日粮添加蜂花粉对肉杂鸡抗氧化性及血清生化指标的影响

活性氧(ROS)自由基,在生物体衰老与疾病以及正常的免疫、代谢与细胞信号传导等过程中都起着重要的生理作用.为了防御自由基对机体的损伤,机体在进化过程中形成了一套抗氧化防御机制,包括各种抗氧化酶类及其非自由基中间产物[1-2].抗氧化酶是生物体抗氧化的第一道防线,它们相互之间具有协同防止活性氧的损伤效应,并且能够彼此再生,形成网络抗氧化剂[2-3].     

The investigation stride of mucosal immunoloagy and animal infectious disease preservation

黏膜免疫学研究是近几年来研究进展最快的领域之一。黏膜免疫的规律、特点及其调控机制等方面的知识得到了丰富和充实,并且对黏膜相关的疫病的发生机制及其防制提供了新的依据。在此,就黏膜免疫学的意义、黏膜免疫的主要途径、黏膜免疫与动物疫病防制、黏膜免疫与疫苗、黏膜免疫的研究动态等进行了综述。     

性成熟启动时间不同的母鸡瘦素及其受体mRNA表达的差异

为探讨瘦素（leptin）及其受体在禽类性成熟启动过程中的作用,试验采用120羽60日龄伊莎蛋母鸡,随机均分为2组,分别饲养于光照逐渐延长（以光／暗为8h／16h为起点每周增加0．5h光照,简称长光照组）和恒定的短光照（光／暗为8h／16h,简称短光照组）条件下,记录体重变化与性成熟时间。长光照组和短光照组母鸡分别于136和151日龄时开产。在136日龄时,每组取10只鸡宰杀后取血液、脂肪和下丘脑组织,分别检测血清leptin水平、脂肪leptin mRNA与下丘脑leptin受体mRNA的表达。结果表明：136日龄时,长光照组和短光照组母鸡血清雌二醇（E2）和leptin水平均无显著差异（P〉0．05,n=10）。相对定量RT-PCR结果显示：136日龄时,长光照组母鸡脂肪leptin mRNA表达丰度极显著高于短光照组（P〈0．01,n=10）,但下丘脑leptin受体mRNA的表达水平无显著差异（P〉0．05,n=10）。以上结果提示：15d的性成熟时间差异并不伴随产蛋母鸡血清leptin及下丘脑leptin受体mRNA表达水平的显著变化,而脂肪leptin mRNA表达水平与血清leptin蛋白水平的不一致性则提示循环leptin的其他组织来源。     

杜仲叶对肉杂鸡血清中部分生化指标的影响

试验以观察不同剂量杜仲叶水煎液对内杂鸡血清中总胆固醇、甘油三酯、葡萄糖含量的影响为目的,选用1日龄内杂鸡272只,随机分为4组,Ⅰ组为对照组,饮用自来水,Ⅱ～Ⅳ组为杜仲叶低、中、高剂量组,饮水中杜仲叶浓度分别为5,10,15g/L,试验期6周.分别于2,4和6周末每组随机抽样8只鸡进行心脏采血,测定其血清总胆固醇、甘油三酯和葡萄糖的含量.结果表明.与对照组比较,2,4和6周末杜仲叶各剂量组血清中总胆固醇和甘油三酯的含量显著降低(P<0.05或P<0.01),总胆固醇含量随周龄增加有降低趋势;葡萄糖的含量在2周龄时差异不显著(P>0.05),4,6周龄显著低于对照组(P<0.05或P<0.01).结论:杜仲叶能够显著降低血清中总胆固醇、甘油三酯和葡萄糖的含量.     

左旋氧氟沙星对蛋鸡大肠杆菌病的疗效观察

某鸡场193日龄罗曼蛋鸡发生以腹泻和产蛋率下降为特征的大肠杆菌病。按WHO推荐法进行药敏试验,测得大肠菌菌株对左旋氧氟沙星、恩诺沙星、强力霉素分别为极敏、高敏和中敏。将发病鸡3820只随机分为4组,第1组为对照组,第2、3、4组分别用50mg/L的左旋氧氟沙星、50mg/L的恩诺沙星、100mg/L的强力霉素连续5d饮水给药。结果表明,饮用左旋氧氟沙星组鸡群的精神状态、腹泻率、产蛋率均优于恩诺沙星组和强力霉素组。     

