The Contribution of Skeletal Muscle Metabolism to Aerobic Scope of Rainbow Trout (Oncorhynchus mykiss)
Date
2020-04-28
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Abstract
Beyond cellular maintenance, fish require additional energy to accomplish activities such as swimming, digestion, growth, and reproduction. Aerobic scope is the capacity to increase metabolic rate above the minimum (i.e. standard vs maximal metabolism) to meet the demands required for these other activities. Increasing temperatures often increase the standard metabolic rate, reducing and limiting aerobic scope, and it has been suggested this may ultimately limit heat tolerance in fishes. Many different tissues collectively contribute to metabolic rate, but we do not know if specific tissues dominate energy use in fishes, nor how they are impacted by temperature. This thesis investigated the hypothesis that red, aerobic muscle is the primary contributor to the aerobic metabolism, and thus aerobic scope, of a swimming fish. Swim tunnel respirometry using rainbow trout (Oncorhynchus mykiss) and measures of oxygen consumption on isolated, working muscle were used to determine their respective aerobic scopes, using oxygen as a proxy for aerobic metabolism across a range of temperatures, up to those approaching the critical thermal maximum of rainbow trout. Further, the mass of red muscle in fish, along with measures of metabolic rate, were used to assess the contribution of red muscle metabolism to that of the whole fish. It was found that red muscle was not a major contributor of aerobic metabolism compared to the whole fish, and thus it was not a major component of aerobic scope. However, red muscle showed similar effects of temperature on both resting and maximum metabolism as that seen in whole fish, increasing the standard metabolic rate at high temperatures but not affecting the maximum metabolic rate. Further, red muscle power output was significantly reduced at high temperatures while metabolic rate was not, potentially implicating the cost of maintenance of muscle as one contributing factor to the high mortality rate of fish at high temperatures.
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Keywords
aerobic scope, muscle metabolism, oxygen consumption, rainbow trout
Citation
McCaffrey, T. M. F. (2020). The Contribution of Skeletal Muscle Metabolism to Aerobic Scope of Rainbow Trout (Oncorhynchus mykiss) (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.