Developing technologies to produce reproductively sterile finfish and oysters, and characterizing changes of gene expression in the pituitary of sterile fish by single-cell RNA sequencing

Abstract

Aquaculture is the fastest-growing food sector and is viewed as a long-term sustainable approach to meet the rising global demand for seafood. During the expansion and advancement of aquaculture, minimizing ecological impacts should be pursued concomitantly with maximizing production. Undesired maturation and reproduction are major challenges in aquaculture in terms of genetic introgression, precocious maturation, and reproduction-related mortality, which can have profound ecological and economic impacts. Farming reproductively sterile animals effectively mitigate these challenges and promote environmentally and economically sustainable aquaculture practices. We have developed a novel immersion-based gene-silencing sterilization technology in zebrafish, which has enormous application potential for aquaculture. This dissertations aimed to 1) transfer the novel technology and apply it to aquaculture species, using salmonids and oysters as the models, and evaluate their gonadal development; 2) advance this technology in a traceable manner using fluorescence-labeled Morpholino; 3) investigate the changes of gene expression in the pituitary of sterile fish by single-cell RNA sequencing. The successful production of sterile salmonids achieved in this study demonstrated a proof of principle for this new sterilization technology, facilitating future transfer and application to other commercially important finfish aquaculture species. The delivery of traceable fluorescence-labeled Morpholinos represented a strategy that can accelerate the development and optimization of this technology in both finfish and oysters. Comparing gene expression in the pituitaries between fertile and sterile female fishes provided new insights into pituitary responses to the absence of ovary development at a single-cell resolution. The development and advancement of sterilization technologies in this study would facilitate farming sterile populations, promote cost-effective and ecologically responsible aquaculture practices, and serve as a model for expanding sustainable aquaculture globally.