Department of Animal Science, University of Manitoba, Winnipeg Manitoba, Canada.
Anim Sci J. 2009 Feb;80(1):19-26. doi: 10.1111/j.1740-0929.2008.00590.x.
The effect of high levels of microbial phytase supplementation in diets for growing pigs was studied in a 2-week performance and nutrient digestibility trial involving 28 growing pigs weighing 16.4 +/- 1.06 (mean +/- SD) kg. Seven corn-barley-soybean meal-based diets consisting of a positive control (PC) formulated to meet or exceed NRC nutrient requirements; a negative control (NC) with non-phytate P reduced by 0.1% unit from NRC requirement and fed without or with 500 or 1000 U/kg; a doubled negative control (DNC) with no added inorganic P and fed without or with 2000 or 4000 U/kg. Chromic oxide was added as an indigestible marker and all diets were fed as mash. Pigs fed the PC diet had a higher P digestibility compared with those fed the NC (P < 0.02) and the DNC (P < 0.001) diets. Supplementing the NC diet with pyhtase tended to improve P digestibility (P < 0.10). However, addition of phytase to the DNC diet resulted in linear (P < 0.001) and quadratic (P < 0.03) increases in P digestibility with an overall improvement of 8% and 121% at 4000 phytase U/kg of diet, respectively, compared with the PC and DNC diets. Apparent total tract digestibility of N, OM and DM were higher (P < 0.05) in the PC diet compared with the DNC diet, but not the NC diet (P < 0.10). No effect of phytase addition to NC was observed on Ca, N, DM and OM digestibility. Phytase addition to the DNC diet resulted in a linear increase (P < 0.05) in N, DM and OM digestibility but not Ca. Increasing the levels of phytase supplementation in the NC and the DNC diets linearly decreased fecal P (P < 0.05) content by 45 and 42%, respectively. Adding phytase at 1000 or 4000 U/kg increased P retention (P < 0.05) by 14.3 or 15.6% units, respectively, compared with the PC diet. Urinary P excretion was higher in the group fed the PC diet compared with those fed the NC and DNC diets (P < 0.05). The results of this study show that complete removal of inorganic P from growing pig diets coupled with phytase supplementation improves digestibility and retention of P and N, thus reducing manure P excretion without any negative effect on pig performance.
在一项为期两周的生长猪生产性能和养分消化率试验中，研究了高水平微生物植酸酶在生长猪日粮中的作用，涉及 28 头体重为 16.4±1.06（均值±SD）kg 的生长猪。7 种以玉米-大麦-豆粕为基础的日粮，包括一个阳性对照（PC），按照或超过 NRC 营养需求进行配制；一个阴性对照（NC），从 NRC 需求中减少 0.1%单位的非植酸磷，不添加或添加 500 或 1000U/kg 的植酸酶；一个双阴性对照（DNC），不添加无机磷，不添加或添加 2000 或 4000U/kg 的植酸酶。添加氧化铬作为不可消化的标记物，所有日粮均以糊料形式饲喂。与饲喂 NC 日粮的猪相比，饲喂 PC 日粮的猪的磷消化率更高（P＜0.02），饲喂 DNC 日粮的猪的磷消化率更高（P＜0.001）。在 NC 日粮中添加植酸酶可提高磷消化率（P＜0.10）。然而，在 DNC 日粮中添加植酸酶可使磷消化率呈线性（P＜0.001）和二次（P＜0.03）增加，与 PC 日粮和 DNC 日粮相比，日粮中添加 4000U/kg 植酸酶可分别提高磷消化率 8%和 121%。PC 日粮中氮、有机物和干物质的全肠道表观消化率均高于 DNC 日粮（P＜0.05），但与 NC 日粮相比无差异（P＜0.10）。NC 日粮添加植酸酶对钙、氮、干物质和有机物消化率无影响。 DNC 日粮添加植酸酶可使氮、干物质和有机物消化率呈线性增加（P＜0.05），但钙消化率无变化。NC 日粮和 DNC 日粮中植酸酶添加水平线性增加，粪便磷含量分别降低 45%和 42%（P＜0.05）。与 PC 日粮相比，日粮中添加 1000 或 4000U/kg 植酸酶可分别提高磷保留率 14.3 或 15.6 个单位（P＜0.05）。与饲喂 NC 日粮和 DNC 日粮的猪相比，饲喂 PC 日粮的猪的尿磷排泄量更高（P＜0.05）。本研究结果表明，从生长猪日粮中完全去除无机磷，同时添加植酸酶，可提高磷和氮的消化率和保留率，从而减少粪便磷的排泄，而对猪的生产性能没有任何负面影响。
