R. Bras. Zootec.01/Jul/2009;38(special issue):36-42.
Biotechnology applied to salmoniculture
This work presents a conceptual analysis of the main biotechnologies used in Chilean salmoniculture, which is based on the production of Atlantic salmon (Salmo salar, 356.407 t),silver salmon or coho (Oncorhynchus kisutch, 116.481 t), (O. tshawytscha, 2.062 t) and rainbow trout (O. mykiss, 189.178 t).These activities are focused on the photoperiod artificial manipulation to obtain out-of-season spawning, in the use of hormonal therapies which allow synchronizing the final oocyte maturation (FOM) and sexual maturity acceleration or the increase in milt volume produced by males. Such actions are carried out using GnRHa in doses close to 10 µg/kg of fish. Once sexual maturity is reached, in vitro manipulation of gamets must often be done due to either the prolonged storage (particularly milt) they have to undergo in order to transport them where fertilization takes place, or awaiting for the ichtiopathological results, usually taken to broodstock. The production of “all female” populations is also common. Frequently, these populations in rainbow trout are triploided (through shock temperature close to 28º C or pressure close to 8.000 psi) to obtain sterile species which improve productive perfomance of cultured populations without sexual maturity signs. Besides, the perspectives of industrial use of transgenic organisms in the culture of salmonids are analyzed.