This study examined the effects of 2 corn-expressed phytases, differing in enzyme concentration within the grain (3,000 or 9,677 Fytase unit [FTU]/g), on broiler performance and tibia mineralization when used as a component in pelleted feed. Dietary treatments included a positive control (PC), with industry-recommended levels of calcium and phosphorous, and a negative control (NC), lower in calcium and nonphytate phosphorous. Six diets containing corn-expressed phytase at high or low grain concentrations, formulated to 3,000, 6,000, or 9,000 FTU/kg, were created using the NC. Diets were conditioned at 70°C for 15 s and pelleted using a 4.76 × 38.1 mm pellet die. Descriptive enzyme recovery after pelleting (58–360%) and mixer CV based on enzyme activity (8–24%) demonstrated variability with the phytase assay and did not show trends across treatment main effects. Diets were fed to Hubbard × Ross 708 (n = 1,632) male broilers for 39 d. On day 21, five birds/pen were euthanized, and tibiae were excised to determine tibia mineralization. Treatments were arranged in a 2 (corn-phytase product) × 3 (phytase inclusion) factorial in a randomized complete block design. Broilers fed the NC had increased day 0–39 feed conversion ratio (FCR) compared with all other treatments (P < 0.05). Broilers provided PC and NC produced expected differences in tibia ash as a percentage or as mg/bird (P < 0.05). While there were no differences between phytase products, birds that were fed a phytase inclusion of 9,000 FTU/kg had higher tibia ash/bird and tibia ash percentage (P < 0.05). This study demonstrates that corn-expressed phytases can improve day 21 tibia mineralization and day 0 to 39 FCR, regardless of concentration in the grain.

这项研究检查了两种玉米表达的肌醇六磷酸酶（用作谷物饲料中的一种成分）对谷物中肉鸡生产性能和胫骨矿化的影响，谷物中的酶浓度不同（3,000或9,677 Fytase单位[FTU] / g）。饮食治疗包括阳性对照（PC）和行业推荐的钙和磷水平，以及阴性对照（NC），钙和非植酸磷含量较低。使用NC配制了六种日粮，这些日粮含有高或低谷物浓度的玉米表达的肌醇六磷酸酶，配制成3,000、6,000或9,000 FTU / kg。将日粮在70°C下调理15 s，并使用4.76×38.1 mm的颗粒模头进行制粒。制粒后的描述性酶回收率（58–360％）和基于酶活性的混合器CV（8–24％）表现出植酸酶测定的可变性，并且未显示出主要治疗效果的趋势。将日粮喂入Hubbard×Ross 708（n = 1,632）雄性肉仔鸡39天。在第21天，对5只鸟/笔施以安乐死，并切除胫骨以确定胫骨矿化。在随机完整区组设计中，将处理安排为2（玉米植酸酶产物）×3（包含植酸酶）析因。FCR）与所有其它处理（比较P <0.05）。肉鸡提供的PC和NC产生的胫骨灰分的百分比或毫克/鸟的预期差异（P  <0.05）。虽然植酸酶产物之间没有差异，但饲喂植酸酶含量为9,000 FTU / kg的家禽的胫骨灰/鸟和胫骨灰百分比更高（P <0.05）。这项研究表明，无论谷物中的浓度如何，玉米表达的肌醇六磷酸都可以改善21天胫骨矿化和0至39天FCR。