环介导等温扩增技术在转基因饲料成分检测中的应用

本文介绍了一种适合转基因饲料成分检测的新方法—环介导等温扩增技术(LAMP),概述了该方法的原理与特点、应用实例及其在饲料转基因成分检测中的应用展望。     

饲料中的转基因成分在蛋鸡体内代谢残留的研究

用含20%抗草甘膦转基因豆粕的饲料喂养鸡蛋,通过检测其内脏、肌肉、血液、粪便及肠道微生物的豆粕转基因成分,探讨饲料中转基因成分在鸡蛋体内的代谢残留状况。以定性PCR检测含20%转基因豆粕的饲料及蛋鸡的8种内脏样品(肠、胰腺、食道、肝、腺胃、肾、心脏、肌胃)、肌肉、血液、蛋品、粪便、肠道微生物的转基因豆粕的工具基因CaMV35S启动子与NOS终止子以及目的基因CP4-EPSPS等外源基因成分。PCR检测结果表明:除了含20%转基因豆粕的饲料外,蛋鸡的8种内脏器官、肌肉、血液、蛋品、粪便及肠道微生物中均未检出转基因豆粕的CaMV35S、NOS、CP4-EPSPS等外源基因成分。检测结果表明:长期喂养含20%转基因豆粕饲料的蛋鸡的8种内脏器官、肌肉、血液、蛋品、粪便及肠道微生物中均未发现有转基因成分残留,说明饲料中的转基因成分,通过肠胃消化降解后吸收,不会在鸡的组织器官内残留。     

饲料产品中转基因成分的分析及问题研究

概括介绍了当前转基因产品标志管理现状,以及对饲料中转基因成分的定性和定量检测的方法。     

《饲料安全及其检测技术》

本书针对饲料安全内容，介绍了解决饲料安全采取的对策及措施，对饲料及添加剂安全质量标准、饲料加工过程中的HACCP技术、饲料添加剂安全评价规程等方面进行了全面的论述。对饲料安全检测技术，主要介绍了饲料中各种有毒有害物质、兽药、农药及转基因成分的检测方法，包括对各种重金属元素残留的分析以及对牛羊源性成分、     

饲料中转基因成分的实时荧光PCR检测研究

本试验采用实时荧光PCR方法对饲料中的转基因成分进行了检测研究。对国产的14份猪饲料、3份水产饲料和3份荷兰进口代乳粉共20份样品进行了大豆、玉米、棉花、油菜和大米物种特异性基因和CaMV35S、NOS、FMV35S、NPTⅡ、PAT、BAR、GOX、CryⅠA(b)、CryⅠA(b)-CryⅠA(c)、rrsoy外源基因检测。在11份样品中检出转基因成分,其中8份样品中含有转基因大豆成分,2份样品中含有转基因大豆和转基因棉花成分,1份样品中含有转基因大豆、转基因油菜和转基因棉花成分。     

进口饲料中牛源性与转基因成分的检测

本文介绍了进口饲料中牛源性与转基因成分的PCR检测方法。该方法用异硫氰酸胍提取进口饲料样品DNA,以牛特异性引物扩增模板DNA,扩增产物为271bp,PCR产物经限制性酶切片段分析,与预期设想一致;方法灵敏度实验结果显示,饲料样品中含有0.1%的牛源性成分时仍能检出。同时,根据转基因农作物最常使用的外源基因设计引物,在进口饲料中检测出35S启动子和NOS中止子等转基因成分,具有快速、简便、准确等特点。     

饲料产品中转基因成分定量分析的问题与对策

文章综述了国内外农产品转基因成分标识管理的现状,评价了现有转基因作物定量检测方法的特点与弊端,提出了以基因特异性为依据、建立更适合饲料等复杂产品中转基因成分定量检测的改进建议。     

