饲用木聚糖酶活力的综合评价

试验采用综合分析方法评价了1种饲用木聚糖酶的活力。评价内容包括耐酸性试验、耐胃液试验、热稳定性试验和实际底物降解试验。在pH5.4～6.8条件下,该酶活力较稳定,保持在5000U/g以上,但随着pH的降低,活力迅速下降;在胃液中作用一段时间后该酶的活力损失很快,1.5h后其活力就下降到原有的37.4%;热稳定性试验中,该酶在90℃的环境中作用5min后,酶活损失不超过5%;实际底物降解试验中,反应4h后,无淀粉麦麸的降解率可以达到5%以上。试验结果表明,以上几个指标能够较为充分、准确的评价该木聚糖酶的可应用性,从而为饲料酶活性的系统评价提供了参考,为饲料加工和动物生产提供了更为可靠的数据。

Overall Evaluation of Xylanase as Feed Additives

Activity of a kind of xylanase was assessed in this study by four respective experiments to evaluate whether it was acid-resistant or heat-resistant,whether the activity of xylanase can keep down after passing through the stomach which was with low pH and contains activated pepsin and whether it was also effective to raw materials such as wheat bran.As a result,the activity of this xylanase kept above 5 000 U/g when pH value of buffer varied between 5.4 and 6.8,while drops down fast when pH was below 5.4.The activity decreased fast when the xylanase was in gastric juice of finishing pigs,dropping down to 37.4% of the initial after 1.5 hours’ reaction.In heat-resistant experiment,it was observed that the activity of the xylanase loses no more than 5% of the initial when left in a 90℃ oven for 5 minutes.Further more,this xylanase could break down starch-free wheat bran by 5% after 4 hours’ reaction.These indexes could give a comparatively accurate evaluation on xylanases and therefore provide more reliable date to feed producers and farmers.