Article

Repeatability of standard metabolic rate, active metabolic rate and aerobic scope in young brown trout during a period of moderate food availability

Zoophysiology, Department of Biological Sciences, Aarhus University, DK-8000 Aarhus C, Denmark.
Journal of Experimental Biology (Impact Factor: 2.9). 05/2011; 214(Pt 10):1668-75. DOI: 10.1242/jeb.054205
Source: PubMed

ABSTRACT

Standard metabolic rate (SMR) and active metabolic rate (AMR) are two fundamental physiological parameters providing the floor and ceiling in aerobic energy metabolism. The total amount of energy available within these two parameters confines constitutes the absolute aerobic scope (AAS). Previous studies on fish have found SMR to closely correlate with dominance and position in the social hierarchy, and to be highly repeatable over time when fish were provided an ad libitum diet. In this study we tested the temporal repeatability of individual SMR, AMR and AAS, as well as repeatability of body mass, in young brown trout (Salmo trutta L.) fed a moderately restricted diet (0.5-0.7% fish mass day⁻¹). Metabolism was estimated from measurements of oxygen consumption rate (M(.)(O₂)) and repeatability was evaluated four times across a 15-week period. Individual body mass was highly repeatable across the entire 15 week experimental period whereas residual body-mass-corrected SMR, AMR and AAS showed a gradual loss of repeatability over time. Individual residual SMR, AMR and AAS were significantly repeatable in the short term (5 weeks), gradually declined across the medium term (10 weeks) and completely disappeared in the long term (15 weeks). We suggest that this gradual decline in repeatability was due to the slightly restricted feeding regime. This is discussed in the context of phenotypic plasticity, natural selection and ecology.

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Available from: Tommy Norin, Jul 06, 2015
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    • "microbial respiration) followed Rosewarne et al. (2015). Maximal metabolic rate (MMR) was elicited using the chase protocol described previously (Cutts et al., 2002; Norin and Malte, 2011; Svendsen et al., 2014). Individual fish were transferred to a circular trough and chased manually until exhaustion as evidenced by the fish not reacting to being turned upside down and lifted partly out of the water. "
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    ABSTRACT: Ongoing climate change is affecting animal physiology in many parts of the world. Using metabolism, the oxygen- and capacitylimitation of thermal tolerance (OCLTT) hypothesis provides a tool to predict the responses of ectothermic animals to variation in temperature, oxygen availability and pH in the aquatic environment. The hypothesis remains controversial, however, and has been questioned in several studies. A positive relationship between aerobic metabolic scope and animal activity would be consistent with the OCLTT but has rarely been tested. Moreover, the performance model and the allocation model predict positive and negative relationships, respectively, between standard metabolic rate and activity. Finally, animal activity could be affected by individual morphology because of covariation with cost of transport. Therefore, we hypothesized that individual variation in activity is correlated with variation in metabolism and morphology. To test this prediction, we captured 23 wild European perch (Perca fluviatilis) in a lake, tagged them with telemetry transmitters, measured standard and maximal metabolic rates, aerobic metabolic scope and fineness ratio and returned the fish to the lake to quantify individual in situ activity levels. Metabolic rates were measured using intermittent flow respirometry, whereas the activity assay involved high-resolution telemetry providing positions every 30 s over 12 days. We found no correlation between individual metabolic traits and activity, whereas individual fineness ratio correlated with activity. Independent of body length, and consistent with physics theory, slender fish maintained faster mean and maximal swimming speeds, but this variation did not result in a larger area (in square metres) explored per 24 h. Testing assumptions and predictions of recent conceptual models, our study indicates that individual metabolism is not a strong determinant of animal activity, in contrast to individual morphology, which is correlated with in situ activity patterns.
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    • "The risk of underestimating SMR decreases, of course, as the number of ˙ MO 2 values used to estimate SMR increases. This number is highly variable among studies, e.g. one (Wieser & Medgyesy, 1991), three (Crear & Forteath, 2000;McKenzie, 2001;Roche et al., 2013), five (Lefevre et al., 2012), six (Neto & Steffensen, 1997;Schurmann & Steffensen, 1997) or 10 (Norin & Malte, 2011;Boldsen et al., 2013;Svendsen et al., 2014). Recognizing the potential for aberrant low ˙ MO 2 values, others have used 10% of the values (Herrmann & Enders, 2000;Rosewarne et al., 2014), or all ˙ MO 2 values obtained during the quiet part of the daily cycle (Castanheira et al., 2011), or after a specific time since the beginning of the experiment (Cutts et al., 2002). "
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    • "There are fewer data available on interindividual variation in MMR, but the magnitude of the variation appears to be similar (Norin & Malte, 2011Killen et al., 2012;Metcalfe, N. B. et al., 2016;Norin et al., 2015). This interindividual variation in MMR is consistent (repeatable) across time (Norin & Malte, 2011;Marras et al., 2010;Svendsen et al., 2014), although repeatability appears to be higher for SMR than for MMR both in a stable environment (Norin & Malte, 2011) and under different environmental conditions (Norin et al., 2015). There is evidence from O. mykiss that the origin of variation in MMR may be linked to the cardiovascular system (Claireaux et al., 2005). "
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