成的作用,降低发病率和死亡率,提高免疫保护率,有利于提高鸡新城疫疫苗的免疫保护力和鸡的抗病力。     

茯苓多糖对雏鸡细胞免疫活性的影响及其抗肿瘤作用

给1日龄AA雏鸡经腹腔注射马立克氏病病毒(MDV)强毒株(0．2mL／只)，并从当日开始给试验组雏鸡以3个剂量连续肌肉注射茯苓多糖1周，分别于7、14、28、42、56日龄取脾组织，制备脾细胞悬液，用ELISA法检测了雏鸡淋巴细胞转化率、NK细胞活性及MФ活性，并与对照组比较。结果表明，3个剂量均可显著提高雏鸡的淋巴细胞转化率、NK细胞活性及MФ活性，且中剂量组效果优于其他2个剂量组。证实茯苓多糖能提高MDV强毒株感染雏鸡的细胞免疫活性．并具有抗肿瘤作用。     

龙牙楤木嫩叶拌料对雏鸡增重及抗病力影响的试验

按2%添加东北龙牙木的鲜嫩叶于低日龄雏鸡日粮中．从1日龄开始连续饲喂3周。结果试验组雏鸡平均体重比对照组多增重25克;试验组雏鸡成活率比对照组提高15％;雏鸡22日龄用传染性支气管炎病毒（IBV）攻击后．试验组雏鸡死亡率比对照组减少58.34％。     

马立克病毒感染对鸡体液免疫的影响

为了验证和探讨马立克病毒(MDV)对肉鸡的免疫抑制作用,同时对比研究MDV疫苗和强毒株对机体免疫力的影响,试验通过人工攻毒MDV,建立MD模型,各组SPF鸡于2日龄注射NDV+H9N2 AIV灭活苗,7日龄时以LaSota株NDV弱毒疫苗饮水免疫,在SPF鸡14,21,28,35,42日龄时,各组无菌采血25份,分离血清,利用血凝/血凝抑制试验研究各组ND和H9N2的体液抗体水平。结果表明:在整个试验周期,疫苗对照组和空白对照组NDV和H9N2 AIV抗体水平差异不显著;攻毒组SPF鸡在21~42日龄时,NDV和H9N2 AIV抗体水平显著或极显著低于对照组。     

抗鸡传染性法氏囊病病毒冻干卵黄抗体与同类产品的比较试验

本研究鸡传染性法氏囊病冻干卵黄抗体和市售精制液体卵黄抗体分别以10羽份和3 mL超剂量肌肉注射各10只18日龄SPF雏鸡,观察14 d均安全。两种抗体以1羽份剂量分别肌肉注射各20只18日龄SPF雏鸡24 h后,用IBDV强毒TL株攻击,连续观察144 h,2个试验组分别有20/20、17/20的雏鸡健活,剖检没有发现法氏囊病变;二者分别以1羽份剂量连续2 d肌肉注射各20只18日龄已经被IBDV强毒TL株攻击12 h的SPF雏鸡,连续观察96 h,2个试验组有19/20、17/20的雏鸡健活,而预防和治疗试验中的阳性对照组中20只鸡均有法氏囊特征性病变发生（20/20）,且死亡率在85%（17/20）以上,阴性对照组雏鸡均正常。     

几种常用药物对自然感染IBDV雏鸡死亡率的影响

试验组雏鸡在１１～２０日龄分别投给治疗量的痢特灵、喹乙醇、庆大霉素、敌菌净、鸡宝－２０和中草药．在１５日龄免疫接种新城疫ＬａＳｏｔａ弱毒苗。该批试验鸡在４３日龄时突然暴发ＩＢＤ，症状典型、死亡率高．统计发现各用药组雏鸡死亡率均低于对照组，其中以敌菌净最为显著，比空白对照组低２３．４４％。     

