黄华属植物叶表皮特征及其生物学意义

在光学显微镜下观察披针叶黄华复合体、高山黄华复合体及黄华属其它种的叶表皮特征。结果表明,表皮细胞形状、垂周壁式样及气孔器类型具有重要的分类学意义。表皮细胞形状为多边型和不规则型,垂周壁式样为平直或具波纹。黄华属植物除新疆黄华,之字枝黄华,东亚黄华,柔毛黄华上表皮无气孔外,其余的上下表皮均具气孔,气孔器类型多为不规则型,只有紫花黄华为不等细胞型,有些无规则型中稍混有不等细胞型。笔者认为气孔器类型对划分属内种上等级具有一定价值。对披针叶黄华复合体、高山黄华复合体和黄华属不同种间气孔指数方差分析结果表明,气孔指数在居群水平及不同种间变化差异极显著,气孔大小及气孔指数主要受环境因子的控制。     

河南省部分地区鸡源致病性大肠杆菌生物学特性的研究

从河南省不同发病鸡群中采取典型鸡大肠杆菌病痛料，分离鉴定出8株鸡大肠杆茵。8株分离茵对雏鸡具有不同程度的致病作用，其中以兰考株和南阳株致病力最强，可使接种雏鸡100％发病死亡，其次是西华株和登封株，致死率均达75％。药敏试验结果表明：8个茵株均对氟苯尼考、头孢噻呋、头孢曲松、头孢唑啉、阿米卡星、卡那霉素、氯霉素高度敏感；大多数茵株对氧氟沙星、环丙沙星、氨苄西林、链霉素严重耐药。O因子血清凝集试验结果表明：8个茵株的血清型，大多数为O78，占75％，少数为O119占25％。     

我国部分地区病死畜禽无害化处理中心病原灭活情况调查

为了解我国病死畜禽无害化处理环节病原灭活效果,2020年对11个省(自治区)52个病死畜禽无害化处理中心开展抽样检测、问卷调查.通过对样品进行病毒核酸检测和病毒核酸阳性样品病原活性检测发现,化制法、发酵法、碳化法、酸解法均可灭活非洲猪瘟、猪瘟、口蹄疫和猪繁殖与呼吸综合征等4种疫病病原.通过问卷调查发现,无害化处理中心因...     

3种龙胆科植物的资源分配对策

选择青藏高原东缘同一生境类型下具有不同交配系统特点和不同传粉者丰度的3种龙胆科植物湿生扁蕾(Gentianopsis paludosa)(自花授粉)、祁连獐牙菜(Swertia przewalskii)(高昆虫访问异花授粉)和线叶龙胆(Gentiana farreri)(低昆虫访问异花授粉)为对象,研究其资源分配特征。结果表明,1)3种植物的花粉胚珠比例(P/O)存在显著差异(P0.05),湿生扁蕾的P/O显著低于另外两种异花授粉植物的(P0.05),祁连獐牙菜的P/O显著低于线叶龙胆的(P0.05);2)3种植物的繁殖分配比例存在差异,湿生扁蕾的繁殖分配比例显著高于另外两种异花授粉植物的(P0.05),线叶龙胆的繁殖分配比例显著高于祁连獐牙菜的(P0.05);3)在繁殖分配比例与个体大小关系上,湿生扁蕾与其个体大小不存在显著相关关系(P0.05),而另外两种异花授粉植物则与其各自个体大小之间存在显著负相关关系(P0.05)。研究表明,交配系统类型和传粉者丰度与植物的资源分配模式有关,尽管3种植物的繁殖绝对投入量都与其个体大小显著正相关(P0.05),但自花授粉植物相对于异花授粉植物具有较高的繁殖分配比例,并且这种较高的繁殖分配比例不受个体大小影响,这种高繁殖投入的资源分配模式可能与自花授粉植物具有繁殖保障,从而降低其繁殖代价有关。     

Characterization of polymorphisms of transferrin receptor and their association with susceptibility to ETEC F4ab/ac in pigs

Diarrhoea caused by enterotoxigenic Escherichia coli (ETEC) expressing F4 (F4ab, F4ac and F4ad) fimbriae is a significant cause of mortality and morbidity in newborn and weaned pigs. The locus controlling susceptibility towards ETEC F4ab/ac has been mapped to SSC13q41, in which TFRC (transferrin receptor) was localized and considered as a positional candidate gene for ETEC F4ab/ac receptor. In this study, we determined susceptibility/resistance to ETEC F4ab/ac in a total of 755 F2 animals from a White Duroc x Erhualian intercross using a microscopic enterocyte adhesion assay. We identified two TFRC polymorphisms (SNPs 591 A>G and 632 A>G) in a single exon after comparative sequencing analysis of 2371-bp amplicons containing the complete coding region of TFRC using RNA of eight full-sib F2 animals with susceptible and resistant phenotypes. The intron sequences flanking the two exon polymorphisms were obtained, revealing an intron polymorphism (SNP 291 C>T). We genotyped the 19 founder animals of the White Duroc x Erhualian intercross for the identified polymorphisms, showing that only the 291 C>T polymorphism is a highly informative marker. We further genotyped all 59 F1 and 755 F2 animals for the 291 C>T polymorphism, and the association of this polymorphism with susceptibility/resistance to ETEC F4ab/ac in these F2 animals was evaluated by the transmission disequilibrium test. The result showed that the 291 C>T polymorphism is not a causal mutation, however, has a significant linkage disequilibrium with the ETEC F4ab/ac, especially F4ac receptor locus.     

