Effects of fermented soybean meal with Bacillus velezensis, Lactobacillus spp. or their combination on broiler performance, gut antioxidant activity and microflora

Objective: A series of experiment were conducted to evaluate the effects of replacing a part of soybean meal (SBM) at 6% of broiler diets with fermented soybean meal (FSBM) obtained by single or two-stage fermentation by measuring growth performance, antioxidant activity in the jejunum and distal intestinal microflora.Methods: Soybean meal samples were prepared by single-stage fermentation using Bacillus velezensis (Bv) (FSBMB), or Lactobacillus spp. (as commercial control) (FSBML). Additional SBM sample was prepared by two-stage fermentation using Bv and subsequently using Lactobacillus brevis ATCC 367 (Lb) (FSBMB+L). Enzyme activity, chemical composition, trichloroethanoic acid-nitrogen solubility index (TCA-NSI) and antioxidant activity were measured. Then, in an in vivo study, 320 Ross308 broilers were divided into four groups with ad libitum supply of feed and water. Four groups were fed either a corn-soybean meal diet (SBM), or one of fermented SBM diets (FSBMB+L, FSBMB, and FSBML). Growth, serum characteristics, microflora, and the mRNA expression of selected genes were measured.Results: Compared to SBM, FSBMB+L contained lower galacto-oligosaccharide, allergic protein, and trypsin inhibitor, and higher TCA-NSI by about three times (p