An Overview on the Processes Involved in the Production of Triploid Fish for Aquaculture

Abstract

Production of Triploid fish for aquaculture involves the manipulation of chromosome number of cultured fish to produce offspring with three sets of chromosomes. They have a large cell size and nucleus which contains 33% more alleles for growth thereby exhibiting fast growth which is a good culture characteristic. Triploid fish can be produced by applying shock either through temperature (cold shock- 2oC to 6oC and heat shock- 38 to 40oC), pressure (7000 – 10000psi) or the use of chemicals (Cytochalasin B, Nitrous oxide) to fertilized eggs. The use of temperature shock is less expensive with pressure and heat shock giving the best results. The success of shock induction depends on the time and duration of shock, the temperature and pressure used. Sterility in triploids occurs as a result of genetic incompatibility of chromosome sets during meiosis to form two equal haploid sets thereby producing abnormal gametes and the sterility leads to increased growth. Triploids exhibit good carcass quality and can help to increase fish production and reduced the risk of genetic pollution of wild stocks when they are accidentally or intentionally released into aquatic ecosystems. The production of triploids for aquaculture can therefore be encouraged for increased production and the ethical aspects should be addressesed.