体外法研究不同剂量延胡索酸二钠对绵羊瘤胃发酵的影响

利用体外产气法研究添加不同剂量延胡索酸二钠对绵羊瘤胃发酵的影响。采用单因素完全随机设计,发酵底物以可溶性淀粉和纤维素为碳源,以胰蛋白胨为氮源,对照组不添加延胡索酸二钠,试验1、2、3组分别添加占发酵底物干物质1.0%、2.0%和3.0%的延胡索酸二钠。结果显示,与对照组相比,添加1%的延胡索酸二钠（试验1组）可显著（P<0.05）提高瘤胃的总挥发性脂肪酸、乙酸、丙酸、丁酸产量以及体外产气量和干物质降解率;添加2%的延胡索酸二钠（试验2组）可显著（P<0.05）提高瘤胃的总挥发性脂肪酸、乙酸、丙酸、丁酸产量和干物质降解率;添加3%的延胡索酸二钠组（试验3组）的瘤胃氨氮浓度、总挥发性脂肪酸和乙酸产量、产气量、干物质降解率与对照组差异不显著（P>0.05）,但丙酸产量显著增加（P<0.05）。综上表明,添加1%和2%的延胡索酸二钠会显著提高绵羊瘤胃发酵性能,但添加3%的延胡索酸二钠,瘤胃发酵能力有所降低。     

延胡索酸二钠对早期断奶羔羊生长性能、瘤胃发酵功能及胃肠道发育的影响

本研究旨在探讨饲粮中添加延胡索酸二钠对早期断奶羔羊生长性能、瘤胃发酵功能及胃肠道发育的影响。试验选用30只(50±5)日龄、体重为(25±2)kg的公羔,随机分为3组,每组10只。对照组饲喂基础饲粮,试验组在对照组的基础上添加0.5%和1.0%的延胡索酸二钠。试验期70 d。结果显示:1)饲粮添加延胡索酸二钠提高了平均日增重,其中1.0%组显著高于对照组(P0.05)。2)延胡索酸二钠未显著影响瘤胃液p H(P0.05),而显著降低了氨态氮浓度(P0.05);延胡索酸二钠极显著降低了瘤胃液乳酸浓度(P0.01);1.0%组瘤胃液总挥发性脂肪酸、乙酸和丙酸浓度显著高于对照组(P0.05)。3)试验组小肠绒毛高度均高于对照组,其中0.5%组羔羊的十二指肠、空肠、回肠的肠绒毛高度分别显著增加了30.3%、30.6%、46.1%(P0.05);试验组的十二指肠绒毛高度/隐窝深度显著大于对照组(P0.05),其中0.5%组的绒毛高度/隐窝深度较对照组增加了58.6%;0.5%和1.0%组羔羊的瘤胃壁乳头高度分别比对照组提高139.84和156.74μm(P0.05);试验组瘤胃壁乳头密度与对照组比较无显著差异(P0.05)。结果表明,添加延胡索酸二钠显著提高了羔羊的生长性能,促进了早期断奶羔羊瘤胃及肠道的发育。     

Fraction Distributions of Lead,Cadmium, Copper,and Zinc in Metal‐Contaminated Soil before and after Extraction with Disodium Ethylenediaminetetraacetic Acid

Abstract: The fraction distributions of heavy metals have attracted more attention because of the relationship between the toxicity and their speciation. Heavy‐metal fraction distributions in soil contaminated with mine tailings (soil A) and in soil irrigated with mine wastewater (soil B), before and after treatment with disodium ethylenediaminetetraacetic acid (EDTA), were analyzed with Tessier's sequential extraction procedures. The total contents of lead (Pb), cadmium (Cd), copper (Cu), and zinc (Zn) exceeded the maximum permissible levels by 5.1, 33.3, 3.1, and 8.0 times in soil A and by 2.6, 12.0, 0.2, and 1.9 times in soil B, respectively. The results showed that both soils had high levels of heavy‐metal pollution. Although the fractions were found in different distribution before extraction, the residual fraction was found to be the predominant fraction of the four heavy metals. There was a small amount of exchangeable fraction of heavy metals in both contaminated soils. Furthermore, in this study, the extraction efficiencies of Pb, Cd, and Cu were higher than those of Zn. After extraction, the concentrations of exchangeable Pb, Cd, Cu, and Zn increased 84.7 mg·kg^?1, 0.3 mg·kg^?1, 4.1 mg·kg^?1, and 39.9 mg·kg^?1 in soil A and 48.7 mg·kg^?1, 0.6 mg·kg^?1, 2.7 mg·kg^?1, and 44.1 mg·kg^?1 in soil B, respectively. The concentrations of carbonate, iron and manganese oxides, organic matter, and residue of heavy metals decreased. This implies that EDTA increased metal mobility and bioavailability and may lead to groundwater contamination.     

