东北虎电刺激采精研究

对黑龙江东北虎林园的17只东北虎进行了23次电刺激采精,并对取得的精液进行了品质分析。结果表明,不同虎个体对电刺激采精的电压敏感度各异,在平均电压为(4.8±1.3)V时射精。所采集精液量平均为(4.0±1.2)mL,pH值为7.1±0.3,精子密度为(23.4±33.8)×106个/mL,精子活率为(62.9±20.0)%,畸形率为(45.1±15.0)%。从总体上看,12月份和1月份采精效果最好,有精率占全年的57.2%,10月份和11月份的采精效果最差,无精率占全年的44.4%,说明东北虎精液品质受季节影响。     

广州市2015年禽类市场禽流感流行病学监测

为了解2015年广州市禽类市场的禽流感病毒污染情况,为科学制定人感染禽源流感病毒的防控措施提供基础数据,对2015年广州市12个区部分禽类市场的3 447份样本进行了禽流感病毒荧光RT-PCR检测。结果显示：全部样品的A型禽流感病毒和H9亚型禽流感病毒的阳性率分别为12.56%和6.24%。1月份为A型和H9亚型禽流感阳性率最高的月份,阳性率分别为23.94%和14.73%。从化区的A型禽流感病毒阳性率最高（24.48%）,黄埔区的H9亚型禽流感病毒阳性检出率最高（14.76%）。不同类型样品中,A型禽流感病毒阳性率最高为砧板、刀具类（15.16%）,最低为冰鲜生鲜（7.78%）。H9亚型禽流感病毒阳性检出率最高为笼具（8.25%）,最低为置物台面（2.84%）。结果表明：广州市禽类市场冬春季节禽流感病毒阳性率较高;全市各区禽类市场普遍存在禽流感病毒污染;禽类交易各环节中,宰杀和饲养环节的污染最为严重。建议在加强活禽交易市场全面清洗消毒的基础上,对不同季节、不同交易环节,采取差异化的和基于风险的消毒、监测措施,以降低人通过禽类市场感染禽流感病毒的风险。     

长期轮作连作对不同作物土壤磷组分的影响

对长期轮作连作条件下的大豆、玉米、小麦土壤磷组分进行研究,试验结果表明,供试土壤在不施肥情况下,土壤全磷以轮作区降幅最大,而土壤有效磷以小麦连作区降幅最大,土壤磷组分以大豆连作区土壤中的Ca2-P降幅最大;在施有机肥的情况下,土壤全磷以大豆连作区增幅最大,而土壤有效磷以轮作区增幅最小,土壤磷组分以轮作土壤中的Ca2-P增幅最大。     

盐胁迫下胡杨的离子响应

分析土壤和植物组织中的各种离子关系,发现胡杨对盐分不是简单的拒吸机制;对根系环境中的NaCl,胡杨吸收的钠离子显著少于不耐盐的杂种胡杨,而吸收的氯离子却大大超过后者.这与以往报道盐胁迫的胡杨根细胞中形成大量富含氯离子的小液泡是一致的,是一种特殊的区隔化构造.与杂种胡杨相比,胡杨有相对较发达的茎干组织,根和茎干占植株总生物量的比例较大,能吸收和储存有害盐离子而减少其进入叶组织,这是胡杨抗盐性的形态解剖学特性.     

Potato viruses in China

Potato (Solanum tuberosum L.) is globally the fourth largest staple crop after rice, wheat and maize. China is the largest potato producer worldwide, accounting for 26.3% and 22.2% of the global total area and yield, respectively. Viral diseases have been a limiting factor for sustainable production of potato in China. This article provides update and comprehensive information on the most important viruses, their effect on yield and their control in China. Meristem culture is currently the most widely used technique for production of virus-free potato plants and these plants are used as nuclear stock for the production of certified seed tubers. Although a significant increase in tuber yield has been achieved using certified seed potatoes, lack of application of a national seed potato production scheme has hindered progress. Conventional breeding using virus-resistant cultivars introduced from other countries as parents has already led to the production of Chinese cultivars. Use of virus-resistant wild Solanum species and genetic transformation techniques will provide new virus-resistant varieties in the future to further enhance control of potato viruses in China.     

