本试验研究了小麦型饲粮中添加木聚糖酶对肉仔鸡养分利用及消化器官发育的影响。将240只1日龄爱拔益加肉仔鸡随机分为4个处理，每个处理5个重复，每个重复12只鸡，分别饲喂在含40%小麦的饲粮中添加不同水平木聚糖酶（0、500、1 000和5 000 U/kg）的试验饲粮。试验期21 d。结果表明，木聚糖酶对17～21日龄肉仔鸡粗蛋白质、钙及总磷利用率及粪便含水率无显著影响（P>0.05）；趋于提高17～21日龄肉仔鸡干物质利用率（P=0.093）及表观代谢能值（P=0.110）；各组肉仔鸡养分表观利用率无显著差异（P>0.05）。添加木聚糖酶未显著影响21日龄肉仔鸡小肠、胃、胰腺和脾脏相对重量（P>0.05）。1 000 U/kg酶组显著降低了21日龄肉仔鸡回肠相对长度（P<0.05）。木聚糖酶对21日龄肉仔鸡胫骨干重、长度、灰分及磷含量无显著影响（P>0.05）。本研究表明：含40%小麦的肉仔鸡饲粮中添加不同水平的木聚糖酶对肉仔鸡养分利用及大部分肠道器官发育均未产生显著作用；超量添加对肉仔鸡养分利用无进一步改善作用，也未产生负面影响。

The trial was conducted to study the effects of different levels of xylanase on the nutrients utilization, digestive-related organs development of broilers fed wheat-based diets. Two hundred and forty 1-day-old Arbor Acres broilers were allocated to 4 dietary treatments （with 5 replicates of 12 chicks each） in a randomized complete block design. A wheat-corn-based basal diet containing 40% wheat was designed with 0, 500, 1 000 and 5 000 U/kg xylanase supplemented, respectively. The trial lasted for 21 d. The results showed that supplementing xylanase improved the apparent dry matter digestibility (P=0.093) and AME (P=0.110), but the apparent utilization ratio of crude protein, Ca and P and fecal moisture ratio was not significantly improved in broilers at 17～21 d (P>0.05). No significant differences were observed in the nutrients utilization among the xylanase groups (P>0.05). Supplementation of 1 000 U/kg xylanase decreased significantly the relative length of ileum of broilers at 21 days of age (P<0.05). No significant differences were observed in the relative weight of intestine, gaster, pancreas and spleen of broilers at 21 days of age among groups (P>0.05). Supplementation of xylanase did not affect significantly tibia weight and length, ash and P content in tibia of the broilers at 21 days of age. These data indicated that xylanase, even over supplementation did not significantly improve nutrients utilization and most of digestive-related organs development of broilers fed diets with 40% wheat, and increasing supplementation of xylanase had no deleterious effects.［Chinese Journal of Animal Nutrition, 2010，22（1）:157-162］