Embryonic development, survival and growth of triploid Zebra Clam II strain of the Manila clam Ruditapes philippinarum

Triploid breeding with large individuals, high yield, and excellent disease resistance is widely used in aquaculture. However, the functional roles of triploid in the Zebra Calm II strain of Manila clam Ruditapes philippinarum has not been highlighted. In this study, the Zebra Clam II strain of the Manila clams were treated with cytochalasin B (CB) at a final concentration of 0.5 mg/L at 26 degrees C for 17 min to induce triploidity. The results showed that triploid induction rate of first-hatched D-larvae was 64.73 % and the triploid proportion of 180-day-old larvae was 72.5 %. Furthermore, the hatching rate in triploid (60.54 +/- 2.19 %) was significantly lower than that in the control group (92.47 +/- 0.58 %) (p < 0.05). Moreover, the development time of D-larvae in the experimental group was delayed by 145 min, and the survival rate of 15-day-old larvae in experimental group (46.08 +/- 4.49 %) was significantly lower than that in the control group (62.57 +/- 2.68 %) (p < 0.05), but have no significantly changes in the survival rate of triploids in larval to adult stages (p > 0.05). However, the daily relative growth rate of experimental group was significantly higher than that the control group at all daily ages except 360 days (p < 0.05). Moreover, at 480 days of larvae, the growth of the shell length and shell width in the experimental group was 19.2 % and 22.3 % higher than that in the control group, respectively. Altogether, the results in this study provide a scientific basis for the triploid breeding of Zebra Clam II, which has great potential to improve the quality and efficiency of clam farming.