Prevalence and antimicrobial resistance of Salmonella isolates in Moroccan laying hens farms     

《The Journal of Applied Poultry Research》2016,25(4):539-546

Increasing emergence of salmonellosis presents a threat to the effective control of foodborne disease in humans. The purpose of this study was to evaluate the prevalence of drug susceptibility and molecular characteristics of non-typhoidal Salmonella (NTS) isolated from laying hens (LH) in 3 Moroccan regions, Rabat-Salé-Zemmour-Zaër (RSZZ), Souss-Massa-Drâa (SMD), and the grand Casablanca (GC). A total of 351 samples were collected from 30 consumer egg laying houses at the end of the egg laying period from April to July 2011. Sixty-four out of these 351 examined samples were contaminated by Salmonella. The Salmonella isolated strains were then serotyped and tested for drug susceptibility and analyzed by polymerase chain reaction (PCR) for the presence of the invasion-associated genes invA and spvC and nalidixic acid resistance-associated qnr gene. The prevalence of NTS infection in LH was estimated to be 73.3%. Seven Salmonella enterica serovars were identified: Enteritidis (37.5%), Kentucky (31.2%), Infantis (10.9%), Typhimurium (6.2%), Thompson (6.2%), Agona (4.6%), and Amsterdam (3.1%). Drug susceptibility testing showed that 65.6% of Salmonella were resistant to at least one antibiotic and 25% were resistant to ciprofloxacin. All isolates were positive for the invasion gene invA and 28% of them were positive for the virulence gene spvC. All nalidixic acid-resistant S. Enteritidis isolates were negative for qnr plasmid genes. Our findings clearly suggest the necessity to establish an NTS monitoring and control program for LH in Morocco.  相似文献   

Influence of imported sport horses on the genetic evaluation of Swedish Warmblood stallions     

M. Pettersson  S. Eriksson 《Acta Agriculturae Scandinavica, Section A - Animal Sciences》2016,66(4):183-189

There is substantial international influence on the Swedish Warmblood (SWB) sport horse population. The SWB Association suspects that imported horses are pre-selected based on their anticipated performance level, which could lead to biased estimated breeding values (EBVs) for stallions. This study examined different strategies to handle records for imported horses in the genetic evaluation. The stallions were evaluated for 10 traits using 3 different EBV estimation methods that were compared based on ranking comparisons of stallions, accuracy, correlations and absolute differences between EBVs. The results showed that the stallions’ EBVs were affected by imported offspring which, as a group, had higher average scores than horses born in Sweden. Sire EBVs differed by up to 0.6 genetic standard deviation of the trait between methods for stallions with >50% imported offspring. Excluding imported offspring lowered the accuracies and caused larger re-ranking compared with including a fixed effect of origin in the model.  相似文献   

The genetic diversity and structure of 18 sheep breeds exposed to isolation and selection          下载免费PDF全文

M. Ćurković  J. Ramljak  S. Ivanković  B. Mioč  A. Ivanković  V. Pavić  M. Brka  C. Veit‐Kensch  I. Medugorac 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2016,133(1):71-80

The phylogenetic layout of the genotyped (30 microsatellite) 18 sheep breeds in this study demands and provides the opportunity to evaluate both neutral and adaptive components of genetic diversity in a naturally and artificially selected and subdivided sheep population. Seven Pramenka strains from Bosnia and Herzegovina and Croatia characterized by a very low intensity of artificial selection, preserved the highest neutral genetic variability. Eight central and north‐western European breeds under considerable artificial isolation and selection preserved the lowest genetic variability. Only combinations of various phylogenetic parameters offer a reasonable explanation for underlying evolutionary forces working in the investigated island and mainland sheep breeds under variable natural and artificial selection. More than 60% of total genetic, diversity was allocated to virtually unselected Pramenka strains, and an additional 25% to native moderately selected Graue Gehoernte Heidschnucke and intensively selected Ostfriesische Milchschafe. Some economically very important breeds and strains did not contribute to a pool with maximal genetic diversity, while they play an important role in the cultural heritage of respective countries.  相似文献   

