Department of Wildlife and Animal Sciences, University of Pretoria, Hatfield 0028, South Africa; Neuro Livestock Research, Kameeldrift, Brits 0250, South Africa.
Danisco Animal Nutrition & Health (IFF), Wilmington, DE 19803, USA.
Poult Sci. 2024 Nov;103(11):104191. doi: 10.1016/j.psj.2024.104191. Epub 2024 Aug 9.
Dietary phytate P (PP) concentration impacts Ca and P digestibility in broilers. Research was conducted to determine the impact of increasing concentration of dietary PP, with and without phytase, on broiler standardized ileal digestibility (SID) of Ca and P. Digestible (Dig) Ca and P were calculated by multiplying SID and the analyzed dietary Ca and P concentrations. The experiment was a factorial arrangement of 2 phytase (0 and 1,000 U/kg) and 4 PP (0.16, 0.23, 0.29, and 0.34%) concentrations. Treatments were fed for 36 h from 20 to 22 d of age (4 b/pen, n ≥ 7 replicate pens/treatment). Different ratios of corn and corn germ were used to achieve the desired PP concentrations. A limestone with 800 µm geometric mean diameter was used as the sole Ca source to achieve 0.7% Ca in the final diets (96% Ca from limestone). An additional diet was fed that was N, Ca- and P-free, for the determination of endogenous losses of each nutrient. Distal ileal digesta were pooled from all birds in a pen. There were no interactions between PP and phytase on SID Ca or Dig Ca from limestone. Irrespective of phytase inclusion, increasing PP from 0.16 to 0.34% decreased SID Ca from 53.8 to 38.1% (P < 0.05). The SID Ca averaged 41.5 and 51.4% in diets containing 0 and 1000 U phytase/kg, respectively, across all PP concentrations (P < 0.05). Interactions were seen between PP and phytase on SID and Dig P (P < 0.05) with SID P of 31.1, 24.0, 20.1, and 16.3% for broilers fed 0.16, 0.23, 0.29, and 0.34% PP diets without phytase, respectively. When phytase was included at 1000 U/kg, SID P was 89.9, 87.5, 73.9 and 60.4% for diets containing 0.16, 0.23, 0.29 and 0.34% PP, respectively (P < 0.05). Overall, phytase improved SID Ca and P independent of PP concentration. However, with increasing PP concentration, both SID Ca and P were negatively affected.
日粮植酸磷（PP）浓度影响肉鸡的钙和磷消化率。本研究旨在确定日粮 PP 浓度（添加和不添加植酸酶）对肉鸡标准回肠可消化性（SID）钙和磷的影响。可消化（Dig）钙和磷通过乘以 SID 和分析的日粮钙和磷浓度来计算。该实验是植酸酶（0 和 1000 U/kg）和 4 个 PP（0.16、0.23、0.29 和 0.34%）浓度的 2 因素安排。从 20 日龄到 22 日龄（每笼 4 只，每处理 7 个重复笼），鸡群饲喂 36 小时。使用不同比例的玉米和玉米胚芽来达到所需的 PP 浓度。使用 800 µm 几何平均粒径的石灰石作为唯一的钙源，使最终日粮中的钙达到 0.7%（来自石灰石的钙 96%）。还饲喂了一种不含氮、钙和磷的日粮，用于确定每种营养素的内源损失。从每个笼中的所有鸡中收集回肠末端消化物。植酸酶和 PP 对 SID 钙或来自石灰石的 Dig 钙没有互作影响。无论添加植酸酶与否，PP 从 0.16%增加到 0.34%都会使 SID 钙从 53.8%下降到 38.1%（P<0.05）。在含有 0 和 1000 U 植酸酶/kg 的日粮中，SID 钙分别平均为 41.5%和 51.4%（P<0.05），而日粮中的 PP 浓度不同。植酸酶和 PP 之间存在 SID 和 Dig P 的互作（P<0.05），未添加植酸酶时，饲喂 0.16%、0.23%、0.29%和 0.34%PP 日粮的鸡群的 SID P 分别为 31.1%、24.0%、20.1%和 16.3%。当添加 1000 U/kg 的植酸酶时，分别含有 0.16%、0.23%、0.29%和 0.34%PP 的日粮的 SID P 为 89.9%、87.5%、73.9%和 60.4%（P<0.05）。总体而言，植酸酶独立于 PP 浓度提高了 SID 钙和磷。然而，随着 PP 浓度的增加，SID 钙和磷均受到负面影响。