试验性脂肪肝出血综合征鸡氧化应激水平和内皮功能变化

将320只14日龄青脚麻鸡随机分为对照组、高脂模型组、雌激素模型组和高脂结合雌激素模型组,每组设4个重复,每个重复20只,共处理28 d.造模14、28 d,测定肝脏氧化应激、血清肝功能和内皮功能相关参数,并进行肝脏病理组织学观察.结果显示,模型组鸡肝脂含量增加、肝细胞脂肪变性,肝脏血管损伤,出现典型的鸡脂肪肝出血综合征(FLHS)病变;与对照组相比,各模型组肝脏MDA含量升高(P＜0.05),SOD和GSH-Px活性降低,血浆AngⅡ含量增加,血清NO含量降低;相关性分析显示,肝脏脂肪变性程度与肝脏MDA含量正相关(P＜0.01),与肝脏SOD和GSH Px活性呈负相关(P＜0.01);肝脏MDA含量与肝出血分数和血浆AngⅡ含量皆有极显著的相关性(P＜0.01);肝脏SOD和GSH-Px活性与肝出血分数呈负相关(P＜0.01或P＜0.05),与血清NO含量的变化均呈正相关(P＜0.05);血浆AngⅡ含量与肝出血分数呈正相关(P＜0.05).结果表明,FLHS发生和发展过程中氧化应激参与了内皮功能紊乱的形成,血管损伤可能与氧化应激和内皮功能失调有关.     

Recovery of Mutants Impaired in Pathogenicity After Transposition of Impala in Fusarium oxysporum f. sp. melonis

ABSTRACT The ability of transposon impala to inactivate genes involved in pathogenicity was tested in Fusarium oxysporum f. sp. melonis. Somatic excision of an impala copy inserted in the nitrate reductase-encoding niaD gene was positively selected through a phenotypic assay based on the restoration of nitrate reductase activity. Independent excision events were analyzed molecularly and shown to carry reinsertedimpala in more than 70% of the cases. Mapping of reinserted impala elements on large NotI-restriction fragments showed that impala transposes randomly. By screening 746 revertants on plants, a high proportion (3.5%) of mutants impaired in their pathogenic potential was recovered. According to the kinetics of wilt symptom development, the strains that were impaired in pathogenicity were clustered in three classes: class 1 grouped two strains that never induced Fusarium wilt symptoms on the host plant; class 2 and class 3 grouped 15 and 9 revertants which caused symptoms more than 50 and 30 days after inoculation, respectively. The first results demonstrate the efficiency of transposition in generating mutants affected in pathogenicity, which are usually difficult to obtain by classical mutagenesis, and open the possibility to clone the altered genes with impala as a tag.     

Modeling annual production and carbon fluxes of a large managed temperate forest using forest inventories, satellite data and field measurements

We evaluated annual productivity and carbon fluxes over the Fontainebleau forest, a large heterogeneous forest region of 17,000 ha, in terms of species composition, canopy structure, stand age, soil type and water and mineral resources. The model is a physiological process-based forest ecosystem model coupled with an allocation model and a soil model. The simulations were done stand by stand, i.e., 2992 forest management units of simulation. Some input parameters that are spatially variable and to which the model is sensitive were calculated for each stand from forest inventory attributes, a network of 8800 soil pits, satellite data and field measurements. These parameters are: (1) vegetation attributes: species, age, height, maximal leaf area index of the year, aboveground biomass and foliar nitrogen content; and (2) soil attributes: available soil water capacity, soil depth and soil carbon content. Main outputs of the simulations are wood production and carbon fluxes on a daily to yearly basis. Results showed that the forest is a carbon sink, with a net ecosystem exchange of 371 g C m(-2) year(-1). Net primary productivity is estimated at 630 g C m(-2) year(-1) over the entire forest. Reasonably good agreement was found between simulated trunk relative growth rate (2.74%) and regional production estimated from the National Forest Inventory (IFN) (2.52%), as well as between simulated and measured annual wood production at the forest scale (about 71,000 and 68,000 m(3) year(-1), respectively). Results are discussed species by species.     

甲酸和酸盐型添加剂影响奶牛早期泌乳性能的比较

采用第二次收获的多年生黑麦草,分别用甲酸(3升/吨)和酸盐型(6升/吨)添加剂投放于带顶150 吨容量的地面青贮窖青贮。两种青贮料经过乳酸发酵。酸盐处理与甲酸处理的青贮料相比,甲酸多(19 对12g/kg干物质),乳酸(98对 118g/kg干物质)及乙酸(11对 17g/kg干物质)少,而在青贮窖里的损失和产生的浸出液相同。 试验奶牛(平均体重565kg)从泌乳第2周至15周分别饲喂两种青贮料,每头每天青贮料中加 3kg配合料。日粮中含有粗蛋白 190g/kg干物质,代谢能估计值为12.6MJ/kg干物质。与甲酸处理的青贮料比较,酸盐处理组对青贮料干物质摄取量,日乳产量、乳蛋白或体重变化无明显影响,但乳脂率明显增加。 试验结束,与甲酸处理比较,酸盐添加剂在青贮料发酵及奶牛生产性能方面的影响,差异不大。