小麦型饲粮中添加酸性木聚糖酶对肉鸡消化道食糜黏度的影响

Effects of Adding Acid Xylanase in Wheat-Type Diet on Viscosity of Digestive Tract Chyme of Broilers

本试验旨在对比研究酸性和中性木聚糖酶的酶学性质及其在小麦型饲粮中的降黏效果。饲养试验检测2种木聚糖酶(酸性和中性木聚糖酶)对胃肠液的耐受性;pH 3.5条件下测试2种木聚糖酶的相对活性;选用木聚糖纯品和谷物检测2种木聚糖酶的降黏效果;选取512只1日龄的817白羽肉公鸡,随机分为4组(每组8个重复,每个重复16只),对照组饲喂小麦型基础饲粮,试验组在小麦型基础饲粮中分别添加4 U/g中性木聚糖酶、2和4 U/g酸性木聚糖酶,试验期42 d。结果显示:1)相比中性木聚糖酶,酸性木聚糖酶对肉鸡胃肠液有更好的耐受性。2)在pH 3.5条件下,酸性木聚糖酶的相对活性比中性木聚糖酶高64.1%。3)对于高黏(黑麦)阿拉伯木聚糖,相比中性木聚糖酶,酸性木聚糖酶的降黏效果提升了42.9%。4)在小麦型饲粮中添加木聚糖酶提高了肉鸡的生长性能,其中4 U/g酸性木聚糖酶对生长性能的提高效果优于4 U/g中性木聚糖酶。5)对于饲喂小麦型饲粮的肉鸡,4 U/g酸性木聚糖酶组粗蛋白质表观消化率分别比2 U/g酸性木聚糖酶组、4 U/g中性木聚糖酶组和对照组提高了3.5%(P<0.05)、7.4%(P<0.05)和7.9%(P<0.05)。6)与4 U/g中性木聚糖酶组和对照组相比,在小麦型饲粮中添加4 U/g酸性木聚糖酶显著降低了肉鸡肌胃、空肠和回肠食糜黏度(P<0.05)。7)与对照组相比,在小麦型饲粮中添加4 U/g酸性木聚糖酶显著提高了肉鸡胃蛋白酶和胰蛋白酶的活性(P<0.05)。由此可见,酸性木聚糖酶在pH 3.5条件下有更高的活性,更能耐受动物胃肠液,具有更好的降低黏度效果;在小麦型饲粮中添加4 U/g酸性木聚糖酶能改善肉鸡的生长性能、粗蛋白质表观消化率、食糜黏度和消化酶活性,其效果优于同剂量的中性木聚糖酶。

The purpose of this experiment was to compare the enzymatic properties and their viscosity-reducing effects of acidic and neutral xylanases in wheat-type diets.The tolerance of two xylanases(acidic and neutral xylanases)to gastrointestinal fluid was detected by feeding trail;the relative activities of two xylanases were determined under pH 3.5 condition;the viscosity reduced effect of two xylanases was tested using pure xylans and cereals.A total of 512 one-day-old 817 white-feathered broilers were randomly divided into 4 groups(8 replicates in each group and 16 broilers in each replicate),in which the control group were fed the wheat-type basal diet,and the experimental group was supplemented with 4 U/g neutral xylanase,2 and 4 U/g acidic xylanase,respectively.The test period was 42 days.The results showed as follows:1)compared with neutral xylanase,acidic xylanase had better tolerance to broiler gastrointestinal fluid.2)Under the condition of pH 3.5,the relative activity of acidic xylanase was 64.1%higher than that of neutral xylanase.3)For high viscosity(rye)arabinoxylan,acidic xylanase had a 42.9%lower viscosity than neutral xylanase.4)Adding acid xylanase in the wheat-type diet improved the growth performance of broilers,and 4 U/g acidic xylanase has better effect than 4 U/g neutral xylanase.5)For broilers fed the wheat-type diet,the crude protein apparent digestibility of 4 U/g acidic xylanase group was increased by 3.5%(P<0.05),7.4%(P<0.05)and 7.9%(P<0.05)compared with 2 U/g acidic xylanase group,4 U/g neutral xylanase group and control group,respectively.6)Adding 4 U/g acidic xylanase in the wheat-type diet significantly reduced chyme viscosity in gizzard,jejunum and ileum of broilers compared with 4 U/g neutral xylanase group and control group(P<0.05).7)Adding 4 U/g acidic xylanase in the wheat-type diet significantly increased the activities of pepsin and trypsin of broilers compared with control group(P<0.05).It can be seen from the results that the acidic xylanase with higher enzyme activity under the condition of pH 3.5,is more resistant to the gastrointestinal fluid of animals,and can better reduce the viscosity;adding 4 U/g acidic xylanase in the wheat-type diet can improve the growth performance,crude protein apparent digestibility,chyme viscosity and digestive enzyme activities of broilers,and its effect is better than that of neutral xylanase at the same dose.