Tilapia has an obvious sexual dimorphism, and the male is larger than the female, which means a fish production increase in approximately 1.4 times if all males' tilapia mono sex cultures are used. Mono sex culture of tilapia has shown to be a very good tool to increase the level of tilapia production. In aquaculture, sexual reversion of tilapia is carried out by the administration of steroid hormones to larvae from the moment of re-adsorption of the vitelin sack. Steroid hormone is administered during 45 days, when susceptibility to diseases increases. The effectiveness of sexual reversion is below 85 percentages. Many countries are in favor of marketing ecological animals, free of toxic and chemical substances, such as sexual steroids.
In our centre, we have developed a technology for obtaining homogametic brook stocks in O. aureus tilapia that can guaranty “all-male” mono sex progenies. This technology avoids consumers from eating steroid treated tilapia. Experiments carried out in a fish farm, shown that productivity is normally 45 % higher than bisexual tilapia culture. Our main gold is to make available this technology to fish farms which are in charge of producing tilapia fries.
With this project in practice, a new bank of ZZ homogametic female's tilapia of O. aureus could be formed. It would allow continuous production of all male fries of this important species; and consequently, generate the amounts required by the stations in the country to produce tilapia intensively at large scale.
The advantage of not using hormones and other chemicals in tilapia production for human consumption, increase the added value of our production, since these are genetically males tilapia. Besides, there is more efficiency in the use of feed, because the male have a better nutrient conversion rate; competition over food among generations is avoided as well, since they do not reproduce.
