Calcium and phosphorus digestibility in rock- and bone-derived calcium phosphates for pigs and poultry: A review

Abstract

Rock-derived calcium phosphates such as mono-calcium phosphate (MCP), di-calcium phosphate (DCP) and tri-calcium phosphate (TCP), that are added in pigs and poultry feeds to meet P requirements of these animals, are expensive and non-renewable sources of P. Calcium phosphates of animal origin are potentially cheaper because they are mainly by-products of gelatin production from bones, and more renewable sources of P for pigs and poultry than the rock-derived calcium phosphates. This study reviewed data on digestibility of P and Ca in rock-derived and bone-derived calcium phosphates for pigs and poultry. Digestibility of P in rock-derived calcium phosphates for pigs and poultry was greatest for MCP, followed by DCP and then TCP. The mean coefficient of standardized total tract digestibility of P values for rock-derived MCP and DCP in pigs were 0.94 and 0.89, respectively; whereas the mean coefficient of SID of P values for rock-derived MCP and DCP in poultry were 0.82 and 0.77, respectively. The digestibility of Ca in limestone for pigs and poultry was generally lower than that in rock-derived MCP or DCP, which did not differ in Ca digestibility in pigs and poultry. In poultry, the digestibility of P in bone-derived DCP was greater than that of bone-derived TCP. Information was lacking on: (1) Ca digestibility in rock-derived TCP and bone-derived DCP and TCP, and (2) P and Ca digestibilities in bone-derived MCP for poultry. Also, information was lacking on P and Ca digestibilities in bone-derived MCP, DCP and TCP for pigs. Digestibility of P in bone-derived DCP in poultry was or greater than that of rock -derived DCP. Also, digestibility of P in bone-derived TCP in poultry was greater than that of rock-derived DCP. Currently, the commercial use of bone-derived calcium phosphates in pig and poultry feeds is limited by: lack of adequate information on their nutritive value; scarcity of these products for livestock feeding; and lack of awareness by pig and poultry industry stakeholders that these animal-derived calcium phosphates can be cheaper and more sustainable sources of P and Ca for pigs and poultry than rock-derived calcium phosphates. In conclusion, nutritive value of bone-derived calcium phosphates for poultry is greater than that for rock-derived calcium phosphates. There is need for research on P and Ca digestibilities in all bone-derived calcium phosphates for pigs, and in bone-derived MCP for poultry.