Reproduction Management of Herds/Flocks of Exotic Animals: Investigating Breeding Failures in Birds,Reptiles, and Small Mammals     

《Veterinary Clinics of North America: Exotic Animal Practice》2021,24(3):661-695

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叶轮出口边对双蜗壳泵压力脉动的影响     

操瑞嘉  孔祥序  周以松  孙静如 《排灌机械工程学报》2020,38(1):32-38

泵的叶轮扫掠蜗壳隔舌时产生的压力脉动是引起船用泵振动噪声的原因之一.为尽可能弱化这一影响,分别设计了叶片出口边与前后盖板基本面垂直和倾斜的2种不同形式叶轮,将其配置在相同的双蜗壳中,通过数值计算与样机试验相结合的手段,对蜗壳内9个不同位置的压力脉动情况进行对比分析.结果表明:出口边倾斜的叶轮相比于出口边垂直的叶轮可明显改善蜗壳内次脉动的“驼峰”现象,且可以进一步降低隔舌处主波动的压力峰值;对蜗壳内2个隔舌稍前的位置,出口边倾斜的叶轮反而会使得该点的压力系数幅值明显增大,且该点主波动的周期数发生改变;2种叶轮出口边的不同形式对蜗壳出口位置的压力脉动的影响基本相同;采用出口边倾斜叶轮对改善因叶轮与隔舌间的液流压力脉动是可行的.  相似文献   

转基因动物研究进展   总被引：4，自引：0，他引：4  

胡建宏李青旺  王立强江中良于永生  解广勤 《家畜生态》2004,25(2):50-53

转基因动物是现代生物技术中一个极其重要的研究领域，目前已经有转基因小鼠、兔、绵羊、山羊、猪、牛、鸡和鱼等多种转基因动物问世。本文综述了转基因动物的制作方法、转基因动物的应用研究以及所取得的重要成就，并指出了转基因动物存在的主要问题，展望了其发展前景。  相似文献   

Genetic Engineering Approaches to Pig Production*     

B. Brenig  G. Brem 《Reproduction in domestic animals》1991,26(1):14-21

Modern biotechnology promises a number of new applications in animal breeding and production. Although conventional pig breeding has achieved a high level of efficiency and productivity numerous problems have been encountered with animal health and the loss of meat quality. Selection based on phenotypic performance data of individual animals does not take into account the importance of specific genes and their relevance within a complex regulatory system. In most cases it is therefore difficult to trace back the genetic origins of clinically important disorders. The application of genetic engineering techniques in pig production will facilitate diagnosis, improvement of productivity, and animal health by allowing direct genetic manipulation. Attention must be focussed on the physical and genetic analysis of the procine genome. The isolation and characterisation of genes, DNA-markers, polymorphic DNA-fragments, and their chromosomal assignment will be important prerequisites and tools for the elucidation of genetic disorders. Especially the detection of heterozygous carriers of recessive disorders and their elimination from the breeding stock will increase selection accuracy and decrease the generation intervals. But also the rapid and simple detection of infectious diseases, which is sometimes difficult if not impossible at present, will improve animal health and welfare. Although the production of transgenic animals either by DNA-microinjection into zygotes or the use of embryonal stem cells manipulated in vitro is less straightforward than DNA-based diagnosis it will play an important role in the direct manipulation of the porcine genome and genes. Breeding programmes including the use of transgenic livestock have already been developed. There is no doubt that genetic engineering has reached a degree of practical feasibility, allowing it to play an important role in pig breeding in particular and animal production in general.  相似文献   

Manoalide derivatives from a marine sponge Luffariella sp. collected in Palau     

Michio  NAMIKOSHI  Shigeo  SUZUKI  Shiori  MEGURO  Hiroshi  NAGAI  Yoshio  KOIKE  Akira  KITAZAWA  Hisayoshi  KOBAYASHI  Taiko  ODA  Junko  YAMADA 《Fisheries Science》2004,70(1):152-158

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日粮纤维及其对幼龄单胃动物消化功能的影响     

江霞  李彦  许梓荣 《中国饲料》2005,(9):26-28

日粮纤维能提供大量的能量,而且有利于维持动物机体的正常消化功能。本文综述了日粮纤维的代谢及对幼龄单胃动物消化功能的影响。  相似文献   

兽用抗寄生虫药物新剂型及其新技术的研究进展   总被引：8，自引：1，他引：8  

符华林 《中国兽药杂志》2004,38(3):38-42

兽用抗寄生虫药物由于使用频繁,其给药技术研究一直备受重视.目前,兽用抗寄生虫药物新剂型和新技术的研究主要集中在缓释控释制剂和脂质体制剂,其次是透皮给药系统、微囊、微球、环糊精包合物、固体分散体等.但这些新剂型和新技术大多还处于研究阶段,在处方设计或制剂工艺方面都还存在一些问题,今后应加强这些新剂型的工艺和技术研究,以真正发挥这些新剂型的优点.  相似文献   

实验动物微生物学质量控制及效果观察     

陶元清 《青海畜牧兽医杂志》2005,35(4):20-20

以SPF级（无特殊病原体）动物为种源，采取综合防治措施，在屏障设施饲养清洁级实验小鼠和大鼠。经过两年饲养繁育的结果表明：动物微生物学质量符合清洁级动物国家标准，质量控制效果显著。  相似文献   

Impact of Dog Transport on High-Risk Infectious Diseases     

《Veterinary Clinics of North America: Small Animal Practice》2019,49(4):615-627

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Investigation of Interspecies Interactions within Marine Micromonosporaceae Using an Improved Co-Culture Approach     

Navid Adnani  Emmanuel Vazquez-Rivera  Srikar N. Adibhatla  Gregory A. Ellis  Doug R. Braun  Tim S. Bugni 《Marine drugs》2015,13(10):6082-6098

With respect to bacterial natural products, a significant outcome of the genomic era was that the biosynthetic potential in many microorganisms surpassed the number of compounds isolated under standard laboratory growth conditions, particularly among certain members in the phylum Actinobacteria. Our group, as well as others, investigated interspecies interactions, via co-culture, as a technique to coax bacteria to produce novel natural products. While co-culture provides new opportunities, challenges exist and questions surrounding these methods remain unanswered. In marine bacteria, for example, how prevalent are interspecies interactions and how commonly do interactions result in novel natural products? In an attempt to begin to answer basic questions surrounding co-culture of marine microorganisms, we have tested both antibiotic activity-based and LC/MS-based methods to evaluate Micromonosporaceae secondary metabolite production in co-culture. Overall, our investigation of 65 Micromonosporaceae led to the identification of 12 Micromonosporaceae across three genera that produced unique metabolites in co-culture. Our results suggest that interspecies interactions were prevalent between marine Micromonosporaceae and marine mycolic acid-containing bacteria. Furthermore, our approach highlights a sensitive and rapid method for investigating interspecies interactions in search of novel antibiotics, secondary metabolites, and genes.  相似文献