Zinc effects on the juvenile stage physiology of the common cuttlefish Sepia officinalis and immune system study in order to develop in vitro tools

Cuttlefish eggs and juveniles grow inshore where anthropic contamination is high. Following studies on the impact of trace metals on Sepia officinalis egg stage, this work intends to determine the sensitivity of cuttlefish juvenile stage against the trace metal zinc, using diverse biomarkers. Our results showed the low ability of juvenile cuttlefish to regulate the assimilation of dissolved zinc, resulting in an important zinc-sensitivity. Non-lethal exposures (i.e. < 200 μg L -1 ) for periods from one week to two months post-hatchling impacted enzymes involved in digestion and immunity, as well as growth and behavior. For concentrations of 50 μg L -1 and above, trace metal homeostasis modifications were further demonstrated, resulting in fascia damages after a six-week exposure. Moreover, the rearing of prey adapted to juvenile cuttlefish was set up in order to assess trophic contamination.

            The tissue repartition of enzymes involved in cuttlefish’s immune system (phenoloxidases, lysozymes and protease inhibitors) was described, as well as the characterization of hemocyte, in order to provide tools to study early effects of contamination on cuttlefish. This work allowed the development of in vitro culture to study cuttlefish’s immune system in a specific manner.

Keywords : Cuttlefish, Zinc, Pollution – Environmental aspects, Physiology, Immune system, Cephalopoda.