The effects of fermented soybean meal on the growth performance of weaning piglets and further optimization of the solid-state soybean meal fermentation system using novel Bacillus strains
The nutritive value of soybean meal (SBM) in piglets can be increased through bacterial fermentation as antinutritional factors, such as antigenic proteins, that pose challenges while weaning are degraded. Bacillus subtilis BS9 and B5 ferment SBM with high efficiencies, decreasing antigenic high-molecular weight proteins and increasing soluble proteins, under conditions that reduce fermentation costs. In early weaning piglets, BS9 fermented SBM meal did not improve the ADG, ADFI, and FCR from day 1-14, however FCR improved significantly from day 15-28. Fecal characteristics improved week 1-2, while E.coli and coliform fecal counts decreased at 3-4 weeks. Since B5 fermented SBM with similar efficiencies to BS9, the economic feasibility of B5 fermented SBM was improved by reducing moisture content to 40%, without agitation. Gram-negative bacterial growth was deterred in B5 fermentations. Although beneficial effects of improved fecal scores and microbial shedding from fermented SBM are encouraging, improvement could reduce the antinutritional factors.