This study was conducted to optimize the fermentation process of rapeseed meal and to evaluate the quality of fermented rapeseed meal,so as to provide a theoretical basis for the development and utilization of rapeseed meal in aquaculture industry.In this experiment,Bacillus subtilis,Saccharomyces cerevisiae and Lac-tobacillus plantarum were used for solid-state fermentation of rapeseed meal.First,the ratio of different mixed strains,the concentration of cellulase and phytase were optimized.Then the contents of glucosinolates,tannins and phytic acid,crude protein,acid-soluble protein,total acid and pH were used as evaluation indicators.Un-der optimized conditions,rapeseed meal was fermented to evaluate the quality of rapeseed meal before and after fermentation.The results showed as follows:the optimal mixed strains ratio were Bacillus subtilis∶Saccharomy-ces cerevisiae∶Lactobacillus plantarum=1∶1∶2.The optimal cellulose concentration required for fermented rapeseed meal was 1.25%and the phytase concentration was 0.10%.After rapeseed meal was fermented,the contents of glucosinolate,phytic acid and tannins were 33 μmol/g,44.49 mg/g and 9.53 mg/g,respectively,and the degradation rates were 41.92%,40.10%and 59.31%,respectively.The crude protein and acid soluble protein contents increased by 16.59%and 41.85%compared with initial rapeseed meal.The total acid content of fermented rapeseed meal increased by 109.43%,and the pH decreased from 6.53 to 5.68.This study pro-vides a reference for improving the value of rapeseed meal.This study is beneficial to the research on the appli-cation of rapeseed meal as a plant protein source in animal production.[Chinese Journal of Animal Nutrition,2024,36(1):650-657]