Gastrointestinal blood flow and postprandial metabolism in swimming sea bass Dicentrarchus labrax
Gastrointestinal blood flow and postprandial metabolism in swimming sea bass Dicentrarchus labrax
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DOI：
10.1086/588488
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发表时间：
2008-09-01
影响因子：
1.6
通讯作者：
Axelsson, Michael
中科院分区：
文献类型：
--
作者：
Altimiras, Jordi;Claireaux, Guy;Axelsson, Michael
在鲑鱼和鲑鱼中，运动和喂养的代谢成本是相加的，这表明运动期间的胃肠血液流动是为了保持与食物的特定动态作用(SDA)相关的消化和吸收过程。然而，在大多数已发表的研究中，在游泳、低氧和一般压力下，胃肠道血流量会下降。为测试摄食后运动时胃肠血流量是否减少，在摄食前和摄食后用呼吸机游泳时，用流量探头测量心输出量和腹腔肠系膜血流量。以每秒2个身长的速度游泳(bl S(-1))增加的代谢率明显高于摄食(分别比安静增加208%和32%)，心输出量也观察到类似的模式。未投喂鱼的静息胃肠道血流量为13.8+/-0.5mLmin(-1)kg(-1)。摄食后，静息胃肠道血流量增加了82%，但随游泳速度的增加而逐渐减少。在2 bl S(-1)时，投喂鱼的胃肠血流量与未投喂鱼相比没有显著差异，因此，该数据不支持胃肠节制假说。尽管胃肠血流量减少，肠道供氧减少，SDA的大小仍保持不变。摄食后胃肠道的最大氧流量估计为2.6 mmolO-2 h(-1)kg(-1)，但不能满足3.16 mmolO-2 h(-1)kg(-1)的需氧量。因此，SDA必须反映组织的代谢过程，而不是由腹膜肠系膜动脉直接灌流的组织。
In trout and salmon, the metabolic costs of exercise and feeding are additive, which would suggest that gastrointestinal blood flow during exercise is maintained to preserve digestive and absorptive processes related to the specific dynamic action (SDA) of food. However, in most published studies, gastrointestinal blood flow drops during swimming, hypoxia, and general stress. To test whether gastrointestinal blood flow is spared during exercise after feeding, sea bass were instrumented with flow probes to measure cardiac output and celiacomesenteric blood flow while swimming in a respirometer before and after feeding. Swimming at 2 body lengths per second (bl s(-1)) increased metabolic rate considerably more than did feeding (208% vs. 32% increase, respectively, relative to resting), and a similar pattern was observed for cardiac output. In unfed fish, resting gastrointestinal blood flow was 13.8 +/- 0.5 mL min(-1) kg(-1). After feeding, resting gastrointestinal blood flow increased by 82% but then decreased progressively with increasing swimming speeds. At 2 bl s(-1), gastrointestinal blood flow in fed fish was not significantly different compared with that in unfed swimming fish, and, therefore, the data do not support the gastrointestinal sparing hypothesis. The magnitude of the SDA was maintained despite the decrease in gastrointestinal blood flow and the consequent reduction in oxygen supply to the gut. An estimate of maximal oxygen flow to the gastrointestinal tract after feeding yielded 2.6 mmol O-2 h(-1) kg(-1), but this amount is not able to cover the oxygen demand of 3.16 mmol O-2 h(-1) kg(-1). Therefore, the SDA must reflect metabolic processes in tissues other than those directly perfused by the celiacomesenteric artery.