Enhancing the Quality and Nutrient Content of Soybean Milk Waste as Poultry Feed Through Fermentation with Bacillus subtilis

Abstract

This study was conducted to understand the effects of substrate composition and length of fermentation for improving the content and quality of soybean milk waste as poultry feed. The materials used in this study were soybean milk waste (SMW), rice bran, Indigofera leaf flour (ILF), and Bacillus subtilis. A completely randomized design (CRD) was used with a factorial pattern (3 x 3) and 3 replications. Factor A was the composition of the substrate, (A1) 100% SMW, (A2) 80% SMW + 20% rice bran, and (C) 80% SMW + 20% ILF. Factor B was the length of fermentation that consisted of (B1) 2 days, (B2) 4 days, (B3), and 6 days. Parameters measured were phytase activity (PA), crude protein (CP), nitrogen retention (NR), crude fiber (CF), crude fiber digestibility (CFD), and metabolic energy (ME) of SMW fermented with B. Subtilis. There was an interaction (P<0.05) between substrate composition and fermentation time of SMW fermented with Bacillus subtilis on phytase enzyme activity, crude protein, and nitrogen retention. Substrate composition of 80% SMW + 20% ILF and 6 days of fermentation time was the best result which was able to increase phytase enzyme activity (6.71U/mL), crude protein content (41.82%), and nitrogen retention (61.41%) of fermented soybean milk waste. There was an alleviate in crude fiber content (10.49%), an increase in crude fiber digestibility (57.29%), and metabolic energy (2199.80kcal/kg) of SMW fermented with B subtilis.