Chemical form of dietary l‐Carnitine affects plasma but not tissue Carnitine concentrations in male Sprague–Dawley rats

In Experiment 1, rats (n = 54) were randomly assigned to control or one of the four sources of l ‐Carnitine supplemented at either 100 or 200 μmol/kg/day and were allowed to acclimate for 14 days. Following a 12‐h fast, plasma samples were obtained at 0, 5, 10, 15, 30, 60, 120, 240, 480 and 720 min after l ‐Carnitine feeding and assayed for free l ‐Carnitine concentration. Plasma‐free l ‐Carnitine levels were affected by time after treatment intake (p < 0.0001) and l ‐Carnitine source (p < 0.0001). The time × source interaction was not statistically significant (p = 0.99). In Experiment 2, rats (n = 54) were randomly assigned to control or one of the four sources of l ‐Carnitine at either 100 or 200 μmol/kg/day and were acclimated as in experiment 1. Rats were sacrificed 120 min after feeding. Samples of liver and skeletal muscle were obtained and assayed for free l ‐Carnitine concentration. Neither skeletal muscle (p = 0.44) or liver (p = 0.59) tissue concentrations of l ‐Carnitine were affected by any l ‐Carnitine source as compared with the control. We conclude that some differences exist in plasma concentrations of free l ‐Carnitine following ingestion of different chemical forms of l ‐Carnitine. It is unclear if these differences in the circulating concentration of free l ‐Carnitine translate into any physiological differences for the animal. In this study, chemical form of l ‐Carnitine had no effect on skeletal muscle or liver tissue concentrations of l ‐Carnitine in young male Wistar rats.     

饲料添加剂富马酸锌制备新工艺的研究

实验以次氧化锌为原料,经铵浸、除铁、深度除杂、结晶、合成等工序制备饲料添加剂富马酸锌(ZnC4H2O4)。研究结果表明最佳浸出条件为:NH4Cl浓度为4 mol/l,NH4Cl与Zn的物质的量比为4:1,浸出温度为70℃,浸出时间为60 min时,Zn的浸出率高达99%以上;采用双氧水氧化除铁和锌粉置换可基本去除其它杂质元素,同时对所得产品进行了化学成分、XRD、TG-DSC分析验证,结果证明该工艺可制备出纯度较高的富马酸锌。     

超高效液相色谱-串联质谱法测定糕点中富马酸二甲酯

[目的]简便快捷地测定糕点中的防腐剂富马酸二甲酯。[方法]建立了一种使用岛津超高效液相色谱仪LC-30A和三重四级杆质谱仪API 4000联用测定食品中富马酸二甲酯含量的分析方法。[结果]试验表明,富马酸二甲酯标液的线性关系为y=0.972 7x+0.001 2,线性相关系数为0.999 4。采取加标的方式进行方法验证,对同一富马酸二甲酯浓度的加标样品进行6次精密度试验,富马酸二甲酯的回收率范围为98.4%～101.5%,相对标准偏差RSD为1.2%,方法检出限为0.01 mg/L。[结论]该方法准确、快速、操作简便,可用于糕点中富马酸二甲酯的定量分析。     

毛细管气相色谱法测定防霉防蛀片剂中的有效成分

本文采用毛细管柱和FID检测器测定了防霉防蛀片剂中的3个有效成分。本方法的回收率和变异系数分别为富马酸二甲酯102．6％和0．045％， 樟脑100．7％和0．0088％，异龙脑97．6％和0．0065％。     

延胡索酸泰妙菌素中乙酸乙酯残留量的测定

建立了延胡索酸泰妙菌素中乙酸乙酯残留量的测定方法。采用顶空进样毛细管气相色谱法，ZB—WAX毛细管柱，载气为氮气，氢焰离子化检测器，水为溶解介质，检测了延胡索酸泰妙菌素原料药中乙酸乙酯的残留量。结果表明，在所考察的浓度范围内具有良好的线性（r=0．9995），平均回收率为99．62％，RSD为1．2％，检测限为0．18μg。     

延胡索酸二钠对瘤胃微生物体外发酵不同饲料成分的影响

以黑麦草、高羊茅、稻草、花生壳等粗料成分以及玉米、小麦、可溶性淀粉等精料成分为发酵底物研究了延胡索酸二钠对瘤胃微生物体外发酵的影响。结果表明,延胡索酸二钠显著提高了各种底物的发酵产气量(P<0.01),黑麦草粉、高羊茅草粉、稻草粉和花生壳粉的底物消失率分别比对照组提高了26.22%(P<0.05),14.16%(P<0.05),28.54%(P<0.01)和45.09%(P<0.05);延胡索酸二钠显著提高了小麦、玉米和可溶性淀粉的pH值(P<0.05),但对粗料无明显影响(P>0.05);小麦、玉米和可溶性淀粉处理组的乳酸浓度均低于对照组;各种底物的处理组的NH3-N浓度与对照组无明显差异(P>0.05);各种底物中,小麦的总挥发性脂肪酸(total volatile fatty acid)浓度最高,小麦处理组的乙酸浓度、丙酸浓度、丙酸比例均高于对照组(P<0.05);而乙酸丙酸比降低了0.18(P<0.01),延胡索酸二钠提高了所有底物的丙酸浓度及其比例。综合各指标的发酵情况,延胡索酸二钠对各种底物均有一定的效果,是一种潜在的反刍动物饲料添加剂。     

延胡索酸泰妙菌素合成工艺改进

使用乙酸酐对截短侧耳素11'-羟基进行保护,水解掉2-羟基乙酸,与2-巯基乙酸酯化,再与2-二乙氨基乙醇氨化,得到泰妙菌素。工艺中以2-二乙氨基乙醇代替2-二乙胺基乙硫醇作为侧链底物合成延胡索酸泰妙菌素,降低了有毒有害反应物对工业合成路线带来的额外成本。最终质量分数可达到920~960 mg/g。