RESUMO
The present study investigated the effects of dietary fish and sunflower oils as sources of n-3, n-6 polyunsaturated fatty acids (PUFA) on the expression of key lipogenic and cholesterologenic genes in subcutaneous adipose tissue (SAT) and tail adipose tissue (TAT) of fat-tailed sheep. Twenty-six male Afshari lambs were divided into 4 groups. Three groups were fed a high concentrate basal diet plus 100 g/lamb/day oil supplement (OS; 60 g sunflower oil and 40 g fish oil) beyond a 21-day adaptation period for 10, 20, and 30 days (groups OS10, OS20, and OS30; n = 6, each) until slaughter. A control group was slaughtered at the last day of adaptation (OS0; n = 4). Expression of PPARγ, SREBP-1c, and SREBP-2 were determined in TAT and SAT. All transcription factors had lower expression in SAT than TAT. Feeding OS induced a similar pattern of SREBP-1c expression in both TAT and SAT with highest values in OS20. SREBP-2 mRNA decreased by > 50% in TAT of OS30 compared to OS0, whereas the expression of SREBP-2 mRNA did not change in SAT in the same period. PPARγ expression was not affected over time either in SAT or TAT. Plasma concentrations of cholesterol and blood urea nitrogen increased in OS20. The comparison of gene expression responses to OS in TAT vs. SAT suggest that PUFA-mediated effects on lipid metabolism differ between SAT and TAT, which may be linked to the specific role of TAT in energy and water balance under arid conditions.