转基因饲料的PCR检测策略

PCR技术是转基因检测中最常见的方法之一。本文对目前转基因饲料的形势及检测特点进行总结,并从检测层次及检测方法上对转基因饲料的PCR检测策略进行综述。     

饲料中转基因成分的检测分析方法

<正>转基因饲料(genetically modified feed,GMF)是指通过基因重组技术获得的基因改良生物加工而成的饲料(SN/T1201-2003)。目前,转基因农作物的商业化种植面积正在逐年增加,品种日益丰富,鉴于转基因作物潜在的风险性,世界各国纷纷制定相应的政策要求对用于饲料的转基因作物进行风险性评估,并且要求在饲料中的转基因成分不能超过一定数量,如欧盟要求饲料中的转基因成分不能超过     

转基因饲料的安全问题及其对策

本文对转基因饲料的使用现状和可能存在的安全问题进行了分析,提出从建立健全转基因饲料的法规、安全评价检测体系和标识方法,加强对转基因饲料生产、标识的监管等几个方面来搞好转基因饲料的管理。     

Efficiency and Sensitivity of Techniques for Recovering Nematode Eggs from Bovine Feces

Haemonchus contortus eggs were extracted from sheep feces and known numbers were added to helminthologically sterile bovine feces to provide samples with seven, 30 and 60 eggs per gram (epg). At 60 epg, dilution techniques (modified Cornell-McMaster and modified McMaster) tended to overestimate the number of eggs and more eggs were recovered (mean of 121 and 88% respectively) with these techniques than with centrifugal concentration procedures (modified Cornell—63% and Wisconsin— 69%). At 30 epg, all techniques were comparable (modified Cornell-McMaster 67%, modified McMaster 63%, modified Cornell and Wisconsin 64%). At 7 epg, the Wisconsin (61%), modified Cornell (60%) and Cornell-McMaster (94%) techniques were comparable and better than the modified McMaster technique (16%). At all levels of epg, the modified Cornell and Wisconsin techniques recovered eggs from 100% of the samples. The Cornell-McMaster and modified McMaster techniques recovered eggs from 90 and 100% of samples at 60 epg; 40 and 100% at 30 epg; and 21 and 11% at 7 epg. With a gravitational concentration procedure, the Standard Vial, no more than 16% of the eggs at any level of epg were recovered and at 7 epg eggs were recovered from only one-half of the samples. Five gravitational concentration techniques were assessed over 66 to 490 epg. The Ovassay, Fecalyzer and modified Standard Vial techniques were comparable in efficiency (28%, 25% and 24% respectively), but the Standard Vial technique was less efficient (11%).

Introduced into diagnostic parasitology was the concept of predictive values which is the proportion of samples that a technique correctly identifies as being negative for parasite eggs. At 7 epg this was calculated to be zero for the modified Cornell-McMaster, modified McMaster and Standard Vial techniques and 100 for the Wisconsin and modified Cornell techniques.

     

改性蒙脱石对黄曲霉毒素B_1和玉米赤霉烯酮的吸附研究

本试验旨在探究4种不同改性蒙脱石对黄曲霉B1(AFB1)和玉米赤霉烯酮(ZEN)的体外吸附性能。采用体外吸附试验,在霉菌毒素污染的喷浆玉米皮中添加4种改性蒙脱石,检测AFB1和ZEN的浓度变化,以探究不同种类及不同添加比例改性蒙脱石对AFB1和ZEN的吸附作用。结果表明:4种改性蒙脱石对AFB1和ZEN均有显著吸附作用,其中膨润土经十八烷基三甲基氯化铵改性制备的复合改性蒙脱石II型对AFB1和ZEN的吸附效果最好,在添加量为1%时,对AFB1和ZEN的吸附率分别为62.60%和43.38%。在本体外试验条件下,4种改性蒙脱石对喷浆玉米皮中AFB1和ZEN均具有吸附作用,可以降低喷浆玉米皮中的霉菌毒素含量,为改性蒙脱石在饲料脱毒剂的使用提供参考。     

