Walsh G, Murphy R A, Killeen G F, Power R F
Department of Chemical and Environmental Science, University of Limerick, Limerick, Ireland.
Appl Microbiol Biotechnol. 2005 Apr;67(1):70-4. doi: 10.1007/s00253-004-1826-9. Epub 2004 Dec 4.
Methods are described which facilitate quantification of supplemental cellulase, protease and alpha-amylase when added to animal feedingstuffs at normal industrial inclusion levels. The methods entail extraction of the enzymes from the feedingstuffs by agitation in buffer followed by quantification of extract activity using radial diffusion techniques. A linear relationship between the diameter of the zone of hydrolyzed substrate and the log of the enzyme activity applied is observed over a broad activity range. Assay of a feedingstuff supplemented with 1 kg t(-1) cellulase, protease and alpha-amylase yielded net supplemental activity recoveries of 104+/-11.7%, 91.3+/-6.74% and 126+/-29.5%, respectively. A similar assay method did not prove sufficiently sensitive to facilitate detection of xylanase at typical in-feed inclusion levels. The levels of endogenous cellulase, protease and alpha-amylase activity detected in the unsupplemented feedingstuffs were equivalent to 6.4+/-0.47%, 6.6+/-0.82% and 29.0+/-14.1%, respectively, of a 1 kg t(-1) supplement. The methods are technically straightforward and will facilitate determination of enzyme stabilities during processes such as high-temperature pelleting of feedingstuffs, as well as allowing more rigorous quality control related to enzyme-supplemented animal feedingstuffs.
本文描述了一些方法，这些方法有助于在按正常工业添加水平将补充性纤维素酶、蛋白酶和α-淀粉酶添加到动物饲料时进行定量。这些方法包括通过在缓冲液中搅拌从饲料中提取酶，然后使用径向扩散技术对提取物活性进行定量。在很宽的活性范围内，观察到水解底物区域的直径与所施加酶活性的对数之间存在线性关系。对添加了1 kg/t纤维素酶、蛋白酶和α-淀粉酶的饲料进行测定，其净补充活性回收率分别为104±11.7%、91.3±6.74%和126±29.5%。一种类似的测定方法被证明对在典型的饲料添加水平下检测木聚糖酶不够灵敏。在未添加酶的饲料中检测到的内源性纤维素酶、蛋白酶和α-淀粉酶活性水平分别相当于1 kg/t补充剂的6.4±0.47%、6.6±0.82%和29.0±14.1%。这些方法在技术上很简单，将有助于确定在饲料高温制粒等过程中酶的稳定性，也有助于对添加酶的动物饲料进行更严格的质量控制。
