Variation in AIN-93G/M Diets Across Different Commercial Manufacturers: Not All AIN-93 Diets are Created Equal.

Recognizing the importance of standardized experimental diets, the AIN endorsed the generation of diets for rodents, AIN-93G and -93M, that are composed of purified ingredients and meet the nutrient requirements of rodents at different stages of life. Use of these diets was intended to allow for comparability and reproducibility of studies among laboratories and over time. Although it was anticipated that commercial manufacturers would follow the published formulations precisely, this is not always the case. Here, we present the diversity in macronutrient and micronutrient profiles across 15 commercial manufacturers of AIN-93G and -93M. Given the important implications of diet variability for many physiologic responses, the introduction of changes to the formulation of AIN-93 diets by manufacturers defeats the purpose of having such a diet and must be avoided.