The effect of different additives on the fermentation quality, aerobic stability and in vitro digestibility of pea/wheat bi-crop silages containing contrasting pea to wheat ratios

Studies were conducted to compare the effects of using two microbial inoculants, a sulphite salt‐based additive, formic acid and quebracho tannins, on the fermentation quality, nutritive value and aerobic stability of pea/wheat bi‐crop silages. Spring peas (Pisum sativum var. Magnus) and spring wheat (Triticum aestivum var. Axona) were drilled together at rates that gave high (HP/W; 3:1) or low (LP/W; 1:3) pea to wheat ratios. The peas and wheat were harvested at the yellow wrinkled pods and late milk/early dough maturity stage, respectively, and conserved in 1·5‐kg polyethylene bag, laboratory silos. The bi‐crops were conserved without treatment (control) or treated with either of two lactic acid bacteria‐based inoculants [Lactobacillus buchneri; applied at 10⁵ colony‐forming units (CFU) g^–1 fresh weight (FW) or Lactobacillus plantarum (applied at 10⁶ CFU g^–1 FW)], sulphite salts (applied at the rate of 1 ml sulphite solution kg^–1 FW), quebracho tannins (applied at 16 g kg^–1 FW) and formic acid (applied at 2·5 g kg^–1 FW). Six replicates were made for each treatment, and the silos were opened after 112 days of ensilage. The level of peas in the bi‐crop influenced the effectiveness of the additives. With the exception of sulphite salts, all the additives significantly reduced the soluble nitrogen (N) and ammonia‐N concentrations of all the silages. The ratio of lactic acid to acetic acid was generally lower in the LP/W silages than in the HP/W silages, and the additive treatments only increased the in vitro digestible organic matter in dry matter of the LP/W silages. Of all the additives evaluated, formic acid resulted in the least aerobic spoilage in HP/W bi‐crop silages. However, in the LP/W bi‐crops, additive treatment was not necessary for ensuring aerobic stability.     

栲胶生产流程计算机动态模拟教学系统的开发

为了解决栲胶生产流程教学中难教、难学的问题,探讨了利用FLA SH 2004 P rofessiona l制作栲胶生产流程动态模拟系统的设计思想和实现方法.设想通过模拟动态工艺流程的途径,采用FLA SH 2004 P rofessiona l制作栲胶生产流程动态模拟课件;在系统中,建立动态工艺流程、物料流程和重点设备仿真操作动画的人机交互界面,并通过一个集中场景界面连接,直观地显示各种复杂的工艺流程与操作.     

Extraction and analysis of nitrogen,phosphorus and carbon fractions in plant material

A method is described for the extraction and analysis of various nitrogen‐, phosphorus‐ and carbon‐containing fractions from plant material. Lipids were extracted with chloroform/methanol and chloroform/methanol/water. Soluble nitrogen (nitrate, ammonia, and amino acid), phosphorus (inorganic and sugar phosphate) and carbon (sugar and tannin) fractions were extracted with cold trichloracetic acid. Hot soluble nitrogen and phosphorus (nucleic acid) and carbon (starch and tannin) fractions were extracted with hot trichloracetic acid. Protein remained in the residue. A detailed automated scheme is described for the analysis of each of the above fractions. Also included are methods for analyzing triglyceride, hydrolyzable ester phosphate and phytic acid.     

蒙古栎橡子脱毒技术的研究

本文根据单宁的化学性质,选用多种脱毒试剂,在不同条件下进行一系列的脱毒试验,最终确定了石灰水浸泡脱毒方法。用石灰水脱毒,有操作简便,价格低廉,脱除率高等特点,可脱除９０．７％～９７．３％的单宁,本方法对橡子的营养成分无不良影响。     

Preliminary evaluation of potential fodder quality in a range of Leucaena species

Twenty-two taxa and five interspecific hybrids of Leucaena, grown together on a site in Houduras, were evaluated in terms of their potential value as tropical fodder crops. Content of crude protein, organic matter, acid detergent fibre, neutral detergent fibre, total tannin and condensed tannin (proanthocyanidin), as well as in vitro digestibility, were estimated in dried leaf samples, and the accessions ranked according to each of these criteria. The relative palatability of thirteen of the taxa and two of the hybrids was also assessed in a 'cafeteria' trial using fresh leaf material fed to sheep over an 18 day period. Protein, digestibility and palatability estimates, together with previously published yield data, were used to construct three indices of fodder potential, to allow direct comparisons between taxa. The most promising taxa according to these criteria included L. shannonii subsp. shannonii, L. collinsii subsp. zacapana and L. multicapitula, all of which achieved higher scores than the much better-known L. leucocephala subsp. glabrata in the index derived from crude protein and digestibility. When yield and palatability were included in the indices, the very high palatability of L. leucocephala gave it the highest score overall. The most unpromising taxa included L. pulverulenta, L. trichandra, L. esculenta (subsp. esculenta and subsp. matudae), and L. greggii. This revised version was published online in August 2006 with corrections to the Cover Date.     

动态光散射和电泳对工业栲胶溶液稳定性的研究

采用动态光散射(DLS),用现代测试仪器ZetasizerNanoZS系列,从胶体电化学性质的角度,考查了几种植鞣常用的工业亚硫酸化栲胶溶液体系的Zeta电位和粒径以及微粒的分散度指数(PDI)受时间、温度和pH值的影响。结果表明:陈放时间对栲胶溶液的微粒粒径影响不大。温度的变化对栲胶溶液有较大的影响,除厚皮香栲胶溶液以外,其他栲胶溶液的粒径都随温度升高而上升,而Zeta电位则随温度升高而降低。与其他所有的胶体体系一样,pH值对溶液稳定性的影响无疑是最大的,尤其是对溶液Zeta电位的影响,是稳定性的决定因素,其中尤以水解类橡椀栲胶对溶液pH值的变化最为敏感。     

杨梅栲胶磺甲基化制备水泥减水剂研究

栲胶是一种传统的生物质化学品,目前市场需求逐渐萎缩,有必要开辟新的用途,扩大需求。笔者研究了杨梅栲胶磺甲基化改性制备水泥减水剂的工艺及其产物的分敞性能。结果显示,栲胶磺甲基化改性的较佳工艺条件为:磺化剂与栲胶质量比约为0.63,甲醛与栲胶质量比约为0.30,反应温度为90℃左右,反应时间约为3.5h,反应终时溶液pH为6.0～8.0。当减水剂在水泥中掺量均为0.5%时,栲胶经过磺甲基化改性后其混凝土减水率从7.1%增加到13.1%,磺甲基化栲胶的初凝和终凝时间较栲胶分别缩短了95min和520min,栲胶经过磺甲基化改性后对水泥的分散能力大大增强,而缓凝能力有所减弱。     

松墨天牛为害对马尾松针叶化学成分的影响

通过对被松墨天牛为害的不同程度的马尾松针叶化学物质的测定,结果表明:受害的马尾松针叶的内次生物质黄酮和单宁含量随着幼虫钻蛀取食和成虫补充营养为害程度的加重而发生变化,先增加,后降低;受害马尾松针叶内营养物质总糖和可溶性糖含量先降低,后增加.说明了马尾松应激反应的过程是一种随着受害程度的不同,不断变化的动态过程.同时研究表明:马尾松对松墨天牛幼虫钻蛀取食和成虫补充营养的应激反应是不同的.对幼虫钻蛀取食的反应是不显著的;而对成虫补充营养的反应是显著的.说明了马尾松在与昆虫协同进化的过程中,对不同害虫及其不同的虫态产生了适应性.