【作者】 李可贵；

【导师】 付世建；

【作者基本信息】 重庆师范大学 ， 水生生物学， 2010， 硕士

【摘要】 本研究以鲇鱼(Silurus asotus Linnaeus)幼鱼为实验对象,在24.0±1.0℃下,首先研究了摄食(摄食水平为8%鱼体重)(摄食组)对动脉血酸碱状态的影响,以检验餐后“碱潮”现象是否在该鱼中出现;随后,分别考察了力竭性运动(禁食后运动组)和摄食与运动的交互作用(摄食后6 h运动,即摄食后运动组)对力竭性运动后过量耗氧(Excess post-exercise oxygen consumption, EPOC)和酸碱状态的影响,以检验当摄食与运动同时发生时,由摄食导致的餐后“碱潮”现象是否有利于阻止力竭性运动诱导的血液酸化,并对力竭性运动后的恢复过程产生影响。此外,还测定了摄食、运动及摄食与运动交互过程中耗氧率(Oxygen consumption, VO2)、呼吸频率(Ventilation frequency, Vf)、血红蛋白(Hemoglobin, Hb)、血糖、血乳酸、肌乳酸及肌糖原等生理生化指标的变化。研究结果:1.鲇鱼幼鱼摄食前动脉血pH(pHa)为7.74±0.02,摄食后3 h内,pHa无显著变化,摄食后6 h,pHa显著增加了0.14,并达到最大值(7.88±0.02)(P<0.05),直到摄食后12-24 h,pHa才逐渐恢复到摄食前水平;2.鲇鱼幼鱼摄食前动脉血HCO3-浓度([HCO3-]pl)为5.42±0.09 mmol L-1,摄食后[HCO3-]pl伴随着pHa的显著增加而增加,并在摄食后6 h达到最大值(7.83±0.37)(P<0.05),直到摄食后12 h与摄食前水平无显著差异;3.鲇鱼幼鱼摄食后VO2显著升高,摄食代谢峰值时VO2是摄食前的2.24倍,摄食后52 h恢复到摄食前水平;摄食对呼吸频率、动脉血CO2分压(PCO2)、血糖、血乳酸、血红蛋白、白肌乳酸和糖原均无显著影响;4.力竭性运动后鲇鱼幼鱼pHa下降了0.46±0.06,[HCO3-]pl浓度下降了约3 mmol L-1。血乳酸含量显著上升,并在运动后1 h到达最大值。pHa、[HCO3-]pl及血乳酸均在运动后4 h恢复到运动前水平。在力竭性运动后的整个恢复过程中,动脉血PCO2无显著变化;5.力竭性运动后即刻,鲇鱼幼鱼VO2显著升高并达到最大值,随后逐渐恢复到运动前水平。运动后恢复期内VO2(Y, mgO2h-1kg-1)和恢复时间(X, min)的关系可以用如下方程描述:Y=a±b e-cx;6.力竭性运动前鲇鱼幼鱼肌肉乳酸水平为4.8±0.26μmol g-1,运动后2h到达峰值(18.26±0.55μmol g-1),直到运动后8h恢复到与运动前水平无显著性差异;运动前鲇鱼幼鱼白肌糖原水平为18.59±1.36μmol g-1,运动后白肌糖原下降了61%,直到运动后16h仍没完全恢复到运动前水平;7.对于摄食后运动组,由于餐后“碱潮”的存在,鲇鱼幼鱼在力竭运动前具有较高的pHa和[HCO3-]pl,因此力竭性运动后pHa和[HCO3-]pl下降幅度(分别下降了0.36±0.05和2 mmol L-1)显著低于禁食后运动组;力竭性运动后的整个恢复过程中,动脉血PCO2无显著变化;8.对于摄食后运动组,鲇鱼幼鱼VO2在力竭性运动后立即显著上升,随后逐渐下降。由于SDA的存在,摄食后运动组运动前的VO2水平显著高于禁食后运动组运动前水平。摄食后运动组和禁食后运动组力竭性运动后VO2峰值、VO2上升倍率均存在显著差异。然而两个组EPOC没有显著差异;9.对于摄食后运动组,力竭性运动后鲇鱼幼鱼呼吸频率、血红蛋白、血液乳酸、肌乳酸和糖原等指标变化趋势与禁食运动组无显著差异。以上结果表明:1.鲇鱼幼鱼摄食后表现出显著的餐后“碱潮”现象;该现象为除虹鳟外的硬骨鱼类中的首次报道;2.与其它动物不同,鲇鱼餐后“碱潮”现象的补偿(缓解)可能主要通过鳃的作用将过多的代谢碱排泄到周围水环境中而不是依靠血浆PCO2的改变;3.鲇鱼幼鱼餐后“碱潮”现象明显地阻止了力竭性运动带来的动脉血液pHa和[HCO3-]pl浓度的立即下降,但是对力竭性运动后的恢复过程并没有显著的影响。更多还原

