不同钙、镁浓度对褐牙鲆幼鱼生长及SOD和CAT酶活力的影响

Effects of Ca2+ and Mg2+ concentrations on growth,SOD and CAT enzymatic activity of juvenile Paralichthys olivaceus

中文关键词: 褐牙鲆  钙、镁浓度  生长  SOD和CAT酶活力

英文关键词: Paralichthys olivaceus  Calcium and magnesium concentrations  Growth  SOD  CAT

中文摘要:

      在盐度30和水温20 ℃条件下，配制钙、镁（1∶3）总浓度A(700 mg/L)、B(1 100 mg/L)、C(1 600 mg/L，对照）、D(2 200 mg/L)、E(2 800 mg/L）的人工海水，研究了5种人工海水对褐牙鲆Paralichthys olivaceus幼鱼生长、肝脏超氧化物歧化酶（SOD）和过氧化氢酶（CAT）活力的影响。观察发现，褐牙鲆幼鱼初次接触高钙、镁浓度人工海水（D组和E组）时产生应激反应，鱼体呈弓形，呼吸频率降低，摄食不积极，适应7 d左右恢复正常。经60 d养殖实验，各处理组实验鱼食物转化效率(FCE)无显著差异(P>005)，成活率均在90%以上。0~20 d时实验鱼特定生长率(SGR)和摄食率(FI)差异显著(P<005)，低浓度组大于高浓度组，20 d后，FI无显著差异(P>005)，40~60 d时低浓度组SGR小于高浓度组。各处理组SGR和FI随钙、镁总浓度上升呈下降趋势，实验进行到60d时，低浓度组A的SGR和FI分别为高浓度组E的113倍和104倍。不同钙、镁浓度对实验鱼的免疫酶活性亦有显著影响。D组实验鱼SOD酶活力和肝比重显著高于其他各处理组；E组SOD酶活力显著低于其他实验组(P<005)，CAT酶活力也低于其他处理组，但各组间差异不显著(P>005)。研究结果表明，实验初期钙、镁浓度通过影响褐牙鲆的摄食而影响其生长，低钙、镁浓度组实验鱼生长较快，高浓度组生长较慢。经60d养殖驯化，除E组外的各处理组特定生长率差异不显著，过高浓度钙、镁对褐牙鲆的免疫酶活性产生一定抑制作用。建议养殖褐牙鲆时应注意避免水体钙、镁含量过高。

英文摘要:

      The effects of Ca2+ and Mg2+ concentrations (1∶3) in artificial seawater on growth, superoxidase dismutase（SOD）and catalase（CAT） enzymatic activity of juvenile Paralichthys olivaceus were investigated at 20℃ and salinity of 30. Five concentrations of Ca2+ and Mg2+ were set as follows, 700 (group A), 1 100 (group B), 1 600 (group C), 2 200 (group D), and 2 800 (group E) mg/L, respectively. It was found that stress response occurred including bend of fish body and reduction of ventilation rate and food intake in juvenile fish under high Ca2+ and Mg2+ concentrations and the fish recovered after a week. After 60 d experiment, the survival rates of all groups were over 90%, and there were no significant differences in food conversion efficiencies (FCE) among different groups (P>005). However, the effects of Ca2+ and Mg2+ concentrations in artificial seawater on specific growth rates (SGR) and food intake (FI) at 0~20 d were significant (P<005). After 20 d, there was no significant difference in FI (P>005). During 40~60 d, the SGRs in low Ca2+ and Mg2+ concentrations groups were lower than that in high concentrations groups. The SGR and FI of all groups decreased when Ca2+ and Mg2+ concentrations increased. At 60 d, the SGR and FI of group A were 113 and 104 times as that of group E, respectively. Significant influences were also observed in immuno enzymatic activity of liver among these groups (P<005). The activity of SOD and hepatosomatic index of group D were significantly higher than those of other groups . However, the activity of SOD of group E was lower than other groups. The activity of CAT of group E was also lower than other groups but no significant difference (P>005). The results indicated that the concentrations of Ca2+ and Mg2+hindered the growth of juvenile P. olivaceus by changing their food intake. The fish in low Ca2+ and Mg2+ concentration groups grew fast and those in high Ca2+ and Mg2+ concentration groups grew slowly. There were no significant differences in the SGR of all the groups except for group E after 60 d rearing experiment. High Ca2+ and Mg2+ concentrations could restrain immuno enzymatic activity of juvenile P. olivaceus. It is suggested that high concentration of Ca2+ and Mg2+ should be avoided in the culturing of juvenile P. olivaceus.