P的表观回肠消化率(AID),P,在外源植酸酶水平升高的情况下,评估了油菜粉中植酸的消失。在实验1中,使用精确饲喂的公鸡测定法来确定常规和切肉切除的Leghorn公鸡中的植酸(肌醇1,2,3,4,5,6-hexakis;InsP6)和肌醇磷酸(InsP6-3;InsP-P)消失。公鸡用25g油菜粉与0、500、1,000或2,000FTU/kg外源植酸酶混合的作物插管。在实验2中,使用随意饲喂的肉鸡测定了InsP6和InsP-P的消失以及P的AID和ATTR。处理由含有45%卡诺拉粉作为P.的唯一来源的半纯化饮食组成。添加植酸酶以将植酸酶活性增加0、500、1,000或2,000FTU/kg。实验包含每个处理6个重复。油菜粉含有高的植酸酶活性(1,630FTU/kg饲喂),这是由于在来源于油菜粉的饲料研磨机中被市售植酸酶污染。在精密饲喂公鸡的实验1中,植酸酶或鸟类对InsP6和InsP-P消失没有影响(P>0.05);然而,植酸酶线性降低(P<0.05)排泄物中InsP3的浓度。在实验2中,随意喂养的鸡,植酸酶线性增加(P<0.05)回肠InsP6和InsP-P消失,植酸酶对排泄物InsP6和InsP-P消失有二次效应(P<0.05)。日粮植酸酶活性增加导致P的AID线性增加(P<0.05),植酸酶对P的ATTR具有二次效应(P<0.05)。滴定高水平的植酸酶(1,600至3,600FTU/kg饲喂)降低了精密饲喂公鸡的InsP3浓度,但不影响整体植酸水解,所有治疗的比例为78%或更高;然而,随意饲喂肉鸡的总植酸酶活性从700增加到2,700FTU,可增加植酸的消失和P的消化率。
Apparent ileal digestibility (AID) of P, apparent total tract retention (ATTR) of P, and phytic acid disappearance in canola meal were evaluated in the presence of increasing levels of exogenous phytase. In Experiment 1, a precision-fed rooster assay was used to determine phytic acid (myo-inositol 1,2,3,4,5,6-hexakis; InsP6) and inositol phosphate (InsP6-3; InsP-P) disappearance in conventional and cecectomized Leghorn roosters. Roosters were crop intubated with 25 g of canola meal mixed with 0, 500, 1,000, or 2,000 FTU/kg of exogenous phytase. In Experiment 2, InsP6 and InsP-P disappearance and AID and ATTR of P were determined using ad libitum-fed broiler chickens. Treatments consisted of semi-purified diets containing 45% canola meal as the sole source of P. Phytase was added to increase phytase activity by 0, 500, 1,000, or 2,000 FTU/kg. Experiments contained 6 replicates per treatment. Canola meal contained a high phytase activity (1,630 FTU/kg as-fed) due to contamination with a commercially available phytase at the feed mill from which the canola meal was sourced. In Experiment 1 with precision-fed roosters, there was no effect (P > 0.05) of phytase or bird type on InsP6 and InsP-P disappearance; however, phytase linearly reduced (P < 0.05) InsP3 concentrations in excreta. In Experiment 2 with ad libitum-fed chickens, phytase linearly increased (P < 0.05) ileal InsP6 and InsP-P disappearance, and phytase had a quadratic effect (P < 0.05) on excreta InsP6 and InsP-P disappearance. Increasing dietary phytase activity resulted in a linear increase (P < 0.05) in AID of P and phytase had a quadratic effect (P < 0.05) on ATTR of P. In conclusion, titration of high levels of phytase (1,600 to 3,600 FTU/kg as-fed) reduced InsP3 concentrations in precision-fed roosters but did not affect overall phytic acid hydrolysis, which was 78% or greater for all treatments; however, increasing the total phytase activity from 700 to 2,700 FTU in ad libitum-fed broiler chickens increased phytic acid disappearance and P digestibility.