The effects of hypoxia on ketone body metabolism and cardiac function in the shortnose sturgeon (Acipenser brevirostrum)

Abstract

The goal of this study is to understand the effects of chronic hypoxia on ketone body metabolism and cardiac function in shortnose sturgeon (Acipenser brevirostrum) by comparing three different treatment groups: control, chronic hypoxia and starved. Sturgeon will be exposed to either normoxic conditions, DO saturation of 2.75 mg/L, or will be deprived of food as a positive control for ketogenesis (Furné et al., 2012) for 10 days (Secor and Gunderson, 1998). In all 3 treatment groups, ketone body production in the liver, circulating ketones in plasma, and ketone oxidation in cardiac and skeletal muscle will be measured to determine if there is a ketogenic response. In addition, cardiac muscle force production will be measured using either ketone bodies or glucose as a supplemental fuel to determine if ketone bodies can support force production in hearts from each treatment group. I hypothesize that chronic hypoxia will elicit a ketogenic response in shortnose sturgeon. I predict that (1) ketone production in the liver will increase after being exposed to the hypoxic environment for 10 days in comparison to the starved group and (2) that there will be an increase ketolytic enzyme activity in the heart after the hypoxic exposure, which will help maintain cardiac contractility. The results obtained from this experiment will help lead to an understanding as to how vertebrates respond to environmental stress through changes in substrate use and mitochondrial function.