Effects of high phytase dosage on broiler performance and nutrient digestibility

Abstract

The study evaluated the effect of different doses of phytase and two diets (corn and soybean meal, and meat and bone meal) on the performance of broiler chickens and the digestibility of nutrients in feed. A total of 1320 Cobb 500 broilers were used for the performance experiment, 216 Cobb 500 broilers for the metabolism test, and 252 broiler chicks to determine the apparent and standardized digestibility coefficients of amino acids in the diets. The birds were individually weighed and distributed in a completely randomized design, comprising six treatments divided into a 2x3 factorial scheme (two diets and three levels of phytase composing the treatments): vegetable diets with 500, 1000, and 1500 FTU of phytase (T1, T2, T3); and meat and bone meal diets with 500, 1000, and 1500 FTU of phytase (T4, T5, T6). The average final weight gain and weight gain of animals that consumed diets with meat and bone meal and phytase at 500 FTU/kg were similar to those that consumed 1000 FTU/kg of phytase. The digestibility of amino acids for animals that consumed diets with corn and soybean meal and phytase at 500 FTU/kg was similar to those that consumed 1000 FTU/kg; statistically, the level of 1500 FTU/kg was equal to that of 500 FTU/kg. High doses of phytase did not promote improvements in performance and nutrient digestibility, as well as EMAn values; therefore, phytase supplementation at 500 FTU/kg is recommended.