几种常用药物对自然感染IBDV雏鸡死亡率的影响

试验组雏鸡在１１－２０日龄分别投给治疗量的痢特灵、喹乙醇、庆大霉素、敌菌净、鸡宝２０和中草药。在１５日龄免疫接种新城疫ＬａＳｏｔａ弱毒苗。该批试验鸡在４３日龄时突然暴发ＩＢＤ，症状典型，死亡率高。统计发现各用药组雏鸡死亡率均低于对照组，其中以敌菌净最为显著，比空白对照组低２３．４４％。     

鸡用天然缓释免疫增强剂的研究——对介高雏鸡抵抗力及与抗菌药 …

对７日龄艾维茵雏鸡投服缓释免疫增强剂,至３０日龄时试验组成活率为９２．９％,对照组为８２．５％;３０日龄时用４种强毒进行攻击,试验组发病率和死亡率明显低于相应的对照组。用天然缓释免疫增强剂与氯霉素、呋喃唑酮防治鸡白痢、鸡大肠杆菌病的试验结果显示,天然缓释免疫增强剂与１／３￣１／２常用剂量氯霉素或呋喃唑酮合用,其效果优于单用常量抗菌药物。     

MDV对雏鸡血浆MDA含量与SOD活性的影响

为探讨丙二醛(MDA)和超氧化物歧化酶(SOD)在雏鸡马立克病(MD)发病过程中的作用,研究了雏鸡在人工攻毒后血浆MDA含量与SOD活性的动态变化.结果表明,攻毒组接种马立克病病毒(MDV)后第14天,血浆中MDA的含量显著高于对照组(P＜0.05),第7天和第28天高于对照组,第56天时基本接近;血浆中SOD活性在第7天时对照组显著高于攻毒组(P＜0.05),第14天和第28天高于攻毒组,但差异不显著.表明雏鸡在感染MDV后血浆中MDA含量显著升高,SOD活性明显降低,对雏鸡MD的发病诊断有重要的指导作用.     

A comparative evaluation of the protective efficacy of rMd5deltaMeq and CVI988/ Rispens against a vv+ strain of Marek's disease virus infection in a series of recombinant congenic strains of White Leghorn chickens

Marek's disease (MD) is a lymphoproliferative disease of domestic chickens caused by a highly infectious, oncogenic alpha-herpesvirus known as Marek's disease virus (MDV). MD is presently controlled by vaccination. Current MD vaccines include attenuated serotype 1 strains (e.g., CVI988/Rispens), avirulent serotype 2 (SB-1), and serotype 3 (HVT) MDV strains. In addition, recombinant MDV strains have been developed as potential new and more efficient vaccines to sustain the success of MD control in poultry. One of the candidate recombinant MDV strains, named rMd5deltaMeq, was derived from Md5, a very virulent strain of MDV lacking the MDV oncogene Meq. Our earlier reports suggest that rMd5deltaMeq provided protection equally well or better than commonly used MD vaccines in experimental and commercial lines of chickens challenged with very virulent plus (vv+) strains of MDV. In this study, maternal antibody-positive (trial 1) and negative (trial 2) chickens from a series of relatively MD resistant lines were either vaccinated with the rMd5deltaMeq or CVI988/Rispens followed by infection of a vv+ strain of MDV, 648A, passage 10. This report presents experimental evidence that the rMd5deltaMeq protected significantly better than the CVI988/Rispens (P < 0.01) in the relatively resistant experimental lines of chickens challenged with the vv+ strain of MDV. Together with early reports, the rMd5deltaMeq appeared to provide better protection, comparing with the most efficacious commercially available vaccine, CVI988/Rispens, for control of MD in lines of chickens regardless of their genetic background.     

Mortality of one-week-old chickens during naturally occurring Marek's disease virus infection

Marek's disease (MD) is a disease of chickens that occurs worldwide and has serious economic consequences. MD can present as one of several forms, with the most commonly occurring forms being the lymphoproliferative diseases. Under experimental conditions, an early mortality syndrome has been recognized following infection by some but not all strains of MD virus (MDV). This is the first report of a confirmed case of mortality due to naturally occurring MDV infection in 1-week-old, nonvaccinated, chickens. Necrotizing lesions were observed in the bursa of Fabricius, lung, duodenum, jejunum, and proventriculus, and large intranuclear inclusion bodies were a striking feature in tissues with lesions in all birds. Immunohistochemical staining for the pp38 protein of MDV revealed abundant pp38 antigen in the affected tissues, confirming the presence of MDV within the lesions. PCR yielded an amplicon with 97% homology to the meq gene of MDV. No evidence of co-infection by either of the immunosuppressive agents chicken anemia virus and infectious bursal disease virus was detected.     

