Perspectives on avian stem cells for poultry breeding

Spermatogenesis regeneration by transfected spermatogonial stem cells in infertile roosters through testicular transplantation

Investigations pertaining to spermatogonial stem cells (SSCs) have led to the use of these cells in a variety of fields including infertility treatments, production of transgenic animals, and genome editing. The aim of the present study was to investigate the plausibility of regenerating spermatogenesis in infertile roosters by transplanting transfected SSCs into testes. Spermatogonial stem cells were isolated and cultured for seven days. Afterward, pDB2, a plasmid vector carrying a reporter gene, GFP, was transfected into the SSCs. Transfected SSCs were transplanted into the left testis of infertile roosters. Tissue samples from the recipients' testes were obtained six weeks after the transplantation and transplanted SSCs were observed in the basement membrane. After eight weeks, GFP-positive spermatozoa were observed in collected semen from the recipient roosters and GFP gene in spermatozoa was confirmed using PCR. The recipient roosters were mated with hens. Hatchlings were visually checked and their tissue samples were tested by PCR to identify transgenesis but both of them were negative. Overall, it seems that regeneration of spermatogenesis in roosters via transfected SSCs is possible but more studies are need to produce recombinant proteins by this way.

Effects of feeder cells on proliferation of inducible pluripotent stem cells in chicken

Although inducible pluripotent stem cells (iPSC) have been identified in poultry, the induction efficiency is low, because different culture media, feeder cells and feeder layer treatments affect the efficiency of somatic cell reprogramming. We investigated improvement of the feeder culture system for induction of chicken iPSC by comparing the effects of different types and treatments of feeder cells on the growth and proliferation of chicken iPSC. Mouse embryo fibroblasts (MEF), but not Sandoz inbred mouse-derived thioguanine-resistant and ouabain-buffalo rat cells, were suitable feeder cells that supported proliferation of chicken iPSC. Institute of Cancer Research (ICR) mice, but not Kunming mice, were suitable for preparing MEF that support cell proliferation. Also, MEF feeder cells that had been inactivated by mitomycin C were effective. Leukemia inhibitory factor was not required for chicken iPSC culture when MEF feeder cells were used. The optimal feeder culture system for growth and proliferation of chicken iPSC consisted of MEF feeder cells derived from ICR mice that were inactivated by mitomycin C combined with embryonic germ cell culture medium.

Advances in Isolation and Culture of Chicken Embryonic Stem Cells In Vitro

Chicken embryonic stem cells (cESCs) isolated from the egg at the stage X hold great promise for cell therapy, tissue engineering, pharmaceutical, and biotechnological applications. They are considered to be pluripotent cells with the capacity to self-renewal and differentiate into specialized cells. However, long-term maintenance of cESCs cannot be realized now, which impedes the establishment of cESC line and limits their applications. Therefore, the separation locations, isolation methods, and culture conditions especially the supplements and action mechanisms of cytokines, including leukemia inhibitory factor, fibroblast growth factor, transforming growth factor beta, bone morphogenic protein, and activin for cESCs in vitro, have been reviewed here. These defined strategies will contribute to identify the key mechanism on the self-renewal of cESCs, facilitate to optimize system that supports the derivation and longtime maintenance of cESCs, establish the cESC line, and develop the biobank of genetic resources in chicken.

Enhancement of chicken primordial germ cell in vitro maintenance using an automated cell image analyser

Primordial germ cells (PGCs) were isolated from blood samples of chicken embryos. We established four PGC lines: two males (FS-ZZ-101, GFP-ZZ-4ZP) and two females (FS-ZW-111, GFP-ZW-5ZP). We could not detect a significant difference in the marker expression profile, but there was a remarkable difference between the proliferation rates of these PGC lines. We monitored the number of PGCs throughout a three-day period using a high-content screening cell imaging and analysing system (HCS). We compared three different initial cell concentrations in the wells: ~1000 cells (1×, ~4000 (4× and ~8000 (8×. For the GFPZW- 5ZP, FS-ZZ-101 and FS-ZW-111 PGC lines the lowest doubling time was observed at 4× concentration, while for GFP-ZZ-4ZP we found the lowest doubling time at 1× concentration. At 8× initial concentration, the growth rate was high during the first two days for all cell lines, but this was followed by the appearance of cell aggregates decreasing the cell growth rate. We could conclude that the difference in proliferation rate could mainly be attributed to genotypic variation in the established PGC lines, but external factors such as cell concentration and quality of the culture medium also affect the growth rate of PGCs.

Perspectives on avian stem cells for poultry breeding

Stem cells have prulipotency to differentiate into many types of cell lineages. Recent progress of avian biotechnology enabled us to analyze the developmental fate of the stem cells: embryonic stem cells / primordial germ cells (PGCs). The stem cells were identified in the central area of the area pellucida of the stage X blastoderms. These cells could be applied for production of germline chimeras and organ regeneration. Generation of medical substrate in transgenic chickens has considerable interests in pharmaceuticals. Sex alteration of the offspring should be enormously beneficial to the poultry industry. Fertilization of the sex-reversed sperm could lead to sexual alteration of the offspring. These strategies using stem cells / PGCs should be one of the most powerful tools for future poultry breeding.