Proteolysis Associated with the Ensiling of Chopped Alfalfa

Abstract

Proteolysis in ensiled, chopped alfalfa (39% DM) was investigated by 1) measuring the changes in nonprotein nitrogen, free amino N, peptide N, and ammonia N and 2) by extraction of the forage proteins and monitoring the changes in protein constitution by polyacrylamide gel electrophoresis. Nonprotein N, ammonia N, free amino N, and peptide N increased during fermentation; the rates of increase of these end products of proteolysis were greatest during the first 7 d of fermentation. The protein ribulose 1,5-diphosphate carboxylase was completely depleted after 2 d of fermentation of the forage. Other plant proteins were more resistant to proteolysis and remained after 90 d of fermentation. © 1988, American Dairy Science Association. All rights reserved.