Evidence that active transmission of porcine cysticercosis occurs in Venezuela

There is a paucity of quantitative data on the status of porcine cysticercosis in Venezuela, information which is essential for understanding the level of disease transmission. This study was, therefore, conducted in a typical small rural community in Yaracuy State, Venezuela, where previous cases of human Taenia solium taeniasis/cysticercosis had been reported and where the free-ranging pig management practices and the lack of rudimentary sanitary facilities indicated an obvious risk for transmission of the disease. Serum samples from 52 village pigs were screened by enzyme-linked immunosorbent assays for anti-cysticercal antibodies (Ab-ELISA), using T. solium cyst fluid as the antigen and the HP10, monoclonal antibody-based, antigen trapping ELISA for parasite antigen (HP10 Ag-ELISA). Significantly, a high proportion of the animals (65.4% for the Ab-ELISA and 42.3% for the HP10 Ag-ELISA) were sero-positive. Five of the pigs, which were selected on that basis of positive tongue palpation, were killed for autopsy, and large numbers of viable cysticerci were found in the carcases. This unequivocal documentation of porcine cysticercosis in Venezuelan pigs presents clear evidence that T. solium is actively transmitted in Venezuela. Further detailed studies and implementation of appropriate control measures are therefore indicated.     

中药饲料添加剂对断奶仔猪生长性能的影响

选用4 8头2 5日龄杜-长-大杂交断奶仔猪,按性别和体重随机分为三组。在基础日粮相同的条件下,其中两组分别添加抗生素、复方中药饲料添加剂,对照组饲喂基础日粮。断奶后饲养2 8天观察仔猪采食量、日增重、腹泻率等。结果:抗生素组和中药组仔猪日增量分别比对照组提高14 .14 % (P<0 .0 5 )、30 .5 7% (P<0 .0 1) ,而且中药组比抗生素组提高了14 .39% (P<0 .0 5 ) ;它料转化率则分别提高12 .5 %和19.71% ;抗生素组仔猪腹泻率比对照组降低4 2 .31% ,中药组则降低6 9.2 3%。试验说明该中药饲料添加剂能明显提高仔猪生产性能。     

农业机器人田间导航参照点测距的新方法

传统双目视差测距法的测量值为参照点P到双目摄像机基线中心的距离,而农业机器人上的摄像头装置通常被安装在距离地面一定高度,与水平方向呈一定倾角的位置,利用传统双目视差测距法将无法得到导航参照点到机器人机身的水平距离。为此,提出了一种解决农业机器人田间导航参照点测距的新方法。通过改进的BP神经网络标定下的双目系统、改进的SIFT特征匹配,输出导航参照点在世界坐标系下的坐标X,Y),则导航参照点距机器人机身的水平距离可表达为S=(X2+Y2)(1/2)。实验表明:该方法在实际田间测试中的结果最大偏差0.479cm,最小偏差0.032cm,精度高达99%,测距过程耗时共计55ms,计算量较传统双目视差测距显著减小,具有一定的工程实用性与可行性。     

宁乡猪的肥育与胴体性状的聚类分析

本文应用聚类分析方法将宁乡猪的肥育与嗣体性状分成了三类,第Ⅰ类为平均日增重、宰前活重、胴体长、胴体前宽,第Ⅱ类为屠宰率、膘厚及眼肌面积,第Ⅲ类为瘦肉率、肥肉率、花板油比例。从这三类性状中选出的典型性状分别为宰前活重、屠宰率及肥肉率。这与采用其它方法分析的结论是一致的,因此,聚类分析方法在家畜选种工作中的应用是可行的。