Effect of inoculation of herbage prior to ensiling with Streptomyces achromogenes ISP 5028 on chemical composition of silage

Abstract

Enzymes derived from bacteria and fungi have been used as additives in silage production. Increasing attention has been given to the use of cell-wall degrading enzymes such as cellulases, hemicellulases and peroxidases. However, little information has been published on the potential role of actinomycetes in silage production. The experiment reported in this paper examined the changes in chemical composition and predicted nutritive value of herbage inoculated with Streptomyces achromogenes ISP 5028 during 60 days of ensiling. Changes in chemical composition and nutritive value of herbage were examined after 1, 2, 3, 5, 10, 30 and 60 days ensiling. Colonisation of inoculated silage by S. achromogenes ISP 5028 occurred rapidly and after 30 days of ensiling the difference in viable spores was 1000-fold between the control and treated silages (P<0.001). Inoculation reduced the concentration of NDF (P<0.01) and crude hemicellulose (P<0.001) and accelerated the rate of loss of NDF (P<0.05) but not crude hemicellulose (P>0.05) from the cell wall. The changes in the composition of the cell wall facilitated an increase in the concentration of WSC (P<0.001), thus allowing greater concentrations of lactic (P<0.001) and acetic (P<0.01) acids to be formed. Elevated concentrations of various isomeric forms of butyric and valeric acid were also observed in the treated silage compared to the control. Inoculation of herbage with S. achromogenes ISP 5028 prior to ensiling altered the chemical and nutritive composition of silage, however it is not known whether the risks associated with other actinomycetes (respiratory disorders and toxin release) apply to the test organism in these experiments.