Heritability estimates for nutritional quality-related traits of the Pacific oyster, Crassostrea gigas

Pacific oysters, Crassostrea gigas, are the most abundantly harvested shellfish in the world and are ecologically significant. The content of nutrients, including protein, glycogen, lipid, zinc (Zn), and selenium (Se), is important for oyster meat quality, but heritability estimates of such traits have rarely been reported. In this study, 64 full-sib families were generated using a nested mating design. Finally, 18 full-sib families, of which there were nine half-sib families, with each containing 2 full-sib families, were sampled for heritability estimates. The narrow-sense heritabilities of glycogen, protein, lipid, Zn, and Se contents were 0.29 +/- 0.02, 0.38 +/- 0.02, 0.58 +/- 0.08, 0.02 +/- 0.02, and 0, respectively. Negative genetic correlations existed between both glycogen and protein content (-0.95 +/- 0.004) and between lipid and protein content (-0.59 +/- 0.05), whereas a positive correlation was observed between lipid and glycogen content (0.16 +/- 0.06). Weak genetic and phenotypical correlations (r = 0-0.2) were observed between shell height and nutritional quality traits. These data demonstrated that glycogen, protein, and lipid content can be chosen in a selective breeding program, but glycogen and lipids cannot be selected together with protein. Furthermore, performing indirect selective breeding for quality traits by selecting traits related to growth is impossible. This study provides information for the development of breeding strategies for oyster quality traits.