Variation in AIN-93G/M diets across different commercial manufacturers: Not all AIN-93 diets are created equal

Authors: JOSHI, TEJAS - Children'S Nutrition Research Center (CNRC); FIOROTTO, MARTA - Children'S Nutrition Research Center (CNRC)

Submitted to: Journal of Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/26/2021
Publication Date: 9/7/2021
Citation: Joshi, T.P., Fiorotto, M.L. 2021. Variation in AIN-93G/M diets across different commercial manufacturers: Not all AIN-93 diets are created equal. Journal of Nutrition. 151(11):3271-3275. https://doi.org/10.1093/jn/nxab274.
DOI: https://doi.org/10.1093/jn/nxab274

Interpretive Summary: Nutrition studies that use rodents require exact knowledge of the nutrient composition of the diet and should be designed to ensure optimal growth and physiological functions even when used long term. Use of such a diet allows studies to give reproducible results when repeated among different researchers and over time. To address this need nutrition scientists developed a diet comprised of purified ingredients. The recipe for these is known today as AIN-93M (to feed adult rodents) or AIN-93G (to feed pregnant, lactating, or growing rodents). It is manufactured and sold by a number of animal feed companies all over the world. In this study, we evaluated if the AIN-93G or -M diets sold by manufacturers in 8 countries had the same composition as prescribed in the published recipes, as was originally intended. We found that several manufacturers would not disclose their recipe (as required), and that some had modified it. In the manuscript we discuss why these inconsistencies are a concern for nutrition researchers.

Technical Abstract: 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.