Development of xenotransplantation models for sturgeon germplasm: Zebrafish (danio rerio)

Abstract

Sturgeon are the most endangered vertebrate group in the world (IUCN 2016). Sturgeon are endangered due to anthropogenic factors such as overfishing, industrial activity, and harvesting for their caviar (Pikitch et al. 2005). Xenotransplantation is a model for conservation of endangered sturgeon species, but has not yet been performed between a sturgeon donor and a teleost recipient. The goal of this study was to create sterile triploid surrogates. Zebrafish (Danio rerio) were used as model organisms to lay the foundation for the xenotransplantation process for shortnose sturgeon (Acipenser brevirostrum) germplasm to blue tilapia (Oreochromis aureus) surrogates. Triploid induction was tested using a heat shock method. Indicators of ploidy were examined using erythrocyte imaging and larval morphology analysis. A linear discriminant analysis was run on larval morphology traits to discriminate between 14-day old heat shock and non-heat shock larvae. As well, reanimated cryopreserved sturgeon gonad tissue was dissociated and run through a Percoll gradient to determine gonad cell isolation. A t-test revealed a significant difference in survival between heat shock and non heat shock zebrafish embryos at 24 hours post fertilization (t = 15.649, df = 4, p-value = 9.739e-05). Survival was significantly greater for the non-heat shock group compared to the heat shock group. The linear discriminant analysis reported discrimination between the heat shock versus non heat shock zebrafish embryos with an accuracy of 80%. Sturgeon cells were dissociated and colonized the top three Percoll gradient layers. The methodology employed in this study is essential to the research on sturgeon germline chimerism. More specifically, my study contributes to the production of triploid surrogates for transplantation of sturgeon oogonial cells in order to preserve valuable genetic information that is at risk of extinction.