Evaluation of alterations of milk microbiota during medical treatment in the lactation period: application of a Göttingen Minipigs sows animal model

Early gut microbiota (GM) dysbiosis can affect infant’s health and it has been associated to the onset of several pathologies. Breastfeeding is one of the major factors influencing the structure and composition of the infant’s GM. Breast milk provides the infant not only nutrients, bacteriostatic compounds and prebiotic molecules, but it also harbours its own microbiota. The milk microbiota is a dynamic entity shaped by several factors, including maternal medical treatments. A dysbiosis of the milk microbiota could affect the infant’s GM composition. However, the impact of pharmacological treatments on the milk microbiota remains largely unknown. The IMI ConcePTION project aims to produce and disseminate knowledge on the effects of drugs taken during breastfeeding. This thesis contributed to this goal by developing a methodology to investigate the impact on the milk microbiota of amoxicillin, an antibiotic, and metformin, a common treatment for type 2 diabetes. The Göttingen Minipigs® was chosen as animal model because of its physiological and metabolic similarities to humans. Göttingen Minipigs® sows were administered daily either amoxicillin or metformin for three weeks starting from the second week of lactation. Bacterial populations in sows’ milk, sows’ feces and piglets’ rectal swabs were analyzed through sequencing of the V3-V4 hypervariable regions of the 16S rRNA bacterial gene. The Göttingen Minipigs® was revealed to be a suitable translational model for microbiota studies. Sows' milk microbiota composition showed similarities with humans, and we were able to identify changes of taxa relative abundance in both gut and milk. Drug-related changes in milk microbiota did not seem to have detrimental effects. Overall, these results suggest that continuing breastfeeding during maternal treatment with the analyzed drugs should not have any milk microbiota-mediated effect on the infant health. However, further studies are needed to determine the effect of maternal treatment on the piglets’ GM.