Submitted to: Global Aquaculture Advocate
Publication Type: Trade Journal
Publication Acceptance Date: 3/21/2006
Publication Date: 5/21/2006
Citation: Hershberger, W.K., Hostuttler, M.A. 2006. Development of tetraploid rainbow trout may yield improved triploid production. Global Aquaculture Advocate 2006 April/May Pg 80 & 82.
Technical Abstract: The culture of sterile triploid rainbow trout, which carry three sets of chromosomes, can limit losses to sexual maturation and reduce potential problems regarding interactions of escaped fish with natural stocks. We are investigating the development of tetraploid strains that, when crossed with the appropriate diploid strain will create more productive triploids. One of the first hurdles to be overcome in this investigation was to devise treatment procedures that reliably induced tetraploids in a number of different rainbow trout strains. We developed a protocol using hydrostatic pressure treatment that seemed to provide more consistent induction of triploid rainbow trout that previously reported procedures. The current protocol is to treat fertilized eggs incubated at 10 C with 9,000 psi for eight minutes starting 65% of the time required to reach the two cell stage. Crosses made with the tetraploids formed yielded the expected results and the average abnormality level was no different than that expected from crosses using normal diploids. A preliminary growth study using triploids produced from crosses with tetraploid males X diploid females and with tetraploid females X diploid males, and comparing them to normal diploids revealed that the performance of some of the triploids was better than the other groups. Results to date suggest promising potential for the use of tetraploid rainbow trout strains to yield improved triploids for production.