Energy expenditure, food intake, activity and body temperature are measured in mice using the CLAMS instrumentation system located in the MMRU in the CNRC.
Each experiment is individually designed to provide the data needed by the investigator. There are many variables relating to monitoring frequency, timing of events, etc. that can be individualized. These should be discussed and established before starting the experiments. In general, the measurements are as follows:
- Mice should be housed for 72 hours in CLAMS feeder cages to familiarize themselves with the feeding system and to estimate food intake. Then they are transferred to the calorimetry chambers for >72 hours for simultaneous monitoring of food intake, activity, and energy expenditure. To determine energy expenditure, the system monitors O2 and CO2 gas concentrations at both the inlet and outlet ports of each chamber through which a known flow of air is passing. The change in gas concentrations and flow measurements are used to compute VO2, VCO2, RER (respiratory exchange ratio or RQ) and heat production (energy expenditure) is calculated using the Weir equation. Food intake and feeding pattern are measured automatically from the weight of feed removed from specialized feed hoppers installed within the chamber. Activity in the x and z axes is estimated by monitoring the number of infra-red beams broken by the mouse movements.
- For successful pair-feeding experiments, it is essential that the animals identified as “masters” do not have an adverse reaction to being placed in the CLAMS cages, which can occur, albeit rarely. Thus, some preliminary observations of ad lib food intake for the whole cohort should be considered.
- For body temperature monitoring, the investigator must arrange for implantation of the telemetry devices and the mice be allowed to recover 2 weeks before measuring. It is absolutely CRITICAL that the ID of the sensor implanted into each mouse is recorded and the # provided at the start of the study.
- All energy expenditure data will be reviewed for aberrant values and summarized to give you average daily values for all the parameters measured on each mouse as well as average day and night values. You can also have all your raw data files, and access to computer software to analyze the data as you wish. Data will be placed in a shared drive where you can access it after you have been notified. Additionally, Columbus Instruments provides some software (CLAX) that is available to users free of charge to perform some additional data. View publication.
Check MMRU Availability
Use the MMRU calendar via Outlook calendar for CLAMS availability:
- In Outlook, click "Folder List" at the bottom left of the Outlook screen.
- Click the > before "Public Folders" then click the > before "All Public Folders."
- Scroll down to "BCM Pediatrics," then inside to "Nutrition."
- Click the Calendar named "MMRU Schedule."
- To add to favorites, right-click "MMRU Schedule" and then select "Add to Favorites."
- Click "Calendar" (beside "Folder List" at the bottom left of the Outlook screen).