Practical application and advantages of using total digestible amino acids and undigestible crude protein to formulate broiler diets

1. A series of experiments was conducted to determine the effects of dietary levels of total digestible amino acids (TDAA) and undigestible crude protein (UCP) on growth performance of broilers between 11 and 32 days of age. 2. Increasing TDAA in broiler diets from about 160 to 190 g/kg improved feed conversion ratio (FCR) linearly. 3. Increasing dietary levels of UCP from about 30 to 45 g/kg had negative effects on body weight gain (BWG) and FCR. 4. The combination of dietary TDAA and UCP contents provided a better predictor of BWG and FCR in young broilers than diet Crude Protein (CP) content. 5. For formulation of commercial broiler diets more emphasis should be placed on measuring digestibility of protein in feed ingredients and complete feeds. 6. More research is required to measure, quantify and predict the negative effects of proteolytic fermentation in the intestinal tract of broilers on feed utilization and animal health.