Seasonal and photoperiodic regulation of secretion of hormones associated with reproduction in Magang goose ganders

This study examined the reproductive endocrine profile under natural and artificial photoperiods in Magang goose ganders. Group 1 ganders (n=8) served as non-treated controls and were exposed to natural photoperiod throughout the experiment from 13th January to 17th December 2004. Group 2 ganders (n=8) were exposed to 18 h long daily photoperiod for 60 days from 13 January till 15 March 2004 and again to 16 h photoperiod for 75 days till 10th October 2004, and the 11h short photoperiod in the remainder periods of the experiment. In control ganders, plasma LH concentrations were high in normal breeding seasons (August-March) and decreased to low levels in non-breeding season from April to July. Testosterone concentrations changed similarly to that of LH throughout the seasons. Seasonal pattern of PRL concentrations was opposite to those of LH and testosterone, with low values in breeding season and high values in non-breeding season. In artificial photoperiod treated ganders, increasing photoperiod increased PRL and decreased LH and testosterone concentrations, while decreasing photoperiod reversed these changes. There were no seasonal or photoperiod caused changes in plasma T3 concentrations in both control ganders and artificial photoperiod treated ganders. These results demonstrated that in Magang goose ganders that long photoperiod stimulates PRL secretion and decreases LH secretion, which terminates reproductive season in spring and early summer, and short photoperiod stimulates LH secretion and inhibits PRL secretion rendering ganders enter into reproductive season.     

非典型牛海绵状脑病研究进展

非典型牛海绵状脑病为新发现的一种朊病毒病,通常发生于老牛,与典型牛海绵状脑病在病理表型、分子表型和生物表型方面不同。本文结合已发表的文献,对非典型牛海绵状脑病的发现、病原特性、流行病学、检测、发病机理、动物模型研究和实验感染等方面的最新研究进展进行了概述,以期增强人们对该病的认识,并为我国防控该病提供借鉴。     

Rapid detection of contagious ecthyma by loop-mediated isothermal amplification and epidemiology in Jilin Province China

The aim of this experiment was to develop a loop-mediated isothermal amplification (LAMP)assay and to research the recent epidemiology of contagious ecthyma in Jilin Province,China, using the assay. A LAMP assay targeting a highly conserved region of the F1L genewas developed to detect contagious ecthyma virus (CEV). Three hundred and sixty-five casesfrom 64 flocks in 9 different areas of Jilin Province, China, from 2011 to 2014 weretested using the LAMP assay. The results showed that the sensitivity of the LAMP assay was100 copies of the standard plasmid, which is 100-fold higher than the sensitivity of PCR.No cross-reactivity was observed with capripoxvirus, fowlpox virus, foot-and-mouth diseasevirus serotype O, foot-and-mouth disease virus serotype Asia I and bluetongue virus. Theaverage positive rate was 19.73% (72/365), and the positive rate was highest in lambs aged1–6 months. Our results demonstrated that CEV infection was very widespread in the flocksof Jilin Province and that the LAMP assay allows for easy, rapid, accurate and sensitivedetection of CEV infection.     

用RAPD标记研究7个猪种间的亲缘关系

试验利用随机扩增多态ＤＮＡ技术对互助猪、荣昌猪、甘肃白猪、长白猪、约克夏猪、杜洛克猪、汉普猪共７个品种的ＤＮＡ池进行了多态型研究,分析了各品种间的亲缘关系。结果显示：甘肃白猪虽然是由国外品种和地方品种培育而成,但其亲缘关系更接近于中国猪品种;约克夏猪与其它欧洲猪种亲缘关系较远,这可能与约克夏猪在培养过程中亲本遗传背景较为复杂有关。     

凯氏定氮法测定饲料中粗蛋白含量的不确定度分析

<正>采用凯氏定氮法测定饲料中粗蛋白的含量,其测量不确定度来源包括样品称量、消化、定容、蒸馏、标准溶液标定及滴定等过程,通过对上述各因素的不确定度分量进行评估,计算合成不确定度,最终给出样品中蛋白质含量的标准不确定度及扩展不确定度。     

北欧4种燕麦在果洛地区的引种栽培试验

在果洛拉加乡黄河谷地及西哈垄沟内,对引进的４种北欧燕麦进行的引种栽培试验结果表明：４种燕麦中ＹＴＡ较早熟,全生育天数１０４天;ＬＥＮＡ干草产量最高（４２３９９ｋｇ／ｈｍ２）;ＭＥＬＹＳ从籽实产量、茎叶比、营养成份等综合性状评价,都优于其它品种;ＮＥＯＮ的饲草品质最为优秀     

小尾寒羊生理指标测定

对青海省民和县自繁自养的３０只小尾寒羊１０项生理指标进行了测定，结果：体温３８．９４±０．３２℃，呼吸频率２５．６０±７．１０（次／ｍｉｎ），心率８２．２０±１９．２０（次／ｍｉｎ），瘤胃里面动次数２．７７±０．６８（次／２ｍｉｎ），蠕动持续时间１８．４７±６．３６（Ｓ），ＲＢＣ为１０．４１±１．８０（×１０＾１２／Ｌ），Ｈｂ含量１２９±２１．８（ｇ／Ｌ），ＰＣＶ为０．３４９±０．０４３（Ｌ／Ｌ）     

饲料企业如何培育核心竞争力

“核心竞争力是在一个组织内部经过整合了的知识和技能．尤其是关于怎样协调多种生产技能和整合不同技术的知识和技能。”这里的关键词是“整合”二字。核一心竞争力不是技术、不是人才、不是市场、不是企业家．而是通过企业的全体力量和各种因素共同整合的知识与技能。从本质上说,核心竞争力是一种协调力、组织力,是把不同的资源,包括有形的、无形的资源协调和整合起来,成功地进行生产运作的能力。它是一个企业集体的产物,是一个整体的概念,是不可分割的．同时也是其它企业难以模仿和复制的。     

泰乐菌素组份转化机制的研究

泰乐菌素发酵过程中,ＰＨ值的控制及豆油的补加量对组份的转化存在显著影响。研究结果表明,在转化阶段当ＰＨ值控制在适当范围内,对不菌素效价影响不大,但可大大提高泰乐菌素Ａ的含量;同时在发酵中期及转化前这一阶段补加适量豆油,不仅可使效价逐步提高,还中明显促进大菌Ｃ向泰乐菌素Ａ的转化。     

绵羊多胎性状基因调控研究进展

绵羊的繁殖性状受多基因控制，本文综述了现已发现并证明的主基因和QTL住点，如FecB基因、FecX基因、FecX2基因、BMP15(形态发生蛋白15)突变、Q249R突变及Thoka基因等。通过分析这些基因或QTL位点的作用、遗传方式、遗传效应及基因定位，旨在为探讨绵羊多胎性状的基因调控规律提供理论依据。