Cell-mediated immunity in Marek's disease: cytotoxic responses in resistant and susceptible chickens and relation to disease

Two experiments were conducted to study the cell-mediated cytotoxicity of peripheral blood leukocytes (PBL) from chickens inoculated with Marek's disease virus (MDV) against a Marek's disease-derived lymphoblastoid cell line (MSB-1) and to associate the cytotoxicity with incidence of disease. In experiment I, moderately susceptible random-bred, specific-pathogen-free chickens were inoculated with MDV (group 1), vaccinated with a herpesvirus of turkeys (HVT) and inoculated with MDV (group 2), vaccinated with HVT and inoculated with chicken kidney cells (CKC; group 3), and inoculated with CKC only (group 4). Cytotoxic activity in the PBL was detected initially during the first week after MDV inoculation and periodically throughout the observation period (groups 1, 2, and 3). Throughout the observation period, the magnitude of cytotoxic activity was similar in PBL from groups 1 and 2 chickens. The PBL from both surviving and fatally infected chickens (groups 1 and 2) were similarly cytotoxic when sampled during the first 16 days after MDV inoculation. In experiment II, inbred genetically susceptible (line 7) and resistant (line 6) chickens were used. Cytotoxic activity of PBL of significantly greater magnitude was associated with a lower mortality or incidence of gross lesions (or both) in MDV-inoculated line 6 (group B) and HVT-vaccinated and MDV-inoculated line 7 (group C) chickens compared with activity of PBL from MDV-inoculated line 7 (group A) chickens. The cytotoxic activity of PBL from individual inbred chickens did not correlate with the outcome of the infection.     

Comparison of blood and feather pulp samples for the diagnosis of Marek's disease and for monitoring Marek's disease vaccination by real time-PCR

Comparison of blood and feather pulp (FP) samples for the diagnosis of Marek's disease (MD) and for monitoring Marek's diseases vaccination in chickens (serotypes 2 and 3 vaccines) by real time-PCR was evaluated. For diagnosis of MD, quantification of serotype 1 Marek's disease virus (MDV) DNA load was evaluated in 21 chickens suffering from MD. For each chicken, samples of blood and FP were collected and MDV DNA load was quantified. Solid tumors are the sample of choice for MD diagnosis by real time-PCR and, hence, 14 solid tumors were included in the study as positive controls. Load of MDV DNA in FP was equivalent to that detected in solid tumors (threshold cycle [Ct] ratio above 1.7). MDV DNA load in blood samples was lower than in solid tumors and FP samples. Nonetheless, there was a statistically significant correlation of the results obtained from FP and blood (r = 0.92). Results of the Pearson correlation test showed that Ct ratio values of 1.7 in FP correspond to Ct ratio values of 1.2 in peripheral blood. For monitoring vaccines, serotypes 2 and 3 MDV DNA load was evaluated in blood and FP samples of vaccinated chickens. Serotype 2 MDV DNA load was evaluated in samples of blood and FP from 34 chickens vaccinated with SB-1 strain. Serotype 3 MDV DNA load was evaluated in blood and FP samples from 53 chickens vaccinated with HVT strain. For both serotypes, frequency of positive samples and load of vaccine DNA was higher in FP than in blood samples. There was not a statistically significant correlation between the load of SB-1 DNA (r = 0.17) or HVT DNA (r = -0.04) in FP and blood. Our results show that the load of serotypes 1, 2, and 3 DNA is higher in FP than in blood. Diagnosis of MD could be done using both FP and blood samples. Monitoring of MD vaccination by real time-PCR required the use of FP samples. There were a high percentage of false negative samples when using blood to detect serotypes 2 and 3 MDV by real time-PCR.     

