不同磷水平和钙磷比饲粮添加植酸酶对妊娠母猪养分表观消化率的影响

Effects of Different Phosphorus Levels and Calcium to Phosphorus Ratios with Phytase Supplementation on Dietary Nutrients Apparently Digestibility in Pregnant Sows

本试验旨在研究不同磷水平和钙磷比饲粮添加植酸酶对妊娠母猪养分消化率的影响。试验选择遗传背景一致、2-3胎次（预产期前28 d）、体重为（221.91±7.41）kg、预产期相近的健康＂长×大＂二元杂交母猪36头,按照胎次、预产期均衡原则随机分为9个组,每个组4个重复。对照组饲喂基础饲粮（钙、磷水平分别为7.26、5.81 g/kg）;组2为基础饲粮添加植酸酶;组3-5保持钙水平（7.26 g/kg）不变添加植酸酶,减少无机磷添加至对照组的75%、50%、25%[钙磷比为（1.35-1.63）∶1.00];组6-9保持钙磷比不变（1.25∶1.00）添加植酸酶,减少无机磷添加至对照组的75%、50%、25%、0。结果表明：1）正常磷水平下,添加植酸酶显著提高了干物质、粗灰分、有机物和磷的表观消化率（P〈0.05）,极显著降低了粪中磷的排泄量（P〈0.01）,有降低铜、锌排泄量的趋势（P〈0.10）。与对照相比,低磷水平添加植酸酶极显著提高了干物质、粗灰分、有机物、磷、钙、铁、铜、锌的表观消化率（P〈0.01）,显著降低了粪中磷、钙、铁、铜、锌的排泄量（P〈0.05）。2）饲粮在保持钙水平不变或钙磷比不变的条件下添加植酸酶,随磷添加量的降低,干物质、粗灰分、有机物、磷、铁、铜、锌的表观消化率均呈线性或二次升高（P〈0.05）,粪中磷、铁、铜、锌的排泄量呈线性或二次降低（P〈0.01）,保持钙磷比不变,钙、粗蛋白质的表观消化率显著提高（P〈0.05）。3）以表观可消化磷为标准,饲粮保持钙水平不变和钙磷比不变添加植酸酶可分别替代0.91、1.27 g/kg的无机磷,减少24.70%、34.48%的粪磷排泄量。4）钙磷比不变（1.25∶1.00）组饲粮的养分表观消化率极显著高于钙水平不变[高钙磷比（1.35-1.63）∶1.00]组饲粮（P〈0.01）,且粪矿物质的排泄量极显著减少（P〈0.01）。综上所述：1）在本研究条件下,在低无机磷、低钙磷比（1.25∶1.00）饲粮中,添加植酸酶提高养分消化率的效果更显著。2）以表观可消化磷为标准,母猪饲粮的钙磷比为1.25∶1.00时,添加植酸酶可减少1.27 g/kg的磷添加。

The objective of this study was to estimate the effects of different levels of phosphorus （ P） and cal-cium （ Ca） to P ratios with phytase supplementation on nutrients digestibility of sows during pregnancy. Thirty-six healthy and pregnant （2 to 3 fetals, 28 days prior to farrowing） sows （Landrace＆#215;Yorkshire） on the same genetic background with similar body weight （221.91±7.41） kg and close parturition date were randomly di-vided into 9 groups with 4 replicates per group. Sows in the control group were fed a basal diet; those in the group 2 were fed the basal diet supplemented with phytase, those in the groups 3 to 5 were fed diets with the same Ca level （7.26 g/kg） and phytase supplemented, and inorganic P additions were 75%, 50%, 25% （Ca to P ratio was from 1.35 to 1.63 to 1.00） of the control group, respectively; those in groups 6 to 9 were fed diets with Ca to P ratio maintained 1.25∶1.00 and phytase supplemented, and inorganic P additions were 75%, 50%, 25% and 0 of the control group, respectively. The results showed as follows： 1 ） in normal P level （5.81 g/kg） groups, supplementation of phytase significantly improved the apparent digestibility （ AD） of feed dry matter （DM）, ash, organic matter （OM） and P （P〈0.01）, reduced the fecal excretion of P （P〈0.01）, and tended to decrease copper and zinc excretion （P〈0.10）. Dietary supplementation of phytase in lower P level than control group significantly improved the AD of feed DM, ash, OM, P, Ca, iron, copper, and zinc （ P〈0.01） , and reduced the fecal excretion of P, Ca, iron, copper, and zinc （ P〈0.05） . 2） Dietary reduction of P level resulted in a linear or quadratic increase in the AD of DM, ash, OM, P, iron, copper, zinc （ P〈0.05） , and a linear or quadratic reduction in fecal excretion of P, iron, copper and zinc under the condition of unchanged Ca level or Ca to P ratio （ P〈0.05） . AD of Ca and crude protein were significantly in-creased by reducing P level when Ca to TP ratio controlled as 1.25∶1.00 （P〈0.05）. 3） Addition of phytase could replace 0.91 and 1.27 g/kg of inorganic P and reduced fecal P excretion by 24.70% and 34.48% respec-tively when Ca level was maintained 7.26 g/kg and Ca to P ratio was maintained 1.25∶1.00 based on the appar-ent digestible P. 4） Groups with Ca to P ratio controlled 1. 25∶1. 00 had significantly higher nutrient AD and lower excretion of fecal mineral than groups with Ca level maintained 7.26 g/kg （ P〈0.01） . In summary, the lower the Ca to P ratio （1.25∶1.00） and lower inorganic P level, the higher the effect of phytase on nutrient AD in the present study. Supplementation of phytase in diet with Ca to TP ratio maintained 1.25∶1.00 can re-place 1.27 g/kg inorganic P based on digestible P.