The need for more information on the resistance to biological and environmental stressors in triploid oysters

Triploid bivalves, specifically oysters, have become an increasingly popular aquaculture product over the last 3 decades due to their superior growth and meat quality. Despite a significant growth advantage, there remain surprisingly few consistent physiological or metabolic differences between diploid and triploid bivalves. This review summarizes the technical approaches used for triploid production before focusing on how triploidy affects key physiological performances, including growth and survivorship, tolerance to environmental stressors, resistance to disease, and immune performances. Survival trends appear to be similar between diploid and triploid oysters, though some immunological features appear to be enhanced in the larger cells present in triploid animals. Broad disease trends also appear to be similar between diploid and triploid oysters, although this topic remains relatively under-investigated and infrequently considers the genetic background of evaluated stocks, hence large knowledge gaps concerning how ploidy may influence host-parasite dynamics remain. Triploid oysters also seem to be equally capable of tolerating common environmental stressors, but coinciding stress appears to impact them more severely than diploids. The vast majority of work concerning triploid bivalves derive from field-based studies and as such considerable knowledge gaps exist outside of growth and survival prompting the need for more controlled approaches. Specifically, the impact of larger triploid cells that contain 50% more DNA on basic molecular and cellular functioning remains largely unexplored and may represent a fertile ground for fundamental and applied research.