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Respiratory quotient and the stoichiometric approach to investigating metabolic energy substrate use in aquatic ectotherms


Wang, S and Carter, CG and Fitzgibbon, QP and Smith, GG, Respiratory quotient and the stoichiometric approach to investigating metabolic energy substrate use in aquatic ectotherms, Reviews in Aquaculture, 13 pp. 1255-1284. ISSN 1753-5131 (2020) [Refereed Article]

Copyright Statement

Copyright 2020 John Wiley & Sons Australia, Ltd

DOI: doi:10.1111/raq.12522


The respiratory quotient (RQ) has been used extensively as an index to evaluate metabolic energy expenditure in terrestrial animals including humans. In contrast, RQ use in understanding physiology and nutrition of aquatic ectotherms has been restricted due to technical challenges in measuring total CO2 in water. With technical advances in measuring total CO2 in water, RQ in aquatic ectotherms can be accurately determined and is potentially available as a valuable method. Here, we provide a comprehensive review of studies on RQ and metabolic energy substrate use in aquatic ectotherms. Metabolic energy substrate use is evaluated by a reliable stoichiometric bioenergetic approach, based on measuring RQ and nitrogen quotient (NQ) simultaneously. Stoichiometry provides a non‐destructive and unequivocal way to quantify the instantaneous oxidation of each major energy substrate (protein, lipid or carbohydrate). This review aims to refine knowledge about bioenergetics of aquatic ectotherms under different conditions including nutritional aspects of sustainable aquaculture. Notably, stoichiometry provides a promising approach to optimize feeds and feeding regimes to realize sustainable aquaculture under differing conditions and with differing feed ingredients. It also provides an approach to consider climate change impacts and physiological adaptation mechanisms for survival and development in farmed environments and natural ecosystems. Stoichiometric bioenergetics knowledge in aquatic ectotherms has relevance to commercial impacts in the face of overfishing and food security, and ecological significance in the face of environmental change scenarios. We suggest expanding the use of stoichiometry in future bioenergetic research in emerging aquaculture species.

Item Details

Item Type:Refereed Article
Keywords:metabolic energy substrate use, natural ecosystem, respiratory quotient, stoichiometric bioenergetic approach, sustainable aquaculture
Research Division:Agricultural, Veterinary and Food Sciences
Research Group:Fisheries sciences
Research Field:Aquaculture
Objective Division:Animal Production and Animal Primary Products
Objective Group:Fisheries - aquaculture
Objective Field:Aquaculture rock lobster
UTAS Author:Wang, S (Dr Shuangyao Wang)
UTAS Author:Carter, CG (Professor Chris Carter)
UTAS Author:Fitzgibbon, QP (Associate Professor Quinn Fitzgibbon)
UTAS Author:Smith, GG (Professor Gregory Smith)
ID Code:142297
Year Published:2020
Funding Support:Australian Research Council (IH120100032)
Deposited By:Fisheries and Aquaculture
Deposited On:2021-01-06
Last Modified:2021-07-28

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