Using a complete diallel mating system, growth and nutrient composition of muscle tissue, expression oflipid metabolism enzyme genes, and the relationship between crude lipid content and mRNA levels of a lipid metabolismenzyme were compared between two species of tilapia, . At the end of an experimental period of 100 days, the specific growth rate of pure-bred progeny of GIFTtilapia was significantly higher than that of the two hybrids and the pure-bred progeny of . The feed conversionrate, hepatosomatic index, and viscerosomatic index of pure-bred progeny of were significantly higherthan those of experimental groups. There was no significant difference in the moisture, ash, orcrude protein content.Crude lipid content of pure-bred GIFT tilapia progeny was significantly higher than that of other groups. Total aminoacids, essential amino acids, and dispensable amino acids of pure-bred progeny were significantly lower thanother groups. The rate of essential amino acid formation in four Fgenerations was consistent with FAO/WHO standards.Saturated, single unsaturated, polyunsaturated, and n-6 polyunsaturated fatty acids of pure-bred GIFT tilapiaprogeny were significantly higher than those of the two hybrids and the pure-bred progeny of . Correlationanalysis showed a negative relationship between muscle crude lipid content and mRNA levels of FAS (progeny were significantly lower than of GIFT tilapia or hybrids.Thus, hybridization may increase growth performance of offspring and improve meat quality, as well as enhancing theeffect of selective breeding. Although there were no significant differences in mRNA levels of betweenthe two hybrids of GIFT tilapia, higher muscle crude lipid content may amplify mRNA levels of