Joaquim Natércia, Wagner Glenn N, Gamperl A Kurt
Centre of Marine Sciences, Faculdade de Ciências do Mar e Ambiente, Universidade do Algarve, Portugal.
Comp Biochem Physiol A Mol Integr Physiol. 2004 Jul;138(3):277-85. doi: 10.1016/j.cbpb.2004.03.016.
Using Transonic flow probes and a uniquely designed swimming flume, we directly measured cardiac parameters (Q, cardiac output; SV, stroke volume; and fH, heart rate) in winter flounder (Pleuronectes americanus) before and during critical swim speed (Ucrit) tests at 4 and 10 degrees C. Resting Q, SV and fH averaged 9.8 ml min(-1) kg(-1), 0.5 ml kg(-1) (1.0 ml g ventricle(-1)) and 21 beats min(-1) at 4 degrees C and 15.5 ml min(-1) kg(-1), 0.5 ml kg(-1) (0.95 ml g ventricle(-1)) and 34 beats min(-1) at 10 degrees C (Q10 values of 2.13, 0.91 and 2.35, for Q, SV and fH, respectively). Cardiac output, SV and fH increased by approx. 170%, 70% and 60% at both temperatures during the Ucrit test. However, cardiac parameters generally reached near maximal levels almost immediately upon swimming and remained at these levels until Ucrit (0.65 +/- 0.06 bl s(-1) at 4 degrees C and 0.73 +/ -0.07 bl s(-1) at 10 degrees C). This rapid rise in cardiac function to near maximal levels did not appear to be the result of stress alone, as Q only fell slightly when flounder were swum for 75 min at < 0.4 bl s(-1), speeds at which they appeared to swim comfortably. Our results suggest that both Q and Ucrit have been significantly overestimated in flatfishes, and that "lift-off"/slow swimming is energetically expensive. Furthermore, they show that maximum and resting stroke volume (per g of ventricle) are extremely high in the flounder as compared with other teleosts.
使用跨音速流量探头和独特设计的游泳水槽，我们在4摄氏度和10摄氏度下对冬季比目鱼（美洲黄盖鲽）进行临界游泳速度（Ucrit）测试之前及测试期间，直接测量了其心脏参数（Q，心输出量；SV，每搏输出量；以及fH，心率）。在4摄氏度时，静息状态下的Q、SV和fH平均分别为9.8毫升·分钟⁻¹·千克⁻¹、0.5毫升·千克⁻¹（1.0毫升·克心室⁻¹）和21次·分钟⁻¹；在10摄氏度时，分别为15.5毫升·分钟⁻¹·千克⁻¹、0.5毫升·千克⁻¹（0.95毫升·克心室⁻¹）和34次·分钟⁻¹（Q、SV和fH的Q10值分别为2.13、0.91和2.35）。在Ucrit测试期间，两个温度下的心输出量、SV和fH均增加了约170%、70%和60%。然而，心脏参数通常在开始游泳后几乎立即达到接近最大值的水平，并一直保持在这些水平直到达到Ucrit（4摄氏度时为0.65±0.06体长·秒⁻¹，10摄氏度时为0.73±0.07体长·秒⁻¹）。心脏功能迅速上升至接近最大值的水平似乎并非仅由应激导致，因为当比目鱼以<0.4体长·秒⁻¹的速度游动75分钟时，Q仅略有下降，而这个速度下它们似乎游动得很舒适。我们的数据表明，比目鱼的心输出量和Ucrit都被显著高估了，并且“起飞”/慢速游泳在能量消耗上很高。此外，结果显示，与其他硬骨鱼相比，比目鱼的最大和静息每搏输出量（每克心室）极高。
