DECRO – Rat Jacket specification and size selection

In this article, you will find reference tables for selecting the appropriate jacket size for your rat-based DECRO study with accuracy. The tables provided pertain specifically to Wistar Han and Sprague Dawley rat’s strains. Contact us to get additional information for other strains on which the jacket may fit.

This article focuses on presenting the materials and recommendations regarding the size of our jackets.

The equipment procedures  including photos and videos are available. To access it, simply log in to your customer account and click here. 
Articles on shearing the animal and positioning the ECG are also available for rats. 

1. Solution general overview

The DECRO external telemetry system monitors cardiorespiratory function and activity index simultaneously, without surgery or restraint.  

 

DECRO solution is composed of:

- Instrumented jacket(s): embedding plethysmographic sensors and protecting external ECG electrodes. Jackets are specific to the species and size of the animals

- Emitter(s) and batteries: digitizing and transmitting physiological signals to an acquisition unit. The emitter also incorporates the 3D accelerometer to measure activity. 

- Acquisition system: consisting of one or more acquisition units and a analysis server enabling the acquisition of physiological signals

- Software: The LASA software is hosted directly in the system and enables data acquisition, analysis and export.

DECRO can be used on rat, marmoset, dog and minipig. The software and hardware are the same for all the species, only the jackets and consumables are different to fit with the morphology of the model.

2. Rat jacket specification

Our rat jackets are designed to fit on the morphology of subjects weighing between 220 and 600 grams, and are available in four different sizes.

They are constructed from a soft, stretchy, and durable fabric that does not cause any irritation or scratching. These jackets do not incorporate any hook and loop bands, making them easy to put on and take off while ensuring a comfortable fit for the rats

Finally, jackets are equipped with plethysmography sensors directely integrated to the fabric and are designed to secure the ECG electrodes on the animal. 

3. Wistar Han jacket selection tables

A. Wistar Han male

B. Wistar Han female

C. Wistar Han growth curve 

4. Spragues dawley jacket selection tables

A. Sprague dawley male

B. Sprague dawley female

C. Sprague dawley growth curve

5. Size checking 

"How do I know if the jacket is the right size for my rat?"

Generally speaking, if the animal's weight is in the middle of the weight range for a jacket of a certain size, there's little chance that the jacket won't fit the rat.

For example, a male Wistar rat weighing 330 g for a jacket size 1 [  250 gr -  380 gr ]

But if the animal's weight is between two sizes, here are a few tips to check whether the jacket you've chosen is the right size:

For example, according to the weight chart, a 370g rat can correspond to a jacket size 1 and 2. 

If an animal is between two sizes, you should prefer the smaller size so that the jacket can detect the deformation of the animal's trunk. Of course, this does not mean that the jacket should constrain the animal too much. 

Please refer to the following tips to help you determine the jacket size. 

When designing your longitudianl study, if you don't want to change jacket size longitudinally, be sure to anticipate variations in the weight of your animals to ensure that they correspond to the ranges of only one size.

One jacket size can cover approximately 4 to 5 weeks of study, depending on animal strain, age and housing conditions (growth curve and feed intake).

For example, a size 1 for a male wistar rat can cover approximately 250 to 380 grams, i.e. from the 8th to the 11th week of the animal's life (4 weeks). 

A. Evaluating a jacket that's too tight:

You'll see that the jacket is too tight, especially when it comes to equip the animal. This will be difficult, if not impossible. If you manage to equip the animal with the jacket but still have doubts as to whether it will fit, try passing a finger between the two shoulders and the jacket to check that the thoracic bands are not compressing the animal too much.

The finger should go through easily, and normally the fabric remains soft when you stretch the jacket a little. If you find that you're having trouble getting your finger through and that the fabric pressure is too great, remove the jacket. The animal will be compressed.

B. Evaluation of a jacket that's too large:

On the other hand, a jacket that's too large won't stay on the animal for long after it's been equipped. It's easy to put on and take off. Again, even if you manage to fit the animal with a jacket that's too large, it will tend to move behind both shoulder blades. If the jacket moves back even a little, the animal is likely to put a paw on the outside and remove the whole device in the end.

C. Size verification summary

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