Growth performance of transgenic tilapia containing an exogenous piscine growth hormone gene

Three lines of transgenic tilapia were produced harbouring a novel piscine growth hormone (GH) gene construct containing a chinook salmon growth hormone gene spliced to ocean pout antifreeze gene regulatory sequence. One copy to multiple copies of the transgenes were integrated at a single site in the host genome. The initial transmission rate from G0 to G1 generation was found to be less than 10% in these 3 lines indicating a mosaic distribution of the transgene in the germ cells. However, transmission rates from G1 to G2 were found to follow the expected Mendelian ratio. Expression of chinook salmon GH was demonstrated in G0, G1 and G2 transgenic fish in these lines and resulted in dramatic growth enhancement. The average weight of the G1 and G2 transgenic fish was found to be 3 times (P < 0.001) greater than that of their nontransgenic siblings. (C) 1999 Elsevier Science B.V. All rights reserved.