Department of Animal Science, Federal University of Santa Maria, Santa Maria, RS, Brazil.
Department of Animal Science, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil.
Poult Sci. 2023 Feb;102(2):102366. doi: 10.1016/j.psj.2022.102366. Epub 2022 Nov 30.
Two experiments (Exp.) were conducted to evaluate the effects of exogenous carbohydrases on nutrient and energy utilization of corn with different compositions by broilers. In Exp. 1, a total of 448 Cobb 500 male chicks were distributed in a 2 × 4 factorial arrangement (corn from regions geographically located in the North or South of Brazil × 4 carbohydrases supplementation), with 8 replicate cages of 7 birds each. In Exp. 2, 672 Cobb 500 male chicks were fed 12 experimental feeds, in a 3 × 4 factorial arrangement [3 corn endosperm compositions (waxy, semi-dent, or semi-flint) × 4 carbohydrases], with 8 replicate cages of 7 birds. Birds were fed semi-purified test diets with 95.9% corn from d 14 to 24 in both studies. In Exp. 1, α-amylase, β-xylanase, or carbohydrase complex (cellulase, glucanase, and xylanase) were added to the diet. In Exp. 2, α-amylase, β-xylanase, or α-amylase + β-xylanase were supplemented. Digestibility of DM, N, ether extract (EE), Ca, and P as well as AME, AME, and IDE were determined. In Exp. 2, jejunal starch digestibility was determined on d 24. Data were subjected to analysis of variance and means were compared by Tukey test (P ≤ 0.05). Corn from the North origin had higher AME, AME, and digestibility of DM and N compared to the South (P ≤ 0.05). Amylase supplementation led to increases of 3% in AME and 2% in N digestibility when compared to the non-supplemented feeds (P ≤ 0.01). In Exp. 2, the highest ME values and EE digestibility were observed in the semi-flint corn compared to the waxy, whereas the semi-dent presented the highest digestibility of N and starch. Corn diets supplemented with amylase + xylanase had improvements of 2.5% AME and 3% starch digestibility. In conclusion, energy and nutrient utilization of corn by broilers depend on the region where it was grown. Corn genetics, expressed by the endosperm composition, and carbohydrase supplementation influenced energy and nutrient utilization by broilers.
本研究通过 2 个试验评估了不同来源的玉米和外源酶对肉鸡养分及能量利用率的影响。在试验 1 中，448 只科宝 500 雄性肉鸡采用 2×4 因子设计（南北玉米产区×4 种酶制剂添加），每个处理 8 个重复，每个重复 7 只鸡。在试验 2 中，672 只科宝 500 雄性肉鸡采用 3×4 因子设计（3 种玉米胚乳组成类型（糯玉米、粉质玉米和硬粒玉米）×4 种酶制剂），每个处理 8 个重复，每个重复 7 只鸡。在两个试验中，14-24 日龄时，肉鸡均饲喂半纯合基础饲粮，饲粮中 95.9%的玉米。在试验 1 中，饲粮中添加了α-淀粉酶、β-木聚糖酶或复合酶制剂（纤维素酶、葡聚糖酶和木聚糖酶）。在试验 2 中，饲粮中添加了α-淀粉酶、β-木聚糖酶或α-淀粉酶+β-木聚糖酶。在每个试验中，测定了干物质、氮、乙醚浸出物、钙和磷的消化率及代谢能、真代谢能和有效能。在试验 2 中，在 24 日龄时还测定了空肠淀粉消化率。数据采用方差分析，并用 Tukey 法进行多重比较（P≤0.05）。与南部玉米产区相比，北部玉米产区的肉鸡具有更高的代谢能、真代谢能和干物质、氮消化率（P≤0.05）。与未添加酶制剂的饲粮相比，添加淀粉酶可使代谢能和氮消化率分别提高 3%和 2%（P≤0.01）。在试验 2 中，与粉质玉米和糯玉米相比，硬粒玉米的总能值和乙醚浸出物消化率最高，而粉质玉米的氮和淀粉消化率最高。添加淀粉酶+木聚糖酶的玉米饲粮可使肉鸡的代谢能提高 2.5%，淀粉消化率提高 3%。综上所述，玉米产区影响肉鸡对玉米的能量和养分利用率，玉米胚乳组成类型（由玉米基因型决定）和酶制剂添加影响肉鸡对能量和养分的利用。
