The effect of triploidization of Atlantic cod (Gadus morhua L.) on survival, growth and deformities during early life stages

Abstract This study investigated the performance of triploid Atlantic cod ( Gadus morhua L.) produced in an intensive feeding system. Eggs pooled from three females fertilized with sperm from two males were either triploidized by hydrostatic pressure (58,600 kPa, 5 min, 6 °C) 30 min post-fertilization, or were maintained as untreated controls, and then reared under identical standard protocols until day 220 post-hatch. Mortality and growth were monitored from start-feeding while vertebral deformities were assessed by radiology on day 220 post-hatch. The triploid cod had lower survival than the diploid group from start-feeding and during early on-growing. On day 53, there was a significantly higher number of deformed fish among the triploid than the diploid cod. There was also a significantly higher prevalence of fish with one or more deformed vertebrae and prevalence of lordosis in triploids than diploids. The triploid group weighed significantly more than the diploid group before onset of feeding. The results of this study, which is the first that deals with skeletal deformities in triploid farmed Atlantic cod, are in line with previous findings that triploid teleosts are more prone to develop bone deformities. However, the mechanisms underlying this phenomenon are, still unknown.