Comparative analysis of biochemical composition, amino acids, and fatty acids among diploid, triploid, and tetraploid Crassostrea gigas

Tetraploid oysters are artificially produced oysters that do not exist in nature. The successful breeding of 100% triploid oysters resolved the difficulties with traditional drug–induced triploids such as the presence of drug residues and the low triploid induction rate. However, little is known concerning the biochemical composition and nutrient contents of such tetraploids. Therefore, we investigated compositional differences among diploid, triploid, and tetraploid Crassostrea gigas as well as between males and females of diploids and tetraploids. The findings indicated that glycogen, EPA, ∑PUFA and Omega-3 contents were significantly higher in triploid oysters than in diploid or tetraploid; tetraploid oysters had significantly higher C14:0, essential amino acid, and flavor-presenting amino acid contents than diploids or triploids, while diploid oysters had the highest protein content. For both diploid and tetraploids, females had significantly higher levels of glutamate, methionine, and phenylalanine than males but lower levels of glycine and alanine. In addition, female oysters had significantly more EPA, DHA, omega-3 and total fatty acids, a result that may be due to the fact that gonadal development in male oysters requires more energy to sustain growth, consumes greater amounts of nutrients, and accumulates more proteins. With these results, important information is provided for the production of C. gigas , as well as the basis and backing for genetic breeding of oysters.