Effect of Host Age and PKH26 Dye Concentration on Stem Cell Viability, Colonization Rate, and Offspring Performance for Production of Xenogenic Catfish

Abstract

Xenogenesis has been identified as an innovative technology for hybrid catfish (♀ channel catfish, Ictalurus punctatus × ♂ blue catfish, I. furcatus) embryo production. Currently, blue catfish donor stem cells are collected and injected into triploid channel catfish embryos without having prior knowledge of the best time for injections. This is problematic, as valuable stem cells may be wasted if a host fish is not injected at the correct point in ontogeny. Thus, this thesis aimed to determine how host age impacts stem cell viability, colonization rate, and offspring performance for production of xenogenic catfish. To visually confirm colonization and proliferation rates, the concentration of PKH26, a cell tracking dye, was also tested. Here, triploid channel catfish embryos were injected with donor-derived blue catfish stem cells on 0, 1, 2, 3, 4, and 5 days post-hatch (DPH) using PKH26 dye. Injections were found to be successful on each injection day, with 3 DPH having the highest overall survival with and without addition of PKH26 dye after 280 DPH, 46.66% and 58.66% respectively. When visually confirming colonization and proliferation of the PKH26 dyed stem cells there was a significant difference in fluorescence between triploid channel catfish injected on 0 and 5 DPH post-hatch. Concentrations of PKH26 dye were tested in relation to cell viability and time post-staining. Donor-derived stem cell solutions lost viability post-staining with most concentrations of PKH26. The number of overall cells available for injection declined within five min post exposure to PKH26. Together, these findings, suggest that the injection of stem cells into triploid channel catfish should take place quickly and specifically within ~5 min post completion of the PKH26 dying process.