CRISPR/Cas9-mediated mstnb1 disruption enhances growth in rainbow trout

This study was conducted to determine the effects of knocking out the myostatin gene ( mstnb1 ), which restricts muscle development in rainbow trout ( Oncorhynchus mykiss ), using CRISPR/Cas9 technology on growth performance and feed efficiency. Within the scope of this research, which aims to increase sectoral productivity in aquaculture, two different gRNAs targeting the first exon of the mstnb1 gene were designed. Sanger sequencing analyses confirmed the successful creation of mutations in the F0 generation, involving a 5 bp deletion with gRNA1 and a 1 bp insertion and 6 bp deletion with gRNA2. During a 10-month follow-up period between May 2024 and March 2025, the growth parameters of mutant individuals were compared with a wild-type (WT) control group. At the end of the experiment, mutant fish reached an average weight of 825.0 ± 12.3 g, while the WT group remained at 464.1 ± 9.2 g. These results demonstrate that CRISPR/Cas9-mediated mstnb1 disruption successfully induces the "double muscularity" phenotype and has high biotechnological potential in rainbow trout farming, potentially shortening production time and reducing unit costs.