P122 Effects of phytase supplementation on ileal digestibility of phytate phosphorus and total phosphorus of feed ingredients for broiler chickens

This study aimed to evaluate the effect of a heat stable phytase derived from Citrobacter braakii on true digestibility of P and on phytate dephosphorylation at the terminal ileum segment in broiler chickens. Four semi-synthetic diets, each containing either wheat, maize, soybean meal or rapeseed meal as the only source of phosphorus and calcium were supplemented with microbial phytase at 1000 U per kg feed and fed along with a non-supplemented corresponding diet. A total of 540, 24-day old male broiler chickens were used in this 4-day digestibility study. A phosphorus-free diet was used to estimate endogenous ileal phosphorus losses. Ileal contents were collected and analyzed, along with the diets, for total phosphorus and phytate phosphorus. Endogenous ileal phosphorus flow was determined to be 37 mg/kg of feed dry matter. When compared to the control diet, phytase supplementation resulted in a significantly (P<0.05) greater phytate P disappearance from the terminal ileum, for soybean meal, rapeseed meal and maize but not for wheat. Similarly, true ileal phosphorus digestibility was significantly increased when phytase was added to rapeseed meal (+24%), soybean meal (+28 %), wheat (+37 %) and corn (+73 %) based diets. It was concluded that microbial phytase supplementation was effective in improving significantly phosphorus digestibility and phytate degradation in the four tested phytate containing feed ingredients.