Chen Qinghua, Li Mengwei, Wang Xiong
College of Animal Science and Technology, Hunan Agricultural University, Changsha 410128, China.
Anim Nutr. 2016 Mar;2(1):18-23. doi: 10.1016/j.aninu.2016.02.003. Epub 2016 Mar 2.
The enzyme xylanase is more and more widely used in feed production, but different xylanase have different properties, mechanism and application effects. To provide a theoretical basis for choosing more suitable xylanase in feed production, we selected bacterial xylanase (BX), labeled enzyme A, and trichoderma xylanase (TX), labeled enzyme B, and studied the enzymology properties and application effects on growth performance and gut flora in weaned piglets. The results showed that the activity levels of both appear parabolic along with increasing pH or temperature, but the amplitude of enzyme activity changing curves and the pH/temperature of optimal activity level are different, where enzyme A has the optimal activity level at 50 °C with a pH value of 5.0. The optimal activity level of enzyme B was achieved at 70 °C with a pH around 6.0. Enzyme B suffered very little activity loss with moisture level at 16% and temperature from 80 °C to 90 °C. Enzyme A suffered a big drop in activity level when processed with high temperature from around 80 °C to 90 °C, and it was even completely inactivated at 90 °C. Enzyme A has very low activity level after being processed in acid environment, but enzyme B has minor changes in activity level with respect to changes in acid level, indicating significantly different enzymatic properties between the two different sources of xylanases. In feeding experiment, the control group, was fed the basal diet, and the BX group and TX group were fed basal diets supplemented with 0.01% bacterial and fungal xylanases, respectively. The results showed that ADG of the BX group and TX group increased by 3.25% ( > 0.05) and 8.22% ( < 0.05), respectively, and the feed conversion ratio decreased by 6.74% and 7.86% ( > 0.05), respectively compared with the control group; TX group had significantly higher ( < 0.05) ADG compared with BX group; BX group and TX group had significantly lower ileum level than the control group, which were reduced by up to 12.98% ( < 0.05) and 11.68% ( < 0.05), respectively, but the ileal lactic acid bacteria levels were significantly increased by 16.21% ( < 0.01) and 27.02% ( < 0.01), respectively. There were no significant differences ( > 0.05) between BX group and TX group in terms of lactic acid bacteria level. We concluded that fungal xylanase (enzyme B) has better performances in improving weaned piglet growth and in increasing ileal lactic acid bacteria level compared with bacterial xylanase (enzyme A).
木聚糖酶在饲料生产中的应用越来越广泛，但不同来源的木聚糖酶具有不同的性质、作用机制和应用效果。为了为饲料生产中选择更合适的木聚糖酶提供理论依据，我们选用了细菌木聚糖酶（BX，标记为酶A）和木霉木聚糖酶（TX，标记为酶B），研究了它们的酶学性质以及对断奶仔猪生长性能和肠道菌群的应用效果。结果表明，随着pH值或温度的升高，两种酶的活性水平均呈抛物线变化，但酶活性变化曲线的幅度以及最佳活性水平的pH/温度不同，其中酶A在50℃、pH值为5.0时具有最佳活性水平。酶B在70℃、pH值约为6.0时达到最佳活性水平。当水分含量为16%、温度在80℃至90℃时，酶B的活性损失很小。当在80℃至90℃左右进行高温处理时，酶A的活性水平大幅下降，在90℃时甚至完全失活。酶A在酸性环境中处理后活性水平很低，但酶B的活性水平随酸度变化变化较小，表明两种不同来源的木聚糖酶的酶学性质存在显著差异。在饲养实验中，对照组饲喂基础日粮，BX组和TX组分别饲喂添加0.01%细菌和真菌木聚糖酶的基础日粮。结果表明，与对照组相比，BX组和TX组的平均日增重分别提高了3.25%（P>0.05）和8.22%（P<0.05），饲料转化率分别降低了6.74%和7.86%（P>0.05）；TX组的平均日增重显著高于BX组（P<0.05）；BX组和TX组的回肠大肠杆菌水平均显著低于对照组，分别降低了12.98%（P<0.05）和11.68%（P<0.05），但回肠乳酸菌水平分别显著提高了16.21%（P<0.01）和27.02%（P<0.01）。BX组和TX组在乳酸菌水平方面无显著差异（P>0.05）。我们得出结论，与细菌木聚糖酶（酶A）相比，真菌木聚糖酶（酶B）在改善断奶仔猪生长和提高回肠乳酸菌水平方面具有更好表现。
