Testicular germ line cell identification, isolation, and transplantation in two North American catfish species

• Published in: Fish physiology and biochemistry 2018-04, Vol.44 (2), p.717-733
• Main Authors: Shang, Mei, Su, Baofeng, Perera, Dayan A., Alsaqufi, Ahmed, Lipke, Elizabeth A., Cek, Sehriban, Dunn, David A., Qin, Zhenkui, Peatman, Eric, Dunham, Rex A.
• Format: Article
• Language: English
• Subjects: Adults; Animal Anatomy; Animal Biochemistry; Animal embryos; Animal Physiology; Animals; Biomarkers - metabolism; Biomedical and Life Sciences; Blastula; Capacity; Catfish; Catfishes - classification; Catfishes - embryology; Catfishes - growth & development; Catfishes - metabolism; Cell Separation - veterinary; Cell Transplantation - veterinary; Cells, Cultured; Centrifugation; Centrifuging; Density gradients; Embryo, Nonmammalian - cytology; Embryo, Nonmammalian - physiology; Embryos; Fish; Freshwater & Marine Ecology; Freshwater fishes; Fry; Germ cells; Gonads; Heterografts; Histology; Ictalurus furcatus; Ictalurus punctatus; Interspecific; Juveniles; Life Sciences; Male; Morphology; Nuclei; Nucleus; Offspring; Oogonia; Progeny; Spermatogenesis; Spermatogonia; Spermatozoa; Spermatozoa - cytology; Spermatozoa - physiology; Spermatozoa - transplantation; Stem cells; Testes; Testis - cytology; Testis - physiology; Tissue; Transplantation; Zoology
• ISSN: 0920-1742; 1573-5168
• DOI: 10.1007/s10695-018-0467-3

Our aim was to transplant blue catfish germ line stem cells into blastulae of triploid channel catfish embryos to produce interspecific xenogenic catfish. The morphological structure of the gonads of blue catfish ( Ictalurus furcatus ) in ~ 90- to 100-day-old juveniles, two-year-old juveniles, and mature adults was studied histologically. Both oogonia (12–15 μm, diameter with distinct nucleus 7–8 μm diameter) and spermatogonia (12–15 μm, with distinct nucleus 6–7.5 μm diameter) were found in all ages of fish. The percentage of germ line stem cells was higher in younger blue catfish of both sexes. After the testicular tissue was trypsinized, a discontinuous density gradient centrifugation was performed using 70, 45, and 35% Percoll to enrich the percentage of spermatogonial stem cells (SSCs). Four distinct cell bands were generated after the centrifugation. It was estimated that 50% of the total cells in the top band were type A spermatogonia (diameter 12–15 μm) and type B spermatogonia (diameter 10–11 μm). Germ cells were confirmed with expression of vasa . Blastula-stage embryos of channel catfish ( I. punctatus ) were injected with freshly dissociated blue catfish testicular germ cells as donor cells for transplantation. Seventeen days after the transplantation, 33.3% of the triploid channel catfish fry were determined to be xenogenic catfish. This transplantation technique was efficient, and these xenogenic channel catfish need to be grown to maturity to verify their reproductive capacity and to verify that for the first time SSCs injected into blastulae were able to migrate to the genital ridge and colonize. These results open the possibility of artificially producing xenogenic channel catfish males that can produce blue catfish sperm and mate with normal channel catfish females naturally. The progeny would be all C × B hybrid catfish, and the efficiency of hybrid catfish production could be improved tremendously in the catfish industry.