June 24 (SeeNews) - The blue-chip SOFIX index of the Bulgarian Stock Exchange (BSE) added 0.79% to 554.54 points on Thursday, backed by a 6.49% increase in the share price of poultry producer Gradus [BUL:GR6] and a 4.05% rise in the shares of drug maker Sopharma [BUL:SFA], bourse data showed.