新时代饲料跨境电商面临的问题及应对措施研究

随着饲料行业国际市场竞争的日趋加剧,我国饲料企业跨境电商业务受到了严重冲击.近几年,由于农业、畜牧业及肉、蛋、奶等产品的市场价格波动,放大了跨境电商活动中原本就存在的跨境物流、金融支付、网络安全、国际法律公约缺失等问题.为在新的竞争环境下有效降低产品市场价格波动对跨境电商造成的不利影响,应从强化国际间贸易协作,拉动国内...     

中草药复合微生态制剂对急性肝脏损伤蛋鸡肝脏保护作用的研究

试验旨在研究中草药复合微生态制剂（CHCP）对急性肝脏损伤蛋鸡肝脏的保护作用。试验分两部分：①用四氯化碳豆油（SCCl₄）建立蛋鸡急性肝脏损伤模型。选取1 d健康蛋雏鸡108只随机分为4组,模型Ⅰ~Ⅲ组分别按1、2、4 mL/kg体重灌胃10%（V/V）SCCl₄,对照组按2 mL/kg体重灌胃豆油,分别在14、28及35 d时各灌胃一次;②CHCP对蛋鸡急性肝脏损伤的影响。选择1 d 健康蛋雏鸡60只随机分为5组：对照组（豆油）、模型对照组（SCCl₄）及低、中、高剂量CHCP组（SCCl₄+1‰ CHCP、SCCl₄+2‰ CHCP、SCCl₄+4‰ CHCP）,7 d起饮水使用CHCP,14、28 d按2 mL/kg体重剂量给鸡灌胃10% SCCl₄。结果表明,按2 mL/kg体重剂量在14、28 d分别灌胃10% SCCl₄即可造成蛋鸡肝脏损伤,引起肝细胞脂肪变性,空泡样变严重,核固缩,坏死;与模型对照组相比,低、中、高剂量CHCP组蛋鸡血清谷草转氨酶（AST）含量分别降低4.35%（P > 0.05）、7.57%（P > 0.05）及9.79%（P < 0.05）,中、高剂量CHCP组血清谷丙转氨酶（ALT）含量分别降低34.92%（P < 0.01）、36.51%（P < 0.01）,血清总胆红素（TB）含量分别降低25.49%（P < 0.01）、27.45%（P < 0.01）;蛋鸡肝细胞切片显示CHCP不同剂量组肝细胞充血减轻,未见脂滴空泡,排列整齐,细胞质丰富而均匀。结果表明,本试验所用的CHCP按2‰、4‰饮水使用均能减少肉鸡肝细胞坏死,降低血清转氨酶活性及TB水平,对SCCl₄诱导的肝脏损伤有保护作用。     

单播与混播下紫花苜蓿与无芒雀麦生物量对氮肥的响应

禾本科与豆科牧草的混播,是人工草地建植的最主要方式之一,研究氮肥对豆禾混播草地影响对维持混播草地的持续稳定生产具有重要意义。试验在温室栽培条件下研究了3个氮肥梯度(0,75,150 kg N/hm²,记作N₀,N₇₅,N₁₅₀)对无芒雀麦单播,紫花苜蓿单播以及它们混播(分别记作G-G,L-L,G-L)生物量的影响。研究结果表明,1)在单播时,无芒雀麦对氮肥的响应较敏感,施入氮肥显著地提高无芒雀麦的生物量(P<0.05),而对紫花苜蓿的生物量无显著影响(P>0.05)。在混播时,无芒雀麦对有效氮的竞争胜过紫花苜蓿,施氮能显著地增加混播中无芒雀麦牧草的生物量(P<0.05),间接地抑制了紫花苜蓿生物量的发展。2)无芒雀麦和紫花苜蓿混播的总生物量介于它们单播时生物量之间,却高于它们单播时生物量的平均值。3)无芒雀麦单株地上生物量在混播时显著高于单播(P<0.05)。相反,紫花苜蓿的单株地上生物量单播显著高于混播(P<0.05)。这说明在混播系统中,无芒雀麦混播效应表现为积极的促进作用,紫花苜蓿混播效应表现为消极的抑制作用。4)在无芒雀麦和紫花苜蓿的混播中,无芒雀麦和紫花苜蓿的生长处于动态的消长中,这种变化通过土壤无机氮的水平来调控。     

禽呼肠病毒P10、P17非结构蛋白基因的克隆及序列分析

根据GenBank上的禽呼肠病毒(ARV)S1基因序列,设计并合成了一对跨越P10和P17非结构蛋白基因的特异性引物,对13个ARV毒株进行RT-PCR扩增、克隆及序列测定。结果显示,13个ARV毒株的P10蛋白基因ORF全长均为297bp,编码98个氨基酸;P17蛋白基因ORF全长为441bp,编码146个氨基酸。这13个ARV毒株P10、P17蛋白基因核苷酸同源性分别在96.6%~100%和95.2%~99.3%之间,推导的氨基酸同源性分别在98.2%~100%和91.9%~99.0%之间。将这13个ARV毒株与GenBank上其他正呼肠病毒毒株,包括番鸭株(DRV)和飞狐上分离到的内尔森海湾病毒(NelsonBayvirus,NBV)及两个澳洲分离株(ARM-1和SOM-4)进行同源性比较和遗传进化树分析,结果表明,呼肠病毒有地域和种类的差别。     

