Modern bomb calorimeter for accurate determination of energy balance in metabolic studies

点击翻译按钮获取中文摘要

The applicants of this proposal conduct leading-edge basic research in the fields of rodent physiology, metabolism, and cell signalling. Studies to date have investigated how genetic, dietary, and pharmacological manipulations influence whole-body energy balance. Critical to our NSERC-funded research programs is the ability to measure energy balance. Determining the amount of energy consumed by an animal is straightforward from the caloric content of experimental diets and determining energy expenditure is easily measured through the use of metabolic cages, which provide insight regarding the fuel sources used by an animal (fat and carbohydrates), heat production, and physical activity. However, there is a fundamental oversight in this simplified view of whole-body energy balance. Indeed, we assume that all of the calories consumed by a rodent are absorbed (i.e., complete digestive efficiency). This assumption is flawed and can lead to important misinterpretations of whole-body energy balance data. To address this critical gap, we are requesting funds to purchase a state-of-the-art bomb calorimeter to precisely measure fecal energy content – which is a direct measure of digestive efficiency. There is currently one calorimeter located at the University of Guelph; however, this system is located in another department and is highly used by those research groups, is more than 20-years old, is unreliable due to frequent break-downs, and is manually operated leading to high variability between users. Thus we are in urgent need of a modern bomb calorimeter that provides greater accuracy, higher through-put and is accessible to researchers in our department. The impact of acquiring a new calorimeter is significant due to the wide-range of research areas covered by the applicants and users. For example, measuring digestive efficiency will lead to fundamental and important changes in how we interpret food intake and energy balance data, enhance our knowledge of genetic and molecular mechanisms controlling digestive efficiency, improve our understanding of how diet and pharmacological interventions influence body weight regulation, and open up new avenues of investigation. The inability to measure digestive efficiency means that our data interpretations may currently be flawed and we are missing opportunities to uncover novel molecular mechanisms related to body weight regulation. It is anticipated that acquiring a modern calorimeter will enhance the direct training of ~50 highly qualified personnel (HQP) per year across 6 NSERC-funded laboratories. Overall, we anticipate that acquiring a calorimeter will have immediate and significant benefits on numerous NSERC-funded research programs, and will directly enhance HQP productivity and training.