Impact of the Supplementation of Exogenous Protease and Carbohydrase on the Metabolizable Energy and Standardized Ileal Amino Acid Digestibility of Soybean Meals in Two Brazilian Regions

ABSTRACT This study aimed to evaluate the effects of different exogenous protease and carbohydrase in broiler diets on the nitrogen-corrected apparent metabolizable energy (AMEn) and standardized ileal amino acid digestibility (SIAAD) of soybean meals (SBM) in two Brazilian regions (Minas Gerais-MG and Rio Grande do Sul-RS). The total excreta collection of 528 14-d-old chicks was used to determine AMEn in a completely randomized design in a 2 (SBM MG and RS) x 5 (enzyme A, B, C, D and basal diet) + 1 (reference diet, RD) factorial arrangement, totaling 11 treatments, 8 repetitions, and 6 birds per experimental unit. Two experimental treatments (T1 and T6) without enzyme supplementation formulated with SBM MG and RS were used as negative control (NC). The RD without the inclusion of SBM MG and RS was used to correct the nitrogen balance. To determine the SIAAD, ileal content was collected from of broilers and the same experimental design and treatments of the previous trial were used except for the RD, which was replaced with a nitrogen-free diet (NFD) to quantify the excretion of endogenous amino acids. Soybean meal from MG showed the highest levels (p<0.05) of AME and AMEn (3,188 kcal/kg and 2,700 kcal/kg, respectively) in comparison to SBM RS (3,121 kcal/kg and 2,549 kcal/kg, respectively) and, when supplemented with the exogenous enzyme C, also improved the SIAAD (p<0.05), as compared to other enzymes.

摘要
本研究旨在评估巴西两个地区——米纳斯吉拉斯州（Minas Gerais-MG）与南里奥格兰德州（Rio Grande do Sul-RS）——的豆粕（soybean meals, SBM）中，添加于肉鸡日粮的不同外源性蛋白酶（exogenous protease）与碳水化合物酶（carbohydrase）对其氮校正表观代谢能（nitrogen-corrected apparent metabolizable energy, AMEn）及标准回肠氨基酸消化率（standardized ileal amino acid digestibility, SIAAD）的影响。

本研究采用2（MG来源SBM与RS来源SBM）×5（酶A、酶B、酶C、酶D及基础日粮）+1（参考日粮reference diet, RD）析因设计的完全随机方案，通过全收粪法收集528只14日龄肉鸡的排泄物以测定AMEn，共设置11个处理组、8个重复，每个试验单元饲养6只肉鸡。以使用MG来源SBM与RS来源SBM配制、未添加酶制剂的2个试验组（T1与T6）作为阴性对照（negative control, NC）。未添加MG及RS来源SBM的参考日粮RD用于校正氮平衡。

为测定SIAAD，本研究收集肉鸡的回肠内容物，试验设计与处理组均沿用前述试验，仅将参考日粮RD替换为无氮日粮（nitrogen-free diet, NFD），以定量内源氨基酸排泄量。

与南里奥格兰德州来源的SBM（表观代谢能3121 kcal/kg、AMEn为2549 kcal/kg）相比，MG来源SBM的表观代谢能与AMEn水平显著更高（p<0.05），分别为3188 kcal/kg与2700 kcal/kg；且当添加外源性酶C时，其SIAAD亦较其他酶制剂组显著提升（p<0.05）。