Growth studies on juvenile tilapia using pure species, hormone-treated and nine interspecific hybrids

Abstract

. The comparative growth performance of the juveniles of six pure tilapia species, Oreochromis mossambicus, O. spilurus, O. macrochir, O. aureus, O. niloticus and Sarotherodon galilaeus were assessed under standardized conditions in a recirculated water system. The effects of standardized treatments of 17α methyltestosterone and 17β estradiol were assessed by comparison with untreated controls of O. niloticus, O. mossambicus and O. aureus and the growth performance of nine interspecific hybrids in comparison to their parental species were studied. The results showed significant differences in growth rate for the strains of the pure species under the conditions used. Standardized hormone treatment had significant effects on sex ratios and growth performance of all the species studied but did not change their overall performance ranking when compared to the pure species. No hybrid performed significantly better than the best parent for SGR although O. aureus×O. niloticus hybrid was significantly better than O. niloticus when corrected weight gain was used. This work shows that species choice hormone treatment and hybridization have implications for tilapia culture.