粉碎粒度对粗蛋白测定结果的影响

将同一饲料样品按4分法缩分为3份,1份按GB／T6432-94制备样品,另2份过20目和40目筛片粉碎制备样品,按姜懋武提出的改进方法测定粗蛋白（CP）,研究样品的粉碎粒度对CP测定结果的影响。结果表明,不同粉碎粒度制备样品测定的CP结果,不同饲料样品间没有表现出相同的规律。在测定的11个样品中,只有3个样品（仔猪前期颗粒料、生长育肥猪浓缩料和肉用仔鸡后期颗粒料）的CP测定值不受粉碎粒度变化的影响（P〉0．05）,其他8个样品的CP测定值均受饲料粉碎粒度的影响（P〈0．05或P〈0．01）,但不同品种间表现的规律不尽相同。玉米、小麦和大豆等籽实类饲料原料,除玉米20目和40目间无显著差异外,其余不同粉碎粒度间均表现出差异极显著。饼粕类饲料原料中,豆粕与棉粕60目组极显著高于20目和40目组,20目和40目组间差异不显著;花生粕与菜粕20目组显著高于40目和60目组。肉用仔鸡后期浓缩料40目和60目极显著高于20目,40目和60目间差异不显著。     

Effects of N-methyl-D, L-aspartate on secretion of growth hormone-releasing hormone from the boar hypothalamic-preoptic area and median eminence in vitro

N-methyl-D, L-aspartate (NMA) elicited secretion of growth hormone (GH)-releasing hormone from both the hypothalamic-preoptic area and the median eminence that were collected from boars. We suggest that the previously described increase in GH secretion that follows peripheral treatment of swine with NMA is attributable, at least in part, to NMA-stimulated secretion of GH-releasing hormone from the central nervous system.     

伊氏锥虫弱毒株免疫家兔的T细胞应答反应

以ANAE染色法和~3H-TdR掺入的淋巴细胞转化试验,测定了伊氏锥虫弱毒株免疫家兔的T细胞动态变化.结果,免疫兔外周血T细胞增殖反应在免疫后第24d达到高峰,ANAE阳性细胞百分率这72.65%,对照组仅为41.2%;约1周后,出现抑制性T细胞,其增殖反应也明显减弱,最后完全被抑制.而外源性白细胞介素2的加入,可解除这种免疫抑制.攻虫后,特异性T细胞应答反应未再出现强烈的回忆反应,但伊氏锥虫弱毒株免疫家兔获得9/12的保护.因此,T细胞在这种抗锥虫免疫中,没有起到主导作用.     

用单抗研究T细胞与牛流行性白血病发生的关系

本试验对10头患流行性白血病病牛的不同器官的肿瘤组织，用8种单克隆抗体（McAb),TH14B、BAQ44A、PIg45A、BIg715A、PIg501E、cAct105、MM1A、AHCC125染色进行了观察。结果：病牛经临床病理学和免疫琼扩试验而诊断为EBL，通过免疫组织化学检测，在10个病例中发现有9个病例的肿瘤组织对B细胞属性的McAb有很强的染色反应，证明其来源于B细胞。仅有1个病例对B细胞属性的McAb着色很淡，而对T细胞属性的McAb着色很深，呈强阳性反应，说明其来源可能与T细胞有关。     

肉鸡血清肌钙蛋白T与腹水综合征的关系研究

本试验建立了肉鸡血清中心源性肌钙蛋白T(Tn-T)的ELISA测定方法,用于对肉鸡腹水综合征的早期非损伤性诊断指标.结果表明,患腹水综合征肉鸡的血清Tn-T平均测定值为0.242±0.0703 ng/ml,而正常鸡的平均值为0.1 79±0.0467 ng/ml;以血清肌钙蛋白T测定值大于等于0.2 ng/ml作为判定肉鸡腹水综合征的标准,判别准确性达到78%.检测血液中肌钙蛋白T是诊断幼龄鸡早期心脏病的重要方法,可作为一种非损伤性方法用于针对肉鸡腹水综合征的育种方案中.     

新城疫活疫苗对控制鸡大肠杆菌病的效果观察

为了研究鸡新城疫活疫苗紧急免疫控制鸡大肠杆菌病的效果,通过大肠杆菌人工感染30日龄蛋鸡,待出现病症后,紧急免疫新城疫La-sota弱毒苗(Ⅳ系)4羽份.免疫后5～17 d,通过血凝抑制试验测定血清新城疫抗体水平,试验组新城疫抗体水平逐步提高,对照组抗体略有下降,免疫后17 d两组抗体水平差异显著(P＜0.05);对照组...     

融合表达淋巴细胞脉络丛脑膜炎病毒和卵清白蛋白CD8+T细胞表位的减毒鼠伤寒沙门氏菌的构建与鉴定

依据淋巴细胞脉络丛脑膜炎病毒(LCMV)主要保护性抗原CD8 T细胞表位VRRPQASGVYMGNLTAQ和卵清白蛋白(OVA)CD8 T细胞表位SIINFEKL,设计、合成两条编码LCMV和OVA CD8 T细胞表位的寡核苷酸片段,经退火后,克隆入绿色荧光蛋白表达质粒pYAGFP,经PCR扩增和序列测定分析,证实成功构建T细胞表位与绿色荧光蛋白融合表达的重组质粒pYAGFPL-O,将此重组质粒pYAGFPL-O转化减毒鼠伤寒沙门氏菌X4550,获得重组沙门氏菌X4550(pYAGFPL-O).用SDS-PAGE电泳测得重组菌表达的融合蛋白约为30kD.同时,荧光显微镜下观察到X4550(pYAGFPL-O)发出黄绿色荧光.这些结果表明LCMV和OVA T细胞表位已成功表达.重组菌X4550(pYAGFPL-O)的获得为研究沙门氏菌载体携带外源抗原的T细胞应答规律及调控机理打下了重要基础.     

MAGNETIC RESONANCE IMAGING OF THE CANINE BRAIN AT 7 T

The purpose of this study was to describe relevant canine brain structures as seen on T2-weighted images following magnetic resonance (MR) imaging at 7 T and to compare the results with imaging at 1.5 T. Imaging was performed on five healthy laboratory beagle dogs using 1.5 and 7 T clinical scanners. At 1.5 T, spin echo images were acquired, while gradient echo images were acquired at 3 T. Image quality and conspicuity of anatomic structures were evaluated qualitatively by direct comparison of the images obtained from the two different magnetic fields. The signal-to-nose ratio (SNR) and contrast-to-noise ratio (CNR) were calculated and compared between 1.5 and 7 T. The T2-weighted images at 7 T provided good spatial and contrast resolution for the identification of clinically relevant brain anatomy; these images provided better delineation and conspicuity of the brain stem and cerebellar structures, which were difficult to unequivocally identify at 1.5 T. However, frontal and parietal lobe and the trigeminal nerve were difficult to identify at 7 T due to susceptibility artifact. The SNR and CNR of the images at 7 T were significantly increased up to 318% and 715% compared with the 1.5 T images. If some disadvantages of 7 T imaging, such as susceptibility artifacts, technical difficulties, and high cost, can be improved, 7 T clinical MR imaging could provide a good experimental and diagnostic tool for the evaluation of canine brain disorders.