Replacement of fishmeal with Shewanella sp. MR‐7 fermented soya bean meal in Pacific white shrimp.

Reducing the usage of fishmeal in shrimp feed has been a demand for the sustainability of aquaculture. An 8‐week feeding trial was performed to evaluate the potential application of fermented soya bean meal (FSBM) with Shewanella sp. MR‐7 in shrimp diet. The diet with 30% fishmeal was set as the control (FM), and four levels of FSBM (15%, 30%, 45% and 60%, referred as F15, F30, F45 and F60) were formulated to replace fishmeal isonitrogenously. The growth performance, biochemical indexes, immune response, intestinal microbiome composition and response to ammonia stress were determined. Results showed that FSBM groups had comparable growth performance with FM group when the replacement level was not more than 45%. Replacement of 60% fishmeal with FSBM significantly depressed the trypsin activity and the expression of immune‐related genes in hepatopancreas. Intestinal microbiome analysis showed the abundance of beneficial bacteria (Romboutsia) in F60 group decreased while potential pathogen (Vibrio and Fusibacter) enriched. Survival rate of F60 group was significantly lower when exposed to ammonia stress for 48 h. Taken together, FSBM with Shewanella sp. MR‐7 could reduce fishmeal level from 30% to 16.5% without inducing inferior performance on shrimp. [ABSTRACT FROM AUTHOR]