NM 16. Study on the effect of inorganic phosphorus sources and phytase supplementation in weaning-growing barrows

Abstract

A total of 160 pigs (9.95 kg BW) were allotted to 5 treatments -, Control (100 % NRC Ca, P with TCP), TCP (70 % NRC Ca, P with TCP), TCPP (TCP + 500 FTU phytase), MCP (70 % NRC Ca, P with MCP) and MCPP (MCP + 500 FTU phytase). The corn-soy based basal diets were formulated to 3 450 Kcal DE/kg and 18.5 %, 16 % CP for weaning and growing period, respectively. MCPP significantly improved weight gain (P<.05) and other treatments were inferior to control. Pigs fed 70 % Ca, P showed a trend to consume more feed than pigs fed control diet regardless of phytase addition. TCP and MCP treatments showed worse feed conversion compared to control, but when phytase was added, feed conversion was improved to the level of control. Between inorganic phosphorus sources, MCP was better in improving weight gain and feed conversion than TCP (P<.05), and phytase addition was highly significant in improving weight gain and feed conversion (P<.01). Nutrients digestibility of pigs fed TCP and MCP diets were lower than that of pigs fed control diets, however, pigs fed TCPP and MCPP diets showed similar rate of nutrients digestibility with that of pigs fed control diet (P<.05). Phytase addition improved not only phosphorus digestibility, but also digestibility of dry matter and crude protein. Dry matter excretion was substantially reduced by phytase addition (P<.05). Nitrogen and phosphorus excretion showed the same trend with dry matter excretion (P<.05). In growing period, pigs fed TCPP and MCPP diets excreted 31 % less amounts of phosphorus than pigs fed control diet. When the amount of excretion was converted to the amount of excretion per 100 kg weight gain, pigs fed TCPP diet excreted 24.2 % less phosphorus than control, and MCPP excreted 47.5 % less phosphorus than control. It was found that MCP is more efficient inorganic P source than TCP for pigs. And with proper inorganic P source and phytase, P contents in weaning-growing pig diet could be reduced by 30 %.