Phytase and phytate interactions on broilers' diet at 21 days of age

Abstract

Summary: The objective was to evaluate the effects of different levels of phytase in diets with varying amounts of phytate on live performance and bone characteristics of broiler chickens at 21 D. The treatments consisted of a 3 × 5 factorial arrangement, with 3 levels of phytate, high (HP), medium (MP), and low (LP), and 5 diets consisting of a positive control (PC); negative control (NC, with a reduction of 0.15% of calcium [Ca] and 0.15% of phosphorus [P]), and NC diet plus 0, 500, 1,000, or 1,500 FTU kg−1 of phytase. Feed intake peaked with supplementation of 1,051 FTU kg−1 phytase to the LP diets. Bone ash of broilers receiving LP showed a maximum response at 1,101 FTU kg−1. Birds receiving the NC diet had a larger hypertrophic cartilage zone (P < 0.05) than those receiving the PC diet. Serum Ca and P of birds receiving the NC treatment and LP diet were lower than those in broilers fed with the MP and HP diets. Broilers in the NC plus 500 FYT kg−1 treatments had lower tibia P levels than those in the PC treatment; also, broilers receiving HP diets had a higher tibia Ca content than those receiving LP diets (P < 0.05). In general, bone P of birds fed with diets containing HP was higher than that of birds on a LP or MP diet (P < 0.05). The use of 1,101 FTU kg−1 resulted in better bone characteristics when fed with the lowest phytate level, and this level does not negatively affect the other parameters evaluated.

Keywords

• bone mineralization
• feedstuff
• growth
• poultry
• phosphorus