【作者】 庞旭；

【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】 为考察在不同温度下摄食对南方鲇游泳运动能力的影响,验证摄食在高温下比在低温下对其游泳运动能力有更显著影响的假说,本研究以嘉陵江和扬子江广泛分布,伏击取食的南方鲇(Silurus meridionalis)为对象,在不同温度(15, 21, 27和33℃)下,对其特殊动力作用(Specific dynamic action , SDA)、临界游泳速度(Critical swimming speeding,Ucrit)以及耗氧率(Oxygen consumption rate, VO2)进行了研究,旨在考察温度对南方鲇幼鱼代谢对策(Metabolic strategy)的影响,揭示其生理生化适应机制。主要结果:1.实验鱼的静止耗氧率(VO2rest)随着温度的增加VO2rest显著增加,各处理组间均有显著差异(p < 0.05)。摄食后各处理组实验鱼的耗氧率(VO2)在2 h后均显著增加(p < 0.05),经历一个平台期后回落到摄食前水平。各温度处理组实验鱼(15,21,27,33℃)的摄食代谢峰值时间(Time to peak)分别为摄食后的27.14,20.00,13.43,14.00 h,摄食代谢峰值(VO2peak)分别为57.8,112.5,135.0,160.5 mgO2 kg-1 h-1,随温度的增加VO2peak显著地增加(p < 0.05),然而峰值比率(Factorial metabolic scope)没有显著差异。当温度从33℃下降到15℃时,SDA持续时间从60.43h减短到40.29 h,它是一个显著地下降当温度从33℃下降到21时℃(p < 0.05)。当温度从15℃上升到21℃时,摄食代谢系数(SDA coefficient)显著地增加(p < 0.05),但在21,27,和33℃组之间没有显著差异。2.不同温度处理(15,21,27,33℃)禁食组实验鱼的临界游泳速度(Ucrit)分别为2.18,2.74,3.69,3.67 BL s?1,当温度从15℃增加到27℃时,Ucrit随温度的增加显著增加(p < 0.05),但27℃与33℃处理组之间没有显著差异(图2)。各温度处理组的游泳耗氧率随实验鱼游泳速度(U)的增加均显著增加(p < 0.05)。各温度处理组(15,21,27,33℃)实验鱼的活跃耗氧率(禁食实验鱼游泳过程中的最大耗氧率,VO2active)分别为101.4,161.9,240.0,265.2 mgO2 kg-1 h-1,VO2active随温度的增加而显著增加,且各温度组之间均有显著差异(p < 0.05)。3.在15,21,27和33℃条件下,各摄食组实验鱼的Ucrit分别为2.15, 2.41,3.00和2.90 BL s?1。在15℃下,在摄食组和禁食组实验鱼的Ucrit之间没有显著差异(p = 0.66),但在21,27,33℃下,摄食组的Ucrit与禁食组的相比较,分别下降了12.04,18.70,20.98%,且均有显著差异(p < 0.05)。4.各温度处理(15,21,27,33℃)禁食组实验鱼的VO2rest分别为25.43, 36.82,43.72,54.22 mgO2 kg-1 h-1,摄食组实验鱼在摄食代谢峰值时的耗氧率(VO2peak)在相应的温度下分别为49.7,89.8,127.6,163.5 mgO2 kg-1 h-1。在各温度处理下,各摄食组实验鱼的在各游泳速度下的VO2均显著高于禁食组在其相应流速下的VO2(p < 0.05)。各温度处理(15,21,27,33℃)摄食组实验鱼在游泳过程中的最大耗氧率(VO2max)分别是128.1,184.9,269.4,315.4 mgO2 kg-1 h-1,且均显著高于相应温度下禁食组实验鱼在相应温度下的VO2activ(p < 0.05)。结果表明:1.尽管南方鲇幼鱼的最大代谢(VO2max)随着温度的增加而增加,但其摄食后相对代谢剩余空间(VO2max-VO2peak)随着温度的升高而降低;南方鲇摄食对运动能力的削弱随温度的增加而加强的现象归因于其中心心鳃系统和外周系统(消化系统和运动组织)的功能随温度的影响具有不一致性。2.在不同温度下,南方鲇具有不同的代谢对策,这可能与其自身消化、运动以及摄食后运动的代谢需求,机体内外环境离子平衡和外环境溶解氧水平等因素相关。更多还原

【Abstract】 To estimate whether the effects of feeding on swimming performance vary with acclimation temperature and test the hypothesis that digestion has a more notable physiological effect at high temperature than low temperature in juvenile southern catfish (Silurus meridionalis), an ambush forager distributed along the JiaLing and Yangtze Rivers, China, we investigated the specific dynamic action (SDA), critical swimming speeding (Ucrit) and oxygen consumption rate (VO2) of fasting and feeding fish at acclimation temperatures of 15, 21, 27, and 33 oC.The results as follows:1. The pre-fed resting oxygen consumption rate (VO2rest) values increased significantly with temperature (p < 0.05). The VO2 increased significantly 2 h after feeding in every temperature group, then reached a plateau and decreased significantly to the pre-fed