狂犬病毒中和抗体检测试验中病毒回归试验的重要性

狂犬病毒中和试验的病毒回归试验表明,病毒攻毒液的实际剂量与理论剂量不完全一致.建议在新版<中华人民共和国兽用生物制品质量标准>中增加对病毒攻毒实际剂量范围的规定,以使结果的判定更为合理.     

二棘血蜱叮咬中华硬蜱纯化抗原免疫接种宿主后的交叉免疫反应

选用中华硬蜱105kD柱层析纯化抗原对新西兰兔进行免疫接种,再用二棘血蜱进行叮咬,并与单纯二棘血蜱叮咬组和佐剂对照组进行对比,以探讨不同种属硬蜱之间的交叉免疫抗性。结果显示:单纯二棘血蜱叮咬组吸血量为181 3±44 3mg,而二棘血蜱叮咬由中华硬蜱105kD纯化抗原免疫接种组和佐剂对照组新西兰兔后其吸血量分别为102 1±25 3mg和168 5±40 9mg,纯化抗原免疫接种组较单纯二棘血蜱叮咬组和佐剂对照组吸血量分别下降43 7%和39 4%(P<0 01)。同时,纯化抗原免疫接种组也较单纯二棘血蜱叮咬组和佐剂对照组产卵量有显著下降。该研究结果表明中华硬蜱和二棘血蜱之间存在着交叉免疫反应。     

羊、鸡抗鼠脂肪细胞膜抗血清对大鼠体脂与生长性能的影响

应用提取的鼠脂肪细胞膜分别免疫羊和鸡 ,所产生的抗血清用于 Wistar大鼠被动免疫。实验 1: 组腹腔注射羊正常血清 , 组腹腔注射羊抗鼠脂肪细胞膜抗血清 ,剂量均为 1m L /只 ,连续注射 4 d。结果表明 ,羊抗鼠脂肪细胞膜抗血清免疫促进了大鼠体增重 ,降低了体脂沉积 ,与对照组相比 ,7周末体重增加 6 .35 % (P<0 .0 5 ) ,饲料摄入增加6 .85 % (P<0 .0 1) ,料重比 (F/G)提高 4 5 .0 0 % (P<0 .0 5 ) ;肾周、附睾、网膜脂肪垫重量分别降低 2 3.92 % (P<0 .0 5 )、34.4 5 % (P<0 .0 5 )、0 .98% ,脂肪总量降低 2 0 .92 %。实验 2 :1组腹腔注射鸡正常血清 ,2组腹腔注射鸡抗鼠脂肪细胞膜抗血清 ,剂量均为 1m L/只 ,连续注射 4 d。结果表明 ,鸡抗鼠脂肪细胞膜抗血清免疫对大鼠的生长发育产生了不利影响 ,7周末 ,免疫大鼠平均体重较对照组减少 4 0 g(P<0 .0 5 ) ,饲料摄入显著降低 (P<0 .0 1) ;对体脂的沉积和血液中 TG和 FFA的影响没有规律 ,且无统计学意义     

The impact of truncating data on the predictive ability for single‐step genomic best linear unbiased prediction

Simulated and swine industry data sets were utilized to assess the impact of removing older data on the predictive ability of selection candidate estimated breeding values (EBV) when using single‐step genomic best linear unbiased prediction (ssGBLUP). Simulated data included thirty replicates designed to mimic the structure of swine data sets. For the simulated data, varying amounts of data were truncated based on the number of ancestral generations back from the selection candidates. The swine data sets consisted of phenotypic and genotypic records for three traits across two breeds on animals born from 2003 to 2017. Phenotypes and genotypes were iteratively removed 1 year at a time based on the year an animal was born. For the swine data sets, correlations between corrected phenotypes (Cp) and EBV were used to evaluate the predictive ability on young animals born in 2016–2017. In the simulated data set, keeping data two generations back or greater resulted in no statistical difference (p‐value > 0.05) in the reduction in the true breeding value at generation 15 compared to utilizing all available data. Across swine data sets, removing phenotypes from animals born prior to 2011 resulted in a negligible or a slight numerical increase in the correlation between Cp and EBV. Truncating data is a method to alleviate computational issues without negatively impacting the predictive ability of selection candidate EBV.     

