本试验旨在研究在小麦基础饲粮中添加包被及不同水平的木聚糖酶对肉鸡生长性能、养分代谢率、免疫器官和消化器官发育的影响。试验选用15日龄的爱拔益加(AA)肉鸡(公母混养)750羽,随机分为5个处理,每个处理5个重复,每个重复30只。对照组饲喂小麦基础饲粮,试验组饲粮分别在基础饲粮中添加:10 000 U/g包被木聚糖酶,10 000、20 000、30 000 U/g未经过包被处理的木聚糖酶,木聚糖酶的添加量均为150 g/t,试验期28 d。结果表明:1)添加20 000和30 000 U/g未包被木聚糖酶可显著降低22~42日龄肉鸡的料重比(P<0.05),添加30 000 U/g未包被木聚糖酶可显著提高15~42日龄肉鸡的平均日增重(P<0.05),降低料重比(P<0.05);2)添加20 000和30 000 U/g未包被木聚糖酶可显著提高粗蛋白质表观代谢率(P<0.05),添加20 000 U/g未包被木聚糖酶可显著提高表观代谢能(P<0.05),添加10 000 U/g包被木聚糖酶可显著提高粗脂肪表观代谢率(P<0.05);3)添加10 000 U/g包被木聚糖酶和30 000 U/g未包被木聚糖酶可显著提高肉鸡脾脏指数(P<0.05),添加30 000 U/g未包被木聚糖酶可显著提高肉鸡血清免疫球蛋白G的含量(P<0.05);4)添加10 000 U/g包被木聚糖酶、20 000和30 000 U/g未包被木聚糖酶可显著降低肉鸡腺胃的相对重量(P<0.05);添加20 000 U/g未包被木聚糖酶可显著降低胰腺相对重量(P<0.05),添加30 000 U/g未包被木聚糖酶可显著增加十二指肠绒毛高度(P<0.05)。由此可见,饲粮添加木聚糖酶可提高肉鸡生长性能和养分代谢率,减轻消化负担,促进免疫器官发育,以添加30 000 U/g木聚糖酶效果最佳;相同木聚糖酶水平下,包被处理的效果优于未包被处理。

This experiment was conducted to study the effects of adding coated xylanase and different levels of xylanase in wheat based diets on growth performance, nutrient metabolic rates and the development of immune and digestive organs of broilers. A total of 750 15-day-old Arbor Acres broilers (male and female polyculture) were randomly divided into 5 treatments with 5 replicates per treatment and 30 broilers per replicate. The control group was fed a wheat based diet, and test diets were added 10 000 U/g coated xylanase, 10 000, 20 000 and 30 000 U/g uncoated xylanase in the basal diet. The addition of xylanase was 150 g/t, and the test period was 28 days. The results show as follows: 1) the supplementation of 20 000 and 30 000 U/g uncoated xylanase can significantly reduce the ratio of feed to gain of broilers aged 22 to 42 days (P<0.05), and the supplementation of 30 000 U/g uncoated xylanase can increase average daily gain and decrease the ratio of feed to gain of broliers aged 15 to 42 days (P<0.05). 2) The supplementation of 20 000 and 30 000 U/g uncoated xylanase can significantly improve the apparent metabolic rate of crude protein (P<0.05); the supplementation of 20 000 U/g uncoated xylanase can significantly increase the apparent metabolizable energy (P<0.05); and the supplementation of 10 000 U/g coated xylanase can significantly increase the apparent metabolic rate of crude fat (P<0.05). 3) The supplementation of 10 000 U/g coated and 30 000 U/g uncoated xylanase can significantly improve the spleen index of broilers (P<0.05), and the supplementation of 30 000 U/g of uncoated xylanase can significantly increase the content of immunoglobulin G in serum of broilers (P<0.05). 4) The supplementation of 10 000 U/g coated, 20 000 U/g and 30 000 U/g uncoated xylanase can significantly reduce the relative weight of glandular stomach (P<0.05); the supplementation of 20 000 U/g uncoated xylanase can significantly reduce the relative weight of pancreas (P<0.05); and the supplementation of 30 000 U/g uncoated xylanase can significantly increase the duodenal villus height of broilers (P<0.05). In conclusion, xylanase supplementation can improve growth performance and nutrient metabolic rates of broilers, alleviate digestive burden, and promote the development of immune organs, and the supplemental effects of 30 000 U/g xylanase are the best. At the same level of xylanase, the effects of coated xylanase are better than those of uncoated xylanase.