碳酸氢钠对大鳞鲃耗氧率和排氨率的影响

Effects of Carbonate Alkalinity on Oxygen Consumption and Ammonia Excretion in Bulatmai Barbel Barbus capito

在水温(22±0.5)℃和密闭式流水条件下,测定体质量(104.68±2.20)g大鳞鲃Barbus capito在不同碳酸氢钠(NaHC03)浓度(10 mmol/L、20 mmol/L、30 mmol/L、40 mmol/L和50mmol/L)下的耗氧率、排氨率和血浆尿素氮浓度。结果表明:碱度10~30mmol/L组大鳞鲃的耗氧率显著高于对照组(P<0.05),但组间无显著差异(P>0.05);碱度40 mmol/L、50mmol/L组的耗氧率极显著高于其他实验组(P<0.01),说明高碱度影响大鳞鲃的生理活动,提高新陈代谢水平抵御高碱度胁迫。随着碱度的上升大鳞鲃的排氨率逐渐降低,碱度30~50mmol/L组的排氨率依次显著低于对照组(P<0.05)。大鳞鲃血浆尿素氮浓度随碱度的升高而逐渐显著上升(P<0.05)。本试验表明,大鳞鲃为了应对碱度胁迫时的氨中毒,首先调节代谢降低氨的产生量,其次在体内将氨代谢合成尿素排出体外。

The oxygen consumption rate, ammonia excretion rate and urea nitrogen content were monitored in bulatmai barbell Barb us capito with body weight of （104.68 ± 2.20） g in closed a water flow respiration chamber exposed to bicarbonate alkalinity of 10 mmol/L, 20 mmol/L, 30 mmol/L, 40 mmol/L and 50 mmol/L at water temperature of （22 ± 0.5 ）℃ to evaluate effects of carbonate al- kalinity on oxygen consumption and ammonia excretion in bulatmai barbel. There was significantly higher oxygen consumption rate in bulatmail barbell in group 10 - 30 mmol/L than that in the control group （P 〈 0.05）, without significant difference among the other groups （P 〉 0.05 ）. The bulatmai barbell in 40 mmol/L and 50 mmol/L groups had significantly higher oxygen consumption rate than the fish in the other experimental groups did （P 〈 0.01 ）, showing that the physiological activity was affected by high alkalinity, and that then the metabolism level was improved against high alkalinity stress. The ammonia excretion was found to be decreased gradually with increase in alkalinity concentration, significantly lower in 30 - 50 mmol/L alkalinity groups than that in the control group （P 〈 0.05）. There was increase in urea nitrogen content with increase in alkalinity concentration. It is concluded that bulatmai barbell showed first decrease in ammonia production, followed by in vivo metabolism of ammonia synthesis for urea excreted in order to deal with the am- monia poisoning caused by alkalinity stress.