Effects of different fatty acids on cell differentiation and lipid accumulation in preadipocytes of warm water fish cobia (Rachycentron canadum Linnaeus, 1766)

This study investigates the effects of four predominant constituent fatty acids of fish oils, including palmitic acid (16: 0, PAM), oleic acid (18: 1n-9, OLA), eicosapentaenoic acid (EPA, 20: 5n-3) and docosahexaenoic acid (DHA, 22: 6n-3), on cell differentiation and lipid accumulation in the primary culture of cobia preadipocytes. Time-serial (0-20 days) comparisons of the changes in the expression of relevant genes and late-stage (Day 20) adiposity including lipid droplet size and lipid accumulation of the differentiating preadipocytes were also studied. Lipid accumulation was significantly higher when adipocytes were incubated with OLA compared to EPA and DHA and with DHA compared to EPA. Although the expressions of transcription factors C/EBPb and PPARc were significantly higher when treated with EPA than with DHA in the early stage (Day 4), the lipogenic genes FABP1, FATP2 and LPL were equally upregulated. The upregulation by EPA was greater than that by DHA in the late stage (Day 20). Among the fatty acids studied, OLA, which is also abundant in plant oils such as olive or canola oil, was most adipogenic. Although both EPA and DHA were antiadipogenic, EPA was more adipogenic than DHA.