Development of a colloidal gold immunochromatographic assay (GICA) for the rapid detection of Spiroplasma eriocheiris in commercially exploited crustaceans from China

Spiroplasma eriocheiris is an emerging pathogen in freshwater crustaceans. In recent years, Eriocheir sinensis, Procambarus clarkii, Litopenaeus vannamei, Macrobrachium rosenbergii and Macrobrachium nipponense had been infected by this pathogen in China. An immunochromatographic strip test using gold nanoparticles was developed for rapidly detecting this pathogen. The strip test based on the principle of sandwich immunoassay by the specific combination between the pathogen and polyclonal antibody on a nitrocellulose membrane. Positive samples were displayed as red lines at the test and control zones of the nitrocellulose membrane, while negative samples resulted in a red line only at the control zone. The limit of detection was proved to be 10⁶ Color Change Unit/ml. The test strip could be visually detected within 15 min and do not have cross‐reaction with other aquatic bacteria. This test strip allows on‐site rapid detection of S. eriocheiris in crustacean without the requirement of specialized equipment and professional personnel. The one‐step test strips developed in our study had high sensitivity, specificity, reproducibility and stability. In conclusion, this method was proved to be convenient, feasible, rapid and effective for detecting S. eriocheiris.     

稻茬田小麦宽幅精量少耕播种机的设计与试验

为解决长江中下游稻麦轮作区稻茬田免耕播种小麦机具堵塞及土壤黏附严重等问题,结合当地稻茬田播种小麦需要开排水沟的农艺要求,提出了"种-肥-种"宽幅精量播种和带状旋耕相结合的防堵思路,设计了双翼铧式开沟器、宽幅精量排种机构、种沟双圆盘开沟器和浮动覆土板等关键部件,研究设计了一种稻茬田小麦宽幅精量少耕播种机。试验结果表明,宽幅播种方式与带状旋耕相结合较好解决了稻茬田播种小麦堵塞的问题,小麦播幅平均为74.6 mm,平均播深为39 mm,播深合格率为86.7%,施肥方式为侧下方深施肥,平均施肥深度为81 mm,施肥深度合格率为93.3%,均满足国家标准。厢沟平均深度为175 mm,沟面宽度为238 mm,满足排水要求。该研究为应用于稻麦轮作区稻茬田小麦少免耕播种机的设计提供了参考。     

口蹄疫抗体免疫层析试纸的临床应用及性能评价

为评价前期研制的猪口蹄疫O型抗体检测试纸的临床应用效果,检测了162头份口蹄疫病毒(FMDV)多肽疫苗免疫猪血清和87头份灭活疫苗免疫猪血清,并与UBI FMDV抗体检测ELISA和美国BioXL FMDV抗体检测ELISA做平行对比试验。结果显示,试纸与2种ELISA方法的符合率分别为95.06%和96.55%。说明该试纸可以用于猪FMDV O型抗体的临床检测,为评价口蹄疫疫苗免疫效果提供了快速、简便的方法。     

Replacement of fish oil with alternative lipid sources in plant‐based practical feed formulations for marine shrimp (Litopenaeus vannamei) reared in outdoor ponds and tanks

The objective of this study was to demonstrate the feasibility of partial substitution of menhaden fish oil by alternative lipid sources (soybean oil, poultry grease and flaxseed oil) in non‐marine protein‐based shrimp production diet, its influence on fatty acid profile and its final product flavour. Results for the pond study (17 weeks) showed no differences (P ≥ 0.05) in shrimp production among different test diets. Production ranged from 5070 to 5363 kg ha^?1; mean final weight, 18.0 to 21.6 g; weekly growth, 1.04 to 1.25 g; survival, 65.6 to 75.4%; and FCR, 1.37 to 1.45. Results from the tank trial (12 weeks) confirmed these findings, final weight, 13.8–14.8 g; weekly growth, 1.1–1.2 g; survival, 92.5–98.3%; FCR, 1.05–1.11; and final standing crop, 4738–5024 kg ha^?1. The fatty acids profiles of edible tail muscle reared on the various diets displayed a similar fatty acid profile to that of the diets. The sensory test showed no statistical differences in texture, appearance, aroma and flavour between the shrimp fed diets containing menhaden fish oil and soybean oil. These studies demonstrated that practical shrimp feeds containing non‐marine protein ingredients and a percentage of fish oil replaced by alternative lipid sources had no negative impact on mean final weight, weekly growth, survival, FCR, final standing crop, fatty acids profile and organoleptic properties of Litopenaeus vannamei.     

臭氧氧化猪场处理尾水对苦草(Vallisneria spiralis)抗氧化系统的影响

为了探索臭氧氧化技术应用于畜禽养殖废水排放前的预处理对环境可持续发展的影响,用不同浓度臭氧氧化处理经生化工艺处理后的猪场尾水,以苦草为试验材料,从活性氧代谢和抗氧化系统的角度,探讨了沉水植物在臭氧氧化猪场处理尾水中的适应性以及臭氧氧化技术的应用对水生植物的影响。结果表明:与未经臭氧氧化处理相比,臭氧氧化后(AO1 10 mg·L~(-1)、AO2 30 mg·L~(-1)、AO3 50 mg·L~(-1))猪场处理尾水中苦草的过氧化氢(H_2O_2)含量有升高趋势;AO2处理中苦草的抗坏血酸(AsA)-谷胱甘肽(GSH)循环对H_2O_2调节起重要作用,苦草的抗坏血酸过氧化物酶(APX)活性、AsA和GSH含量增加,从而使生物量增加;AO3处理中苦草AsA含量降低,H_2O_2与抗氧化物质之间没有达到平衡,从而使生物量降低。结果显示,试验条件下,30 mg·L~(-1)的臭氧氧化应用于猪场处理尾水,能增强沉水植物的抗氧化系统,促进生长,从而对水生生态系统有调节作用。     