饲用油腊的加工技术及应用

本文介绍了近几年在饲料工业生产中不同饲用油脂添加技术应用及研究,重点对常规喷涂技术、真空喷涂技术和固态油脂喷雾干燥技术进行综述、分析,并对饲料中应用的固态油脂生产加工和应用技术进行了展望。     

A pig–human comparative RH map comprising 20 genes on pig chromosome 13q41 that harbours the ETEC F4ac receptor locus

The enterotoxigenic Escherichia coli (ETEC) F4ac is a major cause of diarrhoea in newborn and young pigs. The locus for the intestinal ETEC F4ac receptor (F4acR) has been mapped to pig chromosome (SSC) 13q41 with known homology to human chromosome (HSA) 3q21 and q29. However, the causative gene and mutation(s) remain unknown. The aim of this study was to characterize gene-derived markers on SSC13q41 for fine mapping of the F4acR locus, and construct a high-resolution pig–human comparative map to select positional candidate genes for F4acR. Pig-specific sequence-tagged site markers were developed for 20 genes that are located in a 6.8-Mb region on HSA3q21 and q29, and a total of 34 single-nucleotide polymorphisms (SNPs) were identified in 14 of 20 markers developed. Eighteen markers were mapped to SSC13q41, while the other two markers ( PLXNA1 and KLF15 ) were assigned to SSC13q32 and SSC7q13, respectively, by radiation hybrid mapping. This result showed that there was a small conserved segment on SSC7 corresponding to HSA3q21. A framework map comprising 18 markers on SSC13q41 was established, refining the synteny breakpoint on SSC13q41 to a region of 12.3 centiRay. The comparative radiation hybrid (RH) map revealed three interesting candidate genes for F4acR from the human genome, viz. MUC4 , MUC13 and MUC20 . Linkage analysis with six marker polymorphisms revealed that MUC4 had the most significant linkage with the F4acR locus.     

低聚糖对雏鸡大肠粪便NH3-N含量及肠道菌群的影响

试验选取1日龄罗曼蛋公雏250只，随机分为5组，试验组饲料或饮水中分别添加海藻糖(500mg／kg)、海藻胶(600mg／kg)、大豆寡糖(500mg／kg)、圆葱寡糖(500mg/d)。结果表明，四种低聚糖均可促进肠道乳酸菌及双歧杆菌的生长繁殖，对魏氏梭菌的生长呈现抑制作用。海藻糖、海藻胶对降低大肠粪便NH3—N含量效果不显著(P＞0．05)，而大豆寡糖效果显著(P＜0．05)，圆葱寡糖效果极显著(P＜0.01)。     

恒河猴肾上腺皮质的显微与超微结构

应用光镜和透射电镜观察，恒河猴肾上腺皮质可分为球状带、束状带和网状带。其特点是：（1）被膜较发达，有时可伸入球状带将其细胞分隔为团块。（2）球状带有时呈指状指入束状带和网状带，其内可见嗜铬细胞；球状带细胞可分为明、暗2种类型，他们排列成团球状、滤泡状、索状和不规则形。（3）网状带较发达，有的可分为内、外2个区；有时网状带呈刺状伸入束状带；有时网状带细胞可见于被膜下或髓质内。（4）有时部分被膜连同皮质一起呈指状伸入髓质内。（5）皮质细胞均含丰富的溶酶体、线粒体和内质网，但不同部位的细胞所含的脂滴在数量、大小、形态和电子密度等方面存在差异。     

口服补液盐配合其它药物治疗仔猪长途运输应激病

１发病情况山东费县探沂镇碗窑村史某 ,从安徽购进９８头长白仔猪 ,由于天气不好 ,误了运输时间 ,一周才到家 ,运回家后死亡４头 ,途中每天喂两次 ,车上铺厚厚垫草 ,猪多拥挤 ,没有活动余地 ,回家后仔猪虚弱全部发病 ,体温升高 ,拉稀 ,呈水样 ,颜色为黄、灰绿色 ,尿黄。根据临床症状 ,剖检变化 ,以及流行病学初步诊断为长途运输引起的猪伤寒病。２临床症状仔猪精神不振 ,喜卧草垛中 ,寒战 ,全部不食 ,鼻颈无汗 ,眼结膜发红 ,被毛粗乱 ,脱水十分严重 ,体温４０～４１℃ ,脉搏８５次／分 ,呼吸３２次／分 ,腹泻呈黄、灰绿色 ,尿液黄 ,有的肛门…