Abstract: Microbial protein(MCP) is the main contributor to the total protein reaching the small intestine of ruminants. Thus, optimizing ruminal microbial protein synthesis is advantageous for improving the protein status of the animal. Microbial yield in the rumen depends largely on the availability of carbohydrate and nitrogen (N). Synchronizing the rate of carbohydrate fermentation and protein degradation has been suggested as a means to optimize ruminal microbial growth and has becoming the new research focus. The following part will give a brief viewpoint related to the concept and the evaluation method of nutrition synchrony, and the research progress in the synchrony of energy and nitrogen release in the rumen on the synthesis of microbial protein.

Key words: rumen fermentation; carbohydrate; protein; microbial protein; synchrony