In vitro evaluation of limestone, dicalcium phosphate, and phytase on calcium and phosphorus solubility of corn and soybean meal. Academic Article uri icon

abstract

  • A series of in vitro trials was conducted to evaluate the influence of limestone, dicalcium phosphate, phytase, and the digestion phase on Ca and P solubility. Experimental samples were arranged as a 2 2 2 2 factorial and contained corn (experiment 1) or soybean meal (experiment 2) plus limestone, dicalcium phosphate, phytase, and all combinations. Calcium and available P in the samples were maintained at 1.0% with limestone and 0.45% with dicalcium phosphate, respectively. Phytase was added to the samples at 1,000 FTU/kg. Samples were exposed to a 2-step in vitro digestion assay to simulate the gastric and the small intestinal (SI) phases of digestion. In experiment 1, dicalcium phosphate improved (P 0.05) P solubility in the gastric phase, which did not change in the SI phase, except when phytase was supplemented, which reduced (P 0.05) P solubility in the SI phase. The small amount of Ca present in corn is highly soluble, but limestone, dicalcium phosphate, or phytase reduced (P 0.05) Ca solubility in the gastric phase. Solubility was further reduced (P 0.05) in the SI phase in the presence of limestone. In experiment 2, P was more soluble (P 0.05) in the presence of limestone, dicalcium phosphate, or phytase in the gastric phase and compared with P solubility in the SI phase. Calcium solubility was reduced (P 0.05) in the SI phase compared with the gastric phase, except when dicalcium phosphate or limestone was supplemented. In conclusion, P and Ca solubility were influenced by the change in pH between the gastric and SI phases, differences in diet composition, and the Ca:P ratio. Limestone, dicalcium phosphate, and phytase increased P solubility in the gastric phase and reduced P solubility in the SI phase. Phytase had more of an effect on P and Ca solubility in soybean meal than in corn, and this is possibly a result of the high amount of phytate in soybean meal.

published proceedings

  • Poult Sci

author list (cited authors)

  • Walk, C. L., Bedford, M. R., & McElroy, A. P.

citation count

  • 12

complete list of authors

  • Walk, CL||Bedford, MR||McElroy, AP

publication date

  • January 2012