Maternal exposure to purified versus grain-based diet during early lactation in mice affects offspring growth and reduces responsivity to Western-style diet challenge in adulthood

The nutritional environment during fetal and early postnatal life has a long-term impact on growth, development, and metabolic health of the offspring, a process termed "nutritional programming." Rodent models studying programming effects of nutritional interventions use either purified or grain-based rodent diets as background diets. However, the impact of these diets on phenotypic outcomes in these models has not been comprehensively investigated. We used a previously validated (C57BL/6J) mouse model to investigate the effects of infant milk formula (IMF) interventions on nutritional programming. Specifically, we investigated the effects of maternal diet type (i.e., grain-based vs purified) during early lactation and prior to the intervention on offspring growth, metabolic phenotype, and gut microbiota profile. Maternal exposure to purified diet led to an increased post-weaning growth velocity in the offspring and reduced adult diet-induced obesity. Further, maternal exposure to purified diet reduced the offspring gut microbiota diversity and modified its composition post-weaning. These data not only reinforce the notion that maternal nutrition significantly influences the programming of offspring vulnerability to an obesogenic diet in adulthood but emphasizes the importance of careful selection of standard background diet type when designing any preclinical study with (early life) nutritional interventions.