Effect of Aspergillus oryzae Fermentation Extract (Amaferm®) on In Vitro Fiber Degradation

Abstract

The influence of Aspergillus oryzae fermentation extract (Amaferm®) on in vitro fiber degradation was determined by incubating eight ground fibrous feedstuffs with rumen fluid and buffer inoculum. Amaferm® was added at 0, .4, .8, or 1.2 g/L of fermentation mixture. Both NDF and ADF degradabilities were determined after 96 h of incubation. Addition of extract had no effect on NDF or ADF degradability of pure cellulose, low endophyte fescue, wheat straw, corn silage, or prairie hay. Addition of Amaferm® at .8 or 1.2 g/L increased NDF and ADF degradations of bromegrass hay and alfalfa hay; its addition at .4 or .8 g/L, but not at 1.2 g/L increased NDF and ADF degradation of high endophyte fescue hay. In a second set of in vitro fermentations, selective antimicrobials (penicillin, streptomycin, and cycloheximide) were used to assess the influence of Amaferm® on various microbial groups. The enhanced fiber degradation by Amaferm® was attributed to its stimulation of bacterial activity because its addition to whole rumen fluid without or with cycloheximide increased fiber digestion. In contrast, addition of Amaferm® to the whole rumen fluid plus penicillin and streptomycin treatment had no effect on fiber degradation, suggesting that fungal or protozoal activity was not affected by treatment. In conclusion, Amaferm® increased fiber digestibility of certain feedstuffs, and the increase was mediated via stimulation of rumen bacterial, but not fungal or protozoal activities. © 1993, American Dairy Science Association. All rights reserved.