Germ cell transplantation as a potential biotechnological approach to fish reproduction.

Although the use of germ cell transplantation has been relatively well established in mammals, the technique has only been adapted for use in fish after entering the 2000s. During the last decade, several different approaches have been developed for germ cell transplantation in fish using recipients of various ages and life stages, such as blastula-stage embryos, newly hatched larvae and sexually mature specimens. As germ cells can develop into live organisms through maturation and fertilization processes, germ cell transplantation in fish has opened up new avenues of research in reproductive biotechnology and aquaculture. For instance, the use of xenotransplantation in fish has lead to advances in the conservation of endangered species and the production of commercially valuable fish using surrogated recipients. Further, this could also facilitate the engineering of transgenic fish. However, as is the case with mammals, knowledge regarding the basic biology and physiology of germline stem cells in fish remains incomplete, imposing a considerable limitation on the application of germ cell transplantation in fish. Furthering our understanding of germline stem cells would contribute significantly to advances regarding germ cell transplantation in fish.