Search

Triploid oysters have been used for farming to improve growth but have not been created in the Kumamoto oyster, Crassostrea sikamea, which is one of the crucial aquaculture species on the southern coast of China. In the present study, triploids were created using cytochalasin B to inhibit polar body II release in C. sikamea, with the untreated oysters as controls. Triploidy rates of 87 and 57.67%, on average, were obtained in larvae and adults, respectively. Larval growth and survival of the triploid were significantly lower than that of the controls (p < 0.05). In contrast, the triploid postlarvae and adults had a significant growth advantage over the controls (p < 0.05) during the period of 180 (December) to 450 days (September of the next year). Moreover, the triploids clearly exhibited significant sterility in the reproductive season. The glycogen and triglyceride contents in the gonad, adductor muscle, mantle, and gill were higher in triploids than in controls from 180 to 450 days. As a result, high physiological energy supply was strongly correlated with superior growth and reduced reproduction in triploid C. sikamea. The triploid C. sikamea is an excellent oyster species and can be used to improve growth for C. sikamea farming. [ABSTRACT FROM AUTHOR]

The Kumamoto oyster, Crassostrea sikamea , is a potential aquaculture species with a unique shape and delicious taste. It is naturally distributed along the coasts of East Asia, but it was inadvertently introduced into America from Japan, and has formed several geographic populations. In order to evaluate the aquaculture potential of C. sikamea hybrids, a complete diallel cross between two geographical populations (China and America) was conducted by using mixing gametes at an experimental station in Zhanjiang, Guangdong Province in southern China. Two intra-population mating groups (CC and AA) and two reciprocal inter-population crosses (CA and AC) were produced in triplicates. High fertilization rate and hatching rate were observed in all experimental groups, suggesting that there was no sperm-egg recognition barrier between these two geographic populations. Throughout the life cycle, the survival rate of reciprocal hybrids was higher than that of pure breeds. The heterosis in growth of whole weight of reciprocal hybrids in adulthood was significant, which was mainly influenced by mating strategy. In view of the performance difference between the progenies of the two pure populations, the aquaculture potential of the progenies of the American C. sikamea population was higher than that of the progenies of the Chinese indigenous population. The results demonstrated that the crossbreeding between Chinese and American C. sikamea populations can produce considerable heterosis, which can improve the C. sikamea aquaculture industry in southern China. • The survival rate of reciprocal hybrids was higher than that of pure breeds; • The progenies' performance of the American C. sikamea population was higher than those Chinese's population; • Crossbreeding between Chinese and American C. sikamea populations can produce considerable heterosis. [ABSTRACT FROM AUTHOR]