高蛋白饮用型酸乳体系中微粒化乳清蛋白和物理改性淀粉对稳定性的影响

将微粒化乳清蛋白和2 种物理改性淀粉（大麦物理改性淀粉和大米物理改性淀粉）作为酸乳清洁标签的高蛋白饮用型酸乳体系，研究微粒化乳清蛋白（0.5 g/100 mL）和2 种物理改性淀粉（0.5、1.0 g/100 mL）对酸乳体系的影响。结果表明：5 种不同酸乳体系均具有较好的持水性和较高的黏度，其中，大麦物理改性淀粉添加量为1.0 g/100 mL的酸乳体系持水力最高，达70.20%，该体系黏度也最高，为4 422 mPa·s；粒径分布和流变学特性分析结果均显示，大麦物理改性淀粉对酸乳体系的稳定性有较好的维持作用；微粒化乳清蛋白酸乳体系指标值略低于物理改性淀粉体系，但是差异并不明显。     

Occurrence of Problems after Three Techniques of Bilateral Thyroidectomy in Cats

Bilateral thyroidectomy was performed in 106 cats with hyperthyroidism by one of three techniques: original intracapsular, modified intracapsular, or modified extracapsular. Hypocalcemia was detected in the first 3 days after surgery in 11 (22%) of 50 cats treated by the intracapsular technique, 10 (33%) of 30 cats treated by the modified intracapsular technique, and 6 (23%) of 26 cats treated by the modified extracapsular technique. Hypocalcemia was classified as mild or severe. No signs of hypoparathyroidism developed in any of the 13 cats with mild hypocalcemia. Of the 14 cats with severe hypocalcemia, 8 had clinical signs of hypoparathyroidism before and during treatment with calcium and vitamin D, 3 were treated and no clinical signs developed, 2 were not treated but no clinical signs developed, and 1 was lost to follow-up. No cat required permanent calcium or vitamin D supplementation after surgery. Severe hypocalcemia and clinical signs of hypoparathyroidism occurred in 3 (6%) of the 50 cats treated by the intracapsular technique, 4 (13.3%) of the 30 cats treated by the modified intracapsular technique, and 1 (3.8%) of the 26 cats treated by the modified extracapsular technique. Twelve cats had recurrence of hyperthyroidism at a median time of 23 months. The intracapsular technique was used in 11 of these cats, and the modified extracapsular technique was used in 1. No clinical signs of hypothyroidism were detected in any of the cats. The modified intracapsular and modified extracapsular techniques of bilateral thyroidectomy are effective procedures for the treatment of feline hyperthyroidism.     

Comparison of absorptive capacities of original and modified Schirmer tear test strips in dogs

OBJECTIVE: To compare in vitro and in vivo absorptive capacities of modified Schirmer tear test strips with those of original strips, and to establish reference values for use with the modified strips. DESIGN: Prospective study. ANIMALS: 100 dogs. PROCEDURE: In vitro absorptive capacity was determined by immersing strips in an irrigating solution for 15 seconds and recording amount of wetting. In vivo absorptive capacity was determined by placing an original Schirmer tear test strip in 1 eye and a modified strip in the other eye of 50 dogs with normal or abnormal tear production. Time required to wet 10 mm of each strip was recorded. Measurements were repeated 30 minutes later after reversing which strip was placed in the left or right eye. Reference values (mean +/- SD) were determined by recording the time required to wet 10 mm of the modified strip in 50 healthy dogs. RESULTS: Amount of wetting was significantly less and time required to wet 10 mm was significantly greater for the modified strip, compared with the original strip. Reference values determined for the modified strip were 32 +/- 11 seconds in the right eye, 33 +/- 11 seconds in the left eye, and 32 +/- 10 seconds in both eyes. CONCLUSIONS AND CLINICAL RELEVANCE: Absorptive capacities of the original and modified Schirmer tear test strips were significantly different. Reference values determined for 1 strip should not be used for the other strip.     

