Transgenic catfish expressing the Caenorhabditis elegans fat-1 gene offer a promising biotechnological approach to enhance the production of omega-3 polyunsaturated fatty acids, providing an alternative nutritional source for these essential lipids. The application of xenogenesis, an emerging reproductive stem cell surrogacy technology, may facilitate reproduction in transgenic catfish lines. Although gonadal stem cells are traditionally used for xenogenesis, stem cells from other tissues may be a better option when collecting from mature fish. The present study aimed to evaluate the colonization and proliferation efficiency of kidney stem cells isolated from mature fat-1 transgenic channel catfish, Ictalurus punctatus, following transplantation into triploid channel catfish recipients.
At 5 days post hatch (DPH), triploid channel catfish fry were injected with PKH26 labeled kidney derived stem cells (unpurified) obtained from sexually mature fat-1 transgenic channel catfish. Colonization of donor cells was evaluated in recipients using PKH26 dye fluorescence to calculate percent cell and cluster areas. PCR analysis was utilized to determine the percentage of host gonads transgenic for fat-1. No significant differences in body weight, total length and survival were observed between the kidney stem cell injected group and the non-injected control group at 45 and 90 DPH (P > 0.05). Fluorescent imaging revealed that percentage cell area and cluster area were significantly increased from 45 to 90 DPH in kidney stem cells injected treatment (P < 0.05). According to PCR analyses, 75% and 62.5% of recipients were identified as positive for fat-1 at 45 and 90 DPH, respectively. Taken together, these results demonstrate the potential for perpetuating transgenic catfish lines through xenogenesis. Since stem cells are isogenic, this approach may be valuable for propagating superior performing individuals.