微生物菌剂在蔬菜基质研发与应用上的研究进展   总被引：1，自引：0，他引：1  

束胜  蔡忠  朱忠贵  郭世荣 《长江蔬菜》2016,(14):36-40

综述了在固体有机废弃物基质发酵过程中,添加微生物菌剂对堆体温度、p H值、养分含量和C/N等关键腐熟指标的影响,分析了微生物菌剂在蔬菜基质育苗和栽培上的应用效果及其作用机制,并展望了微生物菌剂在未来基质研发上的应用前景,以期为含有微生物菌剂的功能型蔬菜基质开发提供新的思路。  相似文献   

稻米营养品质的研究现状及分子改良途径   总被引：18，自引：0，他引：18  

江良荣  李义珍  王侯聪  黄育民 《分子植物育种》2004,2(1):113-121

本文综述了稻米营养品质(蛋白质、赖氨酸和微量营养素)的经典遗传学和分子遗传学、分子育种的研究现状，并对利用分子标记辅助育种方法提高稻米营养品质作了展望。  相似文献   

棉花分子育种研究进展     

陈秀兰  张玉忠  张军 《棉花学报》1997,(1)

本文主要综述了我国近２０年来棉花分子育种在理论基础、技术方法、育种机理以及新品种培育等方面研究取得的成就及新进展，并讨论了棉花分子育种的发展方向  相似文献   

世界棉花育种科技水平进展与发展对策   总被引：15，自引：1，他引：15  

王淑民 《棉花学报》1996,(1)

９０年代以来，世界棉花育种的特点为：（１）以提高单产为主要目标；（２）以提高纤维品质为主要目标；（３）以保护环境为主要目标。通过不同的育种途径，棉花育种成绩斐然，为人类的发展提供了重要的物质基础。２０００年前，中国棉花育种对策的重点应（１）加强基础研究；（２）改革现行流通体制；（３）改进原棉检测手段；（４）育种目标与市场反馈信息结合。  相似文献   

高产小麦品种模式化选育的初步研究   总被引：4，自引：0，他引：4  

陈化榜  曾北燕 《作物学报》1993,19(2):165-172

本文探讨了高产小麦品种理想模式的概念、特点和品种模式化选育的理论依据及优点。对37个亩产400公斤以上的高产品种的产量与其构成因素、形态性状、生理性状以及这些性状之间的关系进行了多元和简单相关分析。针对山东的生态条件和品种的现状，优化了亩产600-650公斤的品种模式。探讨了各类性状间的有机联系和协调发展产量潜  相似文献   

低酚陆地棉育种亲本配合力的研究   总被引：5，自引：1，他引：5  

马峙英  张桂寅  刘占国  蒋观敏  吴立强  曲健木 《棉花学报》1995,(1)

选择８个现代低酚陆地棉育种亲本（包括４个高酚棉和４个低酚棉品种），按４×４不完全双列杂交设计，对１６个组合的Ｆ×进行了双列分析。结果表明，在所研究的１０个性状中，子棉产量、皮棉产量和纤维整齐度主要受非加性基因控制，单铃重、衣分、比强度、２．５％跨长和麦克隆值则主要由加性基因控制，衣指由加性和非加性基因共同控制，而子指受环境的影响较大；在大多数性状上，高酚棉亲本的加性遗传方差比低酚棉亲本贡献大，而在２．５％跨长和麦克隆值２个性状上，低酚棉亲本的加性遗传方差起着更重要的作用；中７８８６是综合性状比较理想的亲本材料，冀合２２５是较好的高产亲本，冀无２５２和中无１５１是较好的优质低酚棉亲本。综合一般配合力和特殊配合力分析结果，组合中７８８６×冀无２５２可具较好的育种潜力。  相似文献   

早熟优质糯玉米杂交种西山糯的选育与特征特性   总被引：1，自引：0，他引：1  

彭忠华  顾金春  戴保威 《种子》2002,(4):40-41

西山糯是贵州大学农学院玉米研究所以一个利用热带种质改良的温带 材料选育的优良自交系（南糯白）作母本，与一个带有独山白糯地方血缘和自交系（糯－1）作父本组配的糯玉米杂交种，根据品比、区试、生产试验和品质分析结果，该品种生育期早、抗逆性好、品质优良、丰产稳产、适应性广、制种产量较高，于2002年通过贵州省农作物品种审定委员会审定，予以推广。  相似文献