The correct word you might be looking for is "xenotransplantation" (xeno-transplant-ation). Xenotransplantation is taking live cells or tissue from one species and transplanting them into another species.. for example, transplanting a heart valve from a pig into a human. You can find more info on it by looking up "medical grafting". When a transplant comes from a human and goes into another human, as in a liver or heart transplant, it's called "allotransplantation".