Abstract
The study of adipogenesis is one of the most important areas for not only regulating meat quality, but production efficiency associated with fat accretion in the poultry species. Current in vitro models for avian adipogenesis require adipogenic inducers including dexamethasone, 3-isobutyl-1-methylxanthine (IBMX), fatty acids, or insulin. However, problems still remain in these models for testing/screening potential nutritional, hormonal, and pharmaceutical factors because of interfering/overriding effects of the inducing factors. Therefore, the purpose of this study was to develop a simple in vitro method for avian adipogenesis. In this study, chicken serum (CS) and fetal bovine serum (FBS) were compared for adipogenic potential using chicken embryonic fibroblasts (CEF). Oil-red O staining at 4 d in culture of CEF under CS revealed that lipid droplet formation was increased by CS in a dose-dependent manner (0 to 10%). On the contrary, all concentrations of FBS (0 to 10%) alone did not show lipid droplet formation. In accordance with the morphological data of CEF, mRNA expression of genes involved in adipocyte differentiation/determination, fatty acid uptake, and triacylglycerol (TAG) synthesis, were most significantly up-regulated by 10% CS at d 4 compared to 1 or 5% CS. In addition, embryonic cells isolated from quail (QEF) at E5, duck (DEF) at E6, and turkey (TEF) at E6, were tested for adipogenic differentiation by media containing the same concentrations of CS. Similar to the morphological data from CEF, quantitative data of the Oil-red O staining showed that lipid droplet formation in QEF, DEF, and TEF was increased by CS in a dose-dependent manner (0 to 10%). The current study demonstrates that CS alone can induce adipogenesis on embryonic fibroblasts of various poultry species. By providing a new simple in vitro method of avian adipogenesis, diverse nutritional, hormonal, and pharmaceutical factors can be broadly and easily tested for scientific and industrial purposes.