人参皂苷及其衍生物体内抗马立克氏病毒的间接免疫荧光观察与PCR检测

为了探讨人参皂苷及其衍生物体内抗马立克氏病毒的作用机理.用马立克氏病毒人工感染雏鸡模型,采取人参皂苷及其衍生物口服,通过间接免疫荧光试验动态观察人参皂苷及其衍生物能否减少MDV抗原在组织中的分布;通过PCR检测看人参皂苷及其衍生物能否减少MDV的出现.结果显示:人参皂苷组、衍生物组被检组织的阳性细胞数量明显比盐酸吗啉胍阳性对照组被检组织的阳性细胞数量少;MDV病毒核酸的PCR检测显示,药物没有阻止病毒对组织的感染.结果表明,人参皂苷及其衍生物抗马立克氏病毒效果要优于盐酸吗啉胍.     

Anti-idiotype antibodies to Marek''s disease-associated tumour surface antigen in protection against Marek''s disease

Marek's disease-associated tumour surface antigen (MATSA) removed by enzymatic (papain) digestion of Marek's disease tumour cells was fractionated by gel filtration chromatography. The first peak (F1) was used to raise antibody in rabbits. Monoclonal antibody (RPH-6) directed against MATSA and the anti-F1 IgG were used as idiotypic antibodies to raise polyclonal anti-idiotype serum in heterologous hosts; rabbit and goat, respectively. The anti-idiotypes (anti-Id) were purified by affinity chromatography and characterized by competitive binding assay using immunofluorescent (IF) tests.

Day-old white Leghorn chicks were immunized with anti-Id to MATSA (Group 1) or anti-Id to F1 (Group 3) and challenged with virulent Marek's disease virus (MDV) on the tenth day post immunization. In positive control groups, the day-old chicks were inoculated with anti-BALB/c mouse globulin (Group 2) and anti-rabbit globulin (Group 4) and challenged with virulent MDV on the tenth day post inoculation. As compared with positive control groups, the vaccinated groups (1 and 3) had considerably lower level of MATSA positive cells during the post challenge observation period. The protection level against MD in the immunized groups was 66.6% (Group 1) and 86.6% (Group 3).     

马立克氏病病毒的分离和鉴定

从长春、天津、大连地区分离到10株马立克氏病病毒(MDV),经电镜观察、琼脂扩散试验、痘斑及蚀斑形成试验,均符合MDV的特点.通过MDV单克隆抗体、鸡胚细胞培养及致病性试验等鉴定,10株病毒均为血清I群MDV.火鸡疱疹病毒疫苗对其中的C-4株的保护率低于京-1株(P<0.01),而对其它株的保护率与京-1株差异不显著(P>0.05).     

Natural killer cell activity in chickens exposed to Marek's disease virus: inhibition of activity in susceptible chickens and enhancement of activity in resistant and vaccinated chickens

Chickens of 2 genetic lines (lines P and N) were inoculated with a pathogenic strain of Marek's disease (MD) virus (MDV) and chronologically examined for disease response and natural killer (NK) cell expression. The NK cell reactivity was assayed in an in vitro cytotoxicity assay in which effector cells from the spleen of test chickens were reacted with 51Cr-labeled LSCC-RP9 target cells. Chickens of line P developed progressive debilitating disease and a high incidence of gross tumors and death. The NK cell reactivity of line-P chickens infected with MDV was significantly lower than that of uninfected control hatchmates. In contrast, NK cell levels were significantly elevated in MDV-inoculated line-N chickens that were resistant to MD and in chickens of lines P or N that had been inoculated with herpesvirus of turkeys (HVT). NK cell levels were also elevated in line P if chickens were vaccinated with HVT before infection with MDV. Inhibition of NK reactivity in susceptible chickens and elevation of reactivity in naturally resistant or vaccinated chickens may indicate a role for the NK cell system in regulating resistance to MD.