Effect of phytase supplementation and drinking water pH for turkey poults

Abstract

A study was conducted to evaluate the effects of high phytase doses and drinkable water pH on diets for turkey poults on growth performance, nutrient and energy utilization, bone mineralization, and myo-inositol absorption. A total of 420 one-d-old turkey poults were randomly distributed into a 2 × 3 factorial arrangement with 2 water pH levels (5.5 and 8.2) and 3 phytase doses: 0, 1,000, and 2,500 units of phytase (FYT)/kg of diet totaling 6 treatments and 7 replicates of 10 turkeys. Excreta was collected to determine apparent nutrient total tract retention, and ileal digesta was used to determined apparent ileal nutrient digestibility (AID) at 21 d. Phytase linearly improved body weight gain and feed conversion ratio (P < 0.05), whereas water intake was not affected, and water pH did not influence growth performance. Phytase linearly increased AID of crude protein and P, as well as apparent total tract retention of dry matter, crude protein, Ca, and Na (P < 0.05) regardless of water pH. Detected interactions (P < 0.05) showed a linear increase on AID of dry matter and energy utilization at both ileal and total tract levels, which was more pronounced when turkeys drank 5.5 water pH, whereas AID of Ca was only increased by phytase supplementation in combination with alkaline water. Ash, Ca, and P contents in the tibia, as well as plasma concentration of myo-inositol were linearly increased in supplemented chickens, but not affected by water pH. The interactions between phytase and water pH on diet utilization provided conflicting results, but increasing the phytase dose to 2500 FYT increased overall nutrient digestibility, leading to better growth performance, bone mineralization, and greater inositol provision for turkey poults.