Schramm V G, Massuquetto A, Bassi L S, Zavelinski V A B, Sorbara J O B, Cowieson A J, Félix A P, Maiorka A
Department of Animal Science, Federal University of Paraná, Curitiba, Brazil 80035-050.
Department of Animal Science, Federal University of Paraná, Curitiba, Brazil 80035-050.
Poult Sci. 2021 Apr;100(4):101019. doi: 10.1016/j.psj.2021.101019. Epub 2021 Jan 27.
Starch is the main energy source in broiler diets. However, endogenous amylase secretion in young broilers is suboptimal to completely digest dietary starch, so exogenous α-amylase supplementation may help increase starch digestibility. The objective of this study was to assess the supplementation of increasing doses of an exogenous α-amylase (0, 40, 80, 120, and 160 kilo-novo α-amylase units (KNU)/kg) on corn and on a complete corn-soybean meal diet for 25-day-old broilers. Jejunal and ileal apparent digestibility coefficients of available starch, resistant starch, total starch, and DM, DM total tract retention, as well as dietary AME levels were evaluated. Interactions (P < 0.05) between diets and α-amylase showed that the enzyme had a more evident effect on increasing DM jejunal digestibility and AME on corn compared with the complete diet. Corn DM digestibility increased to a maximum of 67.84% with up to 47 KNU/kg, whereas 89 KNU/kg led to a maximum of 53.92% in the complete diet A maximum increase of 64 kcal AME/kg was obtained with 80 KNU/kg on the complete diet, whereas 109 KNU/kg generated 327 kcal AME/kg on corn (P < 0.05). Increasing the α-amylase dose linearly increased ileal digestibility of resistant starch (P < 0.05), and the effect on DM total tract retention was quadratic (P < 0.05). Corn showed a higher digestibility for DM, resistant and total starch, as well as DM total tract retention and AME, compared with the complete diet (P < 0.05). Treatments had no influence on available starch. The inclusion of exogenous α-amylase improves starch, DM, and energy utilization of corn-based and corn-soybean meal-based diets for broilers.
淀粉是肉鸡日粮中的主要能量来源。然而，幼龄肉鸡内源性淀粉酶的分泌不足以完全消化日粮中的淀粉，因此补充外源性α-淀粉酶可能有助于提高淀粉消化率。本研究的目的是评估在25日龄肉鸡的玉米日粮和全玉米-豆粕日粮中添加不同剂量（0、40、80、120和160千诺维α-淀粉酶单位（KNU）/千克）的外源性α-淀粉酶的效果。评估了空肠和回肠中可利用淀粉、抗性淀粉、总淀粉和干物质（DM）的表观消化率系数、DM全肠道留存率以及日粮的表观代谢能（AME）水平。日粮和α-淀粉酶之间的交互作用（P<0.05）表明，与全价日粮相比，该酶对提高玉米日粮空肠DM消化率和AME的效果更明显。玉米日粮中，DM消化率最高可达67.84%，此时α-淀粉酶添加量为47 KNU/千克；而在全价日粮中，添加量为89 KNU/千克时，DM消化率最高可达53.92%。在全价日粮中，添加量为80 KNU/千克时，AME最大增加量为64千卡/千克；而在玉米日粮中，添加量为109 KNU/千克时，AME增加量为327千卡/千克（P<0.05）。增加α-淀粉酶剂量可使回肠抗性淀粉消化率呈线性增加（P<0.05），对DM全肠道留存率的影响呈二次曲线关系（P<0.05）。与全价日粮相比，玉米日粮的DM、抗性淀粉和总淀粉消化率更高，DM全肠道留存率和AME也更高（P<0.05）。各处理对可利用淀粉无影响。添加外源性α-淀粉酶可提高肉鸡玉米日粮和玉米-豆粕日粮中淀粉、DM和能量的利用率。
