健康状况不佳是导致咬尾的一个危险因素

正在多篇系列文章中,顶级的动物福利研究人员解释了他们在国际项目"Fare Well Dock"内获得的结果。该计划调查如何才能不用进行断尾。挪威和芬兰的研究人员深入探讨了健康和咬尾之间的关系——这些现象是相互关联的吗?咬尾有害于动物福利,会对生产者的经济收益产生负面的影响。我们知道,咬尾是一个由多种因素引发的问题,营养、饲喂方案、猪圈设计、饲养密度和玩具的供应情况都会影响发生咬尾的净风险。健康状况不佳也被认为是一个重要的风险因素,但是现有的证据尚不足以证明两者之辛基大     

黏虫CYP9A113基因的克隆及外源物质对基因表达的诱导效应

黏虫是我国作物上最重要的害虫之一。细胞色素P450能够参与昆虫外源物质代谢。本研究采用RACE技术克隆了一条编码黏虫P450基因的cDNA序列,并通过Real-time PCR技术,检测了4种外源物质对该基因表达的诱导效应。该基因被国际P450命名委员会命名为CYP9A113,GenBank登录号为KY436739。利用2.5%高效氯氟氰菊酯乳油的LD_(50)处理黏虫3 h,LD_(10)、LD_(30)和LD_(50)处理12 h和24 h,可诱导表达CYP9A113基因;20%氯虫苯甲酰胺悬浮剂的LD_(10)处理黏虫12、24和48 h,LD_(30)和LD_(50)处理24 h,CYP9A113基因表达呈诱导效应;0.1和0.5 mg/mL香豆素处理6、12、24和48 h,CYP9A113基因表达均呈诱导效应;0.1和0.5 mg/mL吲哚-3-甲醇处理3、6、12、24和48 h,CYP9A113基因表达均呈诱导效应。     

区域特色农业建立的思考

文章阐述了我国强地域性以及发展区域特色农业是自然、社会等多方面的必然要求。以镇江市农科院在江苏丘陵林果业发展上实践为基础,论述了区域特色农业在现代农业中的引领作用,指出政府有力领导是区域特色农业建设的重要保证。     

夏季高温环境下苦瓜种质资源农艺性状的综合评价

[目的]调查统计31份苦瓜种质资源在夏季高温环境下的农艺性状表现并进行耐热性分析评价,旨在建立田间苦瓜种质资源耐热性分析评价的方法和体系及筛选鉴定指标和优良耐热的苦瓜种质资源.[方法]连续两年在福建夏季高温环境下对31份苦瓜种质资源进行大田栽培比较试验,通过调查统计苦瓜的22个主要农艺性状指标,运用相关性分析、主成分分析和逐步回归分析对供试苦瓜种质资源进行综合分析评价.[结果]在高温环境下不同苦瓜供试材料产量差异较大,变异系数为35.48%,第一雌花节位、瓜长、瓜形和瓜瘤形状等果实性状变异系数在9.05%~41.27%,表现出丰富多样性,有利于耐热苦瓜种质资源的筛选.苦瓜产量与单瓜重、叶长呈极显著正相关(P<0.01,下同);单瓜重与瓜肉厚、瓜宽呈极显著正相关;第一雌花节位与植株分枝性呈显著正相关(P<0.05,下同),与主蔓节长呈显著负相关,各农艺性状指标之间反映的存在信息重叠,需要综合分析评价苦瓜种质资源的耐热性.主成分分析将22个农艺性状指标归纳为7个独立的综合指标(累计贡献率达76.654%),前5个主成分可概括为产量因子、瓜形因子、瓜瘤因子、早熟性因子和叶形因子,第六和第七主成分载荷最高的性状指标为种子性状,可概括为种子因子.主成分综合评价和聚类分析表明,表现优于CK的有7份苦瓜种质资源,具有植株分枝性强、主蔓粗壮、叶片大、单瓜重、瓜肉厚等特性.进一步利用逐步回归分析法建立了苦瓜种质资源耐热性评价数学模型F=-5.802+0.004X14+0.113X7+0.169X18+0.095X1+0.039X4+0.025X3+0.059X5+0.073X10-0.115X20+0.103X21+0.045X15,筛选出单瓜重、叶柄长、瓜瘤密度、植株分枝性、叶长、主蔓直径、叶宽、瓜色、种子颜色、种子花纹和瓜肉厚等11个耐热性鉴定指标.[结论]供试的K9、K10、K11、K20、K26、K28和K29等7份苦瓜材料可作为优异的耐热种质资源进行耐热苦瓜品种的选育.建立的数学模型和筛选出的11个鉴定指标可用于田间苦瓜种质资源耐热性的快速鉴定筛选,提高耐热育种效率.     

