Triploidy can be induced by retention of the second polar body following heat or pressure treatment of eggs. Additionally, triploids can be produced by crossing diploid and tetraploid fish (Chourrout et al. 1986). Normally female triploid rainbow trout are sterile, although some males produce aneuploid sperm. the most popular method for producing triploids is heat treatment of salmonid eggs immediately after fertilization using exposure to 28oC for 10 minutes, starting 10 minutes after fertilization. There is some loss of egg viability and generally some percentage of non-triploid fish come through. In commercial farms, triploid induction by pressure treatment has proved more popular.Sterile triploid male rainbow trout show better long term growth potential because of the absence of sexual development. Sterile triploid salmon are of considerable interest in fish farming since they are not subject to the constraints of seasonality and declining value of sexually maturing fish in the crop. In addition to these benefit, triploid sterilization of transgenic strains of fish could be used to reduce or eliminate the undesirable environmental impact of release or escape of transgenic fish.
Relacted articles:
http://www.ncr.dfo.ca/csas/csas/resdoc/1998/a98_166e.htm
