EDTA法测定饲料中钙的过程中指示剂的僵化封闭现象及其消除

ＥＤＴＡ法测定饲料中钙的过程中指示剂的僵化封闭现象及其消除王新平（广东佛山农牧高等专科学校基础部５２８２３１）前言在应用ＧＢ６４３６－８６附录Ｂ“乙二胺四乙酸二钠络合滴定快速测钙”法（补充件）测定饲料中钙含量过程中，常常出现钙红指示剂在等量点附近无敏...     

EDTA络合滴定饲料钙过程中指示剂的封闭现象及其消除

<正> 在应用GB6436—86附录B“乙二胺四乙酸二钠络合滴定快速测钙”法(补充件)测定饲料中钙含量过程中,常常出现钙红指示剂在等当点附近无敏锐的颜色变化甚至无颜色变化的情况,尤其在测定添加了预混料的配合饲料及浓缩饲料时这种情况更为突出。对此,检测人员往往困感不解,从而影响了这种快速、灵敏度高的测钙方法的应用。本文就此试作如下讨论。本文开头所提情况的发生,说明钙红指     

基于钙黄绿素显色的可视化LAMP检测猪流行性腹泻病毒的研究

针对猪流行性腹泻病毒(PEDV)的NP基因设计1套环介导等温扩增(LAMP)引物,在反应体系中添加钙黄绿素/氯化锰指示剂代替传统的反应后添加SYBR Green Ⅰ染料,建立了基于钙黄绿素的可视化LAMP检测PEDV的方法。该方法能在65 ℃ 1 h内特异性扩增PEDV,与猪瘟病毒(CSFV)、猪传染性胃肠炎病毒(TGEV)、猪轮状病毒(PoRV)及大肠杆菌等均无交叉反应,检测下限为3.73 pg/μL,其结果可用肉眼判断,快捷方便。用该方法对龙岩学院动物医学研究所接诊的93份腹泻病例进行检测,结果表明,LAMP方法检测PEDV的阳性率为43.01%(40/93),高于普通PCR的检出率(38.7%,36/93)。本试验建立的可视化LAMP检测方法能用于PED诊断。     

羟基蛋氨酸钙含量测定方法比较研究

本文对测定饲料添加剂羟基蛋氨酸钙含量的3种方法:专属指示剂法、自身指示剂法和电位滴定法进行了比较研究。结果表明,专属指示剂法和电位滴定法重现性比较好,测定结果分别略高于标准值0.08%～0.27%和0.11%～0.30%,而自身指示剂法的重复测定间变异比较大,测定结果比标准值低0.25%～0.45%。     

环介导等温扩增技术快速检测猪细小病毒的试验

利用环介导等温核酸扩增技术(LAMP),建立了一种灵敏、特异、快速的猪细小病毒(PPV)检测方法.该方法针对猪细小病毒非结构蛋白(NS-1)基因保守区域设计6条特异引物,在63℃的等温条件下45 min即可完成反应.最低检测限量为10拷贝的PPV目的基因,比常规聚合酶链式反应(PCR)方法敏感100倍,并具有良好的特异性.以钙黄绿素和Mn2+作为荧光指示剂,可快速、直观判定反应结果.通过对149份临床样品进行检测比较,LAMP与PCR检出阳性样本数分别为33份和27份,表明LAMP方法阳性检出率高于PCR.     

复方穿琥宁注射液对仔猪黄白痢的临床疗郊试验

一、材料 培养基 麦康凯培养基、三糖铁培养基、伊红美兰琼脂培养基。 指示剂 甲基红指示剂、甲萘酚指示剂。     

溶液型微量元素预混合饲料中钙、镁元素的测定探讨

本文就溶液型微量元素预混合饲料中钙、镁元素的测定作一探讨,利用EDTA-2Na与金属离子形成络合物的络合滴定法,在pH=10的条件下,用铬黑T为指示剂测出钙镁总量;在pH=12的条件下,用紫脲酸铵为指示剂测出钙含量;以总量减分量法计算出镁含量。     

消除钙红指示剂僵化、封闭现象的方法

在应用GB6436—86附录B“乙二胺四乙酸二钠络合滴定快速测钙”法（补充件）测定饲料中钙含量过程中，常常出现钙红指示剂在等量点附近无敏锐颜色变化，甚至无颜色变化的现象。这是由于饲料中特别是在添加了预混料的配合饲料中，以及磷酸氢钙、骨粉等饲料添加剂中，常含有Fe~(3 )、AI~(3 )、Co~(2 )、Ni~(2 )、Cu~(2 )、Hg~(2 )等离子，这些离子能与钙红指示剂形成十分稳定的红色配合物，不能被EDTA破坏或被破坏的速度很慢，因而产生了指示剂的僵化、封闭现象，影响了该法测定钙的准确度和精密度。经我们试验研究，可在测定过程中加入…     

