1. The present study examined the potential of new-generation microbial enzymes to improve the utilisation of energy and protein of cottonseed meal (CSM)-containing diets, with the aim of increasing its inclusion level in broiler chickens diets.

2. Four hundred and eighty, one-day-old Ross 308 male broilers were used to assess the utilisation of energy and protein by broiler chickens fed diets containing four graded levels of CSM – none, low (4, 8, 12%), medium (5, 10, 15%) or high (6, 12, 18%) in the starter, grower, and finisher phases, respectively, supplemented with 100 mg/kg of a composite enzyme product (xylanase and β-glucanase).

3. Inclusion of CSM improved (P < 0.01) apparent metabolisable energy (AME), with further improvement (P < 0.001) seen in the enzyme-supplemented diets. Inclusion of CSM reduced (P = 0.002) the metabolisable energy intake (MEI), but this was increased (P < 0.05) with enzyme supplementation.

4. Enzyme addition increased (P < 0.001) the net energy of production (NEp), while heat production (HP) decreased (P < 0.001) with CSM inclusion. More energy was retained as fat (P < 0.05) and protein in birds fed diets with the enzyme, but this was reduced (P < 0.029) by CSM.

5. There was an increase (P < 0.05) in efficiencies of ME use for energy, lipid and protein retention, with higher CSM levels. The enzyme improved (P < 0.013) efficiency of ME use for lipid retention.

6. Feeding diets containing CSM to the broilers enhanced (P < 0.05) protein intake (PI) and protein efficiency ratio (PER). Positive effects (P < 0.05) of enzyme were observed on protein gain (PG) and net protein utilisation (NPU).

7. Results obtained from this study suggested that nutrient utilisation of diets containing CSM by broiler chickens can be improved by enzyme supplementation.

1.本研究研究了新一代微生物酶在提高含棉籽粕（CSM）日粮能量和蛋白质利用率方面的潜力，目的是提高其在肉鸡日粮中的含量。

2.用480只一天大的Ross 308公仔鸡来评估饲喂含有四级CSM的日粮的肉鸡对能量和蛋白质的利用-无，低（4％，8％，12％），分别在起始阶段，生长阶段和完成阶段分别达到中等（5、10、15％）或较高（6、12、18％）的水平，并补充了100 mg / kg的复合酶产物（木聚糖酶和β-葡聚糖酶）。

3. CSM的添加改善了（P <0.01）表观代谢能（AME），并且在补充酶的饮食中改善了（P <0.001）。包含CSM减少了（P = 0.002）可代谢能量的摄入（MEI），但是通过添加酶增加了（P <0.05）。

4.添加CSM后，酶的添加增加了生产的净能量（NEp）（P <0.001），而产热（HP）减少了（P <0.001）。用这种酶饲喂日粮的鸡体内，脂肪和蛋白质的能量保留得更多（P <0.05），但是CSM降低了能量（P <0.029）。

5. ME的能量，脂质和蛋白质保留效率提高（P <0.05），CSM水平更高。该酶提高了ME用于脂质保留的效率（P <0.013）。

6.向肉鸡饲喂含CSM的饲料可增加（P <0.05）蛋白质摄入（PI）和蛋白质效率比（PER）。观察到酶对蛋白质增加（PG）和净蛋白质利用率（NPU）的积极影响（P <0.05）。

7.从这项研究中获得的结果表明，通过添加酶可以改善肉鸡含CSM日粮的营养利用。