Determination Of True Fecal Calcium And Phosphorus Digestibility Values And The Endogenous Fecal Calcium And Phosphorus Losses Associated With Soybean Meal For Gilt And Barrow By The Simple Linear Regression Analysis Technique

This study simultaneous measured the gastrointestinal endogenous Ca and P outputs and true Ca and P digestibility values with gilt and barrow by the regression analysis technique. In addition, comparison of gastrointestinal endogenous Ca and P outputs and true Ca and P digestibility values with gilt and barrow was conducted.Exp.1:For determination of true fecal calcium and phosphorus digestibility values and the endogenous fecal calcium and phosphorus losses associated with soybean meal for gilt, six Landrace×Yorkshire gilts were selected, with average initial body weight 27.6±3.0kg. Six cornstarch-soybean meal-based diets containing six levels of Ca (0.04%,0.09%,0.13%,0.17%,0.22%,0.26%) and P (0.09%,0.18%,0.27%,0.35%,0.44%,0.53%) were formulated from soybean meal(SBM).According to a 6×6 Latin square design. The result suggests that there is a linear relationship between fecal Ca output and dietary Ca input(P＝0.005) . There is a linear relationship between fecal P output and dietary P input(P＝0.006),too. The endogenous Ca and P output are 0.43g/kgDMI and 0.89g/kgDMI. True Ca and P digestibility values are 23.41±1.83% and 41.44±6.59%, respectively. Exp.2:For determination of true fecal calcium and phosphorus digestibility values and the endogenous fecal calcium and phosphorus losses associated with soybean meal for barrow, six Landrace×Yorkshire barrow were selected, with average initial body weight 28.6±1.76kg. Six cornstarch-soybean meal-based diets containing six levels of Ca and P (0.04%,0.09%；0.09%,0.18%；0.13%,0.27%；0.17%,0.35%；0.22%,0.44%；0.26%,0.53%) were formulated from soybean meal(SBM) according to a 6×6 Latin square design. there is a linear relationship between fecal Ca output and dietary Ca input(P＝0.005) . There is a linear relationship between fecal P output and dietary P input(P＝0.0025),too. The endogenous Ca and P output are 0.62g/kg DMI and 1.08g/kg DMI, respectively. True Ca and P digestibility values are 44.34±8.42% and 48.78±10.36%. These results suggest that:Regression analysis technique (REG) can be used for measuring the gastrointestinal endogenous calcium and phosphorus output and true digestibility.The endogenous Ca and P contributions have relatively larger effects on their respective apparent digestibility values at low levels of dietary Ca and P. There were differences between gilts and barrows of Ca and P endogenous outputs.The endogenous Ca output of gilt and barrow are 0.43g/kg DMI and 0.62g/kg DMI. The endogenous P output of gilt and barrow are 0.89g/kg DMI and 1.09g/kg DMI.True Ca digestibility was different between gilts and barrows.The true Ca digestibility of gilt and barrow are 23.41±1.83% and 44.34±8.42%,respectively.The true P digestibility of gilt and barrow are 41.44±6.59% and 48.78±10.36%,respectively.