Nutritional and logarithmic fungal count of brewery spent grain in different conservation techniques and brewery factories’

The objectives of this study was to investigate the effect of conservation practices (soaking, sun drying and ensiling) on nutritional and fungal load dynamics of wet brewers’ grain (WBG). About 40 kilogram of WBG was collected from four breweries (Meta Abo, Habesha, Dashen and Bedele) located in different districts of the country. Sample was labeled and kept in a separate sterile bag, stored under − 20 O C. For soaking, two kg sample was uniformly treated with salt at 3% on DM basis and placed in cold water submerged plastic container and covered with a lead for partial aerobic storage. Two kg fresh sample was exposed to sun drying for three days, eight hours per day and another 2 kg fresh sample was ensiled in a plastic bottle. Molasses was added at the rate of 3% on DM basis to enhance proper fermentation and compaction inside the silo. All samples except sun dried, were subjected to oven drying at 55 0 C for 72 hrs. Chemical compositions, dry matter losses and, fungal count (yeast and mold colony) were determined by standard laboratory procedure. To determine insacco degradability, samples were incubated 6, 12, 24, 48, 72 and 96 hours in nylon bags (6.5 × 14 cm, 50 µm pore size) placed ventral sac of thee cannulated Boran-Friesian steers (550 ± 15 kg live weight). The sample received from Meta Abo brewery factory had y higher (p < 0.05) acid detergent fiber, lignin and digestible organic matter in the dry matter (DM) but comparable dry matter, ash, crude protein (CP) and neutral detergent fiber with the other breweries. The minimal loss on DM and other nutrients, lower fungal, yeast and mold colony counts and the higher CP digestion kinetics was observed in ensiling techniques. If supply is not a constraint under local conditions, ensiling can be recommended as a best WBG conservation practice.