This important question will be addressed at a special session during NUTRITION 2021 LIVE ONLINE, June 7-10, 2021

In 1906, Helen Dean King developed the Wistar rat, the first purpose-bred rat strain designed to serve as a standardized animal model for human physiology experiments.  Over the years, however, it became evident to nutrition scientists that not only was it important to standardize rodent breeds, but also rodent diets so that they could be used as control diets in nutrition studies to produce reliable, reproducible test results.

To that end, beginning in the 1940s, various rodent diets were proposed.  These early diet formulations, however, were nutritionally inadequate, leading to irreproducible results and erroneous conclusions.  By the 1970s, the situation prompted the formation of a committee of the American Institute for Nutrition (AIN), the predecessor to the current ASN, which led to the first widely accepted, open-source formula diet for rats and mice, published in 1977 in The Journal of Nutrition.  Three years later the formula was modified.  This formula, known as the AIN-76A, provided the precise quantity of purified ingredients that met all nutrient requirements known at that time, becoming the standard for rodent model nutrition studies.

Thirteen years later, the formula was once again revised, with the publication of the AIN-93G (growth) and AIN-93M (adult maintenance) formulas in The Journal of Nutrition.  Although the formulas have been tweaked over the years, the AIN-93 formulas have remained the gold standard for purified rodent diets since their publication.  In fact, the 1993 article in which these diets were published is the single-most cited article in the field of Nutrition and Dietetics, according to a search of all articles classified by Clarivate Analytics’ Web of Science Core Collection™.

Has the time come to update the AIN-93 diet formulas?

Much has changed in the field of nutrition in the 28 years since the AIN-93 formulas were published.  Is it time to revise the AIN-93 rodent diet formulas in light of these changes?  In a March 2021 commentary published in The Journal of Nutrition, “Should the AIN-93 Rodent Diet Formulas Be Revised?,” authors and ASN members David M. Klurfeld, Jesse F. Gregory III, and Marta L. Fiorotto make the case that, yes, the time has come to update the formulas.  Among their concerns, the authors note the need to reconsider the formulations for dietary fiber, carbohydrates, fat, and energy density to better respond to our current understanding of animal nutrition requirements as well as the focus of some new and emerging areas of research.

Diet choice can alter data interpretation, potentially affecting reproducibility.

Published March 2020, in Current Developments in Nutrition, “Choice of Laboratory Rodent Diet May Confound Data Interpretation and Reproducibility” underscores the need for standardized purified rodent diets in nutrition studies.  Authors Michael A. Pellizzon and Matthew R. Ricci offer several examples that demonstrate how “diet choice can alter data interpretation, potentially affecting reproducibility and knowledge gained within any given field of study.”  In particular, the authors note how “comparing mismatched (often, purified to grain-based) diets is an all-too-common phenomenon and unfortunately appears to be generally accepted by preclinical research authors and reviewers.”

To begin the important process of reviewing the AIN-93 formulations, the authors of The Journal of Nutrition March 2021 commentary have organized a session as part of NUTRITION 2021 LIVE ONLINE, scheduled to take place virtually on June 9 from 2:00 – 3:30 PM EDT.  The meeting organizers are seeking to determine whether there is consensus among the ASN research community for a reevaluation of the AIN-93 formulations.  If so, they seek to develop a collaborative roadmap to proceed with the reevaluation and the development of new formulations.

ASN members are encouraged to consider the issues raised in The Journal of Nutrition commentary and to participate in the upcoming discussion.  The meeting organizers welcome thoughts and suggestions from ASN members in advance of the session.

Tell us your thoughts and make plans to join the conversation on June 9. Register for NUTRITION 2021 LIVE ONLINE today.


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