玉米秸秆添加畜禽粪便田间条带堆腐对黑土活性有机碳的影响

为明确秸秆田间条带堆腐在农业生产中推广应用的可能性,以吉林省范家屯农业科技示范园黑土为研究对象,探讨秸秆添加不同畜禽粪便田间条带堆腐还田对土壤活性有机碳的影响。以玉米秸秆为供试材料,进行田间堆腐试验,设置本地秸秆覆盖还田(即对照,CK)、秸秆条带堆腐无畜禽粪便(ST)、秸秆条带堆腐+腐熟猪粪(STP)、秸秆条带堆腐+腐熟鸡粪(STC)4个处理。通过测定土壤有机碳(SOC)、土壤微生物生物量碳(MBC)、土壤溶解性有机碳(DOC)、土壤易氧化有机碳(EOC),综合分析土壤活性有机碳的含量和碳库管理指数(CPMI)。结果表明:秸秆条带堆腐还田各处理土壤SOC、MBC、EOC、DOC含量均高于CK处理,其中秸秆条带还田添加畜禽粪便处理更为显著,各活性碳组分含量较CK处理呈升高趋势。相关性分析表明田间条带堆腐土壤SOC、DOC、EOC、CPMI间呈现显著或极显著正相关,与氧化稳定系数(Kos)显著或极显著负相关。玉米秸秆条带堆腐还田有效增加土壤SOC、MBC、DOC、EOC含量,秸秆添加不同畜禽粪便处理中鸡粪更显著增加土壤有机碳和土壤活性有机碳含量,增加CPMI,降低Kos,对改善黑土碳库质量有着积极的作用。     

不同覆盖方式对旱地马铃薯叶片抗氧化生理及产量的影响

为探究西北半干旱雨养条件下不同覆盖措施对旱地马铃薯增产及抗性生理的影响,以'陇薯7号'为材料,设置了玉米秸秆带状覆盖(SM)、地膜覆盖(PM)和无覆盖对照(CK)3种栽培方式,研究了不同处理下马铃薯植株叶片抗氧化酶活性、渗透调节物质和膜脂过氧化物含量、产量及其构成要素的差异.结果表明:SM显著提高马铃薯植株细胞清除自由...     

集条残膜打包机捡拾清理装置设计与试验

针对机收集条残膜因其质地松散、含杂量高造成的转运困难和二次利用率低等问题,在测定分析集条残膜主要物理特性参数的基础上,设计了一种由清杂辊、偏心捡拾滚筒机构、脱膜机构等组成的集条残膜捡拾清理装置。清杂辊弹齿采用双头螺旋线人字形对称排列方式,通过动力学分析,确定清杂辊在运动轨迹为余摆线时的转速为86.3 r/min;利用Matlab软件优化了偏心捡拾滚筒的偏心连杆尺寸,通过性能试验优选滚筒转速为65 r/min、弹齿安装角度为45°;经力学分析和气力流场特性模拟获得残膜能被顺利脱下、抛离时,脱膜叶片端部的线速度最小值为1.485 m/s。整机田间试验表明:在机具前进速度为1.5 m/s时,表层残膜拾净率为90.96%,缠膜率为1.09%,清杂率为77.35%,整机工作效率为0.19 hm~2/h,满足田间作业使用要求。     

PRRSV重组M蛋白表达及胶体金试纸的制备

为建立PRRSV抗体的检测方法,通过扩增PRRSV ORF6基因,将其克隆至pET-28a（＋）中,IP TG诱导重组质粒转化菌表达,经SDS-P AGE和Western blot鉴定,表明重组质粒能够表达目的蛋白;经亲和层析纯化表达蛋白,以SP A标记胶体金,用纯化M融合蛋白和羊抗猪抗体为检测线和质控线研制胶体金试纸,检测猪血清样品,比较与IDEXX ELISA试剂盒检测结果的符合率。结果表明,表达蛋白具有良好的反应性,制备的胶体金试纸与IDEXX ELISA试剂盒检测符合率为89％,该方法为P RRSV抗体的检测提供了快速简便的方法。     

黄土高原丘陵沟壑区一副区小流域淤地坝系效益分析——以王茂沟小流域为例

淤地坝是水土保持治理的主要措施之一，特别是在水土流失最为严重的黄土丘陵沟壑区一副区．其效益更为突出。根据王茂沟流域淤地坝坝系的调查资料．分析了王茂沟流域坝系的蓄洪拦泥、增产、生态、社会效益。研究结果表明，黄土高原丘陵沟壑区的淤地坝坝系在防止沟道侵蚀、提高粮食产量、促进植被恢复及土地利用结构调整、促进农村产业结构调整、提高水资源利用率、便利交通、促进农村科技文化事业的发展等方面发挥着不可替代的作用。