Feeding and digestion in low salinity in an osmoconforming crab, Cancer gracilis I. Cardiovascular and respiratory responses
Feeding and digestion in low salinity in an osmoconforming crab, Cancer gracilis I. Cardiovascular and respiratory responses
复制标题
低盐度条件下渗透顺性蟹（Cancer gracilis I）的摄食和消化。心血管和呼吸系统反应
DOI：
--
复制
发表时间：
2006
影响因子：
2.8
通讯作者：
I. McGaw
中科院分区：
文献类型：
--
作者：
I. McGaw
甲壳类十足目动物的摄食调节生理已受到广泛关注。在这一领域内，关于低盐度下心血管和呼吸系统反应的文献越来越多。大多数物种表现出心动过速，伴有通气率和摄氧量增加。然而，这些先前的实验是在实验前饥饿的动物上进行的，以避免与消化过程相关的代谢增加。由于生物体在经历环境扰动之前不一定挨饿，因此先前实验的结果可能不代表自然的生理反应。本研究调查了一种符合标准的十足目动物，优雅的巨蟹座gracilis，平衡的生理系统（优先级或添加剂的事件）在低盐度环境中的摄食和消化过程中的需求。癌症gracilis表现出典型的增加摄氧量和心血管变量（心率，每搏输出量，心输出量）在100%的海水喂养过程中不太明显的增加。在3天饥饿的螃蟹，暴露于65%的海水导致了显着的心动过缓，伴随着心输出量和血淋巴流速和氧摄取量的暂时减少减少。当螃蟹暴露于低盐度，3小时和24小时后，摄食，心率略有增加，心输出量和通气率保持稳定。虽然氧摄取量短暂下降，但摄食水平很快恢复。在100%SW的恢复阶段，参数出现过冲，表明偿还了氧债。因此，似乎进食和消化是优先在这个物种，使其生存急性暴露于低盐水。此外，结果表明，动物的营养状态是重要的，在调节其生理反应的环境扰动。这强调了在接近自然环境的条件下研究整个生物体水平的生理反应的重要性。
SUMMARY The osmoregulatory physiology of decapod crustaceans has received extensive attention. Within this field there is a growing body of literature on cardiovascular and respiratory responses to low salinity. Most species exhibit a tachycardia coupled with an increase in ventilation rate and oxygen uptake. However, these previous experiments were conducted on animals that were starved prior to experimentation in order to avoid increases in metabolism associated with digestive processes. Because organisms are not necessarily starved prior to experiencing environmental perturbations, results from previous experiments may not represent natural physiological responses. The present study investigated how an osmoconforming decapod, the graceful crab Cancer gracilis, balanced the demands of physiological systems (prioritization or additivity of events) during feeding and digestion in a low salinity environment. Cancer gracilis exhibited a typical increase in oxygen uptake and less pronounced increases in cardiovascular variables (heart rate, stroke volume, cardiac output) during feeding in 100% seawater. In 3-day starved crabs, exposure to 65% seawater resulted in a pronounced bradycardia, with a concomitant decrease in cardiac output and haemolymph flow rates and a temporary decrease in oxygen uptake. When crabs were exposed to low salinity, 3 h and 24 h after food ingestion, heart rate increased slightly and cardiac output and ventilation rates remained stable. Although oxygen uptake decreased transiently, feeding levels were quickly regained. During a recovery phase in 100%SW there was an overshoot in parameters, suggesting repayment of an oxygen debt. Thus, it appears that feeding and digestion are prioritized in this species, allowing it to survive acute exposure to hyposaline water. Furthermore, the results show that the nutritional state of an animal is important in modulating its physiological responses to environmental perturbations. This underscores the importance of studying physiological responses at the whole organism level under conditions closely approximating those of the natural environment.