Departamento de Genética, Antropología Física y Fisiología Animal, Facultad de Ciencia y Tecnología, Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), Bilbao, Spain.
PLoS One. 2022 Sep 1;17(9):e0268053. doi: 10.1371/journal.pone.0268053. eCollection 2022.
Body-size scaling of metabolic rate in animals is typically allometric, with mass exponents that vary to reflect differences in the physiological status of organisms of both endogenous and environmental origin. Regarding the intraspecific analysis of this relationship in bivalve molluscs, one important source of metabolic variation comes from the large inter-individual differences in growth performance characteristic of this group. In the present study, we aimed to address the association of growth rate differences recorded among individual mussels (Mytilus galloprovincialis) with variable levels of the standard metabolic rate (SMR) resulting in growth-dependent shift in size scaling relationships. SMR was measured in mussels of different sizes and allometric functions fitting SMR vs. body-mass relationships were compared both inter- and intra-individually. The results revealed a metabolic component (the overhead of growth) attributable to the differential costs of maintenance of feeding and digestion structures between fast and slow growers; these costs were estimated to amount to a 3% increase in SMR per unit of increment in the weight specific growth rate. Scaling exponents computed for intraindividual SMR vs body-mass relationships had a common value b = 0.79 (~ ¾); however, when metabolic effects caused by differential growth were discounted, this value declined to 0.67 (= ⅔), characteristic of surface dependent processes. This last value of the scaling exponent was also recorded for the interindividual relationships of both standard and routine metabolic rates (SMR and RMR) after long-lasting maintenance of mussels under optimal uniform conditions in the laboratory. The above results were interpreted based on the metabolic level boundaries (MLB) hypothesis.
动物代谢率的体型大小缩放通常是异速生长的，质量指数的变化反映了内源性和环境来源的生物体生理状态的差异。关于双壳类软体动物中这种关系的种内分析，代谢变化的一个重要来源来自于该群体中生长性能的个体间差异很大。在本研究中，我们旨在研究个体贻贝（贻贝）之间记录的生长率差异与标准代谢率（SMR）的变化水平之间的关联，这种变化导致了体型大小缩放关系的变化。测量了不同大小的贻贝的 SMR，并比较了 SMR 与体重关系的不同异速函数拟合。结果揭示了一个代谢成分（生长的开销）归因于快速生长和慢速生长之间维持摄食和消化结构的差异成本；这些成本估计为体重特定生长率每增加 1%，SMR 增加 3%。个体内 SMR 与体重关系的缩放指数具有共同的值 b = 0.79（~¾）；然而，当考虑到由不同生长引起的代谢效应时，这个值下降到 0.67（=⅔），这是表面依赖过程的特征。在实验室中，在最佳均匀条件下长时间维持贻贝后，标准和常规代谢率（SMR 和 RMR）的个体间关系也记录了这个缩放指数的最后值。上述结果是基于代谢水平边界（MLB）假设来解释的。
