SKELETAL DEFORMITIES OF THE GILTHEAD SEA BREAM (SPARUS-AURATA, L) - STUDY OF THE SUBCOMMISSURAL ORGAN (SCO) AND REISSNERS FIBER (RF)

A high incidence of lordotic curvatures has been detected in commercia l cultures of Sparus aurata. We have studied juvenile and adult lordot ic specimens to elucidate whether the subcommissural organ and its sec retion, the Reissner's fiber, play any role in the development of this syndrome. Animals were X-radiographed and then the brain and spinal c ord dissected out and processed for light microscopy. Adult lordotic f ishes had a well developed swim-bladder whereas juvenile did not. The central canal of the spinal cord showed dramatic alterations, and an a ltered Reissner's fiber was always present. Our histochemical results suggested a hyperactivity of the subcommissural organ in lordotic fish es.