Regulation of small-molecule compounds on LC-PUFA biosynthesis during adipogenic transdifferentiation of Salmo salar muscle cells and preparation of cell-cultured fish fat.

Fish cells possess limited long-chain polyunsaturated fatty acid (LC-PUFA) biosynthetic capacity, representing a key bottleneck for improving the nutritional quality of cell-cultured fish meat (CFM). In this study, stearidonic acid-enriched mixed fatty acids (MFAs) in combination with small-molecule compounds were used to regulate LC-PUFA synthesis during the adipogenic transdifferentiation of Salmo salar muscle cells (SsMCs). The results demonstrated that MFAs promoted the adipogenic transdifferentiation of SsMCs in a concentration-dependent manner, and the combined treatment of MFAs and small-molecule compounds significantly increased intracellular LC-PUFA content. Transcriptomic analysis indicated that this combination might exert its effects through activating adipogenic transcriptional cascades and modulating the expression of fatty acid metabolism-related genes. Moreover, three-dimensional (3D) suspension culture further increased the LC-PUFA content in transdifferentiated cells, an effect potentially attributed to the 3D microenvironment. Volatile compound profiling showed that transdifferentiated SsMCs contained higher relative levels of volatile compounds compared with non-transdifferentiated SsMCs. This study provides a theoretical foundation and technical support for targeted regulation of the nutritional quality of CFM.