Danisco Animal Nutrition and Health, IFF, Willem Einthovenstraat 4, 2342 BH Oegstgeest, The Netherlands.
School of Agriculture and Food Science, The University of Queensland, Gatton, QLD 4343, Australia.
J Anim Sci. 2022 Jun 1;100(6). doi: 10.1093/jas/skac179.
The effect of a novel consensus bacterial 6-phytase variant (PhyG) on total tract digestibility (ATTD) of minerals and bone ash was evaluated in pigs fed diets containing medium- and high-solubility limestone (MSL and HSL, 69.6 and 91.7% solubility, respectively, at 5 min, pH 3.0) in a randomized complete block design. For each limestone, eight diets were formulated: an inorganic phosphate-free negative control (NC) based on wheat, corn, soybean-meal, canola-meal and rice-barn [0.18% standardized total tract digestible (STTD) P and 0.59% Ca]; the NC supplemented with 250, 500, 1,000, or 2,000 FTU/kg of PhyG, and; the NC with added monocalcium phosphate (MCP) and limestone to produce three positive controls (0.33, 0.27, and 0.21% STTD P, and 0.75, 0.70, and 0.64% Ca, respectively; PC1, PC2, PC3). In total, 128 pigs (12.8 ± 1.33 kg, 8 pigs/treatment, housed individually) were adapted for 16 d followed by 4 d of fecal collection. Femurs were collected from euthanized pigs on day 21. Data were analyzed by one-way ANOVA with means separation by Tukey's test, and by factorial analysis (2 x 4: 2 levels of limestone solubility, 4 STTD P levels, and 2 × 5: 2 levels of limestone solubility, 5 PhyG dose levels). Phytase dose-response was analyzed by curve fitting. A consistent negative effect of HSL on ATTD P and Ca was observed in control diets (P < 0.001). Across phytase-supplemented diets, HSL reduced (P < 0.05) ATTD Ca and P (% and g/kg) compared with MSL. Across limestones, increasing phytase dose level increased (P < 0.05) ATTD P exponentially. Limestone solubility had no effect on bone ash, but PhyG linearly increased (P < 0.05) bone ash; 500 FTU/kg or higher maintained bone ash (g/femur) equivalent to PC1. In conclusion, ATTD P and Ca were reduced by a high compared with a medium soluble limestone, but the novel phytase improved ATTD P and Ca independent of limestone solubility.
在一项随机完全区块设计中，研究人员以猪为对象，喂食含有中可溶性石灰石（MSL）和高可溶性石灰石（HSL）（分别在 5 分钟时具有 69.6%和 91.7%的溶解度，pH 值为 3.0）的日粮，评估一种新型共识细菌 6-植酸酶变体（PhyG）对矿物和骨灰总肠道消化率（ATTD）的影响。对于每种石灰石，均配制了 8 种日粮：一种基于小麦、玉米、豆粕、菜粕和稻谷糠的无无机磷酸盐负对照（NC）[0.18%标准化总肠道可消化（STTD）磷和 0.59%钙]；NC 分别补充 250、500、1000 或 2000 FTU/kg 的 PhyG，以及添加一水磷酸钙（MCP）和石灰石以制成三种正对照（0.33、0.27 和 0.21% STTD 磷和 0.75、0.70 和 0.64%钙，分别为 PC1、PC2 和 PC3）。共有 128 头猪（12.8 ± 1.33 公斤，每处理 8 头猪，单独饲养）适应 16 天，然后进行 4 天的粪便收集。在第 21 天处死猪后收集股骨。数据通过单因素方差分析进行分析，均值通过 Tukey 检验进行分离，并通过因子分析（2 x 4：2 个石灰石溶解度水平，4 个 STTD P 水平，2 x 5：2 个石灰石溶解度水平，5 个 PhyG 剂量水平）进行分析。通过曲线拟合分析植酸酶剂量反应。在对照日粮中，HSL 对 ATTD P 和 Ca 有一致的负作用（P < 0.001）。在添加植酸酶的日粮中，与 MSL 相比，HSL 降低了（P < 0.05）ATTD Ca 和 P（%和g/kg）。在两种石灰石中，植酸酶剂量水平的增加使 ATTD P 呈指数增长（P < 0.05）。石灰石溶解度对骨灰无影响，但 PhyG 线性增加（P < 0.05）骨灰；500 FTU/kg 或更高剂量可维持与 PC1 相当的骨灰（g/股骨）。总之，与中可溶性石灰石相比，高可溶性石灰石降低了 P 和 Ca 的 ATTD，但新型植酸酶提高了 P 和 Ca 的 ATTD，而与石灰石溶解度无关。
