Abstract

Triploid fish are excellent models for use in commercial scale because they can show higher rates of growth, carcass yield and meat quality. If sterile, tambaqui (Colosso mamacropomum) triploids can be used to avoid the problems related to early puberty, especially the negative impacts of male sexual maturation on harvest weight. In the present study, we evaluated the triploidy induction efficiency (thermal shocks) in the fish tambaqui Colossoma macropomum, the most important Neotropical species used for aquaculture. To verify the result of the triploidy experiments, we used a protocol of ploidy identification through analysis of mitotic chromosomes of early life stages (larvae cytogenetics). We obtained better results of hatching and triploid rates through temperature shock at 41°C for 2 min (heat shock) than cold shock. In conclusion, additional treatments will allow to refine the protocols to obtain 100% of triploidy in tambaqui, particularly those from heat shocks. These methodologies can also be applied to other Neotropical fish species, as alternative methods for breeding programs and to delineate conservation plans for the proper management of the stocks.

Keywords

triploid, fish genetics, chromosome manipulation, aquaculture, fish farms, tambaqui,harvest weight, polyploidy, even chemicals, fertilization