Aquaculture 2022

February 28 - March 4, 2022

San Diego, California

PRODUCING INFERTILE SALMONIDS FISH FOR AQUACULTURE BY AN IMMERSION-BASED GENE SILENCING TECHNOLOGY

 

Lan Xu* ,  Yonathan Zohar  and Ten-Tsao Wong

 

 Department of Marine Biotechnology & Institute of Marine and Environmental Technology

University of Maryland Baltimore County , Baltimore, MD 21202

xulan1@umbc.edu

 



 It is imperative that highly effective containment methods are available to prevent  highly selectively bred aquaculture animals escaping  from captivity and propagate and/or interbreed with wild stocks. The use of reproductively sterile farmed animals is the  most  effective strategy for genetic-containment in aquaculture.  Sterility carries environmental significance,  preventing the escapees from spreading and genetic mixing with natural populations .  Sterilization  also prevents sexual maturation and minimizes energy input toward gonadal growth while enhancing flesh development and promoting animal health . Furthermore, sterility is a means for producers to protect their valuable strains from unauthorized propagation.

We have developed a technology to efficiently produce infertile fish by disrupting primordial germ cell development in embryos without  introducing any genetic modification. This technology administers Vivo -conjugated  Morpholino oligomer (MO) through bath-immersion targeting  at Deadend (Dnd), an essential protein for early germ cell development in fish ,  which led to the elimination of germ cells and consequently sterile fish.

 We have applied this novel sterilization technology to several salmonids, including rainbow trout, Atlantic salmon, and coho salmon. In coho salmon, the treated fish and control fish were reared for 14 months before examining their gonadal development. Infertile coho salmon (Fig.1 C & c) with the absence of gonad were achieved through dnd knock-down by immersion. Histology also shows the devoid of any germ cells in treated sterile fish compared with control fish. Optimizations towards better survival and higher sterility rates are ongoing. These sterile animals also provide excellent opportunities to study the involvement of germ cells/gonads in the development and regulation of the reproductive neuroendocrine axis. The contrast of gene expression profiles between 3-year-old sterile and fertile rainbow trout in spawning season is discussed.