国标钙测定方法的改进

钙是饲料常规营养分析必需检测的项目 ,目前钙的测定方法很多 ,如原子吸收法和分光光度法等 ,国家标准 (ＧＢ/Ｔ6 4 3 6 - 92 )采用的是容量分析法。笔者对国标附录Ｂ :乙二胺四乙酸二钠络合滴定快速测定钙 (补充件 )中的检测方法做了一些改进 ,现介绍如下。1　方法原理将试样中的有机物破坏 ,使钙溶解制备成溶液 ,用乙二胺、三乙醇胺、盐酸羟胺和淀粉溶液消除干扰离子的影响 ,在碱性溶液中以钙黄绿素为指示剂 ,用乙二胺四乙酸二钠 (ＥＤＴＡ)标准溶液络合滴定钙。2　方法改进把ＧＢ/Ｔ6 4 3 6 - 92附录Ｂ中 3 2项“盐酸 1 3(Ｖ1 Ｖ2 )”…     

鱼饲料表观消化率测定方法的综述

消化率是评价饲料营养价值的重要指标,也是确定日粮配方的依据。由于鱼所生长环境的特殊性,使得测定鱼的消化率比较困难。体外测定法主要采用酶解法,而体内测定法主要采用间接指示剂的方法进行测定,以酸不溶灰分(AIA)、Cr2O3、Y2O3、La2O3、Yb2O3为指示剂测定表观消化率,不同的指示剂在不同的鱼、不同的饲料中其测定值的精确性有较大的差异。文中简要的介绍了3种体外测定方法并重点叙述了指示剂的使用,为鱼消化率测定方法提供参考。     

商会自治的基石——商会自治规范研究

在现代法律秩序中,商会自治规范是制定法的基础和必要的补充,甚至在某些方面替代了制定法;商会自治规范主要包括商会组织规范、行为规范、惩罚规范以及争端解决规范等;其效力仅及于其内部成员;商会自治规范和制定法之间存在冲突,但也存在整合的基础。     

癸氧喹酯干混悬剂含量测定的改进

采用高效液相色谱法测定癸氧喹酯干混悬剂的含量,在2-250μg/mL范围内,峰面积的常用对数与进样量浓度的常用对数呈良好的线性关系,R^2=1(n=5),平均回收率为99.24%~99.51%,RSD在0.05%~0.28%。此方法分析时间短,样品前处理简便、定量结果准确,重现性好,结果满意,为其质量控制提供了依据。     

猪毛色遗传的研究进展

本文概述了猪的毛色类型、猪的毛色遗传模式,着重综述了猪毛色基因分子基础的研究进展,指出存在问题并就未来发展方向做了思考。     

Comparison of 2 methods of centesis of the bursa of the biceps brachii tendon of horses

REASONS FOR PERFORMING STUDY: Centesis of the bicipital bursa using an 8.9 cm long spinal needle has been reported but the alternative of employing a 3.8 cm long hypodermic needle requires validation. OBJECTIVE: To compare the efficacy of 2 different methods of centesis of the bicipital bursa and to evaluate the usefulness of ultrasonographic imaging to determine the location of solution administered when centesis of the bursa is attempted. METHODS: For Trial 1, 6 clinicians, who had no previous experience of centesis of the bicipital bursa, attempted to inject a solution composed of an aqueous radiopaque contrast medium and physiological saline solution (PSS) into the bicipital bursae of 2/12 horses using the previously described distal approach to inject one bursa and a proximal approach to inject the contralateral bursa. The bicipital tendon and bursa were examined ultrasonographically before and after injection; and both shoulders were examined radiographically to identify the location of the medium. In Trial 2, another 6 clinicians, also with no previous experience of centesis, repeated Trial 1, using 6 horses, but the radiopaque contrast medium was mixed with air instead of PSS. RESULTS: Accuracy of centesis using the proximal approach was 39% and that of the distal approach 28%. Ultrasonographic examination of the shoulder allowed the location of solution and air to be accurately predicted in all 12 shoulders examined. CONCLUSIONS: Clinicians who have had no previous experience performing centesis of the bicipital bursa are unlikely to be successful in centesis using either approach. Radiographic examination after injecting a radiopaque contrast medium may be necessary to assess the success of centesis especially if bursal fluid is not obtained during centesis. Injecting air along with the radiopaque contrast medium provides more accurate ultrasonographic confirmation of centesis and better radiographic definition than does injection without air.     

不同样本商品蜂蜜中硒含量的测定

用硝酸和高氯酸消化蜂蜜,使硒游离出来,在微酸性环境下,硒和2,3-二氨基萘(DAN)生成有较强荧光的物质,用环己烷萃取,在激发波长378nm,荧光波长518nm处测定其荧光强度。蜂蜜中硒含量范围:0.10～0.82μg/g。表明:蜂蜜应视为天然富硒营养品。     

乳酸杆菌益生作用机制的研究进展

乳酸杆菌作为益生菌广泛用于人和动物。本文综述了乳酸杆菌改善宿主健康的机制。乳酸杆菌可通过产生抗菌物质如乳酸、过氧化氢、细菌素,或者通过竞争营养或肠道黏附位点来抑制致病菌;通过诱导黏附素的分泌或阻止细胞凋亡而增强肠道的屏障功能,从而保护肠道。文章重点讨论了乳酸杆菌表面成分（表面蛋白、脂磷壁酸和肽聚糖）与肠道受体（Ｃ型凝集素受体、Ｔｏｌｌ样受体和 Ｎｏｄ样受体）,阐述了他们结合后启动免疫调节信号,调控肠道免疫功能以发挥改善健康作用的机制。     

