3种红枣消解方法的对比研究

[目的]推荐实用、准确、高效、方便、快捷的消解预处理方法。[方法]采用3种消化方法处理同一红枣样品,利用火焰原子吸收法测定样品中Fe、Zn、Ca的含量。[结果]3种消化方法对测定结果的影响不大。[结论]非完全消化法是值得推广的样品消解方法。     

不同能量水平日粮对中卫山羊泌乳母羊消化率的影响

选择10只胎次相近,出生时间相近,健康母羊和羔羊的平均体重差异不显著(P>0.05),随机分为二组,每组5只。分为泌乳前后两个时期以不同能量水平日粮饲喂各组母羊,结果表明:第一组试验羊的能量和后期蛋白质消化率稍高于第二组试验羊,第一组试验羊前期的蛋白质消化率稍低于第二组。     

土壤消解方法研究及对上海浦东环境汞背景值初步调查

利用欧洲标准样作控制,对比研究了土壤总Hg测定的3种消解方法,并对浦东垃圾焚烧发电厂周围土壤总Hg的背景值进行了初步研究,结果发现浦东土壤Hg背景值达到192.68 ng/g,明显高于其它城市,这与上海的工业历史、农业施肥习惯有关,值得注意的是浦东地区土壤中的气态Hg(一个样品除外)含量都很高。     

青海农区冷季肉牛的饲草饲料管理技术研究

冷季饲草料中粗蛋白和干物质含量是肉牛生产性能提高的重要因素,而且饲草料资源的不同组合对肉牛生产性能的影响也有很大差异,通过对青海省冷季饲草料的干物质和粗蛋白的分析,并对三组试验动物喂食三种不同日粮后,对消化率、增重、料肉比的统计数据进行方差分析后,发现日粮的组分的选择、配比与肉牛的增重、料肉比的关系,并讨论了青海省农区冷季饲草料的资源状况,在饲草料的组分、配比方面给出了科学的建议。     

Inhibitory activity of proteinaceous α-amylase inhibitors from Triticale seeds against Eurygaster integriceps salivary α-amylases: Interaction of the inhibitors and the insect digestive enzymes

In many countries, the Sunn pest, Eurygaster integriceps Puton (Hemiptera: Scutelleridae) is one of the most important insect pests of wheat. Chemical control of E. integriceps is not efficient making it essential to find other control methods. Plant α-amylase inhibitors expressed as transgenes have emerged as a promising way of controlling insect pests and several crop species expressing transgenic amylase inhibitors have been shown to be resistant to certain insect pest. Here we report inhibition of salivary α-amylases of E. integriceps by semi-purified proteinaceous α-amylase inhibitors from Triticale (TAI). A dose dependent trend of inhibition of the enzyme was observed using TAI with an I₅₀ value of 0.79 μg of TAI. At the highest concentration of the inhibitor used here, we found 87% inhibition of amylase activity. The inhibitory activity was maximal at pH at 5.0, which is in accordance with the pH optimum of the salivary gland enzymes. Kinetic studies of enzyme-inhibitor interaction revealed a kind of partial mixed inhibition with an apparent inhibitory constant value (K_i[app]) of 1.1 μg of TAI against salivary α-amylase in the assay medium. In gel inhibition assays showed that all isoforms of salivary glands α-amylase were sensitive to the TAI, although to different degrees. Moreover, the effectiveness of TAI was retained in different stages of pre-oral and oral digestion of E. integriceps, although some inhibitory activity was lost, possibly by the action of the insect proteases. These findings indicate that TAI shows promise for use in the management of this pest. To the best of our knowledge, this is the first study of inhibitor-insect digestive enzymes interaction, based on the insect feeding strategy and digestion process.     

A step-wise in vitro method to estimate kinetics of hydrolysis of feeds

Nutritional feed values are currently based on aggregate criteria such as the ileal or faecal digestibility. Digestibility is the result of two competing processes: digestion and passage. In order to develop mechanistic models of digestion to be used for feed evaluation, both processes have to be quantified. The aim of this study was to determine the hydrolysis kinetics of main constituents (organic matter, N and starch) in wheat, barley, wheat bran and soybean meal, using a three-step, enzymatic in vitro method mimicking digestion in the stomach, small and large intestine of pigs. Kinetics of hydrolysis (i.e. solubilisation of feed constituents) was modelled using an exponential segmented model estimating the extent and rate of digestion in each digestive segment. Digestion of organic matter of soybean meal occurred mainly in the stomach (67% vs. < 30% for other feeds) resulting from an efficient protein hydrolysis at this site. Organic matter of cereals was mainly digested in the small intestine (55%), as a result of starch digestion. Fractional digestion rates of organic matter were higher in the stomach than in the small intestine (20–35 vs. 2–15%/min). The potential digestibility of organic matter was nearly 87% for wheat and soybean meal, 78% for barley and 61% for wheat bran, which correspond to typical in vivo digestibility values. The results of the present study allow characterising different feeds with the objective to model the digestion process in pigs.     

多枝赖草基因组Mb级DNA制备和酶切方法的优化

Mb级DNA的制备和酶切是构建YAC,PAC,BAC,BIBAC和TAC文库与大尺度物理图谱的基础。以浓度0.4%(m/m)NaCl人工模拟盐池中生长的多枝赖草再生叶为材料提取细胞核,经钢丝细胞筛过滤,多次回收滤渣和离心上清中的细胞核,相差显微镜调浓度达108个/mL后,经LMP包埋,蛋白酶K降解核蛋白,脉冲电泳纯化回收后,在LMP胶块中2 Mb以上DNA的浓度约为250 ng/μL。在胶中经Hind III部分酶切再用脉冲电泳回收不同大小范围的DNA,电洗脱浓缩除盐后浓度约为25 ng/μL。用此方法得到的核DNA不但无细胞器DNA等的污染,而且浓度高,可直接用于各种人工染色体文库的构建。     

微量元素铜在反刍动物营养中研究进展

铜是反刍动物必需微量元素之一,铜在反刍动物机体内具有很广泛的分布及多种生物学功能,而反刍动物对铜元素的利用率很低。文中论述了铜在反刍动物体内的分布及消化代谢特点、作用机制、影响铜利用的因素和铜对反刍动物所产生的生物学效应以及今后铜制剂的研制方向。     

大麦糠麸饲粮中添加复合酶制剂对畜禽消化性能的影响

研究了猪鸡不同类型饲粮中添加复合酶制剂对其消化性能的影响。结果表明 ,加酶后使畜禽肠道食糜粘度、粪中大肠杆菌数和腹泻频率都显著下降 ,复合酶制剂还提高了猪空肠粘膜绒毛高度和肉鸡十二指肠粘膜绒毛宽度 ,猪鸡饲粮养分的表观消化率也得到显著改善