Rumen bacteria capable of growth on peptides and amino acids as sole source of energy : numbers and their role in ammonia production

Abstract

Excessive ammonia production by rumen micro-organisms is a major cause of inefficient N retention by ruminants. The microorganisms which break down peptides and amino acids to ammonia were identified originally as typical major species of the rumen ecosystem (Bladen et al, 1961, Appl Microbiol, 9, 175-180) Four rumen-fistulated sheep received 500 g of hay, barley, molasses, fishmeal and vitaminsminerals (500, 299.5, 100, 91 and 9.5 g/kg DM) twice daily. Samples of rumen fluid were removed 2-3 h after feeding, strained, and diluted serially in the basal medium described by Chen and Russell (1990, Appl Environ Microbiol, 56, 2186-2192 Hence numbers of monensin-sensitive bacteria capable of growth on Trypticase were low, but they had a significant, although minor, role in ammonia production by the mixed population.