Abstract
We propard laboratory-scale silages of tofu cake and brewer's grain mixed with or without Italian ryegrass(Lolium multiflourm Lam.)or alfalfa(Medicago sativa L.), irradiated them with gamma rays prior to storage and examined the microflora and fermentation quality of them. 1)Spore-forming bacteria, which can cause butyric fermentation of silage, molds and yeasts, which can cause aerobic deterioration of silage, were eliminated from the silages with doses of 8kGy, 4kGy and 16kGy, respectively. Aerobic bacteria in the silages decreased to less than 10^3 cfu/g with a 16kGy dose. Irrespective of gammairradiation, fow yeasts were detected from the silages containing alfalfe. 2)Among the silages exposed to a 16kGy dose, the silages containing brewer's grain contained the largest amounts of lactic acid and were of the lowest pH. The lactic acid bacteria in them lost ability of colony formation with the 16kGy dose but kept lactic acid producticity. These results suggest that a 16kGy dose are necessary to inhibit butyric fermentation and aerobic deterioration of silage and that addition of brewer's grain in the ensiling process may improve the fermentation quality of the irradiated silage.
