Almeida Ferdinando N, Vazquez-Añón Mercedes, Escobar Jeffery
Novus International, Inc. St. Charles, MO, 63304, USA.
Elanco Animal Health, Greenfield, IN 46140, USA.
Asian-Australas J Anim Sci. 2017 Jul;30(7):985-993. doi: 10.5713/ajas.16.0894. Epub 2017 Jan 13.
The objective of this study was to evaluate increasing doses of a novel microbial phytase (Cibenza Phytaverse, Novus International, St. Charles, MO, USA) on standardized total tract digestibility (STTD) of P in canola meal (CM), corn, corn-derived distiller's dried grains with solubles (DDGS), rice bran (RB), sorghum, soybean meal (SBM), sunflower meal (SFM), and wheat.
Two cohorts of 36 pigs each (initial body weight = 78.5±3.7 kg) were randomly assigned to 2 rooms, each housing 36 pigs, and then allotted to 6 diets with 6 replicates per diet in a randomized complete block design. Test ingredient was the only dietary source of P and diets contained 6 concentrations of phytase (0, 125, 250, 500, 1,000, or 2,000 phytase units [FTU]/kg) with 0.4% of TiO as a digestibility marker. Feeding schedule for each ingredient was 5 d acclimation, 5 d fecal collection, and 4 d washout. The STTD of P increased (linear or exponential p≤0.001) with the inclusion of phytase for all ingredients.
Basal STTD of P was 37.6% for CM, 37.6% for corn, 68.6% for DDGS, 10.3% for RB, 41.2% for sorghum, 36.7% for SBM, 26.2% for SFM, and 55.1% for wheat. The efficiency of this novel phytase to hydrolyze phytate is best described with a broken-line model for corn, an exponential model for CM, RB, SBM, SFM, and wheat, and a linear model for DDGS and sorghum. Based on best-fit model the phytase dose (FTU/kg) needed for highest STTD of P (%), respectively, was 735 for 64.3% in CM, 550 for 69.4% in corn, 160 for 55.5% in SBM, 1,219 for 57.8% in SFM, and 881 for 64.0% in wheat, whereas a maximum response was not obtained for sorghum, DDGS and RB within the evaluated phytase range of 0 to 2,000 FTU/kg. These differences in the phytase concentration needed to maximize the STTD of P clearly indicate that the enzyme does not have the same hydrolysis efficiency among the evaluated ingredients.
Variations in enzyme efficacy to release P from phytate in various feedstuffs need to be taken into consideration when determining the matrix value for phytase in a mixed diet, which likely depends on the type and inclusion concentration of ingredients used in mixed diets for pigs. The use of a fixed P matrix value across different diet types for a given phytase concentration is discouraged as it may result in inaccurate diet formulation.
本研究旨在评估新型微生物植酸酶（美国密苏里州圣查尔斯市诺伟司国际公司的Cibenza Phytaverse）剂量增加对菜籽粕（CM）、玉米、玉米干酒糟及其可溶物（DDGS）、米糠（RB）、高粱、豆粕（SBM）、向日葵粕（SFM）和小麦中磷的标准全肠道消化率（STTD）的影响。
将两组各36头猪（初始体重 = 78.5±3.7 kg）随机分配到2个猪舍，每个猪舍容纳36头猪，然后采用随机完全区组设计将其分配到6种日粮中，每种日粮6个重复。试验原料是日粮中磷的唯一来源，日粮含有6种植酸酶浓度（0、125、250、500、1000或2000植酸酶单位[FTU]/kg），并添加0.4%的二氧化钛作为消化率标记物。每种原料的饲喂方案为5天适应期、5天粪便收集期和4天冲洗期。所有原料中添加植酸酶后，磷的STTD均升高（线性或指数关系，p≤0.001）。
CM中磷的基础STTD为37.6%，玉米为37.6%，DDGS为68.6%，RB为10.3%，高粱为41.2%，SBM为36.7%，SFM为26.2%，小麦为55.1%。这种新型植酸酶水解植酸盐的效率，用折线模型描述玉米最佳，指数模型描述CM、RB、SBM、SFM和小麦最佳，线性模型描述DDGS和高粱最佳。根据最佳拟合模型，使磷的STTD达到最高（%）所需的植酸酶剂量（FTU/kg），CM中为735时达到64.3%，玉米中为550时达到69.4%，SBM中为160时达到55.5%，SFM中为1219时达到57.8%，小麦中为881时达到64.0%，而在0至2000 FTU/kg的评估植酸酶范围内，高粱、DDGS和RB未获得最大响应。使磷的STTD最大化所需的植酸酶浓度的这些差异清楚地表明，该酶在评估的原料中水解效率不同。
在确定混合日粮中植酸酶的基质值时，需要考虑不同饲料原料中植酸酶释放磷的功效差异，这可能取决于用于猪混合日粮的原料类型和添加浓度。不建议在给定植酸酶浓度下，对不同日粮类型使用固定的磷基质值，因为这可能导致日粮配方不准确。
