营养学中氨基酸平衡的度量

本文基于聚类分析理论,提出了失衡度(IBD)这一新的化学指数,借以定量地研究蛋白质营养中的氨基酸平衡问题。当样品中氨基酸完全平衡时,IBD取值为零;而当其氨基酸平衡最差时。IBD取值为1。IBD的氨基酸增量模型为非对称最大值式;且IBD与变异系数(CV)之间有着密切的关系。通过IBD这一指数,可以对各种单一饲料的蛋白质营养价值加以分类列等;通过计算两种以上饲料蛋白质混合物的IBD,可以从理论上预测它们之间是否互补,以及何时发生最佳互补关系。若引申IBD的概念框架,还可以用来研究其它养分之间的平衡关系,并有助于实现计算机配方过程的自动鉴别和筛选。     

南极磷虾粉潜在危害因子分析及风险评价进展

南极磷虾粉是目前南极磷虾船载加工的主要产品之一,富含优质蛋白质、脂质、磷脂、虾青素和矿物质等物质,具有良好的开发利用前景。目前,南极磷虾粉主要用作水产动物饲料及提取油脂等的原料。然而,研究表明南极磷虾粉也存在潜在危害因子不明确等问题,严重限制了其应用领域和范围的拓展。因此,本文分析了南极磷虾粉潜在危害因子的来源、限量标准、检测方法等,介绍了南极磷虾粉风险评估进展,旨在为南极磷虾粉危害因子的减除和深度利用提供参考依据。     

黑龙江龙口自然保护区黑熊春季生境选择

分别于2008年4～5月和2009年4～5月,在龙口自然保护区对黑熊春季生境选择进行了研究,野外工作共设置87个10 m×10 m样方,并调查12个生态因子,其中利用样方41个,对照样方46个。通过Vanderploeg ＆Scavia选择指数得到,黑熊喜爱选择处于高海拔（〉450 m）、上坡位有石砬子且草本盖度适中（10%～40%）的生境,倾向选择乔木密度高（〉10株/100 m2）、郁闭度大（〉40%）、灌木密度较低（〈10%）、隐蔽级低（〈30%）、倒木密度大（〉1根/100 m2）、陡坡（〉30°）且向阳的针阔混交林。主成分分析与资源选择函数分析共同得到海拔、坡度、坡位、植被类型对黑熊生境选择影响较大,坡向和倒木密度影响较小的结果。综合分析,将Vanderploeg ＆ Scavia选择指数、主成分分析与资源选择函数相结合可以更好地反映黑熊生境选择情况。     

Further contributions to the genetic aspect of congenital sensorineural deafness in Dalmatians

Sensorineural deafness is a common congenital disorder in Dalmatians and is genetically transmitted. Different modes of inheritance have been proposed and the objective of this study was to study these by segregation analyses using maximum likelihood procedures. Data from 33 complete Dalmatian families were collected and data from 56 single Dalmatians added. This resulted in a total of 575 dogs with 357 known phenotypes. All dogs were clinically evaluated and electrophysiologically tested with brainstem auditory evoked responses.The prevalence of deafness was 16.5% (9.4% unilaterally deaf, 7.1% bilaterally deaf). Females were 4.4% more affected than males but this difference was not significant. Within the same litter, different phenotypic expressions of deafness occurred, which suggested different expressions of the disease. In addition, two data sets were analysed: the first included normal, uni- and bilaterally deaf dogs, the second had normal and deaf Dalmatians. We found that a recessive allele at a single biallelic major locus fitted our data best, although an incomplete penetrance of the recessive homozygotes was observed.     

Genetic diversity,anti‐microbial resistance,plasmid profile and frequency of the Vi antigen in Salmonella Dublin strains isolated in Brazil

Salmonella Dublin is strongly adapted to cattle causing enteritis and/or systemic disease with high rates of mortality. However, it can be sporadically isolated from humans, usually causing serious disease, especially in patients with underlying chronic diseases. The aim of this study was to molecularly type S. Dublin strains isolated from humans and animals in Brazil to verify the diversity of these strains as well as to ascertain possible differences between strains isolated from humans and animals. Moreover, the presence of the capsular antigen Vi and the plasmid profile was characterized in addition to the anti‐microbial resistance against 15 drugs. For this reason, 113 S. Dublin strains isolated between 1983 and 2016 from humans (83) and animals (30) in Brazil were typed by PFGE and MLVA. The presence of the capsular antigen Vi was verified by PCR, and the phenotypic expression of the capsular antigen was determined serologically. Also, a plasmid analysis for each strain was carried out. The strains studied were divided into 35 different PFGE types and 89 MLVA‐types with a similarity of ≥80% and ≥17.5%, respectively. The plasmid sizes found ranged from 2 to >150 kb and none of the strains studied presented the capsular antigen Vi. Resistance or intermediate resistance was found in 23 strains (20.3%) that were resistant to ampicillin, ciprofloxacin, chloramphenicol, imipenem, nalidixic acid, piperacillin, streptomycin and/or tetracycline. The majority of the S. Dublin strains studied and isolated over a 33‐year period may descend from a common subtype that has been contaminating humans and animals in Brazil and able to cause invasive disease even in the absence of the capsular antigen. The higher diversity of resistance phenotypes in human isolates, as compared with animal strains, may be a reflection of the different anti‐microbial treatments used to control S. Dublin infections in humans in Brazil.     

