Nutritional composition and in vitro digestibility of rehydrated corn grain silages with addition of soybean by-product

The aim of this study was to determine the nutritional composition and in vitro dry matter digestibility (IVDMD) of rehydrated corn grain silage with inclusion of okara (by-product of the aqueous extract of soybean). Five amounts (0, 20, 30, 40 and 50% based on DM) of okara were evaluated. Silage was made in experimental PVC silo (? 12 kg), arranged in a completely randomized design with four replications. After 150 days of ensilage, the silos were opened and samples were taken for analysis. Were determined dry matter (DM), crude protein (CP), ether extract (EE), ash, neutral detergent fiber (NDF) and acid detergent fiber (ADF). The IVDMD silage was determined using an artificial rumen, for 24 h. The values were analyzed by analysis of variance procedure (P <0.05). In the assessment of the silage there was a linear decrease in DM as increased inclusion of okara due to the low dry matter content of okara (19.36%). There was linear increase in ash content of silages with an increase of 0.04% for each percentage unit okara added. This was due to the content of ash (4.79%) in okara added in the silages. For variables NDF, ADF, EE and CP observed increased linearly with increasing addition of okara, due to the high NDF (27.67%), FDA (17.59%), EE (18.07%) and CP (29.85%) in the by-product. This resulted in an increase in the nutritional value of rehydrated corn grain silage, providing, depending on the level of okara added to silage, energy and protein levels close to commercial concentrates for ruminants. Smaller values for IVDMD observed with addition of okara (83.05%, 75.48%, 76.39%, 75.32% and 73.08%, respectively) also relate to the constituents of these final silages, since there was an increase of the fiber (NDF and ADF) and EE content with the addition of okara that compromised the ruminal digestibility of nutrients.