Research

Guidelines and Resources

Master
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Users’ Responsibilities

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• Inform yourself on how to get the best results from these measurements. Recommend:
a. Watch on-line a webinar about this.
b. Read through this website carefully.

• Obtain the appropriate institutional approvals for MMRU (e.g., IACUC protocol, IBC protocol). For reference, the MMRU IACUC protocol number is AN-5020.

• For mice not currently housed within the CNRF, investigator must organize the transfer as discussed in "Procedure for Requesting Use of Facilities."

• Please coordinate your “set-up” times with Mr. Vohra (8-6756). At this time you will:
a. Set up your mice in the cages.
b. Learn how to interrupt the measurements to refill/change feeder.
c. Learn how to stop the experiment at the end and prepare your cages for washing.

• Provide Firoz Vohra an Excel spreadsheet with the IDs, genotype, diet, sex, and date-of-birth of the mice, and beginning body weight, prior to placement within CLAMS cages.

• Provide mice with the correct diet (in a powdered form) in accordance with an approved IACUC protocol. Check for sufficient food in the feeders daily.

• Provide mice with water; check water at the same time as food.

• For long-term studies, cages and water must be changed a minimum of once every five days. If your mice will be in the CLAMS cages for an extended period, place a calendar on the door noting the day(s) when the change out(s) will be performed, and then signing it once you have completed it.

• You MUST check your cages and the mouse in each cage daily (including weekends). You will then complete the CHECK SHEET to verify that the food, water, and health status of each mouse is OK. If sheets are not available, please contact MMRU manager.

• If you use the QMR or treadmill, make sure that you leave them CLEAN after every use.

• Implantation of telemetric devices (training provided by MMRU upon request).

• In publications that include data that were generated please acknowledge the use of the facility. The following is suggested:

Measurements of (select as appropriate: body composition / energy balance / food intake) were performed in the Mouse Metabolic Research Unit at the USDA/ARS Children’s Nutrition Research Center, Baylor College of Medicine, which is supported by funds from the USDA ARS (/cnrc/mmru). The authors acknowledge the expert assistance of Mr Firoz Vohra and the MMRU Core Director, Dr. Marta Fiorotto.” Please send me a copy of the resulting publication.

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General Guidelines to Ensure Accurate, Reproducible and Valid Data

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We have carried out an extensive series of measurements to identify factors that can influence your data, and offer the following suggestions to ensure that your measurements reflect the "true" metabolic state of your animals.

If you transfer your mice to the CNRC, this should be done at least one week prior to the start of your measurements.

One week prior to the start of your measurements, your mice should be individually housed and fed the powdered diet that you will use while they are in the CLAMS.

If you are going to implant a telemetry device, this should be done at least two weeks before you start your measurements.

Adapt mice to food monitoring/calorimetry cages for three days before you perform indirect calorimetry measurements. The first day's data will not be representative of the mouse's intake and should be discarded.

Weigh mice when they go in and when they come out of the feeder cages.

On the fourth day (e.g., Monday a.m., if you start on Friday) transfer mice from the feeder to the calorimetry cages. Collect data for three days. The first day's data will not be representative of the mouse's energy expenditure and normal activity levels and should be discarded.

Weigh mice when they begin and finish calorimetry. Measure mouse body composition.

If you request measurements of resting metabolic rate, feed access will be blocked at 6 a.m. on day four, and oxygen consumption and carbon dioxide production monitored for an additional eight hours. Do not allow anybody into the room. The average of the three lowest energy expenditure values between 10 a.m. and 2 p.m. will be a close approximation of resting metabolic rate.

If you are going to do exercise testing, we recommend you read The American Physiological Society’s "Resource Book for the Design of Animal Exercise Protocols" (available upon request).

All your calorimetry 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 the 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.

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Resources

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The American Physiological Society’s "Resource Book for the Design of Animal Exercise Protocols" (available upon request).

Mini Miter implant manual (available upon request).

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References

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Even PC, Nadkarni NA. Indirect calorimetry in laboratory mice and rats: principles, practical considerations, interpretation and perspectives. Am J Physiol Regul Integr Comp Physiol. 2012;303:R459-76.

Tschöp MH, Speakman JR, Arch JR, Auwerx J, Brüning JC, Chan L, Eckel RH, Farese RV Jr, Galgani JE, Hambly C, Herman MA, Horvath TL, Kahn BB, Kozma SC, Maratos-Flier E, Müller TD, Münzberg H, Pfluger PT, Plum L, Reitman ML, Rahmouni K, Shulman GI, Thomas G, Kahn CR, Ravussin E. A guide to analysis of mouse energy metabolism. Nat Methods. 2011 Dec 28;9(1):57-63.

Allan I. Pack, Raymond J. Galante, Greg Maislin, Jacqueline Cater, Dimitris Metaxas, Shan Lu, Lin Zhang, Randy Von Smith, Timothy Kay, Jie Lian, Karen Svenson, and Luanne L. Peters. Novel method for high-throughput phenotyping of sleep in mice. Physiol. Genomics February 2007 28:(2) 232-238;

Ravussin E, Lillioja S, Anderson TE, Christin L, Bogardus C: Determinants of 24-hour energy expenditure in man. Methods and results using a respiratory chamber. J Clin Invest 1986;78:1568-1578

Jones AS, Johnson MS, Nagy TR. Validation of quantitative magnetic resonance for the determination of body composition of mice. Int J Body Compos Res. 2009;7(2):67-72.

Nagy TR et al., Precision and accuracy of DEXA for determining in vivo body composition of mice. Obesity Research 8: 392, 2000. Brommage R. Validation and calibration of DEXA body composition in mice. Am J Physiol Endo Metab 285: E454, 2003.

Ellacott KL, Morton GJ, Woods SC, Tso P, Schwartz MW. Assessment of feeding behavior in laboratory mice. Cell Metab. 2010 12(1):10-17.

Kaiyala KJ, Morton GJ, Leroux BG, Ogimoto K, Wisse B, Schwartz MW. Identification of body fat mass as a major determinant of metabolic rate in mice. Diabetes. 2010 59(7):1657-1666.

MacLean PS. Comment on: Kaiyala et al. (2010) Identification of body fat mass as a major determinant of metabolic rate in mice (Letter). Diabetes 2011;60:e3.

Response to Comment on: Kaiyala et al. (2010) Identification of Body Fat Mass as a Major Determinant of Metabolic Rate in Mice. Diabetes;59:1657-1666 Diabetes 2011 60:e4

App to analyze energy expenditure data.