In vitro embryogenesis of Macrobrachium rosenbergii larvae following in vivo fertilization

We are currently engaged in the development of methodologies for gene transfer to crustaceans, using Macrobrachium rosenbergii as a model system. Because this species retains its eggs during embryogenesis, it was necessary to develop a means to bring fertilized eggs to hatching in vitro, in order to be able to manipulate them and introduce foreign DNA at different stages of development. By simulating the natural environment to which the eggs are exposed during their period on the abdomen, and by protecting them against fungal and bacterial infection, we succeeded in detaching them from the female as early as 16 h after fertilization, and in bringing them to the stage of free swimming larvae. Hatching is completed in the normal period of 21 days. Larvae are morphologically indistinguishable from those hatched out in vivo and exhibit normal behavior. This system provides normal embryos at any desired stage for experiments in genetic manipulation.