【Abstract】 Feeding and exhaustive exercise are known to elevate metabolism. However, acid-base status may be oppositely affected by the two processes. In this study, we first investigated the acid-base response of Chinese catfish to feeding (the meal size was about 8% of body mass) to test whether an alkaline tide (a metabolic alkalosis created by gastric HCl secretion after feeding) would occur. We then determined the combined effects of feeding and exhaustive exercise on excess post-exercise oxygen consumption (EPOC) and acid-base status to determine whether the alkaline tide induced by feeding protects against acid-base disturbance during exhaustive exercise and affects subsequent recovery. At the same time, we investigated arterial blood acid–base status (pHa and [HCO3-]pl), oxygen consumption (VO2), ventilation frequency (Vf,), hemoglobin (Hb), blood glucose, blood lactate, muscle glycogen and muscle lactate concentrations after feeding, exhaustive exercise and both feeding and exhaustive exercise.The results as follows:1. In fasting fish, the pHa was 7.74±0.02. After feeding, the pHa showed no significant change within 3 h of feeding. However, pHa significantly increased by 0.14 units and reached a peak at 6 h after feeding (7.88±0.02). This transient increase slowly returned to the fasting pHa levels at 12—24 h after feeding.2. In fasting fish, the [HCO3-]pl was 5.42±0.29 mmol L-1. The increase in pHa was accompanied by a significant increase in [HCO3-]pl, which also peaked at 6 h (7.83±0.37 mmol L-1) after feeding and then slowly returned to fasting levels at 12 h.3. After feeding, the VO2 increased significantly, peaking at about 2.24 times higher than that of the pre-feeding level, and the increased metabolism persisted 52 h after ingestion. Feeding had no significant effect on Vf,, PCO2, [glucose]pl, [lactate]pl, Hb, white muscle lactate and white muscle glycogen.4. Exhaustive exercise led to a significant reduction in pHa by 0.46±0.06 units and a reduction in [HCO3-]pl by approximately 3 mmol L-1. After exhaustive exercise, the [lactate]pl significantly increased and peaked at 1 h. The pHa, [HCO3-]pl and [lactate]pl returned to resting levels at 4 h after exercise.5. The VO2 increased significantly after exhaustive exercise and gradually returned to pre-exercise level in fasting fish. The relationship between post-exercise VO2 (Y, mg O2 h-1kg-1) and time after exercise (X, min) was described by the following equation: Y=a±becx.6. The lactate concentration of white muscle rose acutely from a basal value of 4.80±0.26μmol g-1 to a peak level of 18.26±0.55μmol g-1 at 2 h after exercise in fasting fish and returned to pre-exercise level by 8 h. Exhaustive exercise caused a 61% decrease in glycogen, which remained low for at least 16 h post-exercise.7. In both feeding and exhaustive exercise fish, which had a higher pHa and [HCO3-]pl before exercise, exhaustive exercise only caused a reduction in pHa by 0.36±0.05 units and a reduction in [HCO3-]pl by about 2 mmol L-1.8. In both feeding and exhaustive exercise fish, the VO2 recovery profile was similar to those of fasting fish. However, there were significant differences in pre-exercise VO2, peak VO2 and the VO2 factorial scope between fasting and post-feeding fish. The EPOC between fasting and post-feeding fish was not significantly different.9. In both feeding and exhaustive exercise fish, the elimination of the lactate and the restoration of glycogen were similar to those of fasting fish.In conclusion:1. As anticipated, we detected a significant alkaline tide in Chinese catfish after feeding. To our knowledge, this is the first report of an alkaline tide in a teleost other than rainbow trout.2. Unlike other vertebrate classes, the alkaline tide in Chinese catfish may be compensated by excretion of metabolic base to the environment, so the PCO2 of the arterial blood did not change during digestion.3. The alkaline tide did dampen the reduction in pHa and [HCO3-]pl after exhaustive exercise, but recovery from the exhaustive exercise was not affected by digestion.更多还原