蛋清溶菌酶的改造及其抑菌活性

本研究旨在探讨高温酸性改造的蛋清溶菌酶对两种革兰阳性菌G⁺（金黄色葡萄球菌Staphylococcus aureus、枯草芽胞杆菌Bacillus subtilis）和两种革兰阴性菌G^-（大肠杆菌Escherichia coli、鳗弧菌Vibrio anguillarum）的抑制作用。采用高温（57.0±0.1）℃、pH 2.0条件对蛋清溶菌酶进行改造，透射电镜观察改造蛋清溶菌酶的超微结构，8-苯胺基-1-萘磺酸（ANS）测定蛋清溶菌酶改造前后疏水性的变化，圆二色谱法与BeStSel软件分析改造后溶菌酶二级结构的改变，并采用牛津杯法测量改造后蛋清溶菌酶对供试菌的抑菌直径，生长曲线测定法测定改造后蛋清溶菌酶的最小抑菌浓度，Western blot检测4种供试菌菌液与菌体中溶菌酶含量变化。透射电镜结果显示，改造后蛋清溶菌酶为短杆状纤维结构；ANS和圆二色谱法结果显示，改造后蛋清溶菌酶疏水性增强，β折叠含量提高31.7%；牛津杯法显示，改造后蛋清溶菌酶对试验菌的抑菌强弱为鳗弧菌>枯草芽胞杆菌>金黄色葡萄球菌>大肠杆菌；生长曲线测定结果发现，鳗弧菌最小抑菌浓度为8 μmol·L^-1，大肠杆菌、金黄色葡萄球菌和枯草芽胞杆菌的最小抑菌浓度为6 μmol·L^-1；Western blot发现菌液中改造蛋清溶菌酶分子质量未发生改变，而菌体中溶菌酶含量和分子质量发生改变，革兰阳性菌和阴性菌均在10 ku处出现条带，且革兰阳性菌在22 ku处溶菌酶含量增加，但菌液上清均仅在14.3 ku处有条带。结果提示，改造蛋清溶菌酶对革兰阳性菌和阴性菌均具有较强的抑菌效果，为改造蛋清溶菌酶在畜牧业中的应用提供了基础数据。     

Considerations for gastrointestinal cannulation (rumen,duodenum and ileum) in sheep with a ruminal,a simple t-type and a modified t-type cannula

The aim of this study was to investigate the feasibility of simultaneous application of three cannulations and to test the effectiveness of a modified T-type cannula compared to simple T-type cannula. A ruminal, a simple T-type and a modified T-type duodenal and an ilial cannula were used in sheep. No complication was encountered in ruminal cannulation. Although no grafts were used, leakage of digesta was not seen for at least five months in T-type cannula and seven months in modified T-type cannula after surgery. Fibrous tissue grew between the serosa of the intestine and the peritoneum. No erosion of the tissue between intestine and body wall was observed after slaughter. Especially ilial digesta was easily obtained from modified T-type cannula.     

Comparison of four direct algorithms for computing inbreeding coefficients

One widely used measure in genetic analyses of livestock species is the inbreeding coefficient. Computation costs of inbreeding coefficients are of importance for large populations. Very recently, a ‘direct’ method for computing inbreeding coefficients was modified using a relatively efficient method to construct lists of ancestors in which the integrity of chronological order within each ancestral path is kept. Using simulated data, the computational efficiency of the recently modified algorithm was investigated by comparing it with three other algorithms – the original direct algorithm, its previously modified algorithm and another direct algorithm. The recently modified algorithm became considerably faster than the original algorithm and its previous modification when the number of generations increased, and it was fast relative to the other direct algorithm when the average number of generations and family size were not large. When only animals born in the most recent year were evaluated with the knowledge of inbreeding coefficients for their ancestors, the recently modified algorithm outperformed the other algorithms, indicating its possible advantage in updating situations.