肠呼吸抑制胁迫对大鳞副泥鳅呼吸代谢和抗氧化能力的影响

为研究肠呼吸抑制胁迫对气呼吸鱼类大鳞副泥鳅(Paramisgurnus dabryanus)的鳃和肠道呼吸代谢及抗氧化能力的影响,初步探究其生理反馈调节机制,本文选取大鳞副泥鳅成熟个体(n=60)进行肠呼吸抑制胁迫实验。分别对实验组(肠呼吸抑制,n=30)与空白对照组(n=30)的大鳞副泥鳅饲养驯化2周,测定其整体静止代谢率、呼吸频率、鳃和肠道各段的乳酸脱氢酶(LDH)、琥珀酸脱氢酶(SDH)、Na+/K+ATP酶(NKA)、过氧化氢酶(CAT)以及超氧化物歧化酶(SOD)活性。肠呼吸抑制胁迫下,实验组与对照组大鳞副泥鳅整体静止代谢率无显著差异(P0.05),而实验组大鳞副泥鳅鳃部呼吸频率显著加快(P0.05)。与对照组相比,实验组大鳞副泥鳅鳃部的琥珀酸脱氢酶活性显著升高(P0.05),而后肠琥珀酸脱氢酶和Na+/K+ATP酶显著降低(P0.05)。同时实验组大鳞副泥鳅后肠的乳酸脱氢酶活性显著升高(P0.05)。实验组和对照组之间,大鳞副泥鳅鳃和前中肠的过氧化氢酶以及超氧化物歧化酶酶活性无显著差异(P0.05),后肠则有显著性升高(P0.05)。当大鳞副泥鳅肠呼吸受到抑制时,会加强其鳃部有氧呼吸代谢,弥补肠呼吸缺失部分,满足机体生理需求,而气呼吸的后肠会有一定氧化应激反应。

Effect of Intestinal Air-breathing Restriction on Respiratory Metabolism and Antioxidant Capability of Loach (Paramisgurnus dabryanus)

Loach,Paramisgurnus dabryanus,a small-sized fish belonging to the family of Cobitidae of the order Cypriniformes,can breathe air through its mouth when swimming to the water surface.And its accessory breathing organ for O2 and CO2 exchange is its posterior intestine.To investigate the effect of respiratory metabolism and oxidation resistance of gill and intestine as well as related physiological feedback mechanism in P dabryanus,an air-breathing model under intestine breathing restrain treatment was employed.Mature individuals were chosen for intestine respiratory restriction by limiting them under the water surface.The total static metabolism rate,respiratory rate,lactic dehydrogenase activity (LDH),succinate dehydrogenase activity (SDH),Na+/K+ATPase activity (NKA),catalase activity (CAT) and superoxide dismutase (SOD) activity of gill and intestine were examined after 2 weeks' acclimation in control and treatment groups.Data were expressed as Mean ± SE.All the measured data were analyzed and compared with one-way ANOVA and t-test using spss 19.0 and excel.The level of significant difference was set at P ＜ 0.05.The result showed that total static metabolism rates in control and treatment group did not differ significantly (P ＞ 0.05) (Table 1).However,the gill ofP dabryanus in treatment group breathed more quickly than the control group (P ＜ 0.05) (Table 1).In treatment group,succinate dehydrogenase activity of gill showed a significant increase (P ＜ 0.05),while succinate dehydrogenase activity and Na+/K+ATPase activity of posterior intestine showed a significant decrease (P ＜ 0.05) (Fig.lb,c).At the same time,lactic dehydrogenase activity of posterior intestine increased significantly in treatment group (Fig.la).Although there was no significant difference in catalase or superoxide dismutase activity in the gill,anterior and middle intestine between the control and treatment group (P ＜ 0.05),the enzyme activity of posterior intestine in treatment group was lower than that of control group (P ＜ 0.05) (Fig.2a,b).When P dabryanus was intestine breathing restricted,it would enhance its gill aerobic respiratory metabolism as an offset for intestine breathing loss,in order to meet physiological requirements and its air-breathing posterior intestine would have an oxidative stress response.Respiratory metabolism of the gill and posterior intestine of air-breathing loach P dabryanus could be adjusted to adapt environment under different environment stress conditions.