Basics and Applications of an Exponential Nitrogen Utilization Model ('GoettingenApproach') for Assessing Amino Acid Requirements in Growing Pigs and Meat Type Chickens Based on Dietary Amino Acid Eff

摘要

Validated protein evaluation systems are required for improved efficiency of protein conversion processes in food producing animals. Up to now, different procedures have been developed to connect feed protein evaluation based on the value of individual amino acids and estimates of the individual amino acid requirement. An exponential function for the relationship between intake of the limiting amino acid in the diet and observed response on nitrogen deposition in the body is utilized within the 'Goettingen approach'. This approach has the potential to model the process of converting feed into food protein by taking into account an efficiency-based optimized dietary amino acid supply at a desired level of performance within the estimated threshold valueof genetic potential for growth. This chapter provides an overview of the basics and current applications of the procedure. Finally, the results are applied to give conclusions about the ideal dietary amino acid ratio for growing pigs and growing chickens. An important factor that may impact both on the derived requirements and the resultant ideal dietary ratios is the variation of amino acid efficiency in feed. This factor has not been systematically investigated.