Diets

Diets

CONNECT WITH TESTDIET

Have questions about TestDiet product? Contact us online!

Contact Us »

  • SELECTING PROPER Imaging Diets

    We often have questions from customers regarding which diet to choose when their experiments require fluorescence optical imaging of a live animal.  The common complaint is that a grain-based diet produces background fluorescence which interferes with the experiment.  This background fluorescence occurs in part because of the chlorophyll which is found in some of the diet ingredients such as alfalfa, but which also can also be found in other ingredients.

    One option would be the use of purified diets, such as AIN-93M (58M1) or AIN-93G (57W5). Purified diets are created from highly refined ingredients, such as casein, corn starch, crystalline cellulose, and individual vitamins and minerals. Purified diets have historically been the ‘go to’ diets for imaging studies. Some disadvantages of using purified diets are they are more expensive, require a minimum order, have a longer lead time and have a shorter shelf life.

    An alternative option to purified diets would be to use a grain-based diet that contains plant material not known to not be autofluorescent, such as soybean meal, corn and wheat. We offer a line of diets, our Verified series, that do not contain any alfalfa which allows the animals to be maintained on a more normal, standard diet, throughout the study. Based on the Li-Cor article (available on this page), 5V75 and 5K96 diets had 75-95% less fluorescence background than the alfalfa-based diets.

    We also conducted our own study to determine whether a grain-based diet without alfalfa, such as 5V75, is a suitable option to purified diets in fluorescence imaging studies in order to reduce per diem costs. Animals were fed one of three diets, 58M1 (purified), 5001 (grain based with alfalfa) and  5V75 (grain-based without alfalfa) and imaged. The in vivo images were taken using the autoexposure setting for Alexa Fluor 680 (675 nm excitation to 720 nm emission; 640 nm excitation to 700 nm emission) and plum fluorescent protein markers (570 nm excitation to 640 nm emission; 605 nm excitation to 660 nm emission). The results of the study showed that 5V75 did not autofluoresce in the mice, and imaging pictures were comparable to those animals on the purified diet. Our study supports other research findings that alfalfa-free cereal grain diets can be a lower cost alternative to purified diets when conducting fluorescence imaging at certain wavelengths. More details of this study can be found in our literature “The Impact of Laboratory Animal Diets on Autofluorescence Imaging in Animals”.

    Pearl® Imager - In Vivo Animal Imaging Diet Considerations

    Autofluorescence Brochure
     

  • Imaging Diets