饥饿胁迫对刺参(Apostichopus japonicus)免疫和生长的影响

为了探究饥饿胁迫对刺参免疫和生长的影响，在11?13℃条件下，研究体质量为(20±0.15) g的刺参在不同时间(0、10、20、30、40、50、60 d)，饥饿胁迫对体腔液中酸性磷酸酶(ACP)活性、溶菌酶(LZM)活性、超氧化物歧化酶(SOD)活性、呼吸爆发(RB)活性、吞噬活性以及对刺参体质量、脏壁比、存活率的影响。研究结果表明，随着饥饿时间的延长，刺参体腔液中的ACP活性、LZM活性呈现降低的趋势，饥饿60 d后，比初始值分别下降47.06%、17.57%；SOD活性、RB活性和吞噬活性呈现出先上升后下降的趋势，分别在饥饿胁迫第20、20、10天时达到最高值依次为32.88、0.328、1.35 U/ml，其后显著下降，第60天时显著低于初始值，分别下降27.87%、38.08%、53.43%；其体质量在第60天时为初始体质量的68.08%，呈现负生长；脏壁比逐渐增大，第60天时为0.56，显著高于初始值0.44 (P<0.05)。随着存储营养物质的消耗，刺参体质量损失率增加，存活率下降，存活率与体质量损失率之间存在着y = ?0.0354x2+0.4354x 99.117的函数关系，呈二次曲线线性负相关。研究结果显示，饥饿时刺参通过消耗体内的营养物质来满足机体需要，长期的饥饿有可能降低刺参的免疫能力，直接影响刺参的健康和生长。

Starvation Stress Effect on the Immunity and Growth of Sea Cucumber Apostichopus japonicus

In this study we investigated the effects of starvation on the growth and immunity of sea cucumber Apostichopus japonicus. Sea cucumber seedlings with the initial weight of (20±0.15) g were exposed to starvation stress for different periods (0, 10, 20, 30, 40, 50, and 60 d). Non-specific immunity including activities of acidic phosphatase (ACP), lysozyme (LZM), superoxide dismutase (SOD), respiratory burst (RB), and phagocytic activity of coelomic fluid were examined to determine the effects of starvation on the immune responses. The body weight, the ratio of viscera to body wall (VBWR), and the survival rate were measured to determine the effects on the growth. The ACP and LZM activities decreased along with the starvation time: after a 60-day starvation the ACP and LZM activities decreased by 47.06% and 17.57% respectively. The activities of SOD, RB and phagocytosis first increased and then decreased during the 60-day starvation, and they reached their highest values on the 20th, 20th and 10th day respectively. On the 60th day the activities of SOD, RB, and phagocytosis were significantly lower and reached 27.87%, 38.08%, 53.43% of their initial values respectively. The body weights of the sea cucumbers constantly decreased along with the starvation time and reached 68.08% of the initial value on the 60th day. The VBWR increased gradually during the experiment and reached 0.56 on the 60th day which was significantly higher than the initial value 0.44 (P<0.05). The loss rate of the body weight increased and the survival rate decreased along with the starvation time. There was a negative quadric linear correlation between the loss rate of the body weight and the survival rate. These results indicated that sea cucumbers could consume the nutrients in the body wall to meet their needs of energy during starvation. Long-term starvation might cause suppression of immune activities thus affect the health and growth of sea cucumbers.