Bioenergetics of marine teleosts during early life stage

个体鱼M的代谢与体重W之间的关系由异速生长方程M=aW^B表示。质量指数B小于1，因为质量比代谢率M/W通常随着体重的增加而降低。本研究以香鱼（Plecoglossus altivelis altivelis）为研究对象，测定了完整鱼、切碎鱼的耗氧率和排氨率，研究了3种硬骨鱼的代谢-体质量关系的个体发育变化< in vivo>< in vivo>在20 ℃下，用封闭式、半封闭式或恒流呼吸法、M_ a容量呼吸法和氨排泄率吸光法测定了香鱼（0. 00043 - 0. 41 g湿体质量）、红鳍东方鲀（0. 00068 - 2. 7 g）和黄姑鱼（0. 00025 -10 g）的M_< in vivo>a< in vivo>< in vivo>。而香鱼的M_< in vivo>in /W在孵化后即刻随生长而下降，呈双相负异速生长。在体质量基本不变的情况下，河豚鱼和黄花鱼体内和体外的M/W在孵化后的一周内随生长而增加，然后随体质量的增加而下降，并有几个阶段。在这些阶段中，M=aW^bb的a值随发育阶段的转移而增加。三种鱼在个体发育过程中代谢变化的差异可能是由于孵化后器官发生程度的差异所致。河豚鱼和黄花鱼的a值随生长而增加，反映了其形态和生态的变化。

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.