PDF(Pubmed)
Abstract：
An experiment was conducted to test the hypothesis that increasing levels of a novel phytase increases the apparent ileal digestibility (AID) and apparent total tract digestibility (ATTD) of nutrients in diets fed to young pigs. A negative control (NC) diet based on corn, soybean meal, and canola meal that contained approximately 0.83% phytate (i.e., 0.23% phytate-bound P) was formulated to be deficient in Ca, P, and standardized ileal digestible amino acids (AA). Five additional diets were formulated by adding 250, 500, 1,000, 2,000, or 4,000 phytase units/kg of the novel phytase to the NC diets. Eighteen ileal-cannulated pigs (17.81 ± 1.71 kg) were allotted to a 6 × 3 incomplete Latin square design with six diets and three 11-day periods. There were three pigs per diet in each period; therefore, there were nine replicate pigs per diet. The initial 5 d of each period was considered an adaptation period to the diet. For each period, fecal samples were collected via anal stimulation on days 6, 7, 8, and 9, whereas ileal digesta were collected on days 10 and 11 using standard procedures. Results indicated that the AID of crude protein, indispensable AA, and dispensable AA was increased (quadratic, P < 0.05) as the concentration of microbial phytase increased in the diets. Dietary inclusion of the novel phytase at 1,000 or 2,000 FTU/kg increased the AID of total AA from 73.7% to 79.8%. Increasing levels of microbial phytase increased (quadratic, P < 0.05) the AID of dry matter and minerals (i.e., Ca, P, K, Mg, Cu) in the diets. Likewise, a linear increase (P < 0.05) in the AID of ash and Na was observed as the inclusion level of phytase increased in the diets. Increasing levels of microbial phytase increased (linear, P < 0.01) the AID of gross energy (GE) and starch in the diets. A quadratic (P < 0.05) increase in the ATTD of ash, Ca, P, K, and Cu in experimental diets was observed as the concentration of microbial phytase increased in the diets. The ATTD of Mg and GE also increased (linear; P < 0.05) as concentration of dietary phytase increased. In conclusion, the novel microbial phytase used in this experiment was effective in increasing the AID of dry matter, GE, starch, minerals, and AA, as well as the ATTD of gross energy and minerals in diets formulated to be deficient in Ca, P, and AA.
The effect of microbial phytase on amino acid (AA) digestibility has been inconsistent, but in many experiments, relatively low levels of phytase were used and it is not known if greater concentrations of phytase are needed to increase AA digestibility. A novel consensus bacterial 6-phytase variant has been recently developed, but it is not known if this phytase results in increased digestibility of AA and other nutrients. Therefore, an experiment was conducted to test the hypothesis that dietary inclusion of increasing levels of the novel phytase (i.e., 0, 250, 500, 1,000, 2,000, and 4,000 phytase units/kg) increases ileal digestibility of AA and total tract digestibility of energy and minerals in diets for growing pigs. In this experiment, it was demonstrated that increasing levels of phytase increased the apparent ileal digestibility of starch, gross energy, minerals, crude protein, and AA, as well as the apparent total tract digestibility of gross energy and minerals. The impact of phytase on AA digestibility is possibly dependent on diet composition, phytate and phytase sources and concentrations, and pig maturity; however, further research is needed to confirm this.
The effect of microbial phytase on amino acid (AA) digestibility has been inconsistent, but in many experiments, relatively low levels of phytase were used and it is not known if greater concentrations of phytase are needed to increase AA digestibility. A novel consensus bacterial 6-phytase variant has been recently developed, but it is not known if this phytase results in increased digestibility of AA and other nutrients. Therefore, an experiment was conducted to test the hypothesis that dietary inclusion of increasing levels of the novel phytase (i.e., 0, 250, 500, 1,000, 2,000, and 4,000 phytase units/kg) increases ileal digestibility of AA and total tract digestibility of energy and minerals in diets for growing pigs. In this experiment, it was demonstrated that increasing levels of phytase increased the apparent ileal digestibility of starch, gross energy, minerals, crude protein, and AA, as well as the apparent total tract digestibility of gross energy and minerals. The impact of phytase on AA digestibility is possibly dependent on diet composition, phytate and phytase sources and concentrations, and pig maturity; however, further research is needed to confirm this.
