基础日粮类型对回归法测定生长猪对豆粕中磷真消化率的影响

Effect of Basal Diet Types on the Estimation of True Phosphorus Digestibility in Soybean Meal for Growing Pigs by the Regression Method

选用48头平均体重为(30.0±0.1)kg生长公猪,采用2×3因子完全随机区组设计随机分为6个处理,每个处理8个重复,每个重复1头猪。通过在无酪蛋白添加和添加酪蛋白日粮上添加3个水平豆粕,研究基础日粮类型对线性回归法测定豆粕中磷的真消化率的影响。结果表明:日粮总磷摄入量、粪磷排泄量、可消化磷和存留磷均随豆粕水平增加而线性增加(P<0.01);酪蛋白添加日粮显著减少粪磷排泄量,从而提高可消化磷、存留磷、磷的表观消化率和存留率(P<0.01);采食不同类型基础日粮得出磷的真消化率之间无显著差异(P>0.05),但内源磷排泄量差异显著(P<0.01);由此可见,添加可消化蛋白和磷含量高的酪蛋白虽影响对生长猪内源磷排泄量的估计,但不影响对磷的真消化率的计算。

Forty-eight barrows with an average initial BW of （30.0±0.1） kg were allocated to 6 diets in a 2×3 factorial arrangement of 2 diet types （without or with casein supplementation） and 3 soybean meal levels by a randomized complete block design. There were 8 replicates in each treatment group with 1 pig per replicate. The objective of the present study was to investigate the effect of basal diet composition on the estimation of true phosphorus （P） digestibility in soybean meal derived from the linear regression analysis. The results showed that dietary P intake, fecal P output, digested P and retained P were increased linearly with graded increasing levels of soybean meal in each type of diet （P〈0.01）. Compared with diets without casein, the casein-supplemented diets decreased fecal P output, thus leaded to increases in digested P, retained P, apparent total tract digestibility and retention of P （P〈0.01）. There was no difference in determined values of true P digestibility in soybean meal for pigs fed diets with or without casein （P〉 0.05）. The estimates of endogenous P output for pigs fed diets without or with casein supplementation were significantly different （P〈0.01）. In summary, the results of this study indicated that dietary supplementation of casein, which contains highly digestible protein and P, affected the estimation of endogenous P output for pigs instead of true P digestibility associated with soybean meal by the regression method.