Parental contribution and growth hormone gene polymorphism associated with growth phenotypes of red sea bream Pagrus major in mass production: A case study

Red sea bream is one of the most important aquaculture fish species in Japan. To improve the productivity of this fish during seed production, improved growth traits and reduced size variation are needed. In this study, we assessed parental contribution of fast- and slow-growing individuals observed in two different rearing phases in a mass production lot: (1) 50 dph reared in a tank and (2) 200 dph reared in a net cage. We also assessed GH gene (pmaGH) polymorphisms based on a previously developed minisatellite DNA marker. Specific broodstock individuals were significantly associated with fast- or slow-growing individuals at 50 dph and 200 dph. Significant differences in pmaGH minisatellite allele frequencies were observed between fast- and slow-growing groups at 50 dph in the frequency of two alleles (pmaGH-740 and pmaGH-900, respectively). Combining the results of DNA parentage analysis and pmaGH minisatellite allele analysis, one dam and two sires, possessing pmaGH-740, were significantly associated with the slow-growing groups. These results suggest that the minisatellite marker of pmaGH could be a useful tool for growth selection of this fish species.