Effects of high salinity on growth and survival, Na+/K+-ATPase activity and energy metabolism related indexes of razor clam Sinonovacula constricta

Abstract:

To understand the effects of high-salinity on razor clam Sinonovacula constricta, the razor clams were cultured at salinity of 20 (control group) and 30 (experimental group) for 60 days. The growth and survival, Na⁺/K⁺-ATPase (NKA) activity in gills, and indexes of energy metabolism in hepatopancreas and serum were measured at the time point of 0, 10, 30, and 60 d. The results showed that the survival rate of razor clam cultured in experimental group was 45.1%±2.9% in 30-60 d. The specific growth rate of shell length, shell width, shell height and body weight of razor clam cultured in experimental group were 0.15%/d, 0.17%/d, 0.13%/d and 0.61%/d respectively in 60 days, and all of these indexes were significantly lower than those in the control group. The NKA activity of experimental group was significantly lower than control group at the time point of 0, 10, 30, and 60 d. The activity of hexokinase (HK) in hepatopancreas of control group was significantly higher than experimental group at the time point of 10 and 60 d, the same with glucose (GLU), lactic acid (LA) content and lactate dehydrogenase (LDH) activity in serum, which indicated that the anaerobic metabolism level of experimental group was lower than control group at those two time points. The GLU, LA content and LDH activity in serum of experimental group were significantly higher than those in the control group at the time point 30 d, which indicated that the anaerobic metabolism level of experimental group was higher than control group at the time point 30 d. The succinate dehydrogenase (SDH) activity in hepatopancreas of experimental group was significantly higher than control group at the time point 0, 10 and 30 d, which indicated that the level of aerobic metabolism of razor clam increased under high salt stress. In summary, razor clam can maintain a certain survival rate and a certain growth rate under long-term high-salt culture. The osmotic adjustment and the energy metabolism of razor clam have been affected under high-salt culture, and the osmotic adjustment increased its energy consumption. This study provides reference materials for further cultivation of new high-salt-tolerant strains of razor clam.