Development of immunocompetence of broiler chickens

Subpopulations of T-cells, B-cells, macrophages and ellipsoid-associated reticular cells (EARC) could be demonstrated by immunohistochemical staining early in the development of chicken spleen. However, the typical structures of the spleen, such as the peri-arteriolar lymphoid sheath (PALS) and the ellipsoids with their surrounding ring of macrophages, were only formed around embryonic day (ED) 20. These structures and especially the B-cell compartment, i.e., the peri-ellipsoid lymphoid sheath (PELS) gradually matured during the first week posthatch.

Therefore, we analysed at what age broiler chickens could generate a humoral response against the thymus-dependent antigen bovine serum albumin (BSA). Chickens were immunised in ovo (ED16 and ED18) and at 1, 7 and 12 days of age and subsequent BSA-specific immunoglobulin (Ig) M and IgG responses were measured up to 10 days postimmunisation (DPI). No major differences were observed in the relative growth rates, while hatchability was only slightly reduced. Only in chicks immunised on 12 days of age, IgM and IgG responses were high with a normal kinetic pattern. In chicks immunised on 7 days of age, responses were just detectable, but they were absent in chicks immunised in ovo and on the day of hatching (Day 1).

In a subsequent experiment, 1-, 7- and 12-day-old chicks were BSA-immunised and Ig responses were measured for a longer period up to the age of 28 days. The IgG response of chicks immunised at 1 day of age was lower and occurred later (from 28 DPI) than the response of chicks immunised at 7 and 14 days of age (from 14 DPI). It was not increased by a booster immunisation on 29 days of age, in contrast to the response of chicks immunised at 7 and 14 days of age. These findings indicate that vaccination at 1 day of age does not activate the B-cell response resulting in antibody production and support the idea that the immune function of the late embryonic and neonatal chickens is not entirely developed due to the incomplete structural organisation of their secondary immune organs.     

鸡眼区相关淋巴组织对ND疫苗点眼免疫应答Ⅱ.眼区局部T淋巴细胞亚群的变化

本研究采用流式细胞仪技术对鸡眼区相关淋巴组织(HALT)在鸡新城疫疫苗点眼免疫后的局部T淋巴细胞亚群的变化进行了研究。研究发现,LaSota 系ND疫苗点眼免疫后眼区相关淋巴组织对ND疫苗可产生良好的细胞免疫应答。免疫组结膜相关淋巴组织(CALT)和哈氏腺(HG)中CD4 T及CD8 T淋巴细胞数量于首免后迅速升高。免疫期间其百分比含量明显高于非免疫组,到40 日龄时,有恢复到正常值的趋势。     

论"天人合一"与林业可持续发展

在全球环境生态危机不断威胁人类生存的今天 ,人们在重新审视历史时发现 ,中国传统文化对人与自然的认识含有丰富的辩证哲理。与西方追求利益最大化的林业管理理念不同 ,中国古代的林业经营管理思想 ,是以“天人合一”思想为指导 ,实现经济、社会和环境的和谐可持续发展的“生生之道”。随着现代化建设与社会的进步 ,我国面临日益严峻的人口、资源、环境、粮食、能源等诸多问题 ,愈来愈倚赖于林业的可持续发展。可持续发展已成为维系人类生存的途径 ,对古代这一宝贵思想进行回顾与分析 ,可为当代林业的可持续发展提供有力的借鉴。     

Impact of Rabies Vaccination History on Attainment of an Adequate Antibody Titre Among Dogs Tested for International Travel Certification,Israel – 2010–2014

Rabies is endemic in wildlife or domestic carnivore populations globally. Infection of domestic dogs is of particular concern in many areas. In regions where domestic animals are at risk of exposure to rabies virus, dogs should be routinely vaccinated against rabies to protect both pet and human populations. Many countries require demonstration of an adequate level of serum rabies neutralizing antibodies to permit entry of dogs during international travel. We analysed rabies titres of dogs seeking travel certification in Israel to assess demographic and vaccine history factors associated with antibody titres below the acceptable threshold for travel certification. Having received only one previous rabies vaccination and a longer duration since the most recent vaccination was received were primary risk factors for not achieving an adequate rabies virus neutralizing antibody titre for travel certification. These risk factors had stronger effects in younger animals, but were consistent for dogs of all ages. In particular, these findings reiterate the importance of administering at least two rabies vaccinations (the primo vaccination and subsequent booster) to ensure population‐level protection against rabies in dogs globally.     

