Production of animal protein from nonprotein nitrogen chemicals.

Ruminants obtain amino acids (AA) from microbial protein synthesized in the rumen and from feed proteins that escape ruminal degradation. Synthesis of microbial protein provides a mechanism for obtaining AA from NPN. Effectiveness of NPN utilization depends upon production and utilization of ammonia by rumen microbes. Because ammonia is produced from protein and NPN, feeding proteins resistant to microbial degradation forces utilization of ammonia derived from NPN. The quantity of microbial cells formed in the anaerobic rumen fermentation system is primarily dependnt upon energy supply but can be modulated by types and supplies of other nutrients (i.e. amino-N, minerals growth factors) and by growth rate of rumen bacteria. Potential quantities of NPN that can be utilized with different feed ingredients can be estimated from amounts of feed protein degraded in the rumen, and requiring transformation into protein via growth of rumen microbes, and from amounts of energy provided by feed ingredients. High energy feed ingredients with low amounts of degradable protein are most favorable for NPN utilization, but NPN has also been used successfully with high-fibrous, low energy feed materials. Growth, lactation and reproduction have been obtained on diets containing more than 97% of the nitrogen from NPN, but microbial protein alone cannot provide quantities of AA needed for high levels of productivity. Regulating ruminal degradation of dietary protein and utilizing NPN for rumen protein production is a highly desirable strategy for producing human foods with ruminants.