Effects of size of ingestively masticated fragments of plant tissues on kinetics of digestion of NDF

Ingestively masticated fragments were collected and sized via sieving. Different sizes of esophageal masticate and ruminal digesta fragments, and ground fragments of larger masticated pieces were incubated in vitro, and undigested NDF remaining at intervals of up to 168 h of incubation was determined. The ruminal age-dependent time delay (tau) for onset of digestion of NDF was positively correlated (P < 0.004) with the mean sieve aperture estimated to retain 50% of the fragments between successive sieve apertures (MRA). Degradation rate of potentially degradable NDF (PDF) and level of indigestible NDF were not related (P > 0.10) to MRA of masticated and ground fragments. Estimates of tau were positively related to MRA, with slopes of bermudagrass < corn silage < ruminal fragments of corn silage. It was concluded that fragment size-, and consequently, ruminal age-dependent onset of PDF degradation of a mixture of different fragment sizes results in an age-dependent rate of degradation of the more rapidly degrading of two subentities of PDF. Models are proposed that assume a tau before onset of simultaneous degradation of PDF from two pools characterized as having gamma-modeled age-dependency and age-constant rates. The ruminal age-dependent pool seems to be associated with the faster-degrading pool, and its rate parameter increases with range in MRA in the population of fragments. Conceptually, the ruminal age-dependent rate parameter for PDF degradation seems to represent a composite of several effects: 1) effects of the size-dependent tau; 2) range in MRA of the population of ingestively masticated fragments; and 3) subentities of PDF that degrade via more rapid age-dependent rates compared with subentities of PDF that degrade via age-constant rates. The estimated fractional rates of ruminative comminution of ingestively masticated fragments (0.060 to 0.075/h) were of a magnitude similar to the mean fractional rates of PDF digestion (0.030 to 0.085/h), which implies that ruminative comminution may be first-limiting to fractional rate of PDF digestion. The in vivo roles of ingestive and ruminative mastication of fragments on PDF degradation must be considered in any kinetic system for estimating PDF digestion in the rumen. These results and others in the literature suggest that the rate of surface area exposure rather than intrinsic chemical attributes of PDF may be first-limiting to degradation rate of PDF in vivo.     

Mechanism of Action of Probiotic Function of Lactobacilli

乳酸杆菌作为益生菌广泛用于人和动物.本文综述了乳酸杆菌改善宿主健康的机制.乳酸杆菌可通过产生抗菌物质如乳酸、过氧化氢、细菌素,或者通过竞争营养或肠道黏附位点来抑制致病菌;通过诱导黏附素的分泌或阻止细胞凋亡而增强肠道的屏障功能,从而保护肠道.文章重点讨论了乳酸杆菌表面成分(表面蛋白、脂磷壁酸和肽聚糖)与肠道受体(C型凝集素受体、Toll样受体和Nod样受体),阐述了他们结合后启动免疫调节信号,调控肠道免疫功能以发挥改善健康作用的机制.     

Evaluation of serum concentrations of biomarkers of skeletal metabolism and results of radiography as indicators of severity of osteochondrosis in foals

OBJECTIVE: To determine whether serum concentrations of biomarkers of skeletal metabolism can, in conjunction with radiographic evaluation, indicate severity of osteochondrosis in developing horses. ANIMALS: 43 Dutch Warmblood foals with varying severity of osteochondrosis. PROCEDURE: 24 foals were monitored for 5 months and 19 foals were monitored for 11 months. Monthly radiographs of femoropatellar-femorotibial and tibio-tarsal joints were graded for osteochondral abnormalities. Serial blood samples were assayed for 8 cartilage and bone biomarkers. At the end of the monitoring period, foals were examined for macroscopic osteochondrosis lesions. RESULTS: Temporal relationships were evident between certain serum biomarkers and osteochondrosis severity in foals during their first year. Biomarkers of collagen degradation (collagenase-generated neoepitopes of type-II collagen fragments, type-I and -II collagen fragments [COL2-3/4C(short)], and cross-linked telopeptide fragments of type-I collagen) and bone mineralization (osteocalcin) were positive indicators of osteochondrosis severity at 5 months of age. In foals with lesions at 11 months of age, osteochondrosis severity correlated negatively with COL2-3/4C(short) and osteocalcin and positively with C-propeptide of type-II procollagen (CPII), a collagen synthesis marker. Radiographic grading of osteochondrosis lesions significantly correlated with macroscopic osteochondrosis severity score at both ages and was strongest when combined with osteocalcin at 5 months and CPII at 11 months. CONCLUSIONS AND CLINICAL RELEVANCE: The ability of serum biomarkers to indicate osteochondrosis severity appears to depend on stage of disease and is strengthened with radiography. In older foals with more permanent lesions, osteochondrosis severity is significantly related to biomarker concentrations of decreased bone formation and increased cartilage synthesis.