饥饿对草鱼非特异免疫水平的影响

研究了长期饥饿对草鱼(Ctenopharyngodon idellus)非特异性免疫水平的影响。实验选取平均体质量(31.86±1.47)g的草鱼,随机分为2个实验组(对照组和饥饿组),每组3个平行,饥饿处理15、30、45和60 d,测定饥饿对草鱼头肾和脾中自然杀伤(NK)细胞的杀伤活性、血清和肝胰脏中溶菌酶活性、血清中碱性磷酸酶活性的影响。结果表明:受饥饿胁迫的影响,草鱼自然杀伤性细胞在脾和头肾中的杀伤活性显著低于对照组(P0.05)且不随着饥饿时间的延长发生显著性变化;随着饥饿时间的延长,血清和肝胰脏中溶菌酶呈现先升高后降低的趋势,血清碱性磷酸酶在饥饿15、45、60 d时显著低于对照组;饥饿组的碱性磷酸酶活性在饥饿30 d以后,维持恒定。由此可见,长时间的饥饿胁迫降低了草鱼的免疫水平。相比较而言,自然杀伤细胞的杀伤活性在反映鱼类免疫状况时比溶菌酶和碱性磷酸酶可能更为灵敏。

Effects of Starvation on the Non-specific Immune Parameters of Grass Carp,Ctenopharyngodon idellus

This paper reports the effects of long-term starvation on non-specific immune parameters of Grass Carp (Ctenopharyngodon idellus). Fish with body weight (31.86±1.47)g were randomly divided into two groups (the control group and the starvation group), and three parallel samples were investigated in each experimental group. Cytotoxicity of natural killer cells against K562 in the spleen and head-kidney was detected by LDH releasing assay when the fish were starved for 15, 30, 45 or 60 d, and the activities of lysozyme in the serum and hepatopancreas and alkaline phosphatase in the serum were also examined. The results indicated that under starvation stress the natural killer activity was significantly lower in starvation group than that in control group in the kidney and spleen of the Grass Carp fingerlings(P<0.05), and the activity no longer prominently decreased as starvation time extended. The activity of lysozyme in the serum and hepatopancreas showed the trend of first-decrease then-increase with the increase of the starvation time and the activity of alkaline phosphatase in the serum was significantly lower compared to the control group on 15 d, 45 d, and 60 d, which maintained at a constant level after 30 d. All these results suggest that under long-term starvation stress the non-specific immune level of Grass Carp fingerlings decreases. Natural killer cell activity is one of the critical indexes to evaluate the cellular immunity, which is more specific and sensitive than the activity of lysozyme or alkaline phosphatase.