1. Introduction
In terms of value, shrimp are the most important seafood product traded globally with production from aquaculture estimated at 3.1 million metric tonnes valued at US$12 billion in 2008 (Shrimp News International, 2009). Domestication and selective breeding of several penaeid shrimpspecieshas resulted in the developmentof elitegenetic lines thathavetraitssuchassuperior growth andsurvivalperformance,