脂肪酸混合物可使仔猪的生长最佳化

在寻找安全、有效和经济的饲料级抗生素促生长剂(AGPs)替代品中,研究人员对猪的营养日益了解。现在普遍认为没有任何一种物质可简单地替代在法规控制下已成功和安全地使用于所有食品动物的药物类型抗菌剂混合物。就现代农场中的年幼猪来说,他们认为,达到类似于使用     

养猪提倡湿喂法

对当前农村养猪来说,出生14～60日龄的断乳仔猪,食物中干物质的比重都是由20%骤然增加到80%,且大部分是干物质形式,仔猪难以适应,拉稀的可能性大大增加。实际上,从乳汁到流食混合物到干食应是一个缓慢的适应过程,以便使仔猪有足够的时间完善胃肠道内各种酶系统和微生态的转化与     

大豆多肽的性质及其研究进展

大豆多肽(Soy peptide)是大豆蛋白质经酶解作用后的多肽分子混合物。与大豆蛋白相比,大豆肽具有更好的理化性质,含有多种生理活性物质,在机体内具有更多种生理功能,近年来引起人们的广泛关注。     

水环境中石油类物质测定方法的分析探讨

石油类物质是指原油和石油制品的总称，其品种繁复杂，是各种烃类的混合物。石油类物质可以溶解态、乳化态和分散态存在于各种水体中。由于工业废水、生活污水以及石油泄露等原因进入正常水体的石油类物质日益增加，导致水环境受到严重污染。     

美国学者成功研制出能够与除4C型单增李斯特菌外的血清型全部反应的混合单克隆抗体

美国SEOKAHEO等人用13种血清型单增李斯特全菌混合物免疫小鼠，制备出2株单克隆抗体。结果表明，这2株抗体对除4c、4e外的11种血清型单增李斯特活菌和热致死单增李斯特菌均有高亲和力，     

柴油机零部件的积炭及其清除方法

柴油机的气缸盖、缸套、活塞,活塞环、气门、喷油器等零件以及燃烧室,在使用一段时间后,表面会黏着一层积炭.积炭是由于柴油及渗入气缸中的机油燃烧不完全而形成的一种复杂的混合物,它具有密实、疏松、柔软等形态,颜色从黑至灰白,形成部位的温度约为200℃.由于积炭的导热性较差,零件表面大量积炭,将导致零件局部过热,使其刚度、强度下降,严重时还会造成喷油器偶件烧结、气门烧蚀、活塞环卡死和拉缸等严重事故.     

4LZ-0.8型水稻联合收割机清选装置气固两相分离作业机理

为解决小型水稻联合收割机脱净率和损失率问题,提高脱粒清选质量,利用两相流动力学理论,分析了4LZ-0.8型水稻联合收割机脱粒清选分流筒中气流和杂物颗粒两相流动的规律。建立了杂物颗粒流的运动微分方程,导出了分离筒中杂物漂浮速度计算的一种方法,通过比较不同粒径、密度的物料的悬浮速度,得到了杂物颗粒最高速度与气流速度之比随气流速度变化的关系曲线,气流和杂物在分流筒及吸风管中运动时的压力损失随气流速度变化呈现先降后升的规律,压力损失中以加速损失和摩擦损失为主,各约占30%和26%。压力损失曲线存在最小值,此时的气流速度定义为经济气流速度。在喂入量为0.8 kg/s,谷草比为3:1脱粒条件下的经济的清选气流速度9.2 m/s,压力损失为630 Pa。该研究为4LZ-0.8型水稻联合收割机脱粒清选部件的参数优化设计及风机的选择提供了理论依据。     

比久和多效唑混合物的高效液相色谱分析

在吸光度为210nm、流动相配比为甲醇：乙腈：水＝40：20：40的条件下，多效唑和比久均能得到很好的分离。比久的保留时间约为3．19min，多效唑的保留时间约为11．83min。加标回收率：比久为108．69％，多效唑为90．39％。     

The Study on the Effects of Chinese Herbal Mixtures on Growth, Activity of Post-Ruminal Digestive Enzymes and Serum Antioxidant Status of Beef Cattle

Sixteen Limousin×Luxi crossbred beef cattle [099.4±8.67) kg] were used to evaluate the effects of Chinese herbal mixtures (CHM) on growth, activities of post-ruminal digestive enzymes and serum antioxidant status of beef cattle. Treatments were control (no CHM supplementation) and three formulations of CHM (CHM-A, CHM-B and CHM-C) that were arranged as completely randomized design. The calves were fed in indoor individual feeding barn with total mixed ration for 90 d.The CHM-A, CHM-B, and CHM-C was incorporated into the diet at the level of 20 g kg-1 DM (dry matter) of concentrate.The cattle were weighted at the beginning, at the end and every 15 d between to determine growth rate. Blood sample was taken every 30 d to analyze activities of total superoxide dismutase (T-SOD) and glutathione peroxidase (GSH-PX) and concentration of malondialdehyde (MDA). The cattle were slaughtered at the end of experiment and chymus samples from various section of the post-ruminal digestive tract were collected to analyze enzymes activities. All cattle had similar average daily gain, but cattle supplemented with CHM-A tended faster growth (P=0.08) compared to the control and other CHM treatments. Supplementation of CHM did not affect Ph of chymus in any section of the post-ruminal digestive tract.Activities of pepsin, trypsin, chymotrypsin, and lipase in chymus samples were enhanced (P<0.05) to various extents by supplementation of CHM-A, CHM-B, and CHM-C depending on the enzymes and the site of the digestive tract. Amylase activity was increased only by CHM-A and CHM-C from chymus sample collected at the ileum. Supplementation of CHM-A and CHM-B reduced (P<0.05) concentration of MDA, but did not affect GSH-PX activity in the serum of cattle throughout the entire experimental period. Cattle supplemented with CHM-B also had higher (P<0.05) T-SOD activity in the serum at day 30 and 60 as compared with the control and the other two CHM treatments. Chinese herbal mixtures supplemented at the levels of 20 g kg-1 DM of concentrate increased post-ruminal digestive enzymes activity and enhanced serum antioxidant status. Inclusion of CHM-A and CHM-B in the diet may be favourable for ruminant production.