The role of feed protein quality in reducing environmental pollution by lowering nitrogen excretion. I. Survey of principles in protein evaluation for monogastrics: a review.

Environmental pollution by faecal nitrogen excretion motivates a renewed interest in optimising protein utilization of growing-finishing pigs in intensive pig production areas. The importance of digestibility of proteins, availability of amino acids, and the extent of protein retention is emphasized for reducing nitrogen excretion. The principles of various chemical, microbiological, biochemical and biological methods in feed protein quality evaluation offering a better adjustment of protein supply to the requirements of the animal are surveyed.