Bioenergetics of marine teleosts during early life stage

个体鱼的代谢M与体重W之间的关系用异速生长方程M=aW^b表示。质量指数b小于1，因为质量特定代谢率M/W通常随着体重的增加而降低。然而，我们对硬骨鱼早期生命阶段的这种关系还没有足够的信息。在本研究中，我们研究了三种硬骨鱼代谢-体重关系的个体发生变化。用湿体质量0.00043 ~ 0.41 g的阿育鱼、红鳉（0.00068 ~ 2.7 g）和黄花鱼（0.00025 ~ 10 g）在20‰的温度下测定了完整鱼的耗氧量M_<体内>，碎鱼的耗氧量M_<体内>，以及氨排泄量。采用闭式、半封闭或恒流量呼吸法测定M_<体内>，采用容积呼吸法测定M_<体内>，采用氨排泄率吸收法测定氨排泄率。完整鱼的质量比代谢率（M_<体内> /W）从刚孵化（0.00043 g）到30日龄（0.04 g）与体质量无关，基本保持不变，然后逐渐下降。孵育后，ayu体内的M_< >in /W随生长而降低，呈单相负异速生长。在体质量基本不变的情况下，河豚和黄花鱼在体内和体外的体质量比在孵化后1周内均随生长而增加，随后随体质量的增加而降低。各发育阶段M=aW^bb的a值随发育阶段的转移而增大。三种间代谢个体发生变化的差异可归因于刚孵化时器官发生程度的差异。河豚和黄花鱼的a值随生长的增加反映了形态和生态随生长的变化。

The relationship between metabolism of an individual fish M and body mass W is expressed by an allometric equation M=aW^b. Mass-exponent b is smaller than unity, because mass-specific metabolic rate M/W usually decreases with increasing body mass. However, we have not enough information about this relationship during the early life stages of teleosts, In this study, we examined ontogenetic change in the metabolism-body mass relationship with three teleosts.Oxygen consumption of intact fish M_< in vivo>, that of chopped fish M_< in vivo>, and ammonia excretion were determined with ayu Plecoglossus altivelis altivelis (0.00043-0.41 g in wet body mass), tiger puffer Takifugu rubripes (0.00068-2.7 g) and croaker Nibea japonica (0.00025-10 g) at 20ﾟC.M_< in vivo> was determined using one of closed, semi-closed or constant flow respirometry, M_< in vivo> a volumetric respirometry, and ammonia excretion rate an absorptimetry.Mass-specific metabolic rate of intact fish M_< in vivo> /W of ayu was almost constant independent of body mass from just after hatch (0.00043 g) to 30 days old (0.04 g), then decreased. While, M_< in vivo>in /W of ayu decreased with growth immediately after hatch with a monophasic negative allometry. M/W both in vivo and in vitro of puffer and croaker increased with growth during a week after hatch with virtually unchanged body mass, then decreased with increasing body mass with several phases. In these phases, a-value in M=aW^bb increased with transfer of developmental stage. The difference of ontogenetic change of metabolism among three species can be attributed to the difference of extent of organogenesis just after hatch. The increase of a-value with growth in puffer and croaker is considered to reflect morphological and ecological changes with growth.