不同氮效率紫花苜蓿叶特征及其产量效应研究

为探讨不同氮效率紫花苜蓿(Medicago sativa)叶特征差异及其对产量的影响,本研究采用田间小区试验,设4个不同氮效率紫花苜蓿品种('LW6010'、'甘农3号'、'甘农7号'和'陇东苜蓿')和2个施氮处理(0,103.5 kg·hm-2),对比研究不同氮效率紫花苜蓿的叶特征及其生产性能,并采用通径分析法探讨叶...     

《青海畜牧兽医杂志》（1992—1998）论文及作者统计分析

用文献计量方法对《青海畜牧兽医杂志》国内外公开发行后７年间所刊载的论文及其作者进行了统计分析与探讨。主要项目有：论文数量及年度分布、论文学科内容分布、论文地域分布、论文机构分布、单位平均产文量、论文合著率、作者数量及地区分布、作者系统及单位分布、作者个人发文量、作者及单位合作度等。另外还确定出《杂志》１９９２～１９９８年的核心作者和核心单位。     

禽腺病毒血清4型贵州株全基因序列分析

为了解禽腺病毒血清4型(FAdV-4)地方流行毒株的分子进化情况,基于实验室分离的2株FAdV-4贵州株GZ-BJ株和GZ-QL株,分别对2株FAdV-4毒株进行PCR分段扩增,扩增产物克隆至载体,提取质粒进行PCR和双酶切鉴定后筛选出重组质粒进行测序,将测序结果依次拼接得到病毒的全基因组,获得FAdV-4贵州株的全基因序列,并对其进行序列和遗传进化分析。结果显示,通过PCR分段扩增成功获得了2株FAdV-4贵州株(GZ-BJ株和GZ-QL株)的全基因序列,长度分别为43352、43723 bp,FAdV-4 GZ-BJ株全基因序列长度比FAdV-4 GZ-QL株短371 bp,少6个ORF(22K、putative 9.1 ku、u-exon、ORF17、ORF28、ORF42),二者的氨基酸同源性为57.1%。2株FAdV-4贵州株同国内外不同地区FAdV-4毒株核苷酸同源性在88.7%~100%,与FAdV-4经典毒株ON1比对,2株FAdV-4贵州株和国内FAdV-4分离株均缺失ORF19、ORF27、ORF30。系统进化树分析显示,2株FAdV-4贵州株GZ-BJ株和GZ-QL株仍属于Ⅰ群C种FAdV。研究结果表明,2株贵州株FAdV-4 GZ-BJ株和FAdV-4 GZ-QL株较国内外FAdV-4毒株均存在进化与突变,且FAdV-4 GZ-BJ株变化较大,但尚未改变其血清型,这为探索FAdV-4致病机理的分子机制研究提供依据。     

不同覆土厚度对伊犁地区公路护坡植被质量的影响

为提高伊犁地区公路建设中的边坡植被防护质量,促进公路建设与生态环境的和谐发展,依托S242线巩留至尼勒克公路开展了实地边坡试验,利用灰色关联度的分析方法,对5 cm、10 cm、15 cm、20 cm四种表土回填厚度处理的边坡植被建植质量进行了研究。结果表明：随着覆土厚度的增加,公路边坡护坡植被质量逐渐增加,土壤砂粒减小了15%~23%,粉粒含量增加了18%~23%,土壤质地由壤土转变为粉砂质壤土;不同处理下的土壤孔隙度、土壤抗蚀指数、土壤抗冲系数差异显著,其对应的灰色关联度值分别为0.74,0.72,0.71,相比其他指标对护坡植被质量的影响更大;覆土20 cm小区的综合评判值G （k）最大（0.83）,说明在本研究中覆土20 cm小区的护坡植被质量最好。