level. The peak time values were 27.14 h at 15 oC, 20.00 h at 21 oC, 13.43 h at 27 oC, and 14.00 h at 33 oC. The VO2peak increased with temperature (p < 0.05), whereas the factorial metabolic scope did not significantly differ among the four temperature groups. The SDA duration decreased from 65.43 to 40.29 h as the temperature increased from 15 to 33 oC (p < 0.05). The duration of SDA did not differ in temperatures ranging from 15 to 21 oC, but it increased as the temperature increased from 21 to 33 oC (p < 0.05). The SDA coefficient increased from 15 to 21 oC (p < 0.05), but there was no significant difference among 21, 27 and 33 oC.2. The Ucrit values were 2.18, 2.74, 3.69, and 3.67 BL s-1 at 15, 21, 27 and 33 oC, respectively. The Ucrit significantly increased in the temperature zone of 15 to 25 oC (p < 0.05), but there was no significant difference between 27 and 33 oC. The VO2 increased with an increase of the swimming speeds (U) at every acclimation temperature (p < 0.05). The active oxygen consumption rate (VO2active) were 101.4, 161.9, 240.0, and 265.2 mgO2 kg-1 h-1 at 15, 21, 27 and 33 oC, respectively. The VO2active increased with the increase of temperature (p < 0.05).3. The Ucrit of the feeding groups were 2.15, 2.41, 3.00, and 2.90 BL s-1 at 15, 21, 27 and 33 oC, respectively. There was no significant difference between the unfed and fed group at 15 oC (p = 0.66). However, Ucrit values of the feeding groups were 12.04, 18.70, and 20.98% lower than those of the fasting groups at 21, 27, and 33 oC, respectively (p < 0.05).4. The VO2rest values of the fasting groups were 25.43, 36.82, 43.72, and 54.22 mgO2 kg-1 h-1 at 15, 21, 27 and 33 oC, respectively, whereas the resting metabolic rates of the feeding groups in peak times were 49.7, 89.8, 127.6, and 163.5 mgO2 kg-1 h-1 at 15, 21, 27 and 33 oC, respectively. The VO2max values of the feeding groups were 128.1, 184.9, 273.7, and 237.9 mgO2 kg-1 h-1 at 15, 21, 27 and 33 oC, respectively. The VO2max values of all feeding groups were higher than those of the fasting groups at all temperature (p < 0.05).The indications as follows:1. The VO2max increased with increasing temperature, but the relative residual metabolic scope (VO2max-VO2peak) during swimming decreased with increasing in temperature. The present study showed that the impairment of postprandial swimming performance increased with increasing temperature due to the unparalleled changes in the catfish’s central cardio-respiratory, peripheral digestive and locomotory capacities.2. The different metabolic strategies of juvenile southern catfish at different temperatures may relate to changes in oxygen demand, imbalances in ion fluxes and dissolved oxygen levels with changes in temperature.更多还原