三种底物在检测植酸酶酶活中的对比研究

试验采用完全随机的2×3×6试验设计,考察在不同pH(5.0、5.5)条件下应用3种底物(SigmaP0109、P8810和P3168),检测不同酶活水平(1000、3000、5000、6000、7000U/g和10000U/g)的植酸酶时,其检测值之间的对比关系。结果表明:不同pH条件下,P0109与P3168的检测结果之间差异均不显著,P8810与P3168的检测结果之间差异均极显著;底物P0109可以完全替代P3168进行植酸酶酶活测定;P8810与P3168的检测结果之间存在线性关系,线性方程为:y(pH5.5,P3168)=0.7649x(pH5.5,P8810) 152.18(R2=0.9963)、y(pH5.0,P3168)=0.8767x(pH5.0,P8810) 34.818(R2=0.9979),T检验分析曲线换算值和验证值结果差异不显著,证明两个线性方程可以作为底物P8810替代P3168进行植酸酶酶活测定的换算公式。     

饲用植酸酶酶活测定过程中底物的影响研究

参照国标法测定饲用植酸酶活性,研究不同来源的底物植酸钠、底物浓度、底物pH对饲用植酸酶活性的影响。结果表明,以P8810为代表的植酸钠盐水合物作为底物,其测定出的植酸酶酶活显著高于使用以P3168为代表的植酸钠作为底物所测定的植酸酶酶活。以P8810作为底物时,其反应浓度在高于6.6 mmol/L时,会产生底物抑制效应。以P8810作为底物时,调节底物pH至国标中定义的5.5与未调节pH所测得的植酸酶酶活相比较,差异并不显著,且在低底物pH条件下,某些植酸酶同样能够释放出最大催化活性。因此现有的国标法测定饲用植酸酶活性已与实际应用有一定的差别,不能照搬国标方法测定现有饲用植酸酶产品。     

植酸酶的特性及稳定性效果的对比研究

试验就植酸酶的相关特性及其在此基础上的应用选择功效进行研究,并对市场上占有率较高的三个国产知名企业生产的植酸酶产品(P1、P2、P3)进行稳定性研究,比较这三种植酸酶产品在不同pH值、不同温度下(室温、80℃水浴、90℃常湿)和不同储存时间的酶活,为生产实践中合理选择使用植酸酶提供参考依据。结果表明,P2在酶活高峰pH值4.5～5.0表现出的酶活显著高于P1和P3(P0.05)。高温稳定性效果P3显著优于P1和P2(P0.05)。     

底物类型及含水量对瘤胃真菌固体发酵产酶活性的影响

试验采用二因素试验设计,研究不同底物类型及含水量对瘤胃真菌固态发酵产纤维素酶活的影响。发酵底物粗料类型分别为菌糠、花生蔓和玉米秸,含水量分别为30%、40%、50%和60%。试验进行10 d,每2 d取发酵样品测试,监测其中的羧甲基纤维素酶、微晶纤维素酶、β-葡萄糖苷酶和滤纸酶的酶活。试验结果表明:在菌糠、花生蔓及玉米秸3种粗料底物中,花生蔓效果最好,可显著提高羧甲基纤维素酶、微晶纤维素酶和β-葡萄糖苷酶酶活(P0.05)。含水量对纤维素酶活影响明显,含水量为40%时对羧甲基纤维素酶、微晶纤维素酶、β-葡萄糖苷酶和滤纸酶酶活均有显著影响(P0.05)。不同底物类型与含水量的互作对4种酶的酶活影响显著(P0.05)。滤纸酶发酵8 d达到峰值,羧甲基纤维素酶、微晶纤维素酶和β-葡萄糖苷酶均为发酵4~6 d时酶活最高。综合各试验因素,试验以花生蔓为底物粗料,含水量40%,培养发酵4~6 d,纤维素酶活最佳。     

精料类型及精粗比对瘤胃真菌固体发酵产纤维素酶的影响

试验采用二因素试验设计,研究固体发酵底物中精料类型及精粗比对瘤胃真菌产纤维素酶的影响。固体发酵底物精料类型为麦麸和玉米,精料与粗料花生蔓30∶70、40∶60、50∶50、60∶40和70∶30。试验进行10 d,每2 d采一次发酵样品,监测其中的微晶纤维素酶和β-葡萄糖苷酶、羧甲基纤维素酶和滤纸酶酶活。试验结果表明,麦麸作为精料底物可显著提高微晶纤维素酶、羧甲基纤维素酶和β-葡萄糖苷酶酶活(P0.05)。精粗比为70∶30的产β-葡萄糖苷酶和滤纸酶酶活显著高于其他各精粗比(P0.05)。试验条件下,麦麸为固体发酵底物精料,精粗比为70∶30,发酵时间为4~6 d获得较高的酶活。     

木聚糖酶酶活测定方法的研究

本试验研究了影响木聚糖酶测定的因素.结果表明不同底物、不同底物浓度、酶的稀释度和提取时间都会影响到酶活的测定结果,但蒸馏水及缓冲液作为提取液对酶活无显著影响.测定的吸光度在0.3左右(即0.25～0.5)时酶活的变异较小.     

