Epidemiological Cut-off Values (ECOFFs) of Salmonella from Chicken Intestinal Tract for Three Animal-specific Antibiotics

In order to establish epidemiological cut-off values (ECOFFs) of Salmonella for three animal-specific antibiotics (florfenicol,apramycin and danofloxacin) in Guangdong province.A total of 166 strains of Salmonella isolates from chicken intestinal tract from veterinary clinics and farms in Guangdong province in 2017 were recruited in this study,the minimum inhibitory concentrations (MIC) of florfenicol,apramycin and danofloxacin were determined in triplicate for each bacterial strain using the agar dilution method on Mueller-Hinton agar plates according to the CLSI reference method (CLSI-M100-S26).ECOFFs were calculated for the MIC data sets by application of nonlinear regression analysis,NRI(normalized resistance interpretation) and ECOFFinder software.MIC distribution of florfenicol,apramycin and danofloxacin against Salmonella from 2 to >512,4 to >512 and 0.015 to 64 μg/mL,respectively.MIC₅₀ and MIC₉₀ for apramycin,florfenicol and danofloxacin were 256 and >512,16 and >512,0.5 and 16 μg/mL,respectively.MIC distribution of apramycin and florfenicol presented obvious unimodal shape,while that of danofloxacin was a discontinuous multi-peak.The ECOFFs of florfenicol,apramycin and danofloxacin were recommended to be 16,16 and 0.125 μg/mL,respectively.In present study,the ECOFFs of Salmonella from chicken intestinal tract for apramycin,florfenicol and danofloxacin were determined,which provided scientific basis for resistance surveillance.     

黑小麦新品种的创育及其应用策略探讨

本文简要分析了当前黑小麦品种的特点，根据实践对黑小麦新品种的创育提出了不同的目标和途径，介绍了2个黑小麦新品种并对其应用的策略进行了探讨。     

New Varieties of Populus tomentosa Carr. and Breeding Techniques

The main morphological characteristics, producing area and growth characteristics of sixteen new varieties of Chinese white poplar (Populus to-mentoso Carr. ) are reported, aiming at providing referernce for breeding and extension of new varieties.     

对小麦高产理论的探讨

当前小麦高产品种的育种目标定为9000～12000kg／hm^2，以光合生产潜力分析能够成功，采用扬守仁先生育种实践推出的5分制打分法，对小麦品种产量结构分析得出：加强株型选择，提高单株生产力是小麦高产育种的主要途径。     

当前我国青少年主流价值观的建构

当前我国青少年主流价值观的建构应通过课堂教育、典型感化、参与社会实践活动等途径，教育和引导他们树立社会主义的主流价值观。     

呼伦贝尔黄花苜蓿区域试验研究

对呼伦贝尔黄花苜蓿进行区域试验研究结果表明：呼伦贝尔黄花苜蓿在各试验点种植均表现出较强的适应性，鲜草和千草产量与对照品种肇东苜蓿接近，3个试验点3年平均鲜草产量为33865．6kg/hm^2，干草产量为9146．2kg/hm^2，分别比对照的肇东苜蓿低0．6％和3．2％。方差分析表明二者无显著差异，具有良好的丰产性和持久性，对呼伦贝尔高寒地区严酷的自然条件具有很强的适应性，适宜在我国北方高寒地区大面积推广种植。     

青贮玉米育种和栽培的研究与探讨

主要对青贮玉米育种、栽培进行了浅析，并指出其发展前景，旨在推动我国青贮玉米育种研究再上一个新台阶。     

当代大学生择业观存在的问题及其引导

本文分析了大学生择业观取向发展轨迹, 剖析了大学生择业观取向的内在冲突, 阐明了通过择业观念、就业指导、职业生涯规划、社会实践、创业教育等途径来帮助大学生确立正确的择业观。     

玉米新品种正大305的选育研究

正大305是以自选系CTL101为母本,自选系CTL102为父本杂交选育的玉米单交种。在各级试验中表现为高产、稳产、多抗,两年区试比对照农大108、郑单958平均增产9.4%,2006年1月通过辽宁省农作物品种审定委员会审定。适宜在辽宁省郑单958种植的地区种植,适宜密度42 000～45 000株/hm2。     

马铃薯新品种郑薯八号的选育

郑薯八号是从“Memmvrx豫马铃薯一号”的杂交后代中选育而成的。早熟，生育期58天左右。春季每667m^2平均产量1124．26kg，高产可达1397．3kg以上。薯块圆形，浅黄皮白肉，芽眼浅，表皮光滑，商品薯率高。品质优，淀粉含量为12．9％，VC含量高达26．8mg／100g，蛋白质含量为2．12％，还原糖含量0．26％。抗病毒病、晚疫病、环腐病。适宜二季作栽培及一季作早熟栽培。