Estimation of genetic change in the GIFT strain by comparing contemporary progeny produced by males born in 1991 or 2003

During the development of the GIFT (Genetically Improved Farmed Tilapia) strain in Philippines sperm was frozen from a sample of males from founder stocks and subsequent generations. In this paper a comparison of progeny performance produced from cryopreserved sperm from the base population of the GIFT strain, with progeny from freshly colleted sperm from the ninth generation produced in Malaysia was conducted. Differences in performance were used to estimate the genetic change over these nine generations. GIFT proved to be a highly improved strain that had at least a 63 per cent advantage in growth rate accumulated over nine generations of non-continuous selection.