Effect of exogenous xylanase, amylase, and protease as single or combined activities on nutrient digestibility and growth performance of broilers fed corn/soy diets
Effect of exogenous xylanase, amylase, and protease as single or combined activities on nutrient digestibility and growth performance of broilers fed corn/soy diets
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DOI：
10.3382/ps/pew297
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发表时间：
2017-04-01
期刊：
影响因子：
4.4
通讯作者：
Ravindran, V.
中科院分区：
文献类型：
--
作者：
Amerah, A. M.;Romero, L. F.;Ravindran, V.
进行了两个试验(42日龄生产性能和21d群体消化率)，以评价添加外源木聚糖酶、淀粉酶和蛋白酶作为单一或联合活性的玉米日粮对肉鸡的生产性能和营养物质消化率。制定了营养充足的阳性对照(PC)饮食。阴性对照(NC)日粮的代谢能(与86千卡/公斤日粮相似)和可消化氨基酸(1~2%)均低于PC日粮。其他4个处理在对照组的基础上添加木聚糖酶(X)、淀粉酶(A)、蛋白酶(P)或X、A和P的组合(XAP；提供2,000 U的X、200 U的A和4,000 U的P/kg日粮)。所有日粮中AVP和Ca的含量都很低，并含有植酸酶(1000FTU/kg)的背景。在每个试验中，公鸡(罗斯308)被分配到5个处理(分别为10个重复20只/栏和9个重复8只/笼进行生产性能和消化率试验)。在消化率试验中，于21日龄采集回肠消化液，用于测定养分利用率。资料采用单因素方差分析，均数采用Tukey‘s HSD检验。仅XAP较NC有改善(P<；0.05)。X、A或XAP提高(P<；0.05)氮消化率和回肠表观消化能(AIDE)。P和XAP均能提高土壤氮素存留量。在回肠水平上添加酶对能量消化率的相对改善比在排泄物中测得的要大。由补充酶引起的AIDE的测量变化远远高于淀粉、脂肪和蛋白质的计算贡献之和。与对照组相比，添加所有酶降低了(P<；0.05)可溶鼠李糖和甘露糖的回肠流量。在性能试验中，X和XAP都提高了(P<；0.05)增重(WG)，只有XAP提高了(P<；0.05)FCR(P<；0.05)。在整个试验期间(1-42d)，日粮处理对日增重和FI无显著影响(P>；0.05)。X和XAP的FCR均低于NC(分别为1.540和1.509比1.567)。然而，饲喂添加XAP的日粮比饲喂单一活动的雏鸡有更好的(P<；0.05)FCR，而与PC相比有相似的(P>；0.05)FCR。综上所述，这些结果表明X、A和P对肉鸡生产性能和养分消化率有协同作用。在目前的研究中，辅助测量似乎高估了酶的反应。利用淀粉、脂肪和蛋白质未消化部分消化率的改善来计算补充酶对能量的贡献，可能是一种比AIDE中的绝对反应更准确的酶反应测量方法。
Two trials (a 42-d performance and a 21-d cohort digestibility) were conducted to evaluate the performance and nutrient digestibility of broilers fed corn diets supplemented with exogenous xylanase, amylase, and protease as single or combined activities. A nutritionally adequate, positive control (PC) diet was formulated. The negative control (NC) diet was formulated to be lower in metabolizable energy (similar to 86 kcal/kg diet) and digestible amino acids (1 to 2%) compared to PC. The other 4 treatments were based on the NC and they were either supplemented with xylanase (X), amylase (A), protease (P), or a combination of X, A, and P (XAP; to provide 2,000 U of X, 200 U of A, and 4,000 U of P/kg diet). All diets were marginal in AvP and Ca and contained a background of phytase (1,000 FTU/kg). In each trial, male broiler (Ross 308) chicks were allocated to the 5 treatments (10 replicates of 20 birds/pen and 9 replicates of 8 birds/cage for the performance and digestibility trials, respectively). In the digestibility trial, ileal digesta was collected on d21 for the determination of nutrient utilization. Data were subjected to one-way ANOVA and means were separated by Tukey's HSD test. Only the XAP improved (P < 0.05) AMEn compared to NC. X, A or XAP improved (P < 0.05) N digestibility and apparent ileal digestible energy (AIDE). Both P and XAP improved N retention. The relative improvement in energy digestibility due to enzyme supplementation was greater at the ileal level than that measured in the excreta. The measured changes on AIDE due to supplemental enzymes were much higher than the sum of calculated contributions from starch, fat, and protein. Supplementation of all enzymes reduced (P < 0.05) ileal flow of soluble rhamnose and mannose relative to NC. In the performance trial, both X and XAP improved (P < 0.05) weight gain (WG) and only XAP improved (P < 0.05) FCR compared to NC during the starter phase (1-21d). Over the entire period (1-42d), WG and FI were not influenced (P > 0.05) by dietary treatments. Both X and XAP had lower (P < 0.05) FCR compared to NC (1.540 and 1.509 vs 1.567, respectively). However, birds fed diet supplemented with XAP had an improved (P < 0.05) FCR compared to birds fed single activities and had similar (P > 0.05) FCR compared to PC. In conclusion, these results suggest a synergistic effect between X, A and P on broiler performance and nutrient digestibility. In the current study, AIDE measurements appeared to overestimate the enzyme response. Calculation of the energy contribution by supplemental enzymes using the improvements in the digestibility of the undigested fraction of starch, fat and protein may be a more accurate measurement for the enzyme response than the absolute response in AIDE.