水产养殖饲用微生态制剂研究进展

微生态制剂作为新型饲料添加剂,能够有效调节水产动物营养保健和微生态平衡,减少抗生素使用,是理想的抗生素替代品,对保障高效种养殖、食品安全及环境可持续发展意义重大。我国饲用微生态制剂应用起步较晚且发展较慢,仍面临着难点和挑战。本文介绍了微生态制剂及饲用益生菌在鱼、虾及海参养殖中的应用,基于优良益生菌选育、培养条件优化及混合菌株发酵与制剂应用等生物技术研究现状,总结了近年来水产养殖饲用微生态制剂的研究进展,并对未来微生态制剂研究重点和发展前景进行了展望。     

益生菌剂与益生协同剂的协同作用的研究及应用现状

在微生态理论指导下采用已知有益的微生物 ,经培养、发酵、干燥等特殊工艺制成的生物制剂或活菌制剂称为益生菌剂或动物微生态制剂 ,其主要作用是通过生物夺氧、菌群调整、生物拮抗、提高免疫功能和增强酶活性 ,以达到防治动物肠道病原性腹泻和促生长作用。益生菌剂防治动物肠道疾病的效果显著高于抗生素及其他抗菌药物 ,而促生长作用一般尚未达到抗生素水平。因此为提高益生菌剂的促生长作用 ,人们又积极地进行益生协同剂的研究、开发和应用。从微生态学观点和提高动物生产性能出发 ,益生协同剂是指对体内自身的益生菌和从体外进入体内的益…     

微生态制剂的作用机制及其在动物生产中的应用

近年来,微生态制剂的开发与应用受到社会各界的普遍关注。微生态制剂是一类优质饲料添加剂,具有安全性高、无致病性、毒副作用小和生物功能齐全的特点,包括益生菌、益生元和合生元三类物质,其在维持肠道菌群平衡、促进免疫系统发育及提高机体抗氧化性能等方面具有显著作用,可改善生产性能和健康状况,有利于动物生产优质产品。详细论述了微生态制剂的种类和益生菌、益生元和合生元的作用机制以及国内外关于微生态制剂在动物生产中的应用现状和对喀斯特地区健康养殖的应用潜力,从而为微生态制剂的研究方向及生产应用提供参考。     

现代生物技术与饲用微生态制剂

近年来,使用抗生素的副作用越来越多地受到关注,世界上许多国家已出台相应政策来控制抗生素的使用。但是由于养殖行业的迅猛发展,养殖密度加大,养殖动物病害发病的风险提高,急需可替代抗生素的新型绿色饲料添加剂产品。微生态制剂作为一种新型绿色饲料添加剂,在养殖行业发挥了重要作用。随着饲用微生态制剂产品研发的深入,现代生物技术在提升微生态制剂的理论和应用研究方面发挥着重要作用。PCR、核酸分子杂交、基因工程以及组学等技术已应用于微生物菌种鉴定、基因改良、作用机理等研究中。本文对饲用微生态制剂的研发现状进行了阐述,并综述了现代生物技术在饲用微生态制剂研究中的应用。     

微生物发酵中药饲料添加剂的研究进展

微生物发酵中药饲料添加剂突破性地将中药饲料添加剂和微生态饲料添加剂有机结合,具有提高免疫力、促进动物生长等作用,是替代抗生素的理想饲料添加剂。本文对近几年微生物发酵中药的机理及发酵后药性的变化、微生态饲料添加剂以及微生物发酵中药饲料添加剂进行了阐述。     

益生菌饲料的现状、生产和应用效果(二)

6益生菌的使用效果猪瘟和鸡瘟在我国流行较严重,对集约饲养是很大的威胁,饲喂微生态制剂可有效提高动物体内免疫抗体水平,预防疾病爆发,并提高饲料转化率和产品品质[34],有实验表明,养猪使用微生态制剂,可提高日增重11%,改善饲料转化率     

饲用益生菌及其使用效果

益生菌作为饲料添加剂,可用来代替饲用抗生素,增强免疫力促进动物的健康和生长,提高饲养效率,降低饲养成本,用其代替饲用抗生素,可降低动物产品抗生素残留,抑制耐药性病原菌的发展.本文对益生菌饲料的菌种、制法及其使用效果作了介绍,并对如何利用酶制剂和乳酸发酵生产的大量废菌体作为益生菌来源提出了建议.     

饲用微生物的应用及研究现状

1　饲用微生物应用概况饲用微生物又称益生菌、活菌制剂 ,是近年来出现的一类新型饲料添加剂。它是指由许多有益微生物及其代谢产物和生长促进物质组成的 ,可直接饲喂动物的活菌制剂。具有调节动物胃肠道微生物态平衡、维持胃肠道的正常功能、提高宿主的健康水平 ,从而实现其防病、治病、促进生长等功能。由于它是有益活菌制剂 ,又具有无毒、无副作用、无污染、无残留、不产生抗药性等抗生素所不具备的优点 ,所以倍受关注。在饲料行业和畜牧业用有益微生物替代抗生素作为兽药和饲料添加剂 ,现已得到广泛的重视和应用 ,并显示出其光辉的前景…     

微生态制剂在水产养殖中的作用

微生态制剂的主要作用有 :净化水质、改善养殖水体环境 ;抑制病原微生物 ,提高机体免疫力 ;作为饲料添加剂 ,促进养殖生物生长 ;常用的微生物菌群主要有光合细菌、硝化细菌、芽孢杆菌等。综述了微生态制剂在水产养殖中的作用及常用微生物菌群。     

畜禽中药-益生菌复合微生态制剂的研究进展

畜禽中药-益生菌复合微生态制剂是指采用现代发酵技术将益生菌与中药联合发酵,发挥两者的协同作用,以提高畜禽免疫功能、保护畜禽健康的一种新型动物微生态制剂。文中通过调研近几年关于益生菌及中药微生态制剂等方面的文献,综述了畜禽中药-益生菌复合微生态制剂的产生背景及菌种特点,并重点阐述了畜禽中药-益生菌复合微生态制剂的作用机制、在畜禽养殖中的应用及存在问题与建议,以期为畜禽中药-益生菌复合微生态制剂的深入研究提供参考和依据。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.