The influence of feed phosphates on the structural, mechanical and chemical properties of bone tissue in pigs.

The aim of the study was to assess the influence of various feed phosphates on the structural and mechanical properties as well as on the chemical composition of femurs in adult pigs (weight approx. 110 kg). Three types of phosphates--monocalcium phosphate (MCP), dicalcium phosphate (n-DCP) and calcium-sodium phosphate (CSP)--were used alternatively in pigs fed with the standard feed mixture. The MCP and CSP phosphates were typical, imported products used traditionally in pig feeding. Dicalcium phosphate (n-DCP) was manufactured in Poland on the basis of phosphoric acid with the new pro-ecological method. The following parameters were determined: the mean physical density of the samples of the compact and spongy bone tissue, values of Young's modulus, strength and the energy of deformation, and Vickers microhardness (HV). Also the content of C, O, Na, Mg, Al, and Si, as well as Ca, P and Sr was determined. Significant differences in mean values of the mentioned parameters occurred between the studied groups. The best mechanical properties were shown by the bones from the n-DCP group, and the compact bone tissue (diaphysis) contained the most Ca, P, and Sr when compared to the MCP and CSP groups.