“翻转课堂+网络直播”教学模式在餐饮管理专业的教学应用与研究——以“面点制作工艺”课程为例

时代在发展,社会在进步。随着互联网的兴起及新冠疫情的影响,"翻转课堂+网络直播"在课堂中的运用尤显重要。在餐饮专业中,"面点制作工艺"作为专业核心课,这种特殊的教学模式新颖,让课堂充满了新鲜感。通过结合在建的网络平台的大量资源,让学生对"面点制作工艺"课程充满了兴趣。在疫情期间,做到"停课不停教,停课不停学",该教学改革模式在课程中的运用势在必行,将会带来较好的教学效果。     

鸡传染性支气管炎病毒肾致病株的致弱及免疫研究

用已鉴定的广西鸡传染性支气管炎病毒(IBV)分离株G,C,Z和Q分别通过鸡胚传代进行致弱,在一定代次时分别接种敏感鸡作毒力测定试验.然后用已致弱的毒株在实验室进行攻击保护试验,最后取已致弱而且抗原性良好的毒株在广西各地鸡场进行田间应用试验。结果表明,C株在传至40代时,G,Z和Q株分别传至20代时对鸡的毒性均已大大降低;免疫鸡用标准强毒株(M_(41))攻击,然后用病毒回收的技术来衡量其免疫力,结果各株经免疫两次后均有很好的保护率(60％～100％),均显著优于对照组(P<0.01);致弱株分别在南宁、柳州、容县、岑溪和博自5县市的11个鸡场进行田间试验,试验的鸡有30群共103761羽,试验时分别对疫苗免疫对鸡生产性能的影响、安全性和育成率进行观察和测算,结果表明,作者培育的IBV弱毒苗对鸡是安全的,使用C_(60)或C_(80)和G_(20)株先后两次免疫鸡,对IB有较好预防效果,这些弱毒株有希望成为供生产使用的疫苗。     

猪瘟DNA疫苗的临床免疫实验

在前期研究工作筛选出2种DNA疫苗质粒的基础上,采用3种免疫策略(DNA疫苗单独免疫法、DNA疫苗初免蛋白免疫加强的prime-boost方法以及沙门氏菌(Salmonella)载体介导法),于某规模化猪场对猪瘟病毒(CSFV)的DNA免疫效果进行了临床应用研究。随机选择未经猪瘟疫苗免疫的断奶仔猪60头,分6组进行免疫接种,检测免疫猪抗体产生情况并对各组免疫猪进行攻毒试验。免疫猪血清抗体ELISA检测结果表明,pcDSW组、pIRE2IL2组、pcDSW E2protein组和pIRE2IL2 E2protein组均产生了较高的抗体水平,而沙门氏菌介导的2种DNA疫苗质粒诱导的抗体水平不显著。攻毒试验结果表明,pcDSW和pIRE2IL2单独免疫组或prime-boost组能够抵抗致死剂量的CSFV石门强毒攻击,保护率87.50%￣90.00%。其中pcDSW效果好于pIRE2IL2。而沙门氏菌介导的DNA疫苗组不能产生有效保护。不同接种途径的免疫效果比较结果表明,颈部肌肉注射免疫后产生的抗体水平较后肢胫前肌注射免疫产生的抗体水平高。     

生猪肉产量预测的非接触实时在线机器视觉系统

为了准确估测生猪肉产量,该文提出了一种自动提取生猪活体特征的方法,建立了生猪肉产量预测算法。首先,基于自主研发的生猪肉产量预测的机器视觉系统装置实时采集54头活体大白猪的俯视图和侧视图,然后根据图像处理技术对所得的图像进行分析,提取生猪的体长、胸宽、臀宽、体高等体尺参数值;同时通过称量装置获得每头猪的活体质量。其次,将54头生猪样品按2∶1的比例分为校正集和验证集,基于体长、胸宽、臀宽、体高和体质量5个特征参数分别利用多元线性回归法(multiple linear regression,MLR)和偏最小二乘回归法(partial least-squares regression,PLSR)建立不同的肉产量预测模型,通过比较各预测模型的估测精度、相关系数等,确定最佳预测模型。分析结果表明,5个参数中体质量对肉产量预测的权重最大;偏最小二乘回归方法的预测结果较好,最佳预测模型的预测相关系数为0.95,预测误差为3.09 kg。试验结果证实,在检测系统中使用基于生猪的体尺参数和体质量建立的偏最小二乘回归预测模型可快速准确预测生猪肉产量,适于实际生产应用。     

10kV配网工程三项带电作业工序的探讨

为了减少因故障停电影响客户用电,近几年在10kV配网施工中大力开展了带电作业。文从10KV施工及施工管理工作经验出发,对10KV带电施工作业的几项常见施工作业操作步骤进行整理和总结。     

大连地区玉米螟越冬期间气象条件越冬后活虫数的影响

为研究大连地区玉米螟越冬期间气象条件对越冬后活虫数的影响,以期为防治玉米螟提供科学依据。利用大连地区最近10年气象资料和玉米螟越冬后活虫数资料,对玉米螟越冬后活虫数与越冬期间气象要素进行相关性分析。结果表明,玉米螟冬后百杆活虫数受上年10月下旬-11月份温湿条件影响较大。此间温度低有利于其越冬成活;11月份降水多,冬后百杆活虫数多。建立大连地区玉米螟冬后百杆活虫数统计预报模式。