April 25 (SeeNews) - The blue-chip BELEX15 index of the Belgrade bourse closed 0.22% lower at 1,003.84 points on Thursday, dragged down by losses in Fintel Energija [BEL:FINT] - the Serbian subsidiary of Italy's Fintel Energia Group - and oil and gas company NIS [BEL:NIIS], bourse data showed.