云南南亚热带多雨区引进禾本科牧草的适应性及评价

引进国外优良牧草栽培种14个在云南南亚热带多雨区进行种植,结果表明:贝斯莉斯克俯仰臂形草、纳罗克非洲狗尾草、海密尔大黍、海琴绸纹孔颖草、帕春青绿黍和无芒臂形草6个牧草品种在适应性,草产量和质量方面表现较好,适宜在该地区推广种植。     

THIS ARTICLE HAS BEEN RETRACTED Exergy as an ecological application used in the recovery process of benthic communities

Exergy, the thermodynamic function that represents the distance of an open system from equilibrium, is proposed as an ecological indicator for summarizing the complex dynamics occurring in a disturbed community during its recovery processes. These complex dynamics can be difficult to capture by using classical indices. In this study, we sampled macrobenthos using the BACI scheme (before versus after; control versus impact) in tidal wetlands of west Chongming Island, China, an area that has been disturbed by ecological engineering measures. Exergy storage is estimated for benthic communities. The control area is proposed as dynamic reference for estimating local exergy storage of the benthic community. Three different methods were used for estimating exergy on the basis of coefficients: (a) taken for taxa groups; (b) estimated from coding genes given for broad taxonomic groups; and (c) estimated from genome size taken as close as possible to the taxonomic level of the species, providing a basis for inferring similarities. We found a decrease of local exergy content in the disturbed area 9 days after the disturbance. Subsequently, the reference exergy of the benthic community increased (i.e. in the surrounding control area) in accordance with the proposed hypothesis regarding the dynamics of exergy storage during a system's development. Estimates of local exergy arrived at using the three methods provided comparable results. Based on this, we then discuss the feasibility of using the more readily available genome size data for estimating exergy. This result may have important implications for broader application of this indicator to biological systems. Moreover, the adjacent control samples seem to represent an appropriate dynamic reference for estimating the local exergy of disturbed communities. We found that exergy was a useful indicator that integrates the processes underlying the recovery of the benthic community after disturbance.     

主动免疫血管活性肠肽（VIP）对家鸽繁殖性能影响的初探

将３０对青年鸽随机分为三组,第一组用血管活性肠肽（ＶＩＰ）类似物与牛血清蛋白（ＢＳＡ）的偶联物进行主动免疫ＶＩＰ,第二组注射与第一组等量的生理盐水,第三组不做任何处理。在试验的第一阶段,除第三组外,第一、二组鸽在产蛋后立即将书目是拿出,试验结果显示：第一组与第二组鸽月产蛋量和周抱窝数差异不显著。但第一、二组鸽产蛋量与第三组（自然饲养组）差异极显著。在试验的第二阶段（Ｂ处理过程）均不把蛋拿出,则三组     

Identification of resistance gene analogue markers closely linked to wheat powdery mildew resistance gene Pm31

Specific oligonucleotide primers, designed for the sequences of known plant disease resistance genes, were used to amplify resistance gene analogues (RGAs) from wheat genomic DNA. This method was applied in a bulked segregant analysis to screen for the RGA markers linked to the powdery mildew resistance gene Pm31, introgressed into common wheat from wild emmer. Two RGA markers (RGA200 and RGA390) were found to be closely linked to Pm31 and completely co‐segregating with the marker allele of Xpsp3029 linked to Pm31, with a genetic distance of 0.6 cM. These two RGA markers were then integrated into the formerly established microsatellite map of Pm31 region. The result showed the effectiveness of the RGA approach for developing molecular markers linked to disease resistance genes and demonstrated the efficiency of denaturing polyacrylamide‐gel electrophoresis for detecting polymerase chain reaction polymorphism.     

黄河裸裂尻生长激素(GH)基因的PCR扩增和克隆

为了克隆黄河裸裂尻生长激素(GH)基因并获得表达产物,试验采用异硫氰酸胍法提取黄河裸裂尻脑组织总RNA,以分离的RNA为模板,采用RT-PCR扩增获得GH基因cDNA,将cDNA插入质粒pQE30中,并在大肠杆菌RB791中表达,经异丙基-β-D-硫代吡喃半乳糖苷(IPTG)诱导后,SDS-PAGE电泳检测蛋白的表达情况。结果表明:扩增后黄河裸裂尻GH基因长度为508 bp,黄河裸裂尻GH基因与青海湖裸鲤的同源性很高,电泳显示出1条新的分子质量约为14.4 ku的特异性条带。     

安义瓦灰鸡早期生长规律研究

通过对不同羽速基因及不同性别安义瓦灰鸡的早期生长规律进行研究,结果表明:不同性别安义瓦灰鸡的早期生长规律有较大差异(P<0.01),不同羽速基因安义瓦灰鸡的早期生长规律差异不显著;安义瓦灰鸡的生长速度与出壳重无关,出壳重只影响其育雏期的体重;性别对体重的影响较晚,且公鸡大于母鸡。