Increase in the plant protein ratio in the diet of white shrimp,Litopenaeus vannamei(Boone), usingBacillus subtilisE20-fermented soybean meal as a replacement

This study aimed to improve the nutritional value and utilization of soybean meal (SBM) used as feed ingredient for shrimp by an approach of solid-state fermentation with Bacillus subtilis E20. The protein content and B. subtilis E20 proliferation significantly increased, as the initial moisture increased from 30% to 50% during fermentation. Compared with SBM, the protein content of FSBM increased by 19% after fermentation, accompanied by an increase of 18.75% in the total hydrolyzed amino acids. The free amino acid profile and content in FSBM also obviously increased by 374.9% compared with SBM. The FSBM is a good substitute for fish meal (FM) in a diet with 37% protein and 7% lipid content. The maximal replacement levels of FM in shrimp diet with SBM and FSBM were 37.42% and 61.67%, respectively, based on the feed efficiency estimated by a broken-line analysis. The B. subtilis E20-FSBM can be a potential protein source used as a replacement for FM in shrimp diet.