This study was conducted to investigate the effects of dietary amylose/amylopectin (AM/AP) ratio and amylase on growth performance, apparent digestibility of energy and starch, serum biochemical index, and digestive enzymes. The experiment used a 4 × 3 factor design, and 960 one-day-old Arbor Acres (AA) broilers were randomly divided into 12 groups fed diets containing different AM/AP ratio of 0.11, 0.23, 0.35 and 0.47 and combined with 0, 3,000 and 6,000 U/kg amylase. Results showed that 0.23-0.35 AM/AP ratio increased growth performance, while dietary addition of 6,000 U/kg amylase significantly reduced average daily weight gain in broilers. The energy digestibility was significantly reduced along with the increase of dietary AM/AP ratio and in the 6,000 U/Kg amylase-supplemented groups. The digestibility of starch also decreased significantly with the increase of dietary AM/AP ratio, but high dose (6,000 U/Kg) of amylase increased. High AM/AP diet reduced serum insulin concentration, which was increased in amylase-supplemented groups. Furthermore, exogenous amylase increased amylase activity in the jejunal chyme. In conclusion, dietary 0.23-0.35 AM/AP ratio was suggested to maintain a higher growth performance in broilers and high AM/AP ratio diets reduced energy and starch digestibility and serum insulin concentration, which was reversed by dietary amylase.

中文翻译：

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日粮中直链淀粉/支链淀粉的比例和淀粉酶对肉鸡生长性能，能量和淀粉消化率以及消化酶的影响。

这项研究旨在研究日粮直链淀粉/支链淀粉（AM / AP）比例和淀粉酶对生长性能，能量和淀粉的表观消化率，血清生化指标和消化酶的影响。实验采用4×3因子设计，将960日龄的1天大的Arbor Acres（AA）肉鸡随机分为12组，分别饲喂不同AM / AP比分别为0.11、0.23、0.35和0.47的饲料，并与0， 3,000和6,000 U / kg淀粉酶。结果表明，0.23-0.35 AM / AP比可提高生长性能，而日粮中添加6,000 U / kg淀粉酶则可显着降低肉鸡平均日增重。随着日粮AM / AP比的增加以及补充6,000 U / Kg淀粉酶的组，能量消化率显着降低。淀粉的消化率也随着日粮AM / AP比的增加而显着降低，但高剂量（6,000 U / Kg）的淀粉酶增加。高AM / AP饮食降低了血清胰岛素浓度，在补充淀粉酶的组中该浓度升高了。此外，外源淀粉酶增加了空肠食糜中的淀粉酶活性。总之，建议日粮0.23-0.35 AM / AP比例可保持肉鸡更高的生长性能，而高AM / AP日粮则降低能量，淀粉消化率和血清胰岛素浓度，这可由日粮淀粉酶逆转。