Limestone particle size (PS) affects its solubility and thus can influence broiler performance by altering the rate of calcium (Ca) release into the gastrointestinal tract. The objective of this research was to determine, using 2 × 2 × 2 factorial arrangement, the influence of PS (fine and coarse) and supplemented phytase (0 and 1,000 FYT/kg) in diets formulated with 2 Ca and Pi levels (positive control [PC]; negative control [NC]) on live performance, bone ash, and apparent ileal nutrients digestibility (AID). Starter PC: 0.9 Ca and 0.45 Pi; NC: 0.72 Ca and 0.03 Pi. Grower PC: 0.76 Ca and 0.38 Pi; NC: 0.58 Ca and 0.23 Pi. The 8 diets were assigned randomly to a total of 1,512 birds, with 21 birds per pen and 9 pens per treatment. The main effects of PS and Ca and Pi levels had no influence on feed intake (FI), body weight gain (BWG), or feed conversion ratio. Adding phytase improved BWG by 8 g and 50 g and FI by 25 g and 56 g at 0-14 D (P ≤ 0.05) and 0-35 D (P ≤ 0.05), respectively. Interaction between Ca and Pi levels and phytase improved BWG and FI for 0-14 D (P ≤ 0.05) and BWG during 15-28 D (P ≤ 0.05) for PC without phytase and for PC and NC with phytase when compared with NC without phytase. Birds fed PC without phytase, or either PC or NC with phytase were about 96 g heavier than NC without phytase. Birds fed either PC or NC diet with coarse limestone or PC with fine limestone gained approximately 14 g more (P ≤ 0.05) than birds fed NC with fine limestone for BWG at 0-14 D (P ≤ 0.05). Phytase increased tibia bone ash (14 D) by 1% (P ≤ 0.05). AID of Ca and Pi at 14 D was improved (P ≤ 0.05) by 66% when phytase was added to coarse limestone. Results indicate that phytase improved broiler performance without being affected by PS. Furthermore, phytase had greater influence on coarse limestone than on fine limestone for bone ash and AID. Ca and Pi levels were the most influential factors in determining bone ash although phytase inclusion could lead to an improvement during early days.

中文翻译：

---

石灰石的粒径，钙和磷水平以及植酸酶对肉鸡生产性能和养分消化率的影响。

石灰石粒径（PS）影响其溶解度，因此可以通过改变钙（Ca）释放到胃肠道的速率来影响肉鸡的生产性能。这项研究的目的是确定采用2×2×2阶乘排列方式，确定PS和F2含量分别为2和2时，对PS（细和粗）和植酸酶（0和1,000 FYT / kg）的影响（阳性对照） [PC]；阴性对​​照[NC]）的实时性能，骨灰分和明显的回肠养分消化率（AID）。入门级PC：0.9 Ca和0.45 Pi；NC：0.72Ca和0.03Pi。种植者PC：0.76 Ca和0.38 Pi；NC：0.58Ca和0.23Pi。将这8种日粮随机分配给总共1,512只鸡，每只圈养21只鸡，每次处理9只圈养。PS和Ca和Pi含量的主要影响对饲料摄入量（FI），体重增加（BWG），或饲料转化率。在0-14 D（P≤0.05）和0-35 D（P≤0.05）时，分别添加8 g和50 g肌醇六磷酸酶可改善BWG，将25 g和56 g FI分别添加。Ca和Pi水平与植酸酶之间的相互作用改善了0-14 D（P≤0.05）和15-28 D（P≤0.05）期间BWG和FI的水平，而无肌醇六磷酸酶的PC和具有肌醇六磷酸酶的PC和NC与无肌醇六磷酸酶的NC相比植酸酶。饲喂不含肌醇六磷酸酶的PC或带肌醇六磷酸酶的PC或NC的家禽比不带肌醇六磷酸酶的NC的重约96 g。饲喂PC或NC饲喂粗石灰石或饲喂细石灰石的家禽比饲喂NC饲喂细石灰石的家禽在0-14 D时体重增加约14 g（P≤0.05）（P≤0.05）。植酸酶使胫骨骨灰（14 D）增加1％（P≤0.05）。当向粗石灰石中添加植酸酶时，钙和磷在14 D时的AID改善了（P≤0.05）66％。结果表明，肌醇六磷酸酶改善了肉鸡的生产性能，而不受PS的影响。此外，植酸酶对粗灰岩的影响大于对细灰岩的骨灰和AID的影响。钙和磷水平是确定骨灰分的最重要因素，尽管植酸酶的加入可能会导致早期的改善。