鸭疫里默氏杆菌贵州流行株蜂胶灭活疫苗制备     

马光强  刘丽娟  陈国权  吴良涛  杨均  刘军泽  李潇蒙  潘成文  周碧君 《中国畜牧兽医》2022,49(8):3163-3170

【目的】制备鸭疫里默氏杆菌(Riemerella anatipestifer,RA)贵州流行株蜂胶灭活疫苗。【方法】选取RA血清2型贵州流行株(RA-SS-8株)为基础菌株,依次利用分光光度法和平板计数法测定细菌生长曲线,再进行灭活条件筛选,以蜂胶为佐剂制备RA贵州流行株蜂胶灭活疫苗,并进行无菌检验、安全性检验及免疫鸭攻毒保护性试验。【结果】分光光度法测定RA-SS-8株菌液D_{600 nm}值随培养时间变化显示,细菌在0~3 h时增殖缓慢,在3~10 h时增殖趋势明显加快,在10 h以后增殖逐渐趋于平缓,随着培养时间的延长,细菌最终进入衰亡期;平板计数法结果显示,RA-SS-8株D_{600 nm}值为0.1~0.8时,该菌处于对数生长期,且D_{600 nm}值与活菌数呈现良好的线性关系;RA-SS-8株最佳灭活条件为0.2%甲醛溶液、37 ℃灭活12 h;蜂胶灭活疫苗含菌量为3.8×10⁹ CFU/mL,蜂胶干物质含量为10 mg/mL;无菌检验巧克力琼脂培养基上未见菌落生长;安全性检验以2倍免疫剂量接种雏鸭在观察期内未表现出不良反应,大体病变观察未见明显病变;免疫鸭攻毒保护性试验显示,蜂胶灭活疫苗免疫组鸭对RA-SS-8株的攻击后保护率为70%,蜂胶灭活疫苗对试验鸭心脏、肝脏组织均具有良好的保护效果。【结论】本研究成功制备了RA贵州流行株蜂胶灭活疫苗,为蜂胶灭活疫苗制备和动物免疫试验奠定基础。  相似文献   

城市林业概述与发展趋势     

朱志平  张声平 《江西林业科技》2007,(5):62-64

随着社会经济的快速发展和城市化进程的加快,城市环境问题日益成为社会各界和学术界关注的焦点,城市林业在城市建设与发展中的地位和作用越来越受到重视。介绍城市林业的基本概念和内涵,比较城市林业与传统林业在属性、经营管理和功能方面的差别。借助已有的研究数据和成果,阐述城市林业在城市发展中的作用及其能解决的问题。针对城市林业发展的现状和存在的问题,提出现代城市林业面临的机遇和挑战以及未来发展趋势。  相似文献   

当前大学生思想政治教育工作面临的挑战及对策研究     

文洁 《四川畜牧兽医学院学报》2006,4(3):222-225

大学生思想政治教育工作关系到高等院校培养什么样的人才、为谁培养人才的根本性问题.文章论述了在国际竞争加剧、经济全球化、网络化时代已经到来等多重背景下,当前大学生思想政治教育工作面临的挑战,并提出了相应的对策.  相似文献   

中国生态农业面临的机遇与挑战   总被引：21，自引：4，他引：21  

李文华 《中国生态农业学报》2004,12(1):1-3

阐述了我国生态农业发展特点、取得的主要成效与存在的问题、面临的机遇和新的挑战 ,并提出新时期生态农业发展策略。  相似文献   

Immunological　Changes　of　Chicks　Immunized　with　March＇s　Disease　Vaccines　and　Challenged　with　Virulent　MD　Virus     

Liu Zhonggui  Gao Rong  Li Qingzhang  Zheng Shimin  Liu  Yun  Yang Liping 《东北农业大学学报(英文版)》1995,(1)

ＩｍｍｕｎｏｌｏｇｉｃａｌＣｈａｎｇｅｓｏｆＣｈｉｃｋｓＩｍｍｕｎｉｚｅｄｗｉｔｈＭａｒｃｈ＇ｓＤｉｓｅａｓｅＶａｃｃｉｎｅｓａｎｄＣｈａｌｌｅｎｇｅｄｗｉｔｈＶｉｒｕｌｅｎｔＭＤＶｉｒｕｓ￥ＬｉｕＺｈｏｎｇｇｕｉ；ＧａｏＲｏｎｇ；ＬｉＱｉｎｇｚｈａ...  相似文献   

不同H_5亚型禽流感灭活苗对鸡H_5N_1株的免疫效力试验     

唐一鸣  刘金彪  张评浒  刘秀梵 《扬州大学学报(农业与生命科学版)》2006,(2)

采用H5N2和H5N1两种类型的禽流感(A I)油乳灭活疫苗免疫鸡群对高致病性A I流行株H5N1A IV的攻毒保护效力进行了比较。结果表明:在同等免疫剂量条件下,H5N2和H5N1油乳灭活苗对鸡群具有相似或同等的免疫效力,均能抵抗对高致病性A IH5N1流行株的攻击;A I母源抗体对灭活苗免疫具有一定的干扰作用。  相似文献   

