The Diversity of Gut Microbiota at Weaning Is Altered in Prolactin Receptor-Null Mice.

Maternal milk supports offspring development by providing microbiota, macronutrients, micronutrients, immune factors, and hormones. The hormone prolactin (PRL) is an important milk component with protective effects against metabolic diseases. Because maternal milk regulates microbiota composition and adequate microbiota protect against the development of metabolic diseases, we aimed to investigate whether PRL/PRL receptor signaling regulates gut microbiota composition in newborn mice at weaning. sequencing of feces and bioinformatics analysis was performed to evaluate gut microbiota in PRL receptor-null mice (-KO) at weaning (postnatal day 21). The normalized colon and cecal weights were higher and lower, respectively, in the -KO mice relative to the wild-type mice (-WT). Relative abundances (Simpson Evenness Index), phylogenetic diversity, and bacterial concentrations were lower in the -KO mice. Eleven bacteria species out of 470 differed between the -KO and -WT mice, with two genera ( and ) related to metabolic disease development being the most common in the -KO mice. A higher metabolism of terpenoids and polyketides was predicted in the -KO mice compared to the -WT mice, and these metabolites had antimicrobial properties and were present in microbe-associated pathogenicity. We concluded that the absence of the PRL receptor altered gut microbiota, resulting in lower abundance and richness, which could contribute to metabolic disease development.