Abstract
In order to reduce the addition of the inorganic phosphorus (Pi) to the diets of monogastric animals, it is expected that the addition of phytase to the animal diets to release Pi from phytate P in the diets will widespread in the near future. If so, the Pi content in feces and urine of monogastric animals fed with Pi additive-free diets will become remarkably low, and it will greatly reduce the nutrient value for crops. Then it will become important to promote the mineralization of phytate P in feces in composting process. We examined how extent phytase added to diets can decompose phytate P remaining in feces after being excreted.HomePage
Feces of pigs were fed with diets with or without phytase were held indoors for 40 days. The phytase activity was linearly decreased from 1,070U/kg just after the excretion to 45U/kg after 40 days. While during 40 days, about a half of phytate P remaining in feces (1.26mgP/g) was decomposed, phytase activity had almost completely disappeared after 40 days. Thus, further decomposition of phytate P was not expectable.Keywords: phytase, phytate P, inorganic P, pig feces