Mitigating nitrous oxide emissions from agricultural soils by precision management

Nitrous oxide (N₂O) emissions make up a significant part of agricultural greenhouse gas emissions. There is an urgent need to identify new approaches to the mitigation of these emissions with emerging technology. In this short review four approaches to precision managements of agricultural systems are described based on examples of work being undertaken in the UK and New Zealand. They offer the opportunity for N₂O mitigation without any reduction in productivity. These approaches depend upon new sensor technology, modeling and spatial information with which to make management decisions and interventions that can both improve agricultural productivity and environmental protection.     

红枣质量安全追溯对策研究

新疆具有光照时间长、昼夜温差大、年降水量少等优良的自然条件,为红枣的生长提供了卓越的环境,促使新疆成为最优区域的红枣生产地。在中国加入WTO后,红枣生产和加工的经济价值收益可观,在世界贸易中占绝对的主导地位,使得红枣产业的发展突飞猛进,面积迅速增加,成为又一支柱性产业。但是近年来一些有关红枣表面残留农药、加工过程中食品添加剂使用过量等质量安全问题频频出现,为了解决红枣中存在的质量安全问题,并且使新疆的红枣产业能够更健康、安全、持续稳定的发展,做出了相应的分析并提出了解决措施。     

谷物烘干机远程监控系统的性能研究

正我国是粮食生产大国,实现粮食高效高质存储是农业现代化的关键环节。烘干机作为未来智慧粮仓的物质技术装备,其智能化、信息化是研究智慧农业解决方案的重要内容。谷物烘干机远程监控系统的成功研发,实现了谷物烘干时长、工作状态、水分值的检测,可应用于新收获或新收购的水分达不到储运标准的水稻、小麦、大麦、玉米和油菜机械烘干过程,实现物料水分值实时检测,并解决了水分检测设备多依赖进口的问题,推动了国内谷物     

某牛场粪源大肠杆菌0157∶H7的分离鉴定

为了解重庆市某牛场牛群大肠杆菌O157∶H7的感染情况,我们以牛场犊牛为研究对象,采集其新鲜粪便,经LB培养基增菌培养、免疫磁珠富集后,在山梨醇麦康凯琼脂上划线培养,最后PCR扩增eaeA基因目的片段,以此分离鉴定粪源大肠杆菌O157∶H7。结果显示：在所采集的39份犊牛粪便样品中,分离得到一株符合大肠杆菌O157∶H7生长特点且含有eaeA基因的菌株。     

Why cuckoos should parasitize parrotbills by laying eggs randomly rather than laying eggs matching the egg appearance of parrotbill hosts?

The coevolutionary interaction between cuckoos and their hosts has been studied for a long time, but to date some puzzles still remain unsolved. Whether cuckoos parasitize their hosts by laying eggs randomly or matching the egg morphs of their hosts is one of the mysteries of the cuckoo problem. Scientists tend to believe that cuckoos lay eggs matching the appearance of host eggs due to selection caused by the ability of the hosts to recognize their own eggs.In this paper, we first review previous empirical studies to test this mystery and found no studies have provided direct evidence of cuckoos choosing to parasitize host nests where egg color and pattern match. We then present examples of unmatched cuckoo eggs in host nests and key life history traits of cuckoos, e.g. secretive behavior and rapid egg-laying and link them to cuckoo egg laying behavior. Finally we develop a conceptual model to demonstrate the egg laying behaviour of cuckoos and propose an empirical test that can provide direct evidence of the egg-laying properties of female cuckoos. We speculate that the degree of egg matching between cuckoo eggs and those of the host as detected by humans is caused by the ability of the hosts to recognize their own eggs, rather than the selection of matching host eggs by cuckoos. The case of Common Cuckoos(Cuculus canorus) and their parrotbill hosts(Paradoxornis alphonsianus), where it has been shown that both have evolved polymorphic eggs(mainly blue and white), was used to develop a conceptual model to demonstrate why cuckoos should utilize parrotbill hosts by laying eggs randomly rather than laying eggs matching the appearance of host eggs.In conclusion, we found no evidence for the hypothesis that cuckoos lay eggs based on own egg color matching that of the parrotbill-cuckoo system. We argue theoretically that laying eggs matching those of the hosts in this system violates a key trait of the life history of cuckoos and therefore should be maladaptive.