摘要：
进行了一项实验以检验以下假设：增加新型植酸酶的水平会增加饲喂给幼猪的饮食中营养素的表观回肠消化率（AID）和表观总道消化率（ATTD）。基于玉米的阴性对照（NC）饮食，豆粕,和含有约0.83%植酸盐的油菜粉(即，0.23%植酸结合的P)被配制为钙缺乏，P,和标准化的回肠可消化氨基酸(AA)。通过向NC饮食中添加250、500、1,000、2,000或4,000植酸酶单位/kg的新型植酸酶来配制5种额外的饮食。将18只回肠插管的猪（17.81±1.71kg）分配给6×3不完整的拉丁正方形设计，具有6种饮食和3个11天的周期。每个时期每个饮食有三头猪；因此，每个饮食有九只重复的猪。每个时期的最初5天被认为是饮食的适应期。对于每个时期，在第6,7,8和9天通过肛门刺激收集粪便样本,而在第10和11天使用标准程序收集回肠消化物.结果表明，粗蛋白的AID，不可或缺的AA，可有可无的AA增加(二次，P<0.05）随着日粮中微生物植酸酶浓度的增加。在1,000或2,000FTU/kg的饮食中加入新型植酸酶可使总AA的AID从73.7％增加到79.8％。微生物植酸酶水平的增加增加(二次，P<0.05)干物质和矿物质的AID(即Ca,P,K,Mg,Cu）在饮食中。同样，随着日粮中植酸酶含量的增加，灰分和Na的AID呈线性增加（P<0.05）。微生物植酸酶水平的增加增加(线性，P<0.01）日粮中总能量（GE）和淀粉的AID。灰分ATTD的二次增加(P<0.05)，Ca,P,K,随着日粮中微生物植酸酶浓度的增加，在实验日粮中观察到Cu。Mg和GE的ATTD也随着饲料植酸酶浓度的增加而增加（线性；P<0.05）。总之,本实验中使用的新型微生物植酸酶可有效增加干物质的AID，GE,淀粉，矿物,AA,以及配制为钙缺乏的饮食中总能量和矿物质的ATTD，P,AA。
微生物植酸酶对氨基酸（AA）消化率的影响一直不一致，但在许多实验中,使用相对较低水平的植酸酶，尚不清楚是否需要更高浓度的植酸酶来增加AA的消化率。最近开发了一种新的共有细菌6-植酸酶变体，但是不知道这种植酸酶是否会导致AA和其他营养素的消化率增加。因此,进行了一项实验来检验这样的假设，即饮食中包含增加水平的新型植酸酶(即，0、250、500、1,000、2,000和4,000植酸酶单位/kg）增加了AA的回肠消化率以及日粮中能量和矿物质的总道消化率。在这个实验中,结果表明，增加植酸酶水平增加了淀粉的表观回肠消化率，总能量，矿物,粗蛋白，AA,以及总能量和矿物质的表观总道消化率。植酸酶对AA消化率的影响可能取决于饮食组成，植酸和植酸酶的来源和浓度，和猪成熟；然而，需要进一步的研究来证实这一点。
微生物植酸酶对氨基酸（AA）消化率的影响一直不一致，但在许多实验中,使用相对较低水平的植酸酶，尚不清楚是否需要更高浓度的植酸酶来增加AA的消化率。最近开发了一种新的共有细菌6-植酸酶变体，但是不知道这种植酸酶是否会导致AA和其他营养素的消化率增加。因此,进行了一项实验来检验这样的假设，即饮食中包含增加水平的新型植酸酶(即，0、250、500、1,000、2,000和4,000植酸酶单位/kg）增加了AA的回肠消化率以及日粮中能量和矿物质的总道消化率。在这个实验中,结果表明，增加植酸酶水平增加了淀粉的表观回肠消化率，总能量，矿物,粗蛋白，AA,以及总能量和矿物质的表观总道消化率。植酸酶对AA消化率的影响可能取决于饮食组成，植酸和植酸酶的来源和浓度，和猪成熟；然而，需要进一步的研究来证实这一点。