氮肥与密度互作对单粒精播花生根系形态、植株性状及产量的影响

为明确花生单粒精播适宜的氮肥水平和种植密度,本研究于2018年和2019年以‘花育22’为供试花生品种,设置3个氮肥水平(0 kg hm~(–2), N0; 60 kg hm~(–2), N1; 120 kg hm~(–2), N2), 3个种植密度(7.93万株hm~(–2), D1; 15.86万株hm~(–2),D2; 23.79万株hm~(–2), D3),采用二因素裂区试验设计,研究氮肥、密度及其互作对单粒精播花生根系形态、植株性状及产量的影响。氮肥对花生根长、根表面积、根体积、根干重的影响不显著,而密度的影响显著。单株根长、根表面积、根体积及根系干重随密度的增加而降低, D1显著高于D2和D3, D2、D3处理间差异不显著;单位面积根长、根表面积、根体积及根系干重随密度的增加而增加, D1显著低于D2和D3, D2、D3处理间差异不显著。氮肥和密度互作对2019年收获期单位面积根长、根表面积的影响显著,与D1相比, N1处理下D3的增幅显著高于N0和N2处理。氮肥及氮肥与密度互作对植株性状的影响存在年度和时期间的差异,主茎叶片数、侧枝数和主茎第一节间粗随密度增加有降低趋势。氮肥对荚果产量的影响不显著,荚果产量随密度的增加呈增加的趋势。产量与根体积、根干重、主茎叶片数、主茎高及侧枝长呈显著正相关。综上所述,在本试验条件下,花生单粒精播适宜的氮肥(N)水平为60 kg hm~(-2),种植密度为18.8万株hm~(-2)。     

广西县级林地变更调查试点技术方法

为探索广西县级林地年度变更调查技术方法,以鹿寨县为例,运用遥感自动检测技术、森林资源管理信息平台等,对地类及管理属性变化图斑进行变更,形成本期林地数据库和林地变化数据库。文章分析了林地变更调查的关键技术方法,指出了存在的问题,并提出相应的建议。     

治疗仔猪黄白痢中兽药临床处方筛选

为了筛选出治疗仔猪黄白痢的最佳中药处方，确定其合理用药剂量和适用范围，试验将478头确诊为黄白痢的哺乳仔猪随机分为6组，分别用3种预选处方（处方一、处方二和处方三）、氧氟沙星、诺氟沙星、氧氟沙星与诺氟沙星联合用药进行治疗，比较预选处方与对照药物对仔猪黄白痢的治疗效果，筛选最佳的中药处方；并对每种中药处方按照低、中、高3种剂量进行用药，确定预选处方的合理用药剂量；按照发病特点进行用药。探讨预选处方对不同病症的适用性。结果表明：预选处方对仔猪黄白痢的治疗效果优于对照药物，且复发率显著低于后者；3种中药处方中，处方一的疗效最好，治愈率为82．9％，总有效率可迭84．7％，显著高于其他处方；处方一中剂量组的疗效最好，治愈率为88．9％，总有效率可达91．1％，显著高于其他剂量组，而且治愈后无复发现象。     

春蚕一日一回育试养初探

2015年春 ,河南蚕业科学研究院进行了"豫花×湘明"蚕品种全龄一日一回育养蚕试验.结果显示 ,一日一回育龄期经过缩短2d,节约工时 ,节约桑叶 ,通过改进技术措施后产茧量和蚕茧质量能达到普通育基本水平.     

Four years validation of decision support optimising herbicide dose in cereals under Spanish conditions

The Danish decision support system Crop Protection Online (CPO) optimises herbicide weed control. CPO recommends specific herbicide solutions to achieve a required level of control. The aim is to apply herbicides as little as possible but as much as necessary. CPOWeeds is a version of CPO adjusted to conditions in North-eastern Spain. The predicted efficacies and the yield obtained with CPOWeeds were validated in winter cereal field trials from 2010 to 2013. All CPOWeeds treatments were related to the efficacies obtained with standard herbicide treatments decided upon by local advisors. The predictions from CPOWeeds were compared to the actually achieved efficacies in the field trials for the nine weed species at different developmental stages and for 84.2% of the comparisons the obtained efficacies were equal to or higher than predicted. The average difference between predicted and observed efficacies was 2.35 percentage points. Yield was measured in three trials and the recommendations from CPOWeeds were maintaining yield. There were two situations where CPOWeeds were performing suboptimal. One is in the early weed growth stages, as the model is not yet prepared to account for water stress on root action herbicides applied at 10-11 BBCH. The second situation was in fields with a prior unidentified population of resistant Alopecurus myosuroides. For key species in winter cereals in Spain, such as Avena sterilis, Lolium rigidum and Papaver rhoeas, CPOWeeds achieved a satisfactory control level. It was concluded that the use of CPOWeeds allowed optimisation of the herbicide application with a very high robustness. The recommendations were satisfactorily for the conditions of the Northeast of Spain and have the potential to decrease the amount of applied herbicides by at least 30%. Therefore, it can be an important tool in Integrated Weed Management.     

鸽新城疫的流行与防控

鸽新城疫是由新城疫病毒感染鸽群引起的传染病, 在世界各国鸽场均有流行。介绍了鸽新城疫流行情况及特点, 流行毒株的基因型、病毒的毒力、病毒的抗原特性, 提出在做好鸽场内生物安全控制和精细化管理基础上, 使用市售新城疫疫苗进行合理免疫是鸽新城疫防控的关键。