禁抗后仔猪细菌性腹泻的临床诊断与防治

为了促进食品安全和养猪业的健康发展，禁止在饲料中使用促生长抗生素势在必行。随着我国的饲料禁抗相关法规的推行，饲料企业被严格禁止在饲料生产过程中加入抗生素，这也导致了猪场疾病尤其是肠道疾病的高发，而仔猪肠道发育未完全，免疫系统未发育成熟，更容易发生严重的腹泻甚至死亡。文章对几种常见的仔猪细菌性腹泻疾病进行了回顾，病原包括大肠杆菌、沙门氏菌、魏氏梭菌，讨论了它们的临床症状与防控措施，为猪场在防控这些细菌性腹泻提供参考。     

Comparison of Resistance to Tomato Leaf Curl Virus (India) and Tomato Yellow Leaf Curl Virus (Israel) among Lycopersicon Wild Species, Breeding Lines and Hybrids

The objective of this study was to screen wild and domesticated tomatoes for resistance to Tomato yellow leaf curl virus, Israel (TYLCV-Is) and Tomato leaf curl virus from Bangalore isolate 4, India (ToLCV-[Ban4]) to find sources of resistance to both viruses. A total of 34 tomato genotypes resistant/tolerant to TYLCV-Is were screened for resistance to ToLCV-[Ban4] under glasshouse and field conditions at the University of Agricultural Sciences, Bangalore, India. Resistance was assessed by criteria like disease incidence, symptom severity and squash-blot hybridization. All the tomato genotypes inoculated with ToLCV-[Ban4] by the whitefly vector Bemisia tabaci (Gennadius) produced disease symptoms. In some plants of the lines 902 and 910, however, the virus was not detected by hybridization. The tomato genotypes susceptible to ToLCV-[Ban4] by whitefly-mediated inoculation were also found susceptible to the virus under field conditions. However, there were substantial differences between genotypes in disease incidence, spread, symptom severity and crop yield. Despite early disease incidence, many genotypes produced substantially higher yields than the local hybrid, Avinash-2. Sixteen tomato genotypes from India resistant/tolerant to ToLCV-[Ban4] were also tested for TYLCV-Is resistance at the Hebrew University of Jerusalem, Rehovot, Israel. Accessions of wild species, Lycopersicon hirsutum LA 1777 and PI 390659 were the best sources of resistance to both viruses. Lines 902 and 910, which were, resistant to TYLCV-Is were only tolerant to ToLCV-[Ban4] and accession Lycopersicon peruvianum CMV Sel. INRA, resistant to ToLCV-[Ban4], was only tolerant to TYLCV-Is. Implications of using the resistant lines in breeding programme is discussed.     

Optimization of in vitro embryo production and zygote vitrification for the indigenous Vietnamese Ban pig: The effects of different in vitro oocyte maturation systems

The Vietnamese Ban pig is a precious genetic resource that needs to be preserved. In vitro embryo production from in vitro matured (IVM) oocytes is an important tool for the utilization of cryopreserved porcine sperm. The aim of this study was to compare two media for the IVM of Ban pig oocytes. Immature oocytes were subjected to IVM either in a non‐defined (TCM‐199 + pig follicular fluid) or in a defined base medium (POM + epidermal growth factor). At the end of IVM, the oocytes were in vitro fertilized (IVF) with frozen Ban sperm. Ten hours after IVF, the oocytes were either subjected to orcein staining to check fertilization and maturation status or cultured in vitro for 7 days. There was no difference between the two IVM media in terms of percentages of oocyte maturation and blastocyst production. However, the percentage of male pronuclear formation after IVF and the total cell numbers in blastocysts were higher with the defined system. Zygotes obtained by the two IVM systems survived vitrification at similar rates. In conclusion, the two IVM systems were both effective for the production of Ban pig embryos; however, better embryo quality was achieved with the defined one.     

对我国非林区营造速生丰产林数据的分析

杨树在我国的主要林区是以天然更新为主,人工林很少。非林区的杨树主要是以防护林为主。而随着市场对杨树的需求日益增强,大力发展杨树速生丰产林是大势所趋。本文具体分析了国外杨树栽培的成功经验和数据,并结合我国的实际情况,提出应该取长补短迅速培育杨树速生丰产林,可为我国的经济建设提供服务。     

对西方发达国家制定香味烟草制品禁令的思考

健康加拿大控烟组织的一项提案称,建议政府禁止所有的小雪茄烟及香味烟草制品,即所有加香的烟草制品。在此,美国弗吉尼亚农场联盟委员会称,该法案实施后将严重影响美国白肋烟向加拿大的出口,届时,美式混合型卷烟制品有可能在加拿大境内被禁止销售。     

欧盟禁用饲料药物添加剂的历史和法规

欧盟考虑到抗生素耐药性的发展和抗生素耐药基因可能从动物到人微生物的转移,决定从2006年1月1日起禁止抗生素作为生长促进剂,甚至还建议禁止在动物饲料中全面使用所有的抗菌剂。收集和整理欧盟饲料药物添加剂的禁用清单和法规,介绍欧盟禁用饲料药物添加剂的历史及其对动物健康的影响,以期为中国饲料药物添加剂的使用和管理提供借鉴和参考。     

药用半枫荷植物资源研究

药用半枫荷的种类很多,涉及6科8属的植物,是形态特征或临床功效相似的一类植物。该类植物的药用部位广泛,包括：根、茎、枝、叶以及树皮和花蜜,都具有祛风除湿、活血消肿的独特功效,是有很好发展前景的新型药用植物资源。文章对药用半枫荷植物的植物学特征、地理分布、经济价值及研究现状与进展进行了综述。为药用半枫荷植物资源的可持续开发的提供理论基础并提出相应的保护措施。     

限售股解禁的市场反应:机制与特征研究

限售股解禁的市场反应机制可概括为累积效应、提前反应和减持效应。实证研究证明了这三种机制的存在,同时还发现:累积效应是中国股市波动的重要原因之一;提前反应和减持效应均存在且显著为负;限售股解禁因素总体上引发了负向的市场反应;限售股解禁的心理冲击影响可能大于实际减持压力。大幅度提升市场投资需求以有效承接股票供给规模的巨量增加,这可能是缓解限售股解禁压力的重要思路。     

甘英出使大秦原因考

秦汉四百年间，北方的匈奴始终是中原王朝的巨大威胁，东汉前期概莫能外。如何消除匈奴的威胁是一件令东汉朝廷头疼的事情。与汉武帝基本相同，东汉明、和二帝对北匈奴的政策也是军事打击。班超正是在这种情况下被派往西域，经略三十余年的。和帝永元九年（公元97年），西域都护班超派遣副使甘英出使大秦。甘英途径十余国，往返三万八千多里，“穷临西海”，遥望大秦。西汉张骞出使西域是为了联合大月氏夹击匈奴，班超派甘英出使大秦也是为了联合大秦夹击北匈奴，而非发展与大秦的经济贸易。二者活动的目的是一致的，其结果也极为相似，张骞凿空，未得要领而归，甘英西使，穷临秦海乃还。     

河沟螺蛳的增殖研究

在上海市郊三个河段进行了以梨形环棱螺为主的螺蛳增殖试验，结果，不论是自然增殖禁捕还是人工增殖禁捕，均获得较好的增殖效果，螺蛳数量净增１．４２和２．０７倍。增殖效果与栖息水域的环境因子有密切关系，在增殖的同时必须切实加强螺蛳的资源管理。