生长猪饲粮磷水平对磷酸氢钙中磷真消化率评定的影响

摘要

The present study was conducted to investigate the effects of dietary phosphorus (P) levels on the estimation of true total tract digestibility of phosphorusin dicalciumphosphate (DCP) for growing pigs.Fifty-six barrows (average initial BW of 26 ± 0.25 kg) were assigned into 7 treatment groups.There were 8 replicates in each treatment group with 1 pig per replicate.The 7 experimental diets included a corn-soybean meal diet without DCP supplementation and 6 treatment diets supplemented with graded levels of DCP at 0.64％,1.28％,1.92％,2.56％,3.20％,and 3.84％ respectively.Chromic oxide (Cr2O3) was used as digestibility marker.The results showed that apparent total digestibility of P increased (linear P＜0.01 quadratic P＜0.05) with increasing DCP levels for growing pigs.The true total tract digestibility of P in DCP determined by the difference method increased quadraticly with increasing DCP levels.Using the regression method,the true total tract digestibility of P in DCP for growing pigs feed low P diets were calculated to be 87.06％ which was greater than the estimated value of 38.05％ for pigs feed high P diets.In summary,the results of this study indicate that dietary P levels affect the estimates of true total tract digestibility of P in DCP determined by the difference method and the regression method.Dietary P concentration should be set at a level close to the requirement of P when the difference method was used to calculate the true total tract digestibility of P.Furthermore,dietary P levels should be formulated below the requirement of P when the regression method was applied to determine the true total tract digestibility of P in assay feed ingredients.%本试验旨在研究生长猪饲粮磷水平对磷酸氢钙(DCP)中磷的全肠道真消化率评定的影响.选用56头体重为(25.90±0.25)kg的杜×长×大杂交去势公猪,根据体重随机分为7个处理组,每组8个重复,每个重复1头猪.对照组饲喂未添加DCP的基础饲粮,6个处理组在基础饲粮中分别添加0.64％、1.28％、1.92％、2.56％、3.20％、3.84％ DCP.使用全收粪法测定磷的表观全肠道消化率.结果表明:生长猪总磷的表观全肠道消化率随饲粮DCP水平提高呈线性和二次增加(P＜0.05);随着DCP添加水平的提高,由差量法测得无机磷的全肠道真消化率呈二次上升的趋势(P＜0.1),具体表现为无机磷的全肠道真消化率随饲粮DCP水平提高呈现出先增加后降低的趋势;通过线性回归法发现,生长猪饲喂低DCP饲粮后测得磷的全肠道真消化率显著高于饲喂高DCP饲粮(P＜0.05).由此可见,饲粮磷水平显著影响差量法和线性回归法测得DCP的全肠道真消化率;使用差量法测定饲粮原料磷的全肠道真消化率时应将饲粮磷水平维持在接近磷需要量的水平,使用线性回归法测定磷的全肠道真消化率时应将饲粮磷水平控制在低于磷需要量的范围内.