Hunan Institute of Animal Husbandry and Veterinary Medicine, Changsha, China.
College of Animal Science and Technology, Hunan Agriculture University, Changsha, China.
PLoS One. 2021 Nov 15;16(11):e0259865. doi: 10.1371/journal.pone.0259865. eCollection 2021.
The present study aimed to explore the optimal zymogram of combination of 6 carbohydrases (glucoamylase, pullulanase, maltase, thermostable α-amylase, medium temperature α-amylase, and cold-active α-amylase) supplemented in corn-soybean based diet of broilers aged 1 to 3 wk for the maximum starch digestibility, by using in vitro simulated gastrointestinal digestion and response surface method. The third generation of simulated monogastric animal digestion system was used for in vitro digestion experiment. By using single factor completely random design, the optimal supplement levels of single carbohydras were determined by the reducing sugar release amount and improved dry matter digestibility, which were the parameters representing the starch digestibility of the diet. Additionally, Box-Behnken response surface method was used to predict the optimal combination of 6 carbohydrases. The results showed that the optimistic zymogram of 6 carbohydrases in corn-soybean based diet for broilers aged 1 to 3 wk were 297.39 U/g glucoamylase, 549.72 U/g pullulanase, 3.01 U/g maltase, 1,455.73 U/g thermostable α-amylase, 278.64 U/g medium temperature α-amylase, and 1,985.97 U/g cold-active α-amylase, and the associated reduced sugar release amount and improved dry matter digestibility were 215.98 mg/g, and 6.23%, respectively. Furthermore, we conducted in vitro digestion experiments with diets supplemented with the predicted optimistic zymogram and found that the experimental reduced sugar release amount and improved dry matter digestibility were 219.26 mg/g and 6.31% respectively, whose errors to the predicted optimistic reducing sugar release amount and the improved dry matter digestibility were 1.05% and 1.02%. To sum up, the predicted optimal zymogram of 6 carbohydrases in the present study were capable to improve the starch digestibility in diet for broilers aged 1 to 3 wk, which were represented by increased reduced sugar release amount and improved dry matter digestibility.
本研究旨在通过体外模拟胃肠道消化和响应面法，探索 1 至 3 周龄肉鸡玉米-豆粕基础饲粮中 6 种酶（糖化酶、普鲁兰酶、麦芽糖酶、耐热 α-淀粉酶、中温 α-淀粉酶和冷活性 α-淀粉酶）组合的最佳酶谱，以获得最大的淀粉消化率。使用第三代模拟单胃动物消化系统进行体外消化实验。通过单因素完全随机设计，根据还原糖释放量和提高的干物质消化率确定单酶的最佳添加水平，这是代表饲粮淀粉消化率的参数。此外，还采用 Box-Behnken 响应面法预测 6 种酶的最佳组合。结果表明，1 至 3 周龄肉鸡玉米-豆粕基础饲粮中 6 种酶的最佳酶谱为：糖化酶 297.39 U/g、普鲁兰酶 549.72 U/g、麦芽糖酶 3.01 U/g、耐热 α-淀粉酶 1455.73 U/g、中温 α-淀粉酶 278.64 U/g 和冷活性 α-淀粉酶 1985.97 U/g，相应的还原糖释放量和提高的干物质消化率分别为 215.98 mg/g 和 6.23%。此外，我们用预测的最佳酶谱添加饲粮进行体外消化实验，发现实验还原糖释放量和提高的干物质消化率分别为 219.26 mg/g 和 6.31%，与预测的最佳还原糖释放量和提高的干物质消化率的误差分别为 1.05%和 1.02%。综上所述，本研究预测的 6 种酶的最佳酶谱能够提高 1 至 3 周龄肉鸡饲粮的淀粉消化率，以增加还原糖释放量和提高干物质消化率为代表。
