鲫幼鱼游泳运动能力的个体变异与表型关联

为考察鲤科鱼类运动能力的个体变异和表型关联及不同加速度对匀加速游泳能力的影响, 研究在(25±0.5)℃条件下测定鲫(Carassius auratus)幼鱼的静止代谢率(Resting metabolic rate, RMR), 通过临界游泳速度(Critical swimming speed, U_crit)法和过量耗氧(EPOC)法获取实验鱼的最大代谢率(Maximum metabolic rate, MMR)、代谢空间(Aerobic scope, AS=MMR-RMR)、相对代谢空间(Factorial aerobic scope, FAS=MMR/RMR)、U_crit及步法转换速度(Gait transition speed, U_gt), 并在不同加速度(0.083、0.167、0.250、0.333 cm/s2)下测定鲫幼鱼的匀加速游泳能力(Constant accelerated test, U_cat)和U_gt。研究发现: 鲫幼鱼的MMR和AS与U_crit均呈正相关, 但RMR与U_crit不相关; 能量代谢参数(MMR、AS、RMR)与U_gt不相关。U_crit法获取的MMR、AS、FAS与EPOC法均无平均值的显著性差异, 但2种方法获得的上述参数具有较高的个体重复性; 鲫幼鱼的能量代谢参数之间存在表型关联并且关联方向不尽相同。鲫幼鱼的U_crit和U_gt均小于各加速度下的U_cat和U_gt, 加速度对U_cat测定无影响但对U_gt有影响。鲫幼鱼的U_gt与U_crit或U_cat呈正相关, 并且其匀加速游泳能力参数在不同加速度下保持较高的重复性。除0.333 cm/s2外, 其他加速度下鲫幼鱼U_cat的无氧代谢组分(U_cat-U_gt)与U_cat呈正相关; 然而, 鲫幼鱼的有氧代谢组分(U_gt)与无氧代谢组分(U_cat-U_gt)呈负相关。研究表明: U_crit法和EPOC法诱导鲫幼鱼的有氧代谢能力无方法学差异; 鲫幼鱼的能量代谢存在表型关联, 其匀加速游泳能力具有稳定个体差异, 并且该种鱼的有氧代谢与无氧代谢存在权衡。

INDIVIDUAL VARIATION AND PHENOTYPIC CORRELATIONS IN SWIMMING PERFORMANCE OF JUVENILE CRUCIAN CARP

The swimming ability is a fundamental organismal trait to influence growth, survival and even the Darwinian fitness of fish. Energy metabolism involves oxygen uptake, locomotor capacity includes aerobic swimming performance and anaerobic swimming performance, which exhibits great variations in these two physiological functional traits. Trade-off may occur when these two traits can not be optimized simultaneously since aerobic and anaerobic swimming performance pose conflicting demands on the same morphological feature of design. The present study examined the intra-individual variations and phenotypic trait correlations of swimming ability of the cyprinid fish, and investigated the effects of different acceleration speed on the constant acceleration swimming capacity in the cyprinid fish. Swimming performance of the juvenile crucian carp (Carassius auratus) including critical swimming speed (U_crit), and gait transition speed (U_gt) was performed in a U_crit test. The metabolic rates including resting metabolic rate (RMR), maximum metabolic rate (MMR), aerobic scope (AS=MMR–RMR) as well as factorial aerobic scope (FAS=MMR/RMR) were measured by both of theU_crit test and the test of excess post-exercise oxygen consumption (EPOC). A constant acceleration test (U_cat) was employed to examine the U_cat and U_gt in the juvenile crucian carp at four acceleration rates (0.083, 0.167, 0.250 and 0.333 cm/s2). Our study found that U_crit were correlated with MMR and AS with the exception of RMR while U_gt was not related to any parameters of metabolic rates (MMR, AS and RMR) in the juvenile crucian carp. There were no significant difference in parameter average of metabolic traits (MMR, AS and FAS) between two induced exercise methods, and high repeatability was detected in intra-individual level between the two methods. Distinct correlations were found among traits of metabolism. The U_crit and U_gt conducted by U_crit test were smaller than those conducted by U_cat test. The acceleration rate had a determinable influence on U_cat but not U_gt. U_gt correlated positively with either U_crit or U_cat and the constant acceleration swimming capacity had repeatability among four acceleration rates. U_cat was positively correlated to the anaerobic metabolism contribution (U_cat–U_gt) by the acceleration swimming test at three acceleration rates with the exception of 0.333 cm/s2. However, the aerobic metabolic capacity (U_gt) was negatively related to the anaerobic metabolic capacity (U_cat–U_gt) in the juvenile crucian carp by the U_cat test. The study suggested that no methodological difference could be found in aerobic capacity by the test of U_crit and EPOC, and that correlation among traits of energy metabolism and constant individual difference in acceleration swimming performance could be found in the juvenile crucian carp. Performance trade-off was detectable between aerobic metabolic capacity and anaerobic metabolic capacity in this species.