几种鸡新城疫油佐剂灭活疫苗免疫效果的比较     

梁华丽  华炯钢  徐辉  顾亚仙  何永强 《浙江农业学报》2007,19(6):418-422

比较研究了鸡新城疫(ND)二价灭活苗、ND灭活苗、进口ND灭活苗、ND强毒(CNDV)灭活苗和ND克隆-30弱毒苗的免疫效果。结果表明,不同ND疫苗首次免疫鸡所产生的抗体有差异,ND二价灭活苗免疫鸡的抗体上升最快,免疫后20 d左右可达到最高峰。1日龄免疫,14日龄攻毒,ND二价灭活苗、ND灭活苗的保护率分别为5/5,4/5;10日龄和10日龄以上免疫,免疫后7 d或7 d以上攻毒,ND二价灭活苗、ND灭活苗、进口ND苗的保护率分别为4/5~5/5,2/5~5/5,0/5~2/5。攻毒后ND二价灭活苗、进口ND灭活苗免疫的与对照鸡的肛棉拭子NDV阳性数分别为0/5,5/5,5/5。结果表明,ND二价灭活苗免疫效果优于进口ND灭活苗、ND强毒灭活苗,稍优于ND灭活苗。  相似文献   

“特保”对义乌袜业的影响及对策     

李春丽  朱简 《江苏农林职业技术学院学报》2006,(1)

从2005年1月1日开始世界纺织品开始进入"后配额"时代,但是,随之而来的却是世界各国对我国纺织品出口的纷纷设限。袜子是义乌市的传统优势产品,义乌袜子畅销世界各国,但是在国际市场上也面临着一系列的壁垒,尤其是"特保"措施对其影响最大。所以,义乌袜业必须采取必要的措施和步骤,来降低海外风险,这样才能在国际市场中立有一足之地。  相似文献   

Epidemiological studies of piglet diarrhoea in intensively managed Danish sow herds. IV. Pathogenicity of porcine rotavirus     

B Svensmark  J Askaa  C Wolstrup  K Nielsen 《Acta veterinaria Scandinavica》1989,30(1):71-76

Colostrum-deprived piglets inoculated with rotavirus 24 h after birth developed a profuse diarrhoea that spread to non-inoculated, colostrum-deprived litter mates and, occassionally, to colostrum-fed piglets. Case fatality rates in these 3 categories of piglets were 63.2%, 35.7% and 8.3%, respectively. Surviving piglets recovered in 1-2 weeks, but shedded virus via the faeces for up to 3 weeks p.i. The D-xylose test revealed severe malabsorption, with extremely flat absorption curves for up to 3-4 weeks p.i. Malabsorption was more marked in piglets with a long-lasting faecal virus excretion than in piglets where virus disappeared from the faeces within 10 days p.i. Infected piglets (colostrum-fed and colostrum-deprived) had decreased weight gains and were 5 days older at a bodyweight of 25 kg than non-inoculated controls. It is concluded that rotavirus is probably of significance in diarrhoeal syndromes in suckling piglets, alone or in combination with E. coli or other pathogens.  相似文献   

Physiological Predictors in Calves of Dairy Breeds: Part 1. Genetic Parameters of Basal and Induced Growth Hormone Secretion     

Peter Løvendahl  Torkild Liboriussen  Just Jensen  Mogens Vestergaard  Kristen Sejrsen 《Acta Agriculturae Scandinavica, Section A - Animal Sciences》2013,63(3):169-176

Abstract

Genetic variation in plasma growth hormone (GH) concentration before and after GRF (growth hormone releasing factor) stimulation was studied in young bulls (N=284) and heifers (N=212), the progeny of 53 sires of four dairy and dual-purpose breeds (Danish Jersey, Red Dane, Danish Friesian and Danish Red and White). Male and female calves were reared, fed and tested on separate experimental stations; thus sex, station and feeding were completely confounded effects. The animals were tested at about 9 months of age, after a 24 h fast. GH concentration was measured in serial plasma samples collected for 1 h before and 1 h following intravenous administration of 2.0 ug synthetic GRF(1–29)NH₂/kg live weight^>0.75. Prior to statistical analysis, concentrations were log_e-transformed. Response variables were BASELINE (mean GH in -15, -5 and 0 min samples) and PEAK (mean GH in 10, 15 and 20 min samples). A statistical model taking at least three generations of ancestral relationships into account was used to estimate variance and covariance components for traits in male and female calves by use of restricted maximum likelihood methods.

Heritability of BASELINE was low (0.04 ± 0.12) in males but high in females (0.60 ± 0.16). The heritability of PEAK was high in both sexes (males, 0.42 ± 0.16; females, 0.60 ± 0.16). Genetic correlations between the same trait measured in males and females were low for BASELINE (r _g = 0.32±0.55) but high for PEAK (r _g = 0.82±0.15). Within sex, BASELINE and PEAK were both highly genetically correlated (males, r _g=0.62 ± 0.40; females, r _g= 1.00 ± 0.07).

We conclude that growth hormone concentration is a highly heritable trait in juvenile cattle of both sexes, and that GRF stimulation is benificial to the uncovering of genetic differences among animals.  相似文献