Using the host fish, the host fish in surrogate parent fish farming for performing the induction of differentiation into different system or a fish of separation germ cells of different types were transplanted into the host fish germline, of transplanted isolated germ cells to improve the engraftment potential to host gonads, to provide a method to increase the transplant efficiency and challenges in the induction of differentiation into germline by implantation of isolated germ cells, for the problem-solving, from fish the separation germ cells, in the differentiation method of inducing to germline of separation germ cell which consists of implanting into the host fish individual by implantation into the abdominal cavity of the host fish before and after hatching, the host fish individuals who received the transplant, transplant is a low water temperature than the previous host rearing water temperature, and, at a temperature which does not adversely affect the generation and survival of the host fish individuals, move separation germ cells were transplanted into the peritoneal cavity of the host fish is to host the gonads, to the engraftment the time required to, by breeding, to improve the engraftment potential to host fish gonads of separation germ cells, to increase the transplant efficiency in induction of differentiation into germline by implantation of separation germ cells.宿主魚類を用い、宿主魚類とは異系統又は異種の魚類の分離生殖細胞を宿主魚類に移植して生殖細胞系列への分化誘導を行う代理親魚養殖等において、移植した分離生殖細胞の宿主生殖腺への生着能を向上させて、分離生殖細胞の移植による生殖細胞系列への分化誘導における移植効率を増大する方法を提供することを課題とし、該課題解決のために、魚類由来の分離生殖細胞を、孵化前後の宿主魚類の腹腔内への移植により宿主魚類個体に移植することからなる分離生殖細胞の生殖細胞系列への分化誘導方法において、移植を受けた宿主魚類個体を、移植前の宿主飼育水温より低水温であり、かつ、宿主魚類個体の生存と発生に悪影響がでない温度で、宿主魚類の腹腔内へ移植した分離生殖細胞が宿主生殖腺への移動、生着をするのに要する期間、飼育することにより、分離生殖細胞の宿主魚類生殖腺への生着能を向上させ、分離生殖細胞の移植による生殖細胞系列への分化誘導における移植効率を増大する。