白酒酒糟制备多酶益生菌饲料发酵工艺研究

选择产甘露聚糖酶枯草芽孢杆菌L-1、产植酸酶枯草芽孢杆菌L-2、产木聚糖酶YB-5、乳酸片球菌Rp作为制备多酶益生菌饲料的生产菌种。通过单因素和正交试验最终确定最佳底物干基组分为36%白酒酒糟、26%玉米粉、28%麸皮、8%豆粕,料水比10.8,装填量20 g/250 ml。结果表明:多酶益生菌饲料中益生菌活菌数为(1.97±0.09)×10~(11)cfu/g,甘露聚糖酶酶活(11.62±0.26)U/g、木聚糖酶酶活(15.30±0.36)U/g、植酸酶酶活(16.37±0.16)U/g、蛋白酶酶活(15.27±0.16)U/g以及淀粉酶酶活(19.37±0.33)U/g。     

植酸酶酶活的近红外光谱快速检测研究

为探讨应用近红外光谱法快速测定植酸酶酶活的可行性,实验选取134个喷雾干燥和66个吸附干燥植酸酶样品,应用偏最小二乘法建立酶活、水分含量校正模型.结果表明,所建立的校正模型有较高的决定系数(RSQ),较低的交互验证误差(SECV).并对预测值与化学分析值之间进行配对t检验,在置信度为99%下,近红外光谱法与标准参考方法测定酶活、水分的结果之间无显著差异.     

转植酸酶基因玉米植酸酶稳定性的研究

试验以转植酸酶基因玉米(PTC)为原料,通过烘箱高温处理,研究PTC的耐热性能;通过在不同挤压温度(60、80和100℃)和不同物料(750 U/kg PTC组和6 500 U/kg PTC组)组合下,研究PTC在制粒加工工艺中的稳定性。结果表明:PTC具有较好的耐热性能,120℃烘箱处理5 min,其植酸酶酶活损失率为13.38%;但在制粒温度上升时,植酸酶酶活损失率呈明显上升趋势,当制粒温度达到100℃时,PTC的植酸酶酶活损失率在90%以上。     

耐热植酸酶在低钙磷饲粮中添加对仔猪和生长猪的饲用效果研究

为确认经基因工程改造以酵母发酵生产的植酸酶的耐热性及其在肉猪饲粮中的应用效果,本试验结合颗粒饲料生产实际条件检测植酸酶样的耐热性,并以仔猪和生长猪为对象开展饲养试验.以玉米725.00 kg、豆粕203.24 kg、统糠11.26 kg、次粉15.00kg、大豆油15.00 kg和植酸酶30.50kg(5000 U/g)组成混合料,经调质温度为85℃和调质时间为30 s的生产线制粒,分别抽取调质前、调质后和制粒后等3个处理阶段各5个点样,测定各样的植酸酶活量,分别计算出植酸酶在调质前、调质后和制粒后的酶活回收率(%).饲养试验一:90头杜长大仔猪(9.86±0.09)kg随机分为3个处理,每个处理3个重复,每个重复10头;3组分别饲喂3种等蛋白质等能量等钙磷比的玉米-豆粕型试验饲粮(20.0%、13.39 MJ/kg和1.26),为期4周;正对照饲粮含钙0.82%和磷0.65%,负对照饲粮含钙0.62%和磷0.49%,植酸酶饲粮为在负对照饲粮基础上添加植酸酶的饲粮(500 U/kg).饲养试验二:60头杜长大生长猪(22.45±0.67)kg随机分为2个处理,每个处理3个重复,每个重复10头;2组分别饲喂2种等蛋白质等能量等钙磷比的生长猪试验饲粮(17.5%、13.00 MJ/kg和1.0),为期4周;对照饲粮含钙0.66%和磷0.67%,植酸酶饲粮含钙0.56%、磷0.56%和植酸酶(500 U/kg).试验结果表明:(1)调质前、调质后和颗粒产品样的酶活回收率分别为104.8%、73.2%和68.2%(P＜0.05);(2)饲养试验一中的植酸酶组仔猪生产性能与正对照组的差异不显著(P＞0.05),但负对照的增重和耗料增重比分别显著低和高于正对照的(P＜0.05);(3)饲养试验二中的植酸酶组生长猪的耗料量较对照组的降低了9%,耗料增重比降低了11%(P＜0.05).增重提高了2%.此酶样经颗粒料生产全程工序后仍具68.2%的存酶活,具较好的耐热性;在低磷饲粮中应用可提高饲料转化率,因而提高仔猪及生长猪的增重,并降低饲料成本.     

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.     

中华人民共和国农业部公告 第267号

为贯彻落实《兽药生产质量管理规范》(简称《兽药GMP》),进一步推动兽药GMP实施进程,我部制定了《兽药生产质量管理规范检查验收办法》,现予公告。本公告自2003年6月1日起施行。附件:兽药生产质量管理规范检查验收办法二○○三年四月十日第一章 总则 第一条 为推动《兽药生产质量管理规范》(以下简称兽药GMP)的实施,规范兽药GMP检查验收工作,制定本办法。 第二条 农业部负责全国兽药GMP管理和检查验收工作;负责制修订兽药GMP检查验收管理规定;负责兽药GMP检查员队伍建设和监督管理工作,负责国际兽药贸易中GMP互认工作。 …     

鸡败血支原体垂直传播模式及其阻断方法

以国际标准强毒Ｒ株人工感染非免疫产蛋鸡,定时扑杀,分别从鼻窦、眶下孔、气管、肺、气囊、卵巢和输卵管分离ＭＧ,并收集感染鸡所产蛋分离ＭＧ。结果表明,人工感染４８小时后上、下呼吸道及肺已被全面感染,９６小时气囊已被感染,１２０小时输卵管已能分离到ＭＧ,卵巢始终分离不到ＭＧ。人工感染鸡自１４４小时便能在其所产蛋中分离出ＭＧ。药物治疗能在７２小时内消除感染,油乳剂苗则需２４天后逐渐降低蛋内ＭＧ分离率,药物卵内注射、种蛋药浴、高温处理均能杀死卵内ＭＧ,但以研制的